Breeding report of a new peach cultivar ‘Zhong Tao 4'

Abstract: ‘Zhong Tao 4'is a middle-season, freestone peach cultivar, which is derived from a cross be-tween‘Feng Bai'and‘Zhong Youtao 5'.‘Feng Bai'is a middle-season freestone peach cultivar bredby Dalian Academy of Agricultural Sciences and‘Zhong Youtao 5'is an early-season nectarine bred byZhengzhou Fruit Research Institute, CAAS. In March 25, 100 flower buds of‘Zhong Youtao 5'at big budstage were taken and the anthers were collected. Then, the anthers were spread out on clean white paperand dried under 24 °C for 24 h. Before blooming, the corollas of female parent were removed except thestyles, which would be pollinated and bagged immediately. 10 days later, the bag proofs were removed.The fruits were harvested when matured and the cleaned seeds were stratified in refrigerator at about 2-5 °C. At the next spring, the seeds were potted and 19 seedlings were obtained finally. In April, the seedlingswere planted at 1.5 m×4.0 m in density and cultivated as normal. The seedling numbered‘99-44-6'waseventually selected after more than 10 years identification and tests and named as‘Zhong Tao 4'when re-leased. The tree of‘Zhong Tao 4'is vigorous and half-spreading. The sprouting and branching ability aremiddle. The new shoots are green and purplish red on the back. The length of internode is middle in aver-age of 2.07 cm. The green leaves are usually elliptic-lanceolate and middle-sized. Leaf cross section ishorizontal. The length of petioles is middle, with 2-4 reniform glands. The flower is showy with 5 wide-el-liptical petals. The inner of calyx tube is green-yellow. The anthers are white and sterile. The fruit is main-ly round or elliptical. The white skin is mostly covered by rose-red. The average fruit weight is 201 g, max-imum fruit weight more than 300 g. It is freestone and the stone is oval and brown-colored. No stone crackwas found. The fruit flesh is white, fine texture and hard-melting. It is sweet, very low acid and high eat-ing quality. The content of soluble solid, total sugar, total acid and Vitamin C is 13.40%, 11.28%, 0.16%and 9.98 mg·100g- 1fresh, respectively. In middle China, the first flower of‘Zhong Tao 4'opens in theend of March, about 1-2 days earlier than Okubo. The fruit development period is about 90 days and canbe harvested at the end of June. The tree is vigorous and the branching ability is strong. The flower budsmainly appear at the 1-2ndnode. The ratio of single and double flower bud is about 1:2.65. Single flowerbuds mainly appear on the base and top of the branches. Its early fruiting ability is strong. In middle plant-ing density, the yield could reach more than 15 tons per ha in the third season. The fruits mostly set onmiddle or long bearing branches. Suitable cultivation area is the Huanghe River valley and the north of it.It also can be introduced to the Yangtze valley and other regions. The orchard should be build on sandy,light acidic soil. The irrigation and drainage system are also needed. In north China, 1.5 m in the rows and 4 m between rows are recommended and the V shape would be a good choice for training system. In southChina, the density should be lower, and accordingly 4 skeleton branches are suggested. Pollinator, like‘Okubo'or‘Zhong Tao 5', also need to be arranged in ratio of 1:1. Training a stable and specificationtree architecture is the first priority in the first two seasons, especially before middle July. After that, thevegetative growth should be controlled to promote flower differentiation. All bearing branches or smallbearing branch groups should be kept around the skeleton branches and bigger bearing branch groups arenot suggested. Artificial or mechanic pollination is also helpful to get stable yield. After about 40 days offirst flowering, the fruit set should be checked and deformity fruit, injured fruit and bush fruit should bethinning and the suggested yield is about 30.0-37.5 tons per ha.