A new white flesh and stony-hard nectarine cultivar ‘Zhongyou 20’

Abstrcat:‘Zhongyou 20’is an early stony hard peach cultivar with white-flesh, selected from the cross between‘Zhongyou 14’as female parent and‘99-43-58’as male parent. The hybrid cross was made in 2005 and forty-five seeds was acquired and sixteen seedlings were planted in the orchard in 2006, with tree spacing four meters between rows and one meter between trees. In 2009, the fruit tree began to fruit. One of all the individuals was named as‘05-1-138’and showed distinguished from the other offsprings. In 2009, the‘05-1-138’was chosen as a new selection. In 2013，it was grafted on the rootstocks and tested in different place in Henan province and around cities. In December of 2018,‘05- 1-138’was selected when growing in the breeding orchard, then named as‘Zhongyou 20’and was ap- proved by the Approval Committee for Improved Varieties of Forest Tree of Henan Province. Leaf glands are reniform, about 2 to 5 ones with average about 3. Average length of the leaf is 18.6 cm in- cluding the petiole and the average width is 6.3 cm. The leaf petiole is medium with 0.7 to 1.1 cm. The young leaves are glabrous in both surfaces. Leaf form is lanceolate and flat in crossing section. In Zhengzhou area, it begins to sprout at the end of February and blossomed in medium or late March. The flower is non-showy, small, dark pink petals and self-fertile. The initial flowering date is from 15th to 23th of March and lasts 5 to 7 days. After fruiting, the fruit tree showed a moderately growth vigor, a relatively open posture and were extremely productive. The ripe date is in mid-July and fruit skin is with non-hairiness and full of a light red with 100% blush. The fruit properties white flesh, stony hard, clingstone and the shape is round without tip. The suture is slight apparent, extending from base to apex and the base is flat. The eating quality of fruit is sweet and medium acidic flavor. Because of the stony- hard type it has a very long period of keeping on the tree and good storage quality for long distance mar- keting. Red anthocyanin staining of pit cavities was slight near the stone. The maximum of the fruit weight is up to 250 grams, with an average fruit weight between 210 to 230 grams. The soluble solid content (SSC) is varied from 14.1% to 16.2%, containing 10.4% soluble sugar. The total acid content is 0.36% and the vitamin C content is 10.6 mg·100 g-1. The overall fruit is with good quality. The fruit ripening date is in the middle third of July, the fruit development period is about 110 days. The leaves be- gin to fall in later October, and the growth period of the whole year is about 220 days. In the second years, the tree begins to fruit and in the third year the yield can reach up to 1 000 kilograms. In the full productive stage, the yield can reach to 2 500 kilograms per 666.7 m2. After cultivation test, this variety is suitable and can be widely cultivated in Henan province and surrounding provinces.