Breeding of a new Chinese chestnut variety 'Jinyou 2' (Castanea mollissima)

Astract:‘Jinyou 2'is a new chestnut variety selected through seedling selection. In 1987, a seedling chestnut tree over 50 years old from Luotian county of Hubei province was selected for its good growth and fruiting capacity, and determined to be the superior line. The propagation and characteristics observation were performed in 1992. The variety comparative tests are carried out in 2002. After regional adaptability testing at three sites of Hubei Province (including Luotian, Macheng and Yingshan) over four years from 2010 to 2013, it was finally selected in 2017.‘Jinyou 2'has a tall tree, the tree is vigorous with circular crown and semi-open tree form. Main branches are gray and glabrous, lenticels are dense. Young branches are grey-green and glabrous. Matured leaves are long ellipse and deep green, 22.05 cm long, 8.16 cm wide. The average length of catkin is 13.98 cm. The bur is ball and big, averaging 2.5 nuts per bur, nut rate is 52.2%. The spine bundle is short and dense. Fruit is reddish-brown, with good luster. The average fruit weight is 17.68 g. The pulp of nut is faint yellow-colored, and the flesh is fine and smooth. The quality of fresh nut is superior, containing 31.4% starch, 6.09% sugar, 4.10% protein, and 1.26% fat. In Luotian county, ‘Jinyou 2'sprouts in late March, the leaf expansion appears in early April, the catkins full open in late May, and female flowers open from late May to early June, 1.73 female flowers per fruiting branch. The fruit matures in mid-September. The germination rate of bearing base shoot is 66.3%, 1.51 fruiting branches per bearing base shoot. It is resistant to drought, barren and chestnut blight. The fruit has long storage life, after cold storage of 5 months, the nut rotting rate is6.2%. The nut is suitable for processing, the broken rate of the nuts is below 7% when processed to cans or frozen kernel. After complete planting of grafted seedlings, this variety can send forth biennial bearing branches the same year, bear fruits next year, and enter into fruiting period 3 to 4 years later, hashigh yield potential of 264.6 kg per 666.7 m2. Suitable cultivation area is mountain and hilly area in the Yangtze valley and south of China, below 800 m above sea level. Orchard should choose neutral sandy soil which is flat and has ability of moisture and fertilizer retention, suitable tree shape is open center shape. The spacing in the rows and spacing between rows are 3-4 m×4-6 m when cultivated in steep slope mountain, and 6-8 m×3 m in flatland. Mix bud of this variety is on the upper part of biennial bearing branch, which is not suitable for short-cutting in winter. The configurations of pollinizers are‘Luotianzhongchili'and‘Qiancidabanli'.