A new kernel-used apricot cultivar Jingren 4 by distant hybridization

Abstract: Kernel-used apricot is widely planted in three northern regions of China for its outstanding characteristics of cold resistance, drought resistance, and barren tolerance as an irreplaceable economic forest for developing agricultural economy and protecting the natural environment in mountainous areas. Compared with the excellent almond cultivars, the yield of the main cultivated kernel-used apricot in China is lower and the average single kernel mass is also lower. The growing regions of almond are very limited. Selection of innovative germplasm through distant hybridization has been successfully used in fruit breeding. In order to create a new germplasm combining the high yield of almond and the multi-resistance of kernel-used apricot, we made the distant hybridization between kernel-used apricot and almond and obtained F1 progenies. Through evaluation and selection of the hybrid progenies for many years, Jingren 4 bred from the cross of Longwangmao × Italy 4 was finally released as a new cultivar. The plant variety right was granted by the National Forestry and Grassland Administration in December 2022. The fruit of this new cultivar was ovoid with convex apex and the fruit peel was orange yellow when mature, with medium area red color on sunny side. The shell was ovoid with rough shell surface and plump kernel. The average longitudinal diameter, transverse diameter and side diameter of the single shell was 3.77, 2.58 and 1.49 cm respectively, and the fresh shell weight 4.15 g. The kernelwas sweet and large with average single fresh weight 1.15 g, dry weight 0.93 g, and high proportion of double kernel, the average longitudinal diameter, transverse diameter and side diameter of single kernel was 2.47, 1.61 and 0.84 cm respectively. The content of fat in the kernel was 435.96 g·kg^-1 , the content of protein 288.28 g · kg^-1 , the content of Ca 1.11 g · kg^-1 and the content of Fe 23.01 mg · kg^-1 . In Pinggu district of Beijing, the flower blossomed from late March to early April, with the flowering period of 5-7 days. The flowers were solitary and the petals were white. The pistils were significantly higher than the stamens, the proportion of complete flowers was high. The fruit development period was about 100 d and the fruits matured in mid-July. The leaves were dark green and glossy. Trees defoliation started in mid- late November and the vegetative growth periods lasted about 220 days. Jingren 4 had strong sprouting power and started to bear fruit in the second year after high grafting. It had good yield and stability without biennial fruiting. The pollinator trees were necessary for its poor self-flowering ability.