A Detailed Explanation of the Economic Traits and Cultivation Key Points of the Large-Fruited Black Peach

The large-fruited black peach is a mid-to-late ripening seedling variety discovered by a fruit grower in Nanshi Town, Xuecheng District, Zaozhuang City, Shandong Province, in the Zhaishan valley. In 1995 it was introduced and cultivated at the improved variety demonstration base of Nanshi Town First Village by the Xuecheng District Xingnong Seed Company, and there are now about 1800 sq m of fruiting orchards. After 5 years of cultivation observation, the variety's economic traits were deemed stable, and its single fruit weight (average 194.6 g) is clearly greater than that of the "black silkie peach" from Zhejiang, Anhui and other places (average 138 g), so it was named "large-fruited black peach." It is a rare extra-large-fruited black peach variety in China at present, and won first prize in the 1997 national fruit quality evaluation. The fruit's market price is 10 times that of ordinary peaches, and it has excellent development prospects. Its main economic traits and cultivation techniques are introduced below.

I. Main Traits

(I) Morphological characteristics The tree vigor is robust, the tree posture is open, the trunk and perennial branches are grayish brown with a smooth surface, one-year-old branches are purplish red on the sunny side and light green on the shaded side with a glossy sheen, and the lenticels are not obvious. The leaves are 10.3 cm long and 2.5 cm wide, and the petioles are 0.7 cm long; the leaf margins are wrinkled and uneven; the petioles and veins are light red, and the leaves are dark green. The flower buds are medium to large, there is abundant pollen, and the petals are pink, noticeably deeper than those of ordinary varieties.

(II) Fruit economic traits The fruit is nearly round, the fruit apex is flat with a slightly pointed tip, the suture line is moderately deep, and the two halves are symmetrical. The average single fruit weight is 194.6 g, with a maximum of 308 g. When the fruit ripens, the fruit surface is purplish black, the skin is moderately thick and not easy to peel, the flesh is purplish black, the stone clings, and the flesh is hard and melting. The flesh is fine and delicate, with a medium amount of juice, a rich flavor, a delicate fragrance, and top-grade quality. The soluble solids content is 18.6%, the sugar content is 14.6%, and the acid content is 0.136%; 100 g of flesh contains 19.6 mg of vitamin C and 5.18 g of cellulose, and the vitamin C content is clearly higher than that of ordinary peaches. It stores well, with a storage period of 8-12 d at room temperature. The edible rate is 91.6%.

(III) Phenological period In the Xuecheng area, the flower buds sprout in mid-March, the flowering period is in mid-to-late April, and the flowering period lasts 9-13 d, noticeably longer than that of other varieties, giving it a certain ornamental value. The fruit ripens in mid-September, and the fruit development period is 135 d. The leaf-fall period is in late October, and the annual growth period is about 250 d.

(IV) Growth and fruiting habits This variety has the characteristics of a high sprouting rate and strong branching ability. The branches grow vigorously with a large amount of growth, and there are 2-3 branches within one year, forming the canopy quickly. After entering the full fruiting period, the tree body tends toward moderate vigor and grows steadily. On 5-year-old trees, long fruiting branches account for 19.0% of fruiting, medium fruiting branches 49.4%, and short fruiting branches 31.6%; the natural pollination fruit set rate reaches 31.6%, and there is no physiological fruit drop.

(V) Fruit yield performance This variety is extremely prone to forming flower buds, and fast-grown seedlings grafted in the same year can form flower buds in the nursery. For grafted seedlings planted, the fruiting plant rate in the second year reaches 100%, with an average annual yield of 3.8 kg per plant and a high of 5.6 kg; in the third year the highest yield per plant can reach 18.6 kg, and 667 sq m can produce 2100 kg of high-quality fruit.

(VI) Adaptability and stress resistance This variety has strong adaptability and strong drought and barren resistance, and can also achieve high yields on thin mountain and ridge land. Bacterial shot hole disease and gummosis of peach leaves occur relatively lightly.

II. Key Points of Cultivation Techniques

(I) Orchard establishment density On plains, the plant and row spacing is 3 m x 4 m, and on hilly land 2.5 m x 3.5 m or 2.5 m x 3.0 m is suitable.

(II) Trunk height At 40-50 cm on plains and 30 cm on hilly land. The tree shape should preferably be a natural open-center shape with multiple main branches, leaving 3-5 main branches, and the angle between the main branches and the trunk should be controlled at 60o-70o.

(III) Pay attention to flower and fruit thinning This variety has a large number of flowers and no physiological fruit drop, so to improve fruit quality, flower and fruit thinning is extremely important. First, part of the inflorescences should be thinned in time during the flowering period; second, the first fruit thinning should be carried out 2-3 weeks after flowering, with the amount thinned accounting for 50%-60% of the total; the second fruit thinning should be carried out in early June, generally leaving 2-3 fruits on long fruiting branches, 1-2 fruits on medium fruiting branches, and 1 fruit on short fruiting branches or 1 fruit for every two short fruiting branches.

(IV) Strengthen summer pruning Summer pruning is beneficial for ventilation and flower bud differentiation.