A new very early- ripening of distant hybridization between plum and apricot cultivar ‘Longyuanhong’

Abstract：‘Longyuanhong’is a very early ripening plumcot variety with excellent appearance. The seeding was derived from a cross between‘Dashi Early’Plum (Prunus salicina Lindl.) and‘Zhanggongyuan’apricot (P. armeniaca L.) in 2002 at the experimental field. Four hybrid fruits were harvest-ed when the fruit was ripe, and the hybrid seedlings were obtained by embryo rescue method. Test tube seedlings were cultured by proliferation, rooting, domestication and transplanting in greenhouse cultiva-tion. Finally, 58 seedlings of 1 embryo were survived (code name 02-9-3). After regional adaptability testing at four sites (including Jiayuguan, Jingtai, Yuzhong and Qin’an) from 2013 to 2018. The results showed that:‘Longyuanhong’fruit displays large, beautiful appearance, sour and sweet moderate fla-vor and very early ripening. The tree displays stable character, strong cold resistance, high disease resis-tance and strong environmental adaptability. Therefore, it was named‘Longyuanhong’in 2018. The tree pose is semi-open form. Trunk and perennial main branches are dark brown, annual branches are green. The leaf blade shape is elliptic, young leaf color is red, mature leaf is dark green, the back of the leaf is glabrous, leaf blade length is 8.67-9.98 cm and width is 5.37-6.24 cm, both of the leaf blade size and shape are between apricot and plum. There is 4-8 leaf glands which are round, large and the color are green yellow. The corolla shape is suborbicular or elliptic, corolla size is 2.58-2.62 cm, the petals is 0.96 cm wide and 1.19 cm long, the initial color at flowering period is white or light pink and turn pink or deep pink with blooming. The fruit shape is round, pericarp color is green-yellow with more than 50% red on the fruit surface covered with sparse short hairs. The flesh color is yellow, the juice is very little at the beginning of ripening, after 3-5 days storage time the fruit is juicy. The flavor is moderate  sweet and sour, which with both apricot and plum flavor. The average fruit weight is 80.0 g, maximum fruit mass is 164.2 g. The content of soluble solids is 12.5%-14.5%, soluble sugar is 7.52%, titratable ac-id is 1.69%, vitamin C is 40.0 mg · kg-1, and the fruit hardness is 6.35 kg · cm-2. The content of soluble solids can reach 16.0%, which is the best fresh food period.‘Longyuanhong’sprouted in late March and blossomed in early April in Lanzhou, Gansu Province, and the fruit matured in late June, fruit devel-opment period is 79 d. Annual vegetative growth period is 224 d. The flowering period of‘Longyuan-hong’was later than female parent‘Zhanggongyuan’2 d, earlier than male parent‘Dashi Early’Plum 3-5 d. The mature period of the fruit was about 3 d earlier than‘Dashi Early’plum, about 10 d earlier than‘Zhanggongyuan’. Except that the fruit matures earlier than both parents. Other properties charac-ters are between the parents. The germination and flowering period can withstand -4 - -3 ℃ low temper-ature, the soil requirements are not strict, which can adapt the place can be planted plum and apricot.The gumming disease resistance is comparable to control varieties‘Gold queen’, and the anti-bacterial perforation disease is higher than‘Gold queen’. The fruit storage period is long, cold storage life is 1 months and shelf life is over 7 d. The fruit aroma is getting strong as the storage time increases. Suitable cultivation area is including most areas of Gansu, 4-year-old grafting trees generally can hang fruit and 7-year-old trees enter the fruiting period. The adaptation of‘Longyuanhong’is strong, both the slope and flat land can be planted. The high quality and strong annual seedlings apricots can be selected as rootstock. The planting density is generally (3.0-4.0) m × (4.0-5.0) m, 33-56 plants were planted pre 666.7 m². Pollinated trees can select Gold queen,‘Zhanggongyuan’,‘Li Guangxing’or other plum va-rieties. The ratio of‘Longyuanhong’and pollination tree is 4-5 : 1.