早熟油桃新品种‘中油13号’的选育

‘CN 13', an early ripening nectarine cultivar

‘中油13号’是利用我国地方油桃资源、从国外引进油桃品种与我国水蜜桃品种等,通过人工多代杂交培育的油桃新品种。该品种果实圆形,端正,平均单果质量210 g,大果270 g以上。果皮底色白,成熟时全面着鲜红色,有光泽。果肉白色,硬度中,汁液中多,风味浓甜,皮下花色苷较多。果实汁液可溶性固形物含量(ω,下同)13.70%,总糖含量10.92%,总酸含量0.22%,品质优良。果核椭圆形,褐色,黏核。郑州地区3月下旬开花,果实6月下旬成熟,11月上中旬落叶。生长势中强,成花易,以中果枝结果为主;自花结实,丰产性好。适合秦岭、淮河以北地区栽培,其他地区需引种试验。

‘CN 13＇ comes from multi-generation crosses between Chinese landrace nectarine, introduced foreign nectarine and Chinese white peach cultivars. 94-1-47, the female parent, is a middle-season, white-flesh, freestone nectarine with middle acid. ‘CN 4＇, the pollen donation, is an early season, yellow- flesh nectarine with good flavor and keeping quality. The anthers from flowers of male parent were collected in bell stage and dried on clean paper in room. The corollas of female parent were removed in balloon stage in spring of 1999. Then, artificial pollination was followed and all the branches were bagged. Two weeks later, bags were removed. All the trees were managed as normal. In middle July, near maturing, all fruits from artificial pollination were harvested and cleaned in room. After that, the seeds were extracted under clean bench and stratified in temperature of 2-4 ℃ on 2 layer of moist filter paper in petri dishes. In December, when germinated, the seeds were potted in sterile nutrient media. The hybrid seedlings were cultured in greenhouse till transplanted to selective nursery in the next spring. In middle April of 2000, all the seedlings were planted with density of 1.0 m×4.0 m. Based on evaluation of main economic characters of fruits over 2 years, the seedling numbered ＇99-47-17＇ was picked out for its＇ big round fruit, bright color, good eating quality, and stable high yield. It was named ＇CN 13＇ in 2014 and licensed in 2016. The matured fruit is round and most of the white background covered by shining red. The fruit flesh is white, melting, juicy, which tasted sweet. Anthocyanin below skin is middle. The contents of soluble solid, total sugar and total acid in flesh juicy are 13.70%, 10.92% and 0.22%, respectively. The eating quality is very good. The stone is oval, brown and cling to the flesh. The flower is showy and the anther is dark red with much pollen. It is fertile and very fruitful. In Zhengzhou, middle China, the first flower of ＇CN 13＇ comes into bloom mostly appears in late March and the flowering period can last 5-7 days. The fruit matures in late June, about 90 days after blooming. The tree is middle vigorous and semi-opening in canopy. The sprout-ing and branching ability are moderate. The new branches are green and dark-red on sunny side. The aver- age internode length is about 1.97 cm. The leaf is green and lanceolate in shape with 2-4 reniform glands along the petiole. The flower is pink, showy with 5 petals. The tree of ＇CN 13＇ is middle or strong vigorous. The flower buds normally appear from the 1^st-3^rd internode, even in the first year after planted. ＇CN 13＇ has strong early fruit ability. The yield of 3-years-old tree in middle density could reach over 22.5 tons per hm2. The middle length flower branches are suggested to leave for fruit. ＇CN 13＇ is fertile, so it is not nec- essary to bring in pollen donation. Previous testing is distributed mainly in the north China, more tests need to be done in south China. According to the soil fertile and local rainfall, select a suitable planting density. The V-shaping or quad-V shaping are recommended for the north and the south separately. For poor soil, base fertilizer is necessary before planted. In the beginning two years of planted, the shape prun- ing is the first priority so as to build a strong and manageable tree architecture. In full fruit period, stabilize the growth vigor in middle level through fertilizer and yield control. For the canopy, good light penetration is very important for the flower bud formation and fruit quality, so summer pruning must be done routinely to keep it free from water branch and let the lower and inner shoots get enough sun shine.