Introduction to the Xiaguang peach variety and its main characteristics
1 Breeding history
Xiaguang (tentative name), a natural bud mutation of Feicheng peach discovered in 1992, was grafted and propagated, then trial-planted under different site conditions. After years of observation at multiple locations, it showed stable genetic traits, large fruit, excellent quality, strong adaptability, and relatively good storage and transport tolerance.
2 Main traits
2.1 Botanical characteristics This variety has a vigorous tree habit, a relatively open tree posture, a high sprouting rate, strong branching ability, and large new shoot growth. Secondary shoots are moderately produced. Leaves in the middle of new shoots are large, with an average leaf length of 13--14 cm and width of 3--4 cm. Leaf margin serration is relatively shallow. Annual growth (diameter at the base of the trunk) is about 30% greater than that of Feicheng peach, the canopy expands quickly, and it bears fruit early. Long, medium, and short branches all flower easily. In the initial fruiting stage, long and medium fruiting branches predominate; after entering full fruiting stage, medium and short branches predominate in fruiting. Pollen is relatively abundant, and the fruit set rate from self-pollination is high.
2.2 Economic traits of the fruit Large-fruited type, average single fruit weight 255 g, maximum single fruit weight 425 g, average fruit longitudinal diameter 7.05 cm, average transverse diameter 7.18 cm, fruit shape regular. Fruit nearly round, suture shallow, fruit stalk relatively short, stalk cavity medium deep, fruit apex flatly rounded and slightly concave. Fruit surface smooth and glossy, ground color yellow-green, with red on the sun-exposed side. Fruit cracking rate low, about 2% in ordinary years. Flesh milky white, red around the stone, freestone. Stone small, stone weight 5.12 g. Flesh fine and crisp, flavor sweet and fragrant, with a rich aromatic sweetness, quality extremely high, soluble solids content 17.5%, titratable acidity 0.16%, average fruit firmness 8.1 kg/sq cm, relatively tolerant of storage and transport, stored indoors at room temperature for 10 d (days) without skin wrinkling or water loss, making it an excellent late-maturing peach variety.
2.3 Growth and fruiting habits Tree vigor strong, average new shoot growth 45.8 cm, canopy expansion fast, flowering easy, distribution of all types of branches reasonable, among which long fruiting branches account for 41.5% of branch number, medium fruiting branches 20%, and short fruiting branches 27.5%. Flower cluster starting node low, flower buds begin to form from the 2nd--3rd node at the base of the branch, sprouting rate as high as 81.7%. Branching ability strong, at 35.1%, secondary bud rate 31.2%. Physiological fruit drop and preharvest fruit drop slight. Self-pollination ability strong, no pollinizer trees needed, strong early fruiting and high-yielding potential.
2.4 Stress resistance and adaptability Adaptability relatively strong, relatively cold resistant, showing high and stable yields on both sloping land and flat land. Relatively resistant to aphids and spider mites. Relatively resistant to bacterial shot hole disease and gummosis. Drought resistance strong, waterlogging tolerance somewhat weaker.
2.5 Phenological period In Linqu County, Shandong Province, buds break around March 23, first flowering on April 7, full flowering from April 10--14, petal fall in mid-to-late April, single flower period 10 d, whole-tree flowering period can last 15--20 d; if low temperature occurs before and after flowering, the flowering period may be delayed by 2--3 d. Fruit begins coloring in mid-July and matures in late September, fruit development period 160 d, leaves fall in mid-November.
3 Key points of cultivation techniques
3.1 Orchard establishment Row spacing and plant spacing are generally 3--5 m x 4 m, with level trench or large-hole site preparation, trench (hole) width 0.8--1.0 m, seedling height 1.5 m, diameter above the graft union more than 1.2 cm, planted in autumn or spring. Before planting, apply 4000 kg of high-quality base fertilizer per 667 sq m, 50 kg of special fertilizer for fruit trees, and a small amount of urea. Before planting, prune the root system of the seedlings, then soak the roots in 800-fold carbendazim solution for 10 min (minutes) for sterilization. After planting, head the tree at a height of 50 cm, and retain plump buds within the 10 cm shaping zone below the cut. Water thoroughly after planting, and cover the ground below the seedlings with plastic film.
3.2 Soil, fertilizer, and water management From late August to early October, in combination with deep plowing and soil improvement, apply 4000--5000 kg of high-quality farmyard manure per 667 sq m. Apply fertilizer 4 times: before bud break, during the young fruit swelling stage, during the pit-hardening stage, and after fruit harvest. Fertilization at the pit-hardening stage is especially important; in the early stage, nitrogen fertilizer is mainly used, and in the later stage, a nitrogen-phosphorus-potassium compound fertilizer is applied, generally 0.4--0.7 kg per tree is appropriate. After mid-May, carry out foliar topdressing every 10--15 d together with pesticide spraying; in the early stage, mainly 0.3%--0.5% urea, and in the later stage, mainly 0.2% potassium dihydrogen phosphate, or spray 200-fold photosynthetic micro-fertilizer. Irrigate in combination with fertilization, 3--4 times throughout the year, namely before bud break, before flowering, during fruit swelling, and after fruit harvest. Never water during the flowering period, so as to avoid reducing the fruit set rate. During the growing season, the irrigation amount per 667 sq m should be controlled within 20 cubic meters. Drain promptly in the rainy season to prevent waterlogging.
3.3 Training and pruning The natural open-center shape should be adopted, trunk height generally 40--50 cm, basal angle of main branches 45°--55°, and the number of retained branches per 667 sq m must not exceed 90,000. During winter pruning in the 1st--4th a (years) after planting, main branches should be alternately cut short and left long in alternate years, so as to form a firm framework. In the 5th a of winter pruning, leave the secondary shoot behind the extension branch unpruned and not cut back. Each year on the main branches, use long and medium fruiting branches to develop small fruiting branch groups or several single fruiting branches. On the upper side and both sides of the main branches, use water sprouts and vigorous branches to develop 1--2 large fruiting branch groups and 2--3 medium fruiting branch groups, and pay attention to timely renewal of fruiting branch groups.
3.4 Flower and fruit management Flower thinning and fruit thinning must be strict, mainly leaving single fruits, and retaining a certain number of empty nodes (except in years with few flowers), to create conditions for high yield and quality. In fruit arrangement, mainly retain fruit on both sides of the scaffold branches; in the initial fruiting stage, pay attention to retaining medium and long fruiting branches; after entering full fruiting stage, medium and short branches should predominate in fruiting. Retain as few fruits on the upper side of branches as possible.
3.5 Pest and disease control This variety has relatively strong pest and disease resistance, and emphasis should be placed on controlling bacterial shot hole disease, peach fruit borer, and peach fruit moth. On the basis of strengthened integrated management, generally spray 5 degrees Baume lime sulfur mixture once each spring (late March), in early May spray 70% thiophanate-methyl 800--1000-fold solution plus 40% methamidophos 600--800-fold solution, in early June spray 70% mancozeb wettable powder 500-fold solution or 70% thiophanate-methyl 800--1000-fold solution, and in July spray 25% fenpropathrin 1500-fold solution. Thereafter, spray pesticides at appropriate times according to the occurrence and damage of pests and diseases.