Abstract:
A new and distinct variety of nectarine tree ( Prunus persica  sub species  nuciperisica ), denominated varietally as ‘Burnectsix’, and which produces an attractively colored white-fleshed, aromatic, clingstone nectarine, which is mature for harvesting and shipment approximately June 29 to July 8 under ecological conditions prevailing in the San Joaquin Valley of Central California.

Description:
BACKGROUND OF THE NEW VARIETY 
     The present invention relates to a new, novel and distinct variety of nectarine tree,  Prunus persica  (subspecies  nucipersica ), which has been denominated varietally as ‘Burnectsix’. 
     ORIGIN 
     The present variety of nectarine tree resulted from an on-going program of fruit and nut tree breeding. The purpose of this program is to improve the commercial quality of deciduous fruit and nut varieties and rootstocks by creating and releasing promising selections of prunus, malus and regia species. To this end we make both controlled and hybrid cross pollinations each year in order to produce seedling populations from which improved progenies are evaluated and selected. 
     The seedling ‘Burnectsix’ was originated by us from a population of seedlings grown in our experimental orchards located near Fowler, Calif. The seedlings, grown on their own roots, were the result of a controlled cross of the yellow-fleshed ‘Grand Diamond’ nectarine tree (U.S. Plant Pat. No. 4,095), which was used as the seed parent, and an acidic white fleshed nectarine tree, G3.006 (unpatented), which was used as the pollen parent. One seedling, which is the present variety, exhibited especially desirable characteristics and was subsequently designated as ‘B17.025’. This promising new variety was marked for subsequent observation. After the 1996 season, the new variety was selected for advanced evaluation and repropagation. 
     ASEXUAL REPRODUCTION 
     Asexual reproduction of this new and distinct variety of nectarine tree was accomplished by budding to ‘Nemaguard’ Rootstock (non-patented). We performed these asexual reproductions in our experimental orchard which is located near Fowler, Calif. Subsequent evaluations have shown those asexual reproductions run true to the original tree. All characteristics of the original tree, and its fruit, were established and appear to be transmitted through succeeding asexual propagations. We have observed fruit for the past six (6) successive years from approximately 15 propagated trees. 
     SUMMARY OF THE VARIETY 
     ‘Burnectsix’ is a new and distinct variety of nectarine tree, which is of large size, and which has vigorous growth. The new variety is also a regular and productive bearer of relatively large, firm, acidic, aromatic, white fleshed, clingstone fruit which have good flavor and eating quality. This new and novel tree has a medium to high chilling requirement of approximately 750 hours. The tree also produces relatively uniformly sized fruit throughout the tree. The fruit further has a high degree of red skin coloration, and a firm flesh. The fruit of this new tree also appears to have good handling and shipping qualities. In addition to the forgoing, the ‘Burnectsix’ Nectarine tree bears fruit that are ripe for commercial harvesting and shipment on approximately June 29 to July 6 under the ecological conditions prevailing in the San Joaquin Valley of central California. In relative comparison to the seed parent ‘Grand Diamond’, the ‘Burnectsix’ Nectarine is white fleshed and further ripens approximately 5 to 7 days earlier at the same geographical location. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The accompanying drawing, which is provided, is a color photograph of the present Nectarine variety. The photograph depicts two whole mature fruit. Additionally a section of the fruit flesh has been removed from a sagittal exposure to reveal the flesh color. Yet further, flesh has been removed from a single characteristic pit. A vegetative shoot bearing typical leaves is shown. The external coloration of the fruit as shown is sufficiently matured for harvesting and shipment. The colors as seen in this photograph are as nearly true as is reasonably possible in a color representation of this type. Due to chemical development, processing and printing, the leaves and fruit depicted in these photographs may or may not be accurate when compared to the actual specimen. For this reason, future color references should be made to the color plates (Royal Horticultural Society) and the descriptions provided for hereinafter. 
    
    
     DETAILED DESCRIPTION 
     Referring more specifically to the pomological details of this new and distinct variety of nectarine tree, the following has been observed during the fourth fruiting season under the ecological conditions prevailing at orchards located near the town of Fowler, county of Fresno, state of California. All major color code designations are by reference to The R.H.S. Colour Chart (Fourth Edition) provided by The Royal Horticultural Society of Great Britain. 
     Tree: 
       Size.— Generally — Considered medium-large as compared to other common commercial nectarine cultivars ripening in the mid-season of maturity. The tree of the present variety was pruned to a height of approximately 285.0 cm to about 310.0 cm at maturity. 
       Vigor.— Considered vigorous. The present variety grew from about 151.0 cm to about 164.0 cm in height during the first growing season. The variety was pruned to a height of approximately 144.6 cm during the first dormant season and primary scaffolds were selected for desired tree structure. 
       Productivity.— Productive. Fruit set varies from twice to several times more than the desired crop load. Fruit set is spaced by thinning to develop the remaining fruit into the desired market size. The number of the fruit set varies with climatic conditions and cultural practices during the bloom period and is therefore not distinctive of the variety. 
       Bearer.— Regular. Fruit set has been heavy, and thinning was necessary during the past 6 years. 
       Form.— Upright, and pruned to a vase shape. 
       Density.— Medium dense. It has been discovered that pruning the branches from the center of the tree to obtain a resulting vase shape allows for air movement and appropriate amounts of sunlight to enhance fruit color and renewal of fruiting wood throughout the tree. 
       Hardiness.— The present tree was grown and evaluated in USDA Hardiness Zone 9. Winter chilling requirements are approximately 750 hours below 7.0 degrees C. The variety appears to be hardy under typical central San Joaquin valley climatic conditions. 
     Trunk: 
       Diameter.— Approximately 13.7 cm in diameter when measured at a distance of approximately 15.24 cm above the soil level, at the end of the sixth growing season. 
       Bark texture.— Considered moderately rough, with numerous folds of papery scarfskin being present. 
       Lenticels.— Numerous flat, oval lenticels are present. The lenticels range in size from approximately 4.0 to about 7.0 millimeters in width, and from 1.0 to about 2.0 millimeters in height. 
       Lenticel color.— Considered an orange-brown, (RHS Greyed Orange Group N167 C). 
       Bark coloration.— Variable, but it is generally considered to be gray-brown, (RHS Greyed Orange Group 166 A). 
     Branches: 
       Size.— Considered medium for the variety. 
       Diameter.— Average as compared to other varieties. The branches have a diameter of about 6.8 centimeters when measured during the sixth year after grafting. 
       Surface texture.— Average, and appearing furrowed on wood, which is several years old. 
       Crotch angles.— Primary branches are considered variable between about 44 to about 51 degrees from the horizontal axis. This characteristic is not considered distinctive of the variety however. 
       Current season shoots.— Surface texture — Substantially glabrous. 
       Internode length.— Approximately 2.2 to about 2.5 cm. 
       Color of mature branches.— Medium brown, (RHS Greyed Orange 176 C). 
       Current seasons shoots.— Color — Light green, (RHS Yellow Green Group N144 B). The color of new shoot tips is considered a bright and shiny green (RHS Yellow-Green Group 143 B). 
     Leaves: 
       Size.— Considered medium for the species. Leaf measurements have been taken from vigorous, upright, current-season growth at approximately mid-shoot. 
       Leaf length.— Approximately 130.0 to about 134.0 millimeters. 
       Leaf width.— Approximately 32.0 to about 35.0 millimeters. 
       Leaf base shape.— Slightly oblique relative to the leaf longitudinal axis. 
       Leaf form.— Lancelolate. 
       Leaf tip form.— Acuminate. 
       Leaf color.— Dark green, (approximately RHS Green Group 137 A). 
       Leaf texture.— Glabrous. 
       Lower surface.— Medium green, (RHS Green Group 137 D). 
       Leaf venation.— Pinnately veined. 
       Mid - vein.— Color — Light yellow green, (RHS Yellow Green Group 149 D). 
       Leaf margins.— Slightly undulating. 
       Form.— Considered crenate, and occasionally doubly crenate. 
       Uniformity.— Considered generally uniform. 
       Leaf petioles.— Size — Considered medium long. Length — About 9.0 to about 11.0 mm. Diameter — About 1.5 to about 2.0 mm. Color — Pale green, (RHS Green Group 143 C). 
       Leaf glands.— Size — About 1.0 mm in height and about 2.0 mm in width. Number — Generally one per side, occasionally two per side. Type — Globose, considered reasonably unappressed to the petiole margin and moderately small. Color — Orange-brown, (RHS Grey Brown Group N199 C). 
       Leaf stipules.— Size — Medium for the variety. Number — Typically 2 per leaf bud, and up to 6 per shoot tip. Form — Lanceolate in form and having a serrated margin. Color — Green, (RHS Green Group 141 B) when young, but graduating to a brown color, (RHS Greyed Orange group 166 C) with advancing senescence. The stipules are considered to be early deciduous. 
     Flowers: 
       Flower buds.— Generally — The floral buds, depending upon the stage of development, are approximately 6.0 millimeters wide; and about 10.0 millimeters long, conic in form; and slightly appressed relative to the bearing shoot. 
       Flower buds.— Color — The bud scales are reddish-brown, (approximately RHS Greyed Purple Group 183 B). The buds are considered hardy under typical central San Joaquin valley climatic conditions. 
       Hardiness.— No winter injury has been noted during the last several years of evaluation in the central San Joaquin valley. The current variety has not been intentionally subjected to drought or heat stress and therefore this information is not available. 
       Date of first bloom.— Mar. 2, 2002. 
       Blooming time.— Considered mid-season in comparison to other commercial nectarine cultivars grown in the central San Joaquin valley. Date of full bloom was observed on Mar. 8, 2002. The date of bloom varies slightly with climatic conditions and prevailing cultural practices. 
       Duration of bloom.— Approximately 10 days. This characteristic varies slightly with the climatic conditions. 
       Flowers type.— The variety is considered to have a showy type flower. 
       Flower size.— Flower diameter at full bloom is approximately 40.0 to about 43.0 millimeters. 
       Bloom quantity.— Considered abundant. 
       Flower bud frequency.— Normally 1 to 2 buds appear per node. 
       Petal size.— Generally — Considered large for the species. Length — Approximately 19.0 to about 22.0 millimeters. Width — Approximately 18.0 to about 21.0 millimeters. 
       Petal form.— Rotund. 
       Petal count.— Nearly always 5. 
       Petal texture.— Glabrous. 
       Petal color.— Light pink, (RHS Red Purple Group N57 D) to a medium pink, (RHS Red Purple Group N57 C). 
       Fragrance.— Slight. 
       Petal claw.— Form — The claw is considered truncate, and further has a large size when compared to other varieties. Length — Approximately 7.0 to about 9.0 millimeters. Width — Approximately 6.0 to about 7.0 millimeters. 
       Petal margins.— Generally considered variable, from nearly smooth, to moderately undulate. 
       Petal apex.— Generally — The petal apices normally appear entire with the apical groove. 
       Flower pedicel.— Length — Considered medium-long, and having an average length of approximately 4.0 to about 5.0 millimeters. Diameter — Considered average, approximately 2.0 millimeters. Color — A medium brown, (RHS Greyed Red Group 178 B). 
       Floral nectaries.— Color — A Pale green, (RHS Yellow Green Group N144 A). 
       Calyx.— Surface Texture — Generally glabrous. Color — A dull red, (approximately RHS Greyed Purple Group 183 A). 
       Sepals.— Surface Texture — The surface has a short, fine, pubescent texture. Size — Average, and ovate in form. 
       Color.— A dark reddish purple, (approximately RHS Greyed-Purple Group 187 A). 
       Anthers.— Generally, large in size. Color — Red to reddish purple, (approximately RHS Greyed Purple Group 187 C). 
       Pollen production.— Pollen is abundant, and has a yellow color, (approximately RHS Yellow Group 12 A). 
       Filaments.— Size — Variable in length, approximately 17.0 to about 19.0 millimeters in length. Color — Considered a pale pink, (RHS Red Purple Group 62 D). 
       Pistil.— Number — Usually 1, rarely  2. Size — Average. Length — Approximately  16.0 to about 18.0 millimeters including the ovary. Color — Considered a very pale green, (approximately RHS Yellow Green Group 145 B). Surface Texture — The variety has a long glabrous pistil. 
     Fruit: 
       Maturity when described.— Firm ripe condition (shipping ripe). Date of first picking — Jun. 29, 2002. Date of last picking — Jul. 10, 2002. The date of harvest varies slightly with the prevailing climatic conditions. 
       Size.— Generally — Considered relatively large, and uniform. 
       Average cheek diameter.— Approximately 79.0 to about 83.0 millimeters. 
       Average axial diameter.— Approximately 74.0 to about 79.0 millimeters. 
       Typical weight.— Approximately 246.0 grams. This is dependent upon the prevailing cultural practices and therefore is not distinctive of the variety. 
       Fruit form.— Generally — Moderately oblate. The fruit is generally uniform in symmetry. 
       Fruit suture.— Shallow, and extending substantially from the base to the apex. No apparent callousing or stitching exists along the suture line. 
       Suture.— Color — The background color appears to be white, (approximately RHS White Group 155 C), and occasionally some red coloration, (approximately RHS Red Group 46 C) may appear. 
       Ventral surface.— Form — Slightly indented. 
       Apex.— Rounded. 
       Base.— Retuse. 
       Stem cavity.— Rounded, and relatively shallow. The average depth of the stem cavity is about 1.62 cm. The average width of the stem cavity is about 2.10 cm. 
       Fruit skin.— Thickness — Considered medium in thickness, and tenacious to the flesh. 
       Texture.— Considered glabrous. 
       Taste.— Non-astringent. 
       Tendency to crack.— Cracking has not been observed. 
       Color.— Blush Color — This red blush color is variable, from a reddish orange, (approximately RHS Red Group 46 C), to a dark red-purple, (approximately RHS Purple Group N77 A). The blush color ranges from about 75% to about 95% of the fruit surface depending upon the sunlight exposure and the prevailing growing conditions. Ground color — Generally, a light yellow, (approximately RHS White Group 155 C). 
       Fruit stem.— Moderate in length, approximately 6.0 to about 7.0 millimeters. Diameter — Approximately 2.0 to about 3.0 millimeters. Color — Light brown, (approximately RHS Greyed Orange Group 164 C). 
       Flesh.— Ripens — Evenly. Texture — Firm, and dense. Considered melting. Fibers — A few, small, and tender ones may be found. Aroma — Very fragrant. Considered aromatic. Eating Quality — Very good. Flavor — Considered to be sweet and having an acidic flavor. The flavor is viewed as both pleasant and balanced. Juice Production — Moderate. Brix — About 15.0 degrees. This characteristic varies slightly with the number of fruit per tree, prevailing cultural practices, and the surrounding climatic conditions. Flesh Color — Pale yellow, (approximately RHS Yellow Group 4 D). 
     Stone: 
       Type.— Clingstone. 
       Size.— Considered medium to large for the variety. The stone varies with the crop load and tree vigor and is therefore not characteristic of this variety. 
       Length.— Average, about 31.5 to about 35.0 millimeters. 
       Width.— Average, about 22.0 to about 29.0 millimeters. 
       Diameter.— Average, about 18.0 to about 21.0 millimeters. 
       Form.— Obovoid. 
       Base.— The base is usually considered oblique relative to the stone&#39;s vertical axis. 
       Apex.— Shape — The stone apex is raised and has an acute, protruding tip. 
       Stone surface.— Surface Texture — Irregularly furrowed toward apex. Furrows are generally in concentric loops which extend from the apex toward the base. Substantial grooving over the apical shoulders is normally evident. Surface pitting is more prominent generally, and noted more frequently toward the base of the stone. Ridges — The surface texture varies from sharp to rounded. Ventral Edge — Width — Considered medium, and having a dimension of approximately 3.0 to about 4.0 millimeters at the mid-suture. The wings are most prominent over the suture line. Dorsal Edge — Shape — Full, heavily grooved, and having jagged edges. 
       Stone color.— The color of the dry stone is a medium brown, (approximately RHS Greyed Orange Group N170 B). 
       Tendency to split.— Splits have rarely been noted. 
       Kernel.— Size — The kernel is considered small. Form — Considered irregular and immature at fruit ripening. Pellicle — Pubescence has not developed at fruit senescence. Color — Considered a light brown (Greyed Orange N167 B). 
       Use.— The subject variety ‘Burnectsix’ is considered to be a Nectarine tree of the mid-season of maturity, and which produces fruit which are considered firm, attractively colored, and which are useful for both local and long distance shipping. 
       Keeping quality.— Excellent. Fruit has stored well up to 25 days after harvest at about 1.0 degree Celsius. 
       Shipping quality.— Good. The fruit has showed minimal bruising of the flesh or skin damage after being subjected to normal harvesting and packing procedures. 
       Resistance to insects and disease.— No particular susceptibilities were noted. The present variety has not been tested to expose or detect any susceptibilities or resistances to any known plant and/or fruit diseases. 
     Although the new variety of nectarine tree possesses the described characteristics when grown under the ecological conditions prevailing near Fowler, Calif., in the central part of the San Joaquin Valley of California, it should be understood that variations of the usual magnitude and characteristics incident to changes in growing conditions, fertilization, pruning, pest control and horticultural management are to be expected.