Breeding report of a new mid-maturing apricot cultivar Guojin

Abstract: Guojin is a new mid-maturing red apricot cultivar bred from a cross of Chuanzhihong × Sungold at Liaoning Institute of Pomology. Through artificial hybridization, 370 hybrid seeds were obtained in July, 2002 and 102 seedlings were planted in next spring. It was initially selected in 2007 for its fruit size and appearance. The botanical characteristics, biological characteristics, main economic traits of the fruits, adaptability, and resistance were observed at four sites from 2014 to 2018. It was granted the new variety right by the National Forestry and Grassland Administration in 2021.The tree of Guojin had a medium vigor and an open tree gesture. The young branches were glabrous, brown-red in color. The leaves were green in color, elliptic, mucronate, and dentate. The flower buds were pink and the petals are white. The fruits were uniform with an attractive appearance, it was oblate in shape with 90% red coloring. The average fruit was 112.0 g, the largest fruit was 138.2 g. The flesh was orange with medium amount of juice, fine texture and aroma. The stone adherence to flesh was free and kernel flavor was bitter. The soluble solids, titratable acidity, soluble sugar, ascorbic acid content were 13.6%, 9.4%, 1.3%, 6.4 mg·100 g^-1 , respectively. The firmness was 2.1 kg·cm^-2 . The quality was good. The fruits could be stored for about 5 to 7 days in room temperature or about 20 days under 4 ℃. In Xiongyue (122.15° E, 40.18° N) and its surrounding region of Liaoning Province, the flower buds bursted in early March, the blooming stage was early April and could last about 5 days, the fruit development period was 75 d and it matures in the end of July. The leaves fall begined in the end of Octoberand the growth phase was approximately 200 days. Guojin mainly beared fruits on the short and cluster branches. The buds burst rate was 55.7% and hadweak branching ability. It had midde resistance to bacterial perforation disease and gum flow disease, and strong cold resistance. The average yield of 4-yearold trees was 2398 kg per 666.7 m² . It could be cultivated in apricot producing areas in the south of Liaoning Province. The trees should be planted in sandy soil with pH value of 6.5-7.5 and the good drainage conditions. The planting density would be 2 m×4 m. The suitable pollinizer cultivars for it would include Kate, Sungold and Huaxianjiexing. The fruit setting rate was very high, fruit thinning should be necessary and the distance between fruits should be 15 cm.