Patent Publication Number: US-PP20337-P3

Title: Chestnut plant named ‘AU Buck II’

Description:
Latin name of the genus and species of the plant claimed:  Castanea mollissima  Blume. 
   Variety denomination: ‘Au Buck II’. 
   BACKGROUND OF THE INVENTION 
   A Chinese chestnut planting was established at Auburn University, Auburn, AL, from nuts collected in China. The planting was established on the United States Department of Agriculture Horticulture Farm which in later years became the Mainstation Horticulture Farm. Precocious and prolific-bearing, blight resistant seedlings were selected for nut appearance, size and quality. Each generation of seedlings were the product of controlled mass pollination from the most promising seedlings selected from the previous generation. ‘AU Cropper’, ‘AU Leader’ and ‘AU Homestead’ were released from a second generation of approximately 2000 seedlings. A planting of third generation seedlings from controlled mass pollination of ‘AU Leader’, ‘AU Homestead’ and ‘AU Cropper’ was established at the Auburn University Piedmont Substation at Camp Hill, AL. 
   SUMMARY OF THE INVENTION 
   ‘AU Buck II’ is an open pollinated seedling of ‘AU Homestead’. 
   The present invention relates to a new and distinct Chinese chestnut cultivar that is blight resistant, precocious, produces large sized nuts (16.6 g), and begins nut drop about September 15 and continues for a 6–7 week period. A large percent of the nuts drop during the first three weeks after nut drop begins. The nuts mature and start dropping during the early part of the normal ripening period for most Chinese chestnut cultivars in this area. The large crop of large sized nuts is an excellent high energy food source for wildlife such as deer and squirrels. The original 15-year old ‘AU Buck II’ tree is a large tree, 9.14 meters tall, with a canopy width of 11.35 meters, and a canopy area of 101.36 square meters. The tree has a trunk diameter of 37.9 cm at breast height. The ‘AU Buck II’ produced nuts the third year after transplanting, has produced a large crop annually for the size of tree, and produced 127.9 kg (282 pounds) of nuts in 2006. 
   ‘AU Buck II’ cultivar is the second cultivar to mature and drop nuts in a series of four Chinese chestnut cultivars that will provide a continuous nut drop of a high energy wildlife food source from late August through mid-to-late November. ‘AU Buck I’, ‘AU Buck III’ and ‘AU Buck IV’ are the other three cultivars, which are disclosed in U.S. patent application No. 12/012,091, filed on Jan. 30, 2008, and entitled “CHESTNUT PLANT NAMED ‘AU BUCK I’”, U.S. patent application No. 12/012,110, filed on Jan. 30, 2008, and entitled “CHESTNUT PLANT NAMED ‘AU BUCK III’” and U.S. patent application No. 12/012,112, filed on Jan. 30, 2008, and entitled “CHESTNUT PLANT NAMED ‘AU BUCK IV’”, which are hereby incorporated by reference. 
   The new cultivar is able to be asexually reproduced by budding or grafting onto a seedling Chinese chestnut rootstock. The unique characteristics come true to form and are established and transmitted through asexual propagation. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a photograph of nuts of the ‘AU BUCK II’ cultivar. 
       FIG. 2  is a photograph of nuts of the ‘AU BUCK II’ cultivar. 
       FIG. 3  is a photograph of a tree of the ‘AU BUCK II’ cultivar. 
   

   DETAILED BOTANICAL DESCRIPTION 
   The Chinese chestnut,  Castanea mollissima  Blume, is a cold, hardy, temperate zone species native to China. It can be grown between 30° and 50° latitudes. The Chinese chestnut is resistant to chestnut blight fungus  Cryphonectria parasitica . Generally, Chinese chestnuts are grown on a wide range of soils, but well-drained, deep and fertile soils are considered the best. Soils should be slightly acidic with pH 5.6–6.5. The name  mollissima  means soft hair and this species is recognized by dense hair on young leaves and downy yellow terminal parts of the shoots in winter. The leaf blade is thicker, and, in general, mature leaves are broader than those of other species. The nuts have a small scar or hilum. The pellicle or thin membranous skin on the nuts is thin and peels readily from the kernel. The trees are a spreading type and long-lived with a round top. The trees have bark with furrows and buds with 3–4 scales and leaves are 2 ranked, serrated with numerous parallel veins. 
   Chestnuts are monoecious and staminate flowers appear on erect cylindrical catkins with 10–20 stamens and 6-parted calyx. Pistillate flowers are borne on a lower part of the upper staminate catkins and rarely on separate catkins usually 3 in a prickly symmetrical involucre with 7–9 styles and a 6-celled ovary. Nuts are small, brown with a pale scar at the base. Generally, 1–3 nuts per involucre or bur are present. 
   ‘AU Buck II’ is a tall tree that is obovate in shape with high, diffuse and upright branches. The original 15-year old tree is 9.14 meters (29.96 feet) tall with a trunk diameter at breast height of 37.90 cm (14.92 inches). The canopy is 11.35 meters (37.20 feet) wide and covers an area of 101.36 square meters (1091.0 square feet). The average nut length is 30.70 mm (1.21 inches) and the average nut width is 37.70 mm (1.48 inches). The nuts start dropping about September 15 and continue to drop for a 6 to 7 week period. A large percent of the nuts drop during the first three weeks after nut drop begins. The nuts mature and start dropping during the early part of the normal ripening for most Chinese chestnuts cultivars in this area. ‘AU Buck II’ is a precocious and prolific fruiting cultivar. 
   In the planting at the Piedmont Substation, Camp Hill, AL., accurate yields could not be obtained due to extremely heavy wildlife (deer and turkey) feeding. Therefore, the trees were rated for crop load each year. ‘AU Buck II’ has been a producer of a large crop load each season. In the fall of 2006, individual trees were caged with 6 foot (1.83 meters) tall chicken wire prior to nut drop to exclude wildlife and nuts were picked up daily during nut drop. The original 15-year old ‘AU Buck II’ tree produced 127.9 kg (282.0 pounds) of nuts in 2006. This is a much greater yield than the yields of similar aged trees. 
   The table below illustrates the specific differences between the ‘AU BUCK II’ cultivar and the ‘REVIVAL’ cultivar. 
   
     
       
         
             
           
             
                 
             
           
          
             
               The botanical details of this new and distinctive variety of 
             
             
               chestnut tree - with color definitions (except those in 
             
             
               common color terms) referenced to Royal Horticultural 
             
             
               Society&#39;s Colour Chart (RHS) and color was also determined 
             
             
               using an electronic spectrophotometer to determine hue angle 
             
             
               and Chroma (spectrophotometer model CM-2002; Minolta 
             
             
               Camera Co., Japan). 
             
          
         
         
             
          
             
               10/23 ‘AU BUCK II’ CHESTNUT 
             
          
         
         
             
          
             
               Tree: 
             
             
               Size (at maturity) - large-fifteen year old original tree is 9.14 meters tall 
             
             
               with a canopy width of 11.35 meters and a canopy area of 
             
             
               101.36 sq. meters Tree shape is round. 
             
             
               Vigor - very vigorous 
             
             
               Trunk: 
             
             
               Form - upright with branches low and diffuse 
             
             
               Texture - relatively smooth 
             
             
               Color of bark - brown RHS N200B, Chroma C* 11.85, hue angle 85.23 
             
             
               Branches: 
             
             
               Form - upright and spreading 
             
             
               Texture - relatively smooth 
             
             
               Lenticels - few, small 
             
             
               Branching habit - low and spreading 
             
             
               Color - new wood: brown, RHS 200C, Chroma C* 13.80, 
             
             
               hue angle 71.55, mature wood: grey-brown RHS N199A 
             
             
               Chroma C* 13.69, hue angle 91.59 
             
             
               Foliage: 
             
             
               Quantity - abundant 
             
             
               Density - dense 
             
             
               Leaves: 
             
             
               Size - large. Length (cm) 20.5 (17.5-23.5) [20] 
             
             
               width (cm) 8.2 (7.2-9.3) [20] 
             
             
               leaf ratio 2.5 (2.1-3.0) [20] 
             
             
               Shape - oblong-elliptic to obovate 
             
             
               leaf tip - acuminate to acute 
             
             
               leaf base - rounded; equal to oblique 
             
             
               Thickness - thick. Leaf venation 1° pinnate: 2° ± parallel, 
             
             
               prominent abaxially 
             
             
               Texture - moderately coriaceous 
             
             
               Margin - weakly to coarsely serrate; teeth ascending 
             
             
               Petiole - length 0.9 cm (0.5-1.8) [20] 
             
             
               Petiole pubescence - sparingly to generously pubescence of simple hairs 
             
             
               Color - adaxial surface, glabrous blade; scattered simple hairs on main 
             
             
               veins medium green; moderately shiny, RHS 147A, 
             
             
               Chroma C* 14.62, hue angle 120.75 
             
             
               abaxial surface, moderately to densely stellate pubescence on blade; 
             
             
               simple hairs along main veins, RHS 147B, Chroma C* 18.44, 
             
             
               hue angle 110.70 
             
             
               Bloom: 
             
             
               Amount of bloom - heavy 
             
             
               Color - at anthesis, 161D greyed-yellow group, 157D green-white group, 
             
             
               155C white group 
             
             
               Blooming period - mid-May. After foliation in April. 
             
             
               Age at which tree starts flowering - early, 2-3 years alter graft 
             
             
               replacement. 
             
             
               Male flower - Catkin length (cm)-13.7 (11.8-15.7) [15] 
             
             
               Male flower - stamen number per catkin-11.3 (10-12) [15] 
             
             
               Female flower - flower number per bur - 3 
             
             
               Female flower - style number per flower 6.7 (5-8) [12] 
             
             
               Crop: 
             
             
               Bearing - regular annual bearer 
             
             
               Productivity - prolific 
             
             
               Ripening period - long, nuts begins dropping September 14 and 
             
             
               continues for a 4-5 week period. 
             
             
               Distribution of nuts on tree - well distributed, fruits on terminals with 
             
             
               2-4 burs per terminal. 
             
             
               Tenacity - burs crack while on tree and nuts release and drop from bur. 
             
             
               Hull: 
             
             
               Description - spiny round bur 
             
             
               Size - 2.98-3.71″ in diameter 
             
             
               Number of nuts - 2-3 per bur 
             
             
               Dehiscence - splits easily when still on tree 
             
             
               Color - yellow-green at dehiscence, RHS N144C 
             
             
               Nut: 
             
             
               Size - very large; average size- 1.21″ × 1.48″ × 0.81″. 
             
             
               Average weight - 16.6 grams 27 (23-33) nuts per pound. 
             
             
               Form - very large, broader than long, flattened on 1 side, occ. 2, mostly 
             
             
               hemispheric on other side; rounded basally, almost flat distally with little 
             
             
               or no tip. 
             
             
               Blossom end - small pointed tip 
             
             
               Basal end - flattened 
             
             
               Color - light brown, RHS 200B, Chroma C* 14.03, hue angle 40.05 
             
             
               Pubescence - mixed long and short, fine, white hairs densely 
             
             
               covering the ⅛ to ¼ end, otherwise sparse and glabrate elsewhere 
             
             
               Shell - thin 
             
             
               Hardness of shell - relatively hard, yet not rigid 
             
             
               Texture of shell - smooth 
             
             
               Percentage of kernel to nut - very high-90-95% 
             
             
               Kernel: 
             
             
               Size - almost as large as nut size 
             
             
               Form - same as nut shape 
             
             
               Pellicle - thin 
             
             
               Flavor - excellent, very sweet 
             
             
               Color - straw color, RHS 152D, Chroma C* 45.86, hue angle 81.35 
             
             
               Resistance to insects: no unusual susceptibilities noted 
             
             
               Resistance to disease: no susceptibilities to disease noted 
             
             
               The chestnut tree and its nuts herein described may 
             
             
               vary in slight detail due to climatic and soil conditions 
             
             
               under which the variety may be grown; the present 
             
             
               description being of the variety as grown in Camp Hill, 
             
             
               Ala. 
             
             
                 
             
             
               The botanical details of this variety of 
             
             
               chestnut tree - with color definitions (except those in 
             
             
               common color terms) referenced to Maerz and Paul 
             
             
               Dictionary of Color-are as follows: 
             
          
         
         
             
          
             
               ‘REVIVAL’ 
             
          
         
         
             
          
             
               Tree: 
             
             
               Size (at maturity) - large 
             
             
               Vigor - very vigorous 
             
             
               Trunk: 
             
             
               Form - upright with branches spreading in upper 
             
             
               reaches of tree. 
             
             
               Texture - relatively smooth 
             
             
               Color of bark - Silvergray (13-A-1) 
             
             
               Branches: 
             
             
               Form - strong 
             
             
               Texture - relatively smooth 
             
             
               Lenticels - few, small 
             
             
               Branching habit - spreading in upper region of tree 
             
             
               Color - new wood: reddish brown and glossy, mature 
             
             
               wood: silver gray 
             
             
               Foliage: 
             
             
               Quantity - abundant 
             
             
               Density - dense 
             
             
               Leaves: 
             
             
               Size - large. Average length - 5-7″ (including petiole). 
             
             
               Average width - 2″ 
             
             
               Shape - oblong with acute tip and rounded base 
             
             
               Thickness - thick 
             
             
               Texture - smooth 
             
             
               Margin - dentate 
             
             
               Petiole - length: medium. Thickness: medium. 
             
             
               Color - Top side - glossy dark green (22-L-12). 
             
             
               Under side - lighter green (21-D-7). 
             
             
               Bloom: 
             
             
               Amount of bloom - heavy 
             
             
               Color - cream white (17-B-1) 
             
             
               Blooming period - late. After leaf out in April 
             
             
               Age at which tree starts flowering - early; 2-3 years 
             
             
               years after graft replacement. 
             
             
               Crop: 
             
             
               Bearing - regular (yearly) bearer 
             
             
               Productivity - prolific 
             
             
               Ripening period - short. September 15-October 1. 
             
             
               Distribution of nuts on tree - well distributed 
             
             
               Tenacity - burrs crack while on tree and nuts easily 
             
             
               release, many falling by themselves 
             
             
               Hull: 
             
             
               Description - spiny, round burr 
             
             
               Size - 3-4″ in diameter 
             
             
               Number of nuts - 2-3 per burr 
             
             
               Dehiscence - splits easily when still on tree. Some 
             
             
               entire burrs split and fall to ground 
             
             
               Color - brown (15-A-8) 
             
             
               Nut: 
             
             
               Size - large. Average size - 1⅛″ × 1⅛″ × 1″ thick. 
             
             
               Average weight - 24-32 nuts per pound 
             
             
               Form - broad and ovoid on one side, flat on other side 
             
             
               Blossom end - pointed tip 
             
             
               Basal end - flattened 
             
             
               Color - India Red (7-L-6). 
             
             
               Shell - thin 
             
             
               Hardness of shell - relatively hard, yet not rigid 
             
             
               Texture of shell - smooth 
             
             
               Percentage of kernel to nut - very high (95%) 
             
             
               Kernel: 
             
             
               Size - almost as large as nut size 
             
             
               Form - same as nut shape 
             
             
               Pellicle - thin 
             
             
               Flavor - excellent. Very sweet. 
             
             
               Color - Oyster white (10-B-1) 
             
             
               Resistance to insects: no unusual susceptibilities noted 
             
             
               Resistance to disease: very high inherent resistance to 
             
             
               chestnut bark fungus ( Endothia parastica ), no 
             
             
               other susceptibilities to any other disease 
             
             
               The chestnut tree and its nuts herein described may 
             
             
               vary in slight detail due to climatic and soil conditions 
             
             
               under which the variety may be grown; the present 
             
             
               description being of the variety as grown in Alachua, 
             
             
               Fla. 
             
             
                 
             
          
         
       
     
   
   ‘Au Buck II’ is different from ‘AU Gobbler I’ in several ways. For example, the size of the trees, the trunk forms and colors, the branches, the leaves, the crop and the nuts have differences. Specifically, the ‘AU Buck II’ tree is shorter with a canopy area larger than the ‘AU Gobbler I’ tree. The ‘AU Buck II’ branches are upright/spreading, low/spreading and brown (new) or grey-brown (mature); whereas, the ‘AU Gobbler I’ branches are upright, high, diffuse and brown (new) or greyed-green (mature). The leaves differ in size, shape, margin, petiole and color. The ripening period for the ‘AU Buck II’ is around September 14 and continues for a 4–5 week period, but the ‘AU Gobbler I’ ripening period is around August 25 and continues for 4–5 weeks. The average weight of the nuts of ‘AU Buck II’ is 16.6 grams versus 7.7 grams for ‘AU Gobbler I’. Furthermore, ‘AU Buck II’ has roughly 27 nuts per pound, and ‘AU Gobbler I’ has roughly 59 nuts per pound. 
   ‘AU Buck II’ is different from ‘AU Gobbler II’ in several ways. For example, the trees, the trunk colors, the branch colors, the leaves, the crop and the nuts have differences. Specifically, the ‘AU Buck II’ tree is taller with a canopy width and canopy area larger than the ‘AU Gobbler II’ tree. The ‘AU Buck II’ branches are brown (new) or grey-brown (mature); whereas, the ‘AU Gobbler II’ branches re brown (new) or greyed-green (mature). The leaves differ in size, shape, margin and color. The ripening period for the ‘AU Buck II’ is around September 14 and continues for a 4–5 week period, but the ‘AU Gobbler II’ ripening period is around September 5 and continues for 4–5 weeks. The average weight of the nuts of ‘AU Buck II’ is 16.6 grams versus 5.7 grams for ‘AU Gobbler II’. Furthermore, ‘AU Buck II’ has roughly 27 nuts per pound, and ‘AU Gobbler II’ has roughly 65–101 nuts per pound. 
   ‘AU Buck II’ is different from ‘AU Premier’ in several ways. For example, the trees, the trunk colors, the branch colors, the leaves, the crop and the nuts have differences. Specifically, the ‘AU Buck II’ tree is taller with a canopy width and canopy area larger than the ‘AU Premier’ tree, The ‘AU Buck II’ has a grey-brown trunk, and the ‘AU Premier’ has a greyed-green trunk. The ‘AU Buck II’ branches are brown (new) or grey-brown (mature); whereas, the ‘AU Premier’ branches are brown (new) or greyed-green (mature). The leaves differ in size, shape, thickness, texture, margin, petiole and color. The ripening period for the ‘AU Buck II’ is around September 14, and the ‘AU Premier’ ripening period is early September through mid-November. The average weight of the nuts of ‘AU Buck II’ is 16.6 grams versus 1.26 grams for ‘AU Premier’. Furthermore, ‘AU Buck II’ has roughly 27 nuts per pound, and ‘AU Premier’ has roughly 360.3 nuts per pound. 
   ‘AU Buck II’ is different form ‘AU Encore’ in several ways. For example, the trees, the trunk colors, the branch colors, the leaves, the crop and the nuts have differences. Specifically, the ‘AU Buck II’ tree is taller with a canopy width and canopy area larger than the ‘AU Encore’ tree. The ‘AU Buck II’ has a grey-brown trunk, and the ‘AU Encore’ has a greyed-green trunk. The ‘AU Buck II’ branches are brown (new) or grey-brown (mature); whereas, the ‘AU Encore’ branches are brown (new) or greyed-green (mature). The leaves differ in size, shape, thickness, texture, margin, petiole and color. The ripening period for the ‘AU Buck II’ is around September 14, but the ‘AU Encore’ ripening period is late September through late November. The average weight of the nuts of ‘AU Buck II’ is 16.6 grams versus 2.4 grams for ‘AU Encore’. Furthermore, ‘AU Buck II’ has roughly 27 nuts per pound, and ‘AU Encore’ has roughly 189.2 nuts per pound.