Breeding report of a new early seedless grape cultivar ‘Zijin zaosheng’

Abstract: ‘Zijin zaosheng’is an early-ripening and seedless grape with high yield, strong pathogen resis⁃tance and rose-fragrant. The original plant was selected from the variation of‘Venus Seedless’grape inInstitute of Horticulture, Jiangsu Academy of Agricultural Sciences (JAAS). In 2000, stem-segment withsingle bud of‘Venus Seedless’grape was treated by 0.2% colchicine, and 42 single plants were obtainedin 2001. These signal plants began to produce fruits in 2003. After three years observation, it was selectedin 2006 as for its seedless, strong rose- fragrant, good comprehensive characters, stable fruit bearing andstrong pathogen resistance. From 2008, it was evaluated in regional trials under the name of‘3-2D-05’in Lishui, Jiangning and Wuxi. In November of 2015, it was put on records by the fruit, tea and flower vari⁃ety appraisal committee of Jiangsu province and named‘Zijin zaosheng’.‘Zijin zaosheng’belongs to V.vinifera - V. labrusca type, diploid plant and bisexual flower. The growth vigor of the plant is middle.Young shoots and young leaves are yellowish green, leaves surface and back are covered with heavy hair,internode ventral of the shoot are green. Adult leaves are medium size and tend to nearly triangle, threelobes, superfissure, oval hollow petiole is mild overlapping, serration on the leaf edge is short, both side ofthe serration are bossed. There is no or little anthocyanin in the principal vein of leaves surface. Creepingand vertical villi is very heavy among the principal vein of leaves back. The distribution of tendril is incon⁃secutive.‘Zijin zaosheng’has conical cluster, the average cluster length is 16.6 cm, average cluster wideis 9.4 cm, average cluster weight is 317.4 g. The fruit grain is round or short-ellipse, the cluster is com⁃pact, uniform size, pericarp color is purple-black, and average grain weight is 5.2 g. Bloom is thick, andpericarp thickness is medium. The flesh is soft with sweet and strong rose-fragrant. The berries are seed⁃less, but very few berries have remaining remnant seeds. The soluble solid content is 17.2%, titratable ac⁃id content is 0.66%. In the Nanjing area, the time of budburst is usually late March, and flowering at earlyMay.‘Zijin zaosheng’is an early-ripening variety. From bud breaking to harvest time is about 112 d,and it harvest at the middle July in Nanjing, Jiangsu province; the average cluster number per bearingshoot is 1.7, proportion of fruit branches is 90%-95%, germination rate is 95%-100%. The Juvenile peri⁃od is short, just need 2 years, this variety can bear fruits, and more than 1 100 kg for 666.7 m² during fullfruit period.‘Zijin zaosheng’has strong disease resistance, and can be planted in open field or underrain-shelter. The cultivated model is vertical trellis or pergola trellis system. Pruning pattern is short orvery short cane pruning. It is better to remove the shoot tips before flower and remove partial berry andcluster to improve commercial quality of fruits.