Breeding of a new very early-ripening apricot cultivar‘Jinyu’

Abstract:‘Jinyu’is a very early-ripening, fresh apricot cultivar. The seeds were derived from the cross of‘Yuzhouhong’and‘Sungold’in 2005 at experimental field. In the summer of 2005, the hybrid seeds were treated by reference to the method of fresh seed sediment storage immediately. In the spring of 2006, the seeds were sowed routinely. In 2007, the hybrid seedlings were transplanted in a wide-nar- row row (1 m × 1 m × 2 m). The hybrid seedlings blossomed and bore fruit in 2008. In 2010, both pilot test and regional trials were conducted, and the trees had started to bear fruit in 2012. The observation and identification of 2005-yj134 was conducted for 3 consecutive years from 2012 to 2014, the fruit comprehensive characters were excellent. The tree was vigorous with semicircular crown and open tree gesture, purplish brown trunk, tan perennial branches. Annual branches were stout, the ratio of branch length to thickness was 182:1.24, internode length was 2.2 cm, the sunny side was brownish red, and nightside was tawny and smooth, lenticels was transverse and small. Petals were pale pink, 5 mostly, purplish red calyx. Leaf blade was broadly rounded, apex acute, base cordate, margin neat, obtuse. The length and width of leaves were 8.5 cm × 8.0 cm, and leaves were thick, dark green, glossy, wavy. Main veins were light green. Petiole length was 3.1 cm, purplish red. The matured fruit was ovoid, orange. The average fruit weight is 55.2 g, maximum fruit weight is 75 g. Fruit top round flat, slice meat asym- metry. The fruit ground color of fruit peel was orange, the surface was bright and clean, the appearance was beautiful. The flesh with more juice and tastes sweet was orange, had a less of fiber. The contents of soluble solid, total sugar, total acid, and vitamin C were 14.05%, 12.1%, 0.76% and 5.41 mg·100 g-1, respectively. Fruit hardness with skin was 12.6 kg·cm-2, storage-resistant. The edible rate was 96.20%. The fruit had ovoid, bitter, free nucleus. In Shijiazhuang area, the fruit ripened in late May, with 58 d of fruit growth period and 220 d of vegetative growth period. The average perfect flowering rate was 85.06%, the average natural fruit setting rate was 68.31%, germination rate was 73.74% and branching rate was 15.66%, the main fruit was in the short fruit branches and bouquet fruit branches. In general, the fruit did not crack, and there was no browning inside the fruit. Self- pollination does not bear fruit. The average yield in the fourth year after high grafting was 27 t · hm- 2.‘Jinyu’has good tolerance to cold, drought and barren, and strong adaptability. In the growing season, there were no obvious diseases on branches, leaves and fruits.‘Jinyu’was resistant to bacterial perforation disease and coke edge dis- ease, basically no early defoliation phenomenon, production management generally can not spray pre- ventive drugs. Fruits can be stored at room temperature for about 5 days, resistant to storage and trans- portation.‘Jinyu’can be cultivated in the central and southern part of Hebei province and the similar ecological conditions in north and northwest China. Self- pollination by‘Jinyu’produces no fruit, so it is necessary to paired pollinated trees. The ratio of main cultivars to pollinated cultivars was 3-4∶1. The complete flowering rate and fruit setting rate of‘Jinyu’were high, so fruit thinning work should be car- ried out as early as possible.