Characteristics of the peach cultivar Chashan Zaomi
1 Breeding process
In July 1994, 169 well-developed seeds from pure Yuhualu peach obtained by natural pollination were collected. After stratification treatment, they were sown and raised as seedlings. In 1995, 126 progeny seedlings were obtained, numbered 001--126, and in 1996 they were planted at the Chashan practice base of Linyi Normal University. From 1998 to 1999, they fruited successively. In 2000, 5 better-performing lines were top-grafted in the high-tech experimental orchard and production orchard of the Chashan base. After 3 years of trait observation, No. 026 showed early fruiting, large fruit size and good flavor. In 2002, it was identified by an expert group and named Chashan Zaomi.
2 Botanical traits
The tree grows vigorously, with a relatively open tree posture, and new shoot growth reaches 86.2 cm. Perennial branches are grayish white, and one-year-old branches are light brown. Leaves are lanceolate, glossy and dark green. Leaves in the middle part of the branch are 14.2 cm long and 3.89 cm wide, wider than those of other cultivars, with sparse serrations along the leaf margin. In autumn, the leaves turn red. Flower buds are large and plump, mainly compound flower buds. Flowers are rosette type, with a corolla diameter of 3.0 cm, pink, pistils slightly lower than stamens, pollen present, and a high self-fruit-setting rate.
3 Biological traits
3.1 Phenological period In the Chashan area of Shandong, flower bud germination begins in late March, full bloom is in mid-April, fruit ripening is in early to mid-June, and the fruit development period is 60 d (days). Compared with other early-maturing peaches in the same region, such as Chunlei (Hu 005), the ripening period is about 5 d later. Leaves fall in early November.
3.2 Fruit characteristics The fruit is nearly round, uniform, with a protruding fruit apex, obvious suture line and symmetrical sides. The fruit is large, with an average single fruit weight of 160 g. The ground color of the peel is milky white, with pinkish red blush. The flesh is milky white, uniform in maturity, with moderate juice, firm melting texture, aroma, sweet and sour palatability, strong flavor and good taste. The soluble solids content is 11.2%, soluble sugar 8.1%, and titratable acid 0.36%. The pit is clingstone, small and non-splitting, and most seeds do not develop to maturity. The fruit is relatively tolerant to storage and transport.
3.3 Fruiting habit The tree is robust, drought-resistant, tolerant to barren soil and highly adaptable. It flowers easily, with many compound flower buds, and long, medium and short fruiting branches can all bear fruit. In young trees, the proportion of fruiting branches is 36.5% long fruiting branches, 36.9% medium fruiting branches and 26.5% short fruiting branches. A 3-year-old tree yields 20.2 kg per tree, a 4-year-old tree yields 30.3 kg per tree, and in full fruiting period about 1600 kg per 667 sq m.
4 Key cultivation techniques
Chashan Zaomi is drought-resistant, cold-resistant, tolerant to barren soil and adaptable to a wide range of areas. Because the fruit ripens early, it is suitable for development in suburbs. In mountainous and hilly areas, the spacing is 2 m x 3 m, and in plains 4 m x 4 m. The most suitable tree form is the natural open-center form. Although Chashan Zaomi has fertile pollen and a relatively high self-fruit-setting rate, pollinizer trees should also be arranged to increase yield and quality. In the year of planting, attention should be paid to summer pinching to promote branching, accelerate canopy expansion and early shaping. Winter pruning of young trees should adopt the long-shoot pruning method, with more thinning and less heading back. After entering the fruiting period, use two-branch renewal, keep good reserve branches and prevent the fruiting parts from moving outward. In summer, pay attention to removing excessively dense branches, vigorous upright branches and diseased and insect-damaged branches, and appropriately twist shoots to improve ventilation and light conditions. Plant growth regulators should be applied appropriately. For young vigorous trees, spraying or root application of paclobutrazol (also known as PP333) at the early stage of branch growth can effectively control excessive branch growth and help flower bud formation. The effect of paclobutrazol can last 3 a (years).
Pests and diseases during the growing period include peach aphid, red spider mite, peach leafminer moth, anthracnose and bacterial shot hole. For control methods, spray 3--5 degrees Baume lime sulfur mixture before germination to control red spider mite and powdery mildew. Spray peach aphid once-net or imidacloprid once each before and after flowering, and after leaf expansion spray pyridaben, mixed with fungicides such as carbendazim to control pests and diseases. After that, pay attention to the control of peach fruit borer and leafminer moth, spraying Taoxiaoling, diflubenzuron No. 3 or triflumuron respectively. After leaf fall, thoroughly remove dead branches, diseased branches and fallen leaves, and bury them deeply or burn them in a concentrated way.