Abstract:
A new and distinct  Persea americana  variety having strong tolerance to  Phytophthora cinnamomi  when used as a rootstock. It is an extremely vigorous and fast-growing rootstock that is capable of supporting a ‘Hass’ tree growing to 15 ft. in 2 years. It&#39;s yields are generally high and consistent. ‘Uzi’ leaves exhibit burn due to salt damage, but this does not seem to affect the growth or yield of the ‘Hass’ variety.

Description:
Latin name of the genus and species: The avocado cultivar of this invention is botanically identified as  Persea americana  Mill. 
     Variety denomination: The variety denomination is ‘Uzi’. 
     BACKGROUND OF THE INVENTION 
     Avocado root rot is the limiting factor for the growth of avocados throughout the world. Avocado root rot is caused by the fungus  Phytophthora cinnamomi , which attacks and kills the feeder roots of avocado trees. The resultant lack of roots causes the tree to eventually die from water stress. There are a number of varieties of rootstocks that have some tolerance to the disease. These varieties included ‘Duke 7’ (unpatented), the most commonly planted tolerant rootstock in the world; and ‘Thomas’ (U.S. Plant Pat. No. 6,628), another root rot tolerant rootstock. However, even with these rootstocks, growers must still use a variety of methods, including mounding, mulching and the applications of chemical fungicides, to keep the tress from dying in many soils. More resistant rootstocks are necessary to eliminate avocado root rot as a major disease threat. 
     Screening and Greenhouse Evaluation of Rootstocks 
     ‘Uzi’ was identified and characterized using the following screening protocol. As it is difficult to breed avocados because only one in approximately one thousand flowers actually set fruit, plant breeding blocks of avocados were isolated to prevent out-crossing with susceptible rootstocks. The breeding blocks were made up of various combinations of selected rootstocks including, ‘Thomas’ (U.S. Plant Pat. No. 6,628), ‘Barr Duke’ (U.S. Plant Pat. No. 6,627), ‘G6’, ‘Duke 7’, ‘Duke 9’, ‘UC 2001’, ‘UC 2011’, ‘Toro Canyon’ (U.S. Plant Pat. No. 5,642), ‘Spencer’, ‘CR1-71’, ‘G 810’, ‘G 875’, ‘G 755A’, ‘VC 256’, and ‘Steyemarkii’. In order to synchronize blooming, attempts were made to girdle late-blooming varieties and spray early-blooming varieties with the pesticide Unicona-zole-P. 
     Initial screening was carried out by germinating seeds, which were harvested from the breeding blocks, in flats of vermiculite in the greenhouse.  Phytophthora cinnamomi -infested millet was placed in rows along with the young roots of the test seedlings. After 8-10 weeks roots were evaluated and those with a high percentage of surviving roots were transplanted to soil mix incorporated with  P. cinnamomi -infested millet. Rootstocks that survived this test were planted and grown in  P. cinnamomi -infested soils. Survivors were examined more carefully for various types of resistance using asexual propagated material.
         a. Root survival—Rootstocks were grown in typical California avocado soils, inoculated with  P. cinnamomi  and evaluated for growth, root length and percent healthy roots.   b. Root regeneration—Rootstocks were grown in soil inoculated with  P. cinnamomi , treated with Aliette to halt  Phytophthora  root rot and evaluated for root regeneration.   c. Attraction to  P. cinnamomi —Roots of the rootstocks were placed in water baths with motile zoospores of  P. cinnamomi . The numbers of spores attracted to the roots were evaluated.       

     Rootstocks that performed well in the screening and greenhouse evaluations were further tested under field conditions. 
     Selection of ‘Uzi’ 
     ‘Uzi’ was developed at Riverside, Calif. The maternal parent is ‘G6’ (unpatented) avocado variety. The pollen parent is unknown. Specifically, the ‘Uzi’ rootstock variety was selected in 1993 from an agricultural operations land located Riverside, Calif. The fruit were collected from the avocado breeding blocks, the seed removed, and planted in vermiculite. The seeds were grown in a greenhouse. The plants were inoculated with the fungus  Phytophthora cinnamomi . After showing tolerance to the disease, ‘Uzi’ was chosen as a single plant for further testing. Budwood was collected from the plants and grafted to the stumps of adult avocado trees that had been cut down at Irvine, Calif. The new varieties grew into trees which provided budwood for further testing. At least two ‘mother’ trees of the variety are growing in Irvine, Calif., along with the germplasm. During screening and evaluation, ‘Uzi’, which was selected and originally designated ‘PP14’, distinguished itself from other varieties, including the maternal parent ‘G6,’ by having a high tolerance against  Phytophthora  root rot. The properties of ‘Uzi’ were found to be true to type and transmissible by asexual reproduction. 
     BRIEF SUMMARY OF THE INVENTION 
     This invention relates to a new and distinct avocado variety. ‘Uzi’ is an avocado tree having a rootstock that has a high tolerance against  Phytophthora  root rot. It is an extremely vigorous and fast-growing rootstock that is capable of supporting a ‘Hass’ tree growing to 15 ft. in 2 years. It&#39;s yields are generally high and consistent. ‘Uzi’ leaves exhibit burn due to salt damage, but this does not seem to affect the growth or yield of the ‘Hass’ variety. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a eight-year-old top-worked tree of the ‘Uzi’ variety while growing in Irvine, Calif. 
         FIG. 2  illustrates typical mature foliage of the ‘Uzi’ variety with dimensions in centimeters shown at the bottom. 
         FIG. 3  illustrates typical flush foliage of the ‘Uzi’ variety with dimensions in centimeters shown at the bottom. 
         FIG. 4A  illustrates typical inflorescence with dimensions in centimeters shown at the right, and  FIG. 4B  illustrates typical inflorescence by itself. 
         FIG. 5  illustrates a typical external view of the fruit of the ‘Uzi’ variety, with dimensions in centimeters shown at the bottom. 
         FIG. 6  illustrates typical internal views of the fruit of the ‘Uzi’ variety, with and without the seed. Dimensions in centimeters are shown at the bottom. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following is a detailed description of the new ‘Uzi’ variety, which was taken from an approximately eight-year-old mature tree, with the exception as a rootstock for a specific scion when reference is made to root rot resistance and salinity tolerance. The tree is located in an experimental orchard in Irvine, Calif. and is grafted on a  Persea americana  seedling used as a rootstock. 
     The Royal Horticultural Society (R.H.S.) color Chart is used herein for the color description of the rind, seed, bark, leaf, flower, flesh color and other interest of the ‘Uzi’ avocado tree. 
     Trees, Foliage, and Flowers 
     
         
         Tree:
             Growth habit .—Vigorous, upright and spreading when compared to the rootstock ‘Thomas’.     Vigor .—Below are data on the vigor of ‘Hass’ grafted onto the rootstock ‘Uzi’, as determined by trunk diameter measurements from trees planted in an orchard with  Phytophthora cinnamomi  in Escondido, Calif.       
     
       
    
     
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Trunk diameter (cm) 
               
             
          
           
               
                   
                 Rootstock 
                 year 1 
                 year 2 
                 year 3 
                 year 4 
                 year 5 
               
               
                   
                   
               
             
          
           
               
                   
                 PP # 14 ‘Uzi’ 
                 2.85 
                 5.14 
                 8.57 
                 10.6 
                 12.54 
               
               
                   
                 Thomas 
                 2.44 
                 4.29 
                 6.75 
                 8.40 
                 10.84 
               
               
                   
                   
               
               
                   
                 Escondido Ca., with Hass scion 
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Canopy volume (cubic feet) 
               
             
          
           
               
                 Rootstock 
                 year 1 
                 year 2 
                 year 3 
                 year 4 
                 year 5 
               
               
                   
               
             
          
           
               
                 PP # 14 ‘Uzi’.  
                 21.86 
                 163.21 
                 504.3 
                 669 
                 1338.2 
               
               
                 Thomas 
                 13.56 
                 84.48  
                 388.5 
                 367. 
                 1076.2 
               
               
                   
               
               
                 Escondido Ca., with Hass scion 
               
             
          
         
       
         
         
           
             
               
                   Size .—Large. The typical canopy size of a three year old top-worked ‘Thomas’ is 388 cu.ft. By comparison the canopy size of a three year old topworked ‘Uzi’ is 504 cu.ft. The tree is 610-915 cm in height when fully grown at the orchard site in Irvine, Calif. 
               
             
           
         
         Branch:
             Color .—The color of the one year old branch is green (RHS 146C).     Smoothness .—The bark of a one year old branch is smooth.     Lenticels .—The lenticels of a one year old branch are conspicuous.       
     
         Main stem:
             Color .—Brown (RHS N 200C and N 200D).     Texture of bark .—Corky.       
     
         Young shoot (flush):
             Intensity of anthocyanin coloration .—Weak.     Anthocyanin coloration.— Grayed-orange (RHS 165B).     Color .—Grayed-orange (RHS 165B).     Conspicuousness of lenticels .—Medium.     Color of lenticels .—Grayed-purple (RHS 185A).     Size of lenticels.— 1.0-3.0 mm long.     Concentration of lenticels.—+/− 25 lenticels per square cm.     Color of upper side .—Grayed-green (RHS 194B).     Glossiness of upper side .—Medium.     Color of lower surface .—Grayed-green (RHS 193B).       
     
         Mature leaf:
             Length.— 13.0 cm.     Width.— 5.5 cm.     Ratio length/width.— 2.4.     Shape .—Elliptical.     Color of upper side .—Green (RHS 139A).     Color of lower side .—Green (RHS 137B).     Glossiness of upper side .—Medium-high.     Prominence of veins on lower side .—Prominent and in relief.     Color of veins .—Yellow-green (RHS 145A).     General shape and cross-section .—Flat, slightly concave.     Reflexing of apex .—Absent.     Color of petiole .—Yellow-green (RHS 144A).     Anise aroma .—Present.     Margin .—Undulation of margin is weak, and the leaf margin is entire.     Leaf apex shape .—Acute.     Leaf base shape .—Elliptical.     Length of leaf petiole .—Approximately 2.8 cm.     Diameter of leaf petiole.— Approximately 2.0 mm.     Leaf arrangement .—upright.       
     
         Flower:
             Bud size .—Approximately 3 mm in length and approximately 2.5 mm in diameter.     Bud shape .—Ovoid.     Bud color .—Grayed-green (RHS 197C).     Opening .—Belongs to group “B”, female opening (i.e. with mature pistil) occurs in the afternoon, the flower closes over night, and the male opening (i.e. with mature stamens) occurs the next morning; the flower&#39;s opening cycle lasts 20-24 hours.     Petals .—Borne in two whorls of three perianth lobes. The petals possess entire margins and petal coloration is near yellow-green (RHS 151D). Both the upper and lower petal surfaces are near yellow-green (RHS 151D).     Stamen .—There are commonly nine fertile stamens with each having two basal nectar glands that are grayed-orange (RHS 174A) in color and three staminodla. The anthers are tetrathecal.     Pistil .—The single pistil with a slender style and small stigmatic surface has one carpel with one ovule. The ovary is superior.     Sepals.— There are 6 sepals which are approximately 5 mm in length and approximately 3 mm in width, and the color of both sepal surfaces is yellow-green (RHS 151A).     Pedicel .—Commonly approximately 6 mm in length and approximately 2.0 mm in diameter. The coloration is near yellow-green (RHS 151B).     Peduncles.— Approximately 5.7 cm in length and approximately 3.0 mm in diameter. The coloration is yellow-green (RHS 151A).     Number of flowers on inflorescence .—Approximately 108-135 flowers per inflorescence.     Fragrance .—Absent.     Bloom .—Bloom period at Riverside, Calif. experiment station varies with cultural conditions. On average ‘Uzi’ has been found to bloom from 25 th  of January through the 15 th  of March.       
     
       
    
     Fruit, Fruit and Production Characteristics 
     
         
         Fruit:
             Length. 13   7.0 cm.     Width.— 5.5 cm.     Ratio length/width.— 1.3.     Weight.— 53.4 grams.     Shape .—Narrowly obovate, with an apex diameter of approximately 2.2 cm and a base diameter of approximately 3.9 cm at the widest point.     Color of skin  ( when ripe ).—Grayed-purple (RHS N186).     Texture of skin .—Smooth.     Presence of longitudinal ridges .—Absent.     Thickness of skin .—Thin.     Adherence of skin to flesh .—Weak.     Main color of flesh .—Yellow-green (RHS 144B).     Color of intensely colored area of flesh next to skin .—Yellow-green (RHS 144A).     Width of intensely colored area next to skin.— 1.0 mm.     Conspicuousness of fibers in flesh .—Conspicuous.       
     
         Seed:
             Length.— 4.7 cm.     Width.— 4.0 cm.     Weight.— 11.9 grams.     Shape  ( in longitudinal section ).—Circular.     Shape  ( in cross section ).—Circular.     Color of seed coat  ( fresh ).—Grayed-orange (RHS 177A).     Cotyledon color.— Orange-white (RHS 159B).     Time of harvesting .—‘Uzi’ fruit ripen in September/October (in Riverside Calif.).     Resistance to pests .—Strong resistance to  Phytophthora cinnamomi.        Tolerance to salinity .—Medium.     Market use .—The fruit of ‘Uzi’ are not intended for market use, but rather the variety is used as a rootstock onto which commercial varieties, such as ‘Hass’ are grafted.       
     
       
    
     
       
         
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Rootstock rating at Santana, Ventura County, August 2001 1   
               
             
          
           
               
                   
                 Tree rating 
                 Canopy 
                 Trunk  
                 No. trees 
               
               
                 Rootstock 
                 (0-5; 5 = dead) 
                 volume (cu ft) 
                 diameter (cm) 
                 dead 
               
               
                   
               
               
                 ‘Steddom’ 
                 0.80 a 
                 13.89 a 
                 1.92 a 
                 1 
               
               
                 ‘Merensky II’ 
                 0.90 a 
                 15.10 a 
                 1.48 a 
                 1 
               
               
                 ‘Uzi’ 
                 0.90 a 
                 16.92 a 
                 2.02 a 
                 0 
               
               
                 ‘Zentmyer’ 
                 1.05 a 
                 16.48 a 
                 2.05 a 
                 1 
               
               
                 ‘G755A  
                 1.65 a 
                  5.55 a 
                 1.62 a 
                 1 
               
               
                 (Brokaw)’ 
                   
                   
                   
                   
               
               
                 ‘Medina’ 
                 1.90 a 
                 12.66 a 
                 1.70 a 
                 2 
               
               
                 ‘Berg’ 
                 2.20 a 
                 13.80 a 
                 1.29 a 
                 4 
               
               
                 ‘McKee’ 
                 2.35 a 
                  9.05 a 
                 1.52 a 
                 1 
               
               
                 ‘Duke 7’ 
                 2.50 a 
                 11.40 a 
                 1.24 a 
                 4 
               
               
                 ‘Thomas’ 
                 2.65 a 
                 10.22 a 
                 1.15 a 
                 4 
               
               
                 ‘G755 A 
                 2.75 a 
                 11.66 a 
                 1.49 a 
                 2 
               
               
                 (C&amp;M)’ 
                   
                   
                   
                   
               
               
                 ‘UC 2023’ 
                 3.00 a 
                  6.21 a 
                 1.25 a 
                 3 
               
               
                   
               
               
                   1 Mean values in each column followed by identical letters are not statistically different according to Waller&#39;s k-ratio t test. 
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                 Rootstock rating at Santana, Ventura County, November 2002. 
               
               
                 Two-year trial to-date. 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Tree rating 
                 Canopy 
                 Trunk 
                 Fruit rating 
               
               
                 ‘Root- 
                 (0-5; 
                 volume 
                 diameter 
                 (0-5; 
               
               
                 stock’ 
                 5 = dead) 
                 (cu ft) 
                 (cm) 
                 5 = heavy) 
               
               
                   
               
             
          
           
               
                 ‘Merensky 
                 0.17  
                 d 
                 72.27  
                 abc 
                 3.49  
                 ab 
                 0.78  
                 bcd 
               
               
                 II’ 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 ‘Uzi’ 
                 0.50  
                 cd 
                 69.64  
                 abcd 
                 3.64  
                 a 
                 2.50  
                 a 
               
               
                 ‘Steddom’ 
                 1.00  
                 bcd 
                 67.95  
                 abcd 
                 2.94  
                 abc 
                 1.70  
                 abc 
               
               
                 ‘Medina’ 
                 1.06  
                 bcd 
                 79.89  
                 ab 
                 3.26  
                 ab 
                 0.00  
                 d 
               
               
                 ‘Zentmyer’ 
                 1.50  
                 bcd 
                 81.44  
                 a 
                 3.19  
                 ab 
                 0.60  
                 bcd 
               
               
                 ‘Duke 7’ 
                 1.67  
                 bcd 
                 32.48  
                 abcde 
                 2.31  
                 abcd 
                 1.11  
                 abcd 
               
               
                 ‘Berg’ 
                 1.72  
                 bcd 
                 46.57  
                 abcde 
                 2.21  
                 abcd 
                 2.00  
                 ab 
               
               
                 ‘McKee’ 
                 1.78  
                 abcd 
                 30.92  
                 bcde 
                 2.24  
                 abcd 
                 0.22  
                 cd 
               
               
                 ‘G755A 
                 2.30  
                 abcd 
                 19.98  
                 de 
                 1.90  
                 bcd 
                 0.10  
                 d 
               
               
                 (Brokaw)’ 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 ‘Thomas’ 
                 2.60  
                 abc 
                 31.50  
                 bcde 
                 2.02  
                 abcd 
                 0.30  
                 cd 
               
               
                 ‘UC 2023’ 
                 2.95  
                 ab 
                 25.50  
                 cde 
                 1.41  
                 cd 
                 0.20  
                 d 
               
               
                 ‘G755A  
                 4.00  
                 a 
                 15.71  
                 e 
                 0.82  
                 d 
                 0.00  
                 d. 
               
               
                 (C&amp;M)’ 
               
               
                   
               
             
          
           
               
                   
                 Tip burn rating 
                 Canker rating 
                 No. trees 
               
               
                 Rootstock 
                 (0-5) 
                 (0-5) 
                 dead 
               
               
                   
               
               
                 ‘Merensky II’ 
                 0.00 a 
                 0.33 a 
                 0/9  
               
               
                 ‘Uzi’ 
                 0.33 a 
                 0.00 a 
                 1/10 
               
               
                 ‘Steddom’ 
                 0.25 a 
                 0.00 a 
                 2/10 
               
               
                 ‘Medina’ 
                 0.75 a 
                 0.00 a 
                 1/9  
               
               
                 ‘Zentmyer’ 
                 0.38 a 
                 0.63 a 
                 1/10 
               
               
                 ‘Duke 7’ 
                 0.38 a 
                 0.38 a 
                 3/9  
               
               
                 ‘Berg’ 
                 0.17 a 
                 0.83 a 
                 3/9  
               
               
                 ‘McKee’ 
                 0.43 a 
                 0.29 a 
                 2/10 
               
               
                 ‘G755A (Brokaw)’ 
                 0.29 a 
                 0.14 a 
                 3/10 
               
               
                 ‘Thomas’ 
                 0.17 a 
                 1.00 a 
                 4/10 
               
               
                 ‘UC 2023’ 
                 0.00 a 
                 0.00 a 
                 5/10 
               
               
                 ‘G755A (C&amp;M)’ 
                 — 
                 — 
                 8/10 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
             
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 5 
               
               
                   
               
               
                 Rootstock ratings of avocado trees planted in root rot soil at 
               
               
                 Escondido, July 2002 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Tree rating 
                 Canopy 
                 Trunk 
                 Fruit set 
               
               
                   
                 0-5; 
                 volume 
                 diameter 
                 rating 0-5; 
               
               
                 Rootstocks 
                 5 = dead 
                 Cu ft 
                 Cm 
                 5 = heavy 
               
               
                   
               
             
          
           
               
                 ‘Zentmyer’ 
                 0.00  
                 c 
                 397.4  
                 abc 
                 7.12  
                 bcd 
                 1.53  
                 cd 
               
               
                 ‘Rio Frio’ 
                 0.00  
                 c 
                 313.5  
                 cdef 
                 6.33  
                 cdef 
                 2.13  
                 bcd 
               
               
                 ‘Merens I’ 
                 0.00  
                 c 
                 543.6  
                 a 
                 8.74  
                 a 
                 3.50  
                 a 
               
               
                 ‘Merensk II’ 
                 0.02  
                 c 
                 409.0  
                 abc 
                 7.81  
                 abc 
                 2.84  
                 ab 
               
               
                 ‘VC 241’ 
                 0.06  
                 c 
                 238.4  
                 defg 
                 6.19  
                 defg 
                 1.41  
                 cd 
               
               
                 ‘Uzi’ 
                 0.29  
                 bc 
                 504.3  
                 ab 
                 8.57  
                 ab 
                 2.76  
                 ab 
               
               
                 ‘Steddom’ 
                 0.36  
                 bc 
                 376.1  
                 bcde 
                 7.07  
                 bcd 
                 2.43  
                 bc 
               
               
                 ‘Thomas’ 
                 0.44  
                 bc 
                 388.5  
                 bcd 
                 6.75  
                 cde 
                 1.12  
                 de 
               
               
                 ‘Guillemet’ 
                 0.59  
                 bc 
                 192.0  
                 fgh 
                 4.90  
                 fgh 
                 1.12  
                 de 
               
               
                 ‘Spencer 
                 0.63  
                 bc 
                 225.8  
                 efg 
                 5.24  
                 efgh 
                 1.56  
                 cd 
               
               
                 sdlg’ 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 ‘Leo’ 
                 0.67  
                 bc 
                 288.2  
                 cdef 
                 5.89  
                 defgh 
                 1.60  
                 cd 
               
               
                 ‘Spencer 
                 0.69  
                 bc 
                 163.8  
                 fgh 
                 4.65  
                 gh 
                 1.54  
                 cd 
               
               
                 clonal’ 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 ‘Duke 7’ 
                 1.00  
                 b 
                 129.3  
                 gh 
                 4.38  
                 h 
                 1.47  
                 cd 
               
               
                 ‘G755A’ 
                 0.16  
                 b 
                 294.1  
                 cdef 
                 5.86  
                 defgh 
                 1.56  
                 cd 
               
               
                 ‘PolyN’ 
                 4.12  
                 a 
                 65.6  
                 h 
                 1.26  
                 i 
                 0.24  
                 e 
               
               
                   
               
             
          
           
               
                   
                   
                 Tip Burn 
                 Cankers 
                 Dead 
               
             
          
           
               
                   
                 Rootstocks 
                 Number trees affected 
               
               
                   
               
             
          
           
               
                   
                 ‘Zentmyer’ 
                 0 
                 0 
                 0/15 
               
               
                   
                 ‘Rio Frio’ 
                 0 
                 0 
                 0/16 
               
               
                   
                 ‘Merens I’ 
                 0 
                 0 
                 0/14 
               
               
                   
                 ‘Merensk II’ 
                 0 
                 1 
                 0/17 
               
               
                   
                 ‘VC 241’ 
                 0 
                 0 
                 0/16 
               
               
                   
                 ‘Uzi’ 
                 2 
                 0 
                 1/17 
               
               
                   
                 ‘Steddom’ 
                 0 
                 0 
                 1/14 
               
               
                   
                 ‘Thomas’ 
                 0 
                 0 
                 1/17 
               
               
                   
                 ‘Guillemet’ 
                 3 
                 1 
                 2/17 
               
               
                   
                 ‘Spencer sdlg’ 
                 0 
                 0 
                 2/16 
               
               
                   
                 ‘Leo’ 
                 0 
                 0 
                 2/15 
               
               
                   
                 ‘Spencer clonal’ 
                 0 
                 0 
                 5/16 
               
               
                   
                 ‘Duke 7’ 
                 0 
                 0 
                 3/15 
               
               
                   
                 ‘G755A’ 
                 2 
                 1 
                 3/16 
               
               
                   
                 ‘PolyN’ 
                 0 
                 0 
                 14/17  
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                 rootstock trial tree ratio April 2003 1 . 
               
               
                 Four-year trial to-date 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Tree rating 
                 Canopy volume 
                 Trunk diam. 
                   
               
               
                 Rootstock 
                 (0-5; 5 = dead) 
                 (cu ft) 
                 (cm) 
                 Salt 
               
               
                   
               
               
                 ‘MerenI’ 
                 0.00d 
                 551ab     
                 10.7a 
                 0.08cd 
               
               
                 ‘VC241’ 
                 0.06d 
                 281efgh 
                 8.0abc 
                 0.03cd 
               
               
                 ‘Rio Frio’ 
                 0.07d 
                 362efcd 
                 8.7abc 
                 0.00d 
               
               
                 ‘Zentmyer’ 
                 0.07d 
                     410bcde 
                 9.2ab 
                 0.32bc 
               
               
                 ‘MerenII’ 
                 0.18d 
                 532abc     
                 9.4ab 
                 0.21dc 
               
               
                 ‘Spen sdlg’ 
                 0.36d 
                 263efgh 
                 6.9bc 
                 0.00d 
               
               
                 ‘Uzi’ 
                 0.38d 
                 669a   
                 10.6a 
                 0.68a 
               
               
                 ‘Steddom’ 
                 0.39d 
                 478bcd  
                 8.6abc 
                 0.32bc 
               
               
                 ‘Thomas’ 
                 0.47cd 
                 367cdef 
                 8.4abc 
                 0.62ab 
               
               
                 ‘Leo’ 
                 0.77cbd 
                 274efgh 
                 7.3abc 
                 0.13cd 
               
               
                 ‘Guillemet’ 
                 0.83cbd 
                 190ghi  
                 6.2bc 
                 0.13cd 
               
               
                 ‘Duke7’ 
                 1.34cb 
                 127hi  
                 8.8abc 
                 0.16cd 
               
               
                 ‘Spen cl’ 
                 1.44b 
                 211fghi     
                 5.3c 
                 0.12cd 
               
               
                 ‘G755A’ 
                 1.69b 
                 322defg 
                 7.0bc 
                 0.25cd 
               
               
                 ‘PolyN’ 
                 4.15a 
                 77i  
                 1.5d 
                 0.06cd 
               
               
                   
               
             
          
           
               
                   
                   
                 Canker 
                 Fruit 
                 Dead trees 
               
               
                   
                 Rootstock 
                 (0-5; 5 = heavy) 
                 rating 2   
                 (%) 
               
               
                   
               
               
                   
                 ‘MerenI’ 
                 0a 
                 2.97abc 
                 0 
               
               
                   
                 ‘VC241’ 
                 0a 
                 3.41ab 
                 0 
               
               
                   
                 ‘Rio Frio’ 
                 0a 
                 3.73a 
                 0 
               
               
                   
                 ‘Zentmyer’ 
                 0a 
                 3.71a 
                 0 
               
               
                   
                 ‘MerenII’ 
                     0.1a 
                 2.97abc 
                 0 
               
               
                   
                 ‘Spen sdlg’ 
                 0a 
                 3.57ab 
                 7 
               
               
                   
                 ‘Uzi’ 
                 0a 
                 3.47ab 
                 6 
               
               
                   
                 ‘Steddom’ 
                 0a 
                 3.75a 
                 7 
               
               
                   
                 ‘Thomas’ 
                 0a 
                 3.53ab 
                 6 
               
               
                   
                 ‘Leo’ 
                 0a 
                 3.29ab 
                 13 
               
               
                   
                 ‘Guillemet’ 
                 0a 
                 2.90abc 
                 13 
               
               
                   
                 ‘Duke7’ 
                 0a 
                 1.53de 
                 19 
               
               
                   
                 ‘Spen cl’ 
                 0a 
                 2.35bcd 
                 23 
               
               
                   
                 ‘G755A’ 
                 0a 
                 1.78cd 
                 25 
               
               
                   
                 ‘PolyN’ 
                 0a 
                 0.29e 
                 82 
               
               
                   
               
               
                   1 Mean values in each column followed by identical letters are not statistically different according to Waller&#39;s k-ratio t test. 
               
               
                   2 Fruit was rated in November 2003. 
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 7 
               
             
             
               
                   
               
               
                 Temecula, yield 2003 1;2 . 
               
               
                 Four year trial to-date. 
               
             
          
           
               
                   
                 Fruit weight/ 
                 Number 
                 Fruit 
               
               
                 Rootstock 
                 tree (kg) 
                 fruit/tree 
                 weight (kg) 
               
               
                   
               
             
          
           
               
                 ‘Zentmyer’ 
                 15.89a 
                 68.64a 
                 0.219a 
               
               
                 ‘Uzi’ 
                 13.99ab 
                 59.24ab 
                 0.195ab 
               
               
                 ‘Spencer seedling’ 
                 12.52ab 
                 56.27ab 
                 0.181ab 
               
               
                 ‘Merensky II’ 
                 11.83ab 
                 51.12ab 
                 0.185ab 
               
               
                 ‘Rio Frio’ 
                 10.87abc 
                 51.33ab 
                 0.187ab 
               
               
                 ‘Steddom’ 
                 10.01abc 
                 46.20abc 
                 0.175abc 
               
               
                 ‘Thomas’ 
                 8.50abcd 
                 40.12abcd 
                 0.154abc 
               
               
                 ‘G755A’ 
                 8.08abcd 
                 34.56abcd 
                 0.116bc 
               
               
                 ‘VC241’ 
                 7.44bcd 
                 31.75bcd 
                 0.202ab 
               
               
                 ‘Guillemet’ 
                 7.42bcd 
                 30.00bcd 
                 0.196ab 
               
               
                 ‘Spencer clonal’ 
                 6.99bcd 
                 32.00bcd 
                 0.136abc 
               
               
                 ‘Merensky I’ 
                 6.95bcd 
                 32.08bcd 
                 0.148abc 
               
               
                 ‘Leo’ 
                 6.53bcd 
                 28.14bcd 
                 0.140abc 
               
               
                 ‘Duke 7’ 
                 3.33cd 
                 14.81cd 
                 0.138abc 
               
               
                 ‘PolyN’ 
                 1.72d 
                 5.71d 
                 0.076c 
               
               
                   
               
               
                   1 Mean values in each column followed by identical letters are not statistically different according to Waller&#39;s k-ratio t test. 
               
               
                   2 Only fruit which were grade size were picked; remaining fruit on trees to be picked later. 
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 8 
               
             
             
               
                   
               
               
                 Escondido, Tree ratings, July 2002 
               
             
          
           
               
                   
                 Tree 
                   
                   
                   
                 No.  
                   
               
               
                   
                 rating 
                 Canopy 
                 Trunk 
                 No. 
                 trees 
                   
               
               
                   
                 (0-5; 
                 vol. 
                 diam 
                 trees 
                 w/tip 
                 No. trees 
               
               
                 Rootstock 
                 5 = dead) 
                 (cu ft) 
                 (cm) 
                 Dead 
                 burn 
                 w/canker 
               
               
                   
               
               
                 ‘Uzi’ 
                 0.039 b 
                 34.69 a 
                 2.43 a 
                 0 
                 6 
                 0 
               
               
                 ‘Guillemet’ 
                 0.042 b 
                 22.86 a 
                 2.06 a 
                 0 
                 4 
                 0 
               
               
                 ‘Zentmyer’ 
                 0.077 b 
                 22.40 a 
                 2.25 a 
                 0 
                 2 
                 0 
               
               
                 ‘Spencer sdlg’ 
                 0.536 b 
                 27.81 a 
                 2.01 a 
                 0 
                 2 
                 1 
               
               
                 ‘Steddom’ 
                 0.615 b 
                 18.93 a 
                 1.99 a 
                 1 
                 0 
                 0 
               
               
                 ‘Berg’ 
                 0.714 b 
                 21.42 a 
                 1.98 a 
                 0 
                 1 
                 2 
               
               
                 ‘Merensky II’ 
                 0.750 b 
                 32.07 a 
                 2.10 a 
                 2 
                 0 
                 1 
               
               
                 ‘Elinor’ 
                 0.786 b 
                 29.44 a 
                 2.03 a 
                 1 
                 0 
                 2 
               
               
                 ‘Thomas’ 
                 0.846 b 
                 23.07 a 
                 1.85 a 
                 1 
                 2 
                 0 
               
               
                 ‘Pond’ 
                  1.00 ab 
                 30.55 a 
                 2.15 a 
                 1 
                 0 
                 2 
               
               
                 ‘Crowley’ 
                  1.083 ab 
                 23.78 a 
                 1.86 a 
                 2 
                 1 
                 0 
               
               
                 ‘G755A’ 
                  1.231 ab 
                 22.64 a 
                 1.85 a 
                 2 
                 0 
                 0 
               
               
                 ‘Duke 9’ 
                 2.270 a 
                  9.40 a 
                 1.07 b 
                 5 
                 0 
                 0 
               
               
                   
               
               
                 There were significant differences at P = 0.01 between blocks for all tree parameters analyzed. 
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 9 
               
               
                   
               
               
                 tree ratings, April 2003. Two-year trial to-date. 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Tree rating 
                 Canopy 
                 Trunk 
                 Fruit rating 
               
               
                   
                 (0-5; 
                 vol 
                 diam 
                 (0-5; 5 = 
               
               
                 Rootstock 
                 5 = dead) 
                 (cu ft) 
                 (cm) 
                 heavy) 
               
               
                   
               
               
                 ‘Uzi’ 
                 0.267 c  
                 88.76 a 
                 4.193 a  
                 0.0 a 
               
               
                 ‘Berg’ 
                 0.531 c  
                 44.16 a 
                 2.956 bc 
                 0.0 a 
               
               
                 ‘Zentmyer’ 
                 0.600 c  
                 54.37 a 
                 3.393 ab 
                 0.0 a 
               
               
                 ‘Merensky II’ 
                 0.833 bc 
                 68.49 a 
                 3.333 ab 
                 0.0 a 
               
               
                 ‘Steddom’ 
                 0.867 bc 
                 56.42 a 
                 3.127 ab 
                 0.0 a 
               
               
                 ‘Pond’ 
                 0.906 bc 
                 55.05 a 
                 3.188 ab 
                 0.0 a 
               
               
                 ‘Spenser sdlg’ 
                 0.906 bc 
                 51.45 a 
                 2.988 bc 
                 0.0 a 
               
               
                 ‘Crowley’ 
                 0.964 bc 
                 42.05 a 
                 3.021 bc 
                 0.0 a 
               
               
                 ‘Thomas’ 
                 1.071 bc 
                 49.99 a 
                 2.900 bc 
                 0.0 a 
               
               
                 ‘Guillemet’ 
                  0.167 abc 
                 43.64 a 
                 2.960 bc 
                 0.1 a 
               
               
                 ‘Elinor’ 
                  1.393 abc 
                 58.40 a 
                 2.864 bc 
                 0.0 a 
               
               
                 ‘G755A’ 
                 2.156 ab 
                 44.21 a 
                 2.819 bc 
                 0.0 a 
               
               
                 ‘Duke 9’ 
                 2.577 a  
                 32.16 a 
                 1.885 c  
                 0.0 a 
               
               
                   
               
             
          
           
               
                   
                 Salt rating 
                 Canker rating 
                 No. trees 
               
               
                 Rootstock 
                 (0-5; 5 = severe) 
                 (0-5; 5 = severe) 
                 Dead (%) 
               
               
                   
               
               
                 ‘Uzi’ 
                 0.933 ab  
                 0.000 a 
                 0 
               
               
                 ‘Berg’ 
                  0.633 abcd 
                 0.000 a 
                 6 
               
               
                 ‘Zentmyer’ 
                 1.000 a  
                 0.000 a 
                 7 
               
               
                 ‘Merensky II’ 
                 0.154 cd  
                 0.308 a 
                 13 
               
               
                 ‘Steddom’ 
                 0.321 bcd 
                 0.286 a 
                 7 
               
               
                 ‘Pond’ 
                 0.767 abc 
                 0.200 a 
                 6 
               
               
                 ‘Spenser sdlg’ 
                 0.300 bcd 
                 0.200 a 
                 6 
               
               
                 ‘Crowley’ 
                 0.083 d  
                 0.000 a 
                 14 
               
               
                 ‘Thomas’ 
                 0.731 abc 
                 0.000 a 
                 0 
               
               
                 ‘Guillemet’ 
                  0.615 abcd 
                 0.133 a 
                 13 
               
               
                 ‘Elinor’ 
                 0.333 bcd 
                 0.167 a 
                 14 
               
               
                 ‘G755A’ 
                 0.846 ab  
                 0.077 a 
                 13 
               
               
                 ‘Duke 9’ 
                 0.313 bcd 
                 0.500 a 
                 38 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 10 
               
               
                   
               
               
                 Temecula rootstock ratings, Sept 2002 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Tree rating 
                 Canopy 
                 Trunk 
                 Fruit rating 
               
               
                   
                 (0-5; 
                 vol. 
                 diam 
                 (0-5; 
               
               
                 Rootstock 
                 5 = dead) 
                 (cu ft) 
                 (cm) 
                 5 = heavy) 
               
               
                   
               
               
                 ‘Zentmyer’ 
                 0.400 c  
                 40.70 ab 
                 2.79 a 
                 0.00 b 
               
               
                 ‘Crowley’ 
                 0.618 c  
                 40.38 ab 
                 2.86 a 
                 0.00 b 
               
               
                 ‘Elinor’ 
                 0.824 c  
                 40.52 ab 
                 2.54 a 
                 0.00 b 
               
               
                 ‘Guillemet’ 
                 0.882 bc 
                 39.13 ab 
                 2.42 a 
                 0.00 b 
               
               
                 ‘Steddom’ 
                 0.969 bc 
                 29.20 bc 
                  2.13 ab 
                 1.16 a 
               
               
                 ‘Thomas’ 
                 0.969 bc 
                 31.46 bc 
                  2.13 ab 
                 0.00 b 
               
               
                 ‘Pond’ 
                 1.088 bc 
                 54.08 a  
                 2.78 a 
                 0.00 b 
               
               
                 ‘Uzi’ 
                 1.188 bc 
                 35.08 ab 
                 2.56 a 
                 0.00 b 
               
               
                 ‘G755A’ 
                 2.088 ab 
                 37.85 ab 
                 2.41 a 
                 0.00 b 
               
               
                 ‘Spencer sdlg’ 
                 2.906 a  
                 11.96 c  
                 1.39 b 
                 0.00 b 
               
               
                   
               
             
          
           
               
                   
                   
                 Salt damage 
                 Cankers 
                 No. trees 
               
               
                   
                 Rootstock 
                 (0-5; 5 = heavy) 
                 (0-5; 5 = heavy) 
                 dead 
               
               
                   
               
               
                   
                 ‘Zentmyer’ 
                 1.50 ab 
                 0.00 a 
                 0/15 
               
               
                   
                 ‘Crowley’ 
                 1.34 b  
                 0.00 a 
                 1/17 
               
               
                   
                 ‘Elinor’ 
                 1.59 ab 
                 0.00 a 
                 1/17 
               
               
                   
                 ‘Guillemet’ 
                 1.41 b  
                 0.00 a 
                 2/17 
               
               
                   
                 ‘Steddom’ 
                 1.54 ab 
                 0.50 a 
                 2/16 
               
               
                   
                 ‘Thomas’ 
                 1.50 ab 
                 0.00 a 
                 3/16 
               
               
                   
                 ‘Pond’ 
                 1.40 b  
                 0.00 a 
                 2/17 
               
               
                   
                 ‘Uzi’ 
                 1.64 ab 
                 0.00 a 
                 2/16 
               
               
                   
                 ‘G755A’ 
                 2.50 ab 
                 0.36 a 
                 4/17 
               
               
                   
                 ‘Spencer sdlg’ 
                 2.63 a  
                 0.00 a 
                 4/16 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 11 
               
               
                   
               
               
                 Temecula, rootstock ratings, December 2003. 
               
               
                 Two-year trial to-date 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                   
                 Canopy 
                 Trunk 
                 Fruit rating 
               
               
                   
                 Tree rating 
                 vol 
                 diam 
                 (0-5; 5 = 
               
               
                 Rootstock 
                 (0-5; 5 = dead) 
                 (cu ft) 
                 (cm) 
                 heavy) 
               
               
                   
               
               
                 ‘Zentmyer’ 
                 0.313c 
                 207.27a 
                 6.23a 
                 2.063a 
               
               
                 ‘Pond’ 
                 0.906c 
                 307.04a 
                 5.75a 
                 1.813a 
               
               
                 ‘Elinor’ 
                 0.912c 
                 170.37a 
                  4.80a. 
                 1.059a 
               
               
                 ‘Guillemet’ 
                 1.059c 
                 199.37a 
                 5.73a 
                 0.882a 
               
               
                 ‘Uzi’ 
                 1.094bc 
                 206.04a 
                 4.35a 
                 0.813a 
               
               
                 ‘Crowley’ 
                 1.250bc 
                 144.14a 
                 5.04a 
                 1.438a 
               
               
                 ‘Steddom’ 
                 1.281bc 
                 254.94a 
                 4.89a 
                 1.188a 
               
               
                 ‘Thomas’ 
                 1.313be 
                 226.39a 
                 5.16a 
                 1.375a 
               
               
                 ‘G755A’ 
                 2.438ab 
                 175.55a 
                 5.23a 
                 0.625a 
               
               
                 ‘Spencer sdlg’ 
                 2.813a 
                 42.12a 
                 2.26a 
                 0.519a 
               
               
                   
               
             
          
           
               
                   
                   
                 Salt damage 
                 Cankers 
                 Trees 
               
               
                   
                 Rootstock 
                 (0-5; 5 = heavy) 
                 (0-5; 5 = heavy) 
                 dead (%) 
               
               
                   
               
               
                   
                 ‘Zentmyer’ 
                 1.188ab 
                 0.000a 
                 0 
               
               
                   
                 ‘Pond’ 
                 0.321cd 
                 0.000a 
                 13 
               
               
                   
                 ‘Elinor’ 
                 0.469cd 
                 0.000a 
                 6 
               
               
                   
                 ‘Guillemet’ 
                 0.893abc 
                 0.000a 
                 18 
               
               
                   
                 ‘Uzi’ 
                 0.769abcd 
                 0.000a 
                 19 
               
               
                   
                 ‘Crowley’ 
                 0.731abcd 
                 0.000a 
                 19 
               
               
                   
                 ‘Steddom’ 
                 0.167d 
                 0.000a 
                 25 
               
               
                   
                 ‘Thomas’ 
                 1.308a 
                 0.000a 
                 19 
               
               
                   
                 ‘G755A’ 
                 1.167ab 
                 0.000a 
                 25 
               
               
                   
                 ‘Spencer sdlg’ 
                 0.500bcd 
                 0.000a 
                 44