Breeding report of a new tangerine cultivar ‘Axiang No.2'

Abstract: ‘Axiang No.2'is a new tangerine cultivar selected from bud mutation of Nanfeng Tangerine.It was initially selected in 2005 for its good slagging property and early ripening time. The variation maternal plant was discovered in an orchard of Nanfeng Tangerine which was plantedin Lean town, Ahua county. Through grafting, planting of‘Axiang No.2'was expanded in 2006. And the DUS testing finished in 2015. Finally, new variety of tangerine was registered in 2018 after several years' selection.This cultivar is vigorous with semicircular crown and upright tree gesture. The branches of adult fruiting tree are thinner and more. Leaves are long elliptic or narrow lanceolate, 5-7 cm long, 2.5-4.0 cm wide; leaf surface is dark green and back is new green; the main leaf vein is thick; the leaf margin is shallow ripple, leaf tip is notched and base is wedge; the petiole is 1-2 cm long, 0.15-0.2 cm wide; this cultivar has linear winged leaves. Flowers are small, solitary and white; this cultivar has 5 petals which are tongue-shaped and new green; the stigma is cylindrical; the ovary is barrel-shaped and green. The endosperm is light green. The fruit is mainly small, oblate, has orange or orange-yellow peel and bright ware surface. Its flesh is very flavorful and slagging. The fruit weight is 25-45 g, longitudinal diameter is 3.5-4.2 cm, transverse diameter is 4.8-5.6 cm, fruit shape index is 0.65-0.75; and it is seedless (0-2 seeds) . The content of soluble solid is 11.8%-13.2%, the content of titratable acid is 0.42%-0.68%, per100 mL of fruit juice, containing vitamin C is 28.41-37.68 mg. Quality is excellent. The fruit ripens from early November to mid November in Anhua, Hunan Province. It is resistant to drought and cold.The SSR molecular markers were used to identify‘Axiang No.2'. The results showed that‘Axiang No.2'and Nanfeng Tangerine had different DNA levels. It is the genetics basis to become a new cultivar, which is stable variation. It is suitable for cultivation in wide-skinned citrus growing areas in Hunan Province.This cultivar has high and stable yield. The yield of fruit-bearing period can reach above 37500 kg·hm^-2. Orchard should choose neutral sandy soil which is flat and has ability of moisture and fertilizer retention; Virus-free seedlings were planted with row spacing of 3 m × (3-5) m and 667-111 plants per hectare; For young trees, fertilization should before every shooting duration, for adult trees, fertilization depends on the growth of tree potential and the amount of fruit, focusing on winter base fertilizer and strong fruit fertilizer. We should strictly monitor the occurrence and spread of quarantine pests and diseases, and strengthen the comprehensive control of pests and diseases, especially citrus HLB.