小果型西瓜新品种‘众天红’的选育

Breeding report of a new early ripening mini-type watermelon variety ‘Zhongtianhong'

‘众天红’是由母本‘早春红玉’高代自交系26号与父本‘苏联二号’高代自交系93号杂交选育出的早熟小果型一代杂交西瓜新品种。果实高圆形,绿果皮上覆深绿色齿状条带,果皮光滑有少量果粉。果皮厚度为0.4 cm,果肉红,口感脆甜;平均单果质量1 600 g,最大单果质量2 900 g,果形指数1.05;每果实种子粒数约140粒;果实中心可溶性固形物含量12.0%,边部10%,品质好。在郑州地区（东经113.65°,北纬34.76°）春季2—6月栽培,全生育期100 d左右,雌花开放至果实成熟32 d;第一雌花开放节位为6～10节,2个雌花间隔为5～7节。抗逆性好,轻抗枯萎病。常温下货架期约2周。适合在全国各个西瓜产区栽培,以大棚等设施栽培经济效益为最好。666.7 m2产量为2 716 kg。

‘Zhongtianhong＇is a new early ripening mini-watermelon variety. It is selected by crossing inbred line No. 26 as female parent with inbred line No. 93 as male parent. No. 26 was isolated from the progeny of Japanese‘Zaochunhongyu＇and inbred for eight generations. No. 93 was derived from the cobalt-60 irradiated‘ZG-6＇and inbred for sixteen generations. The fruit is highly round in shape, marked on green surface with dark green toothed stripes. The fruit index is 1.05. A little powder is covered on the fruit surface. The rind is 0.4 cm in thickness. The flesh is red and crispy with soluble solid content of 12%in the fruit center and 10% near the rind. The average fruit weight is 1.6 kg and the largest 2.9 kg. The color of seed coat is brown. Averagely there are about 140 seeds in each fruit and the 1 000-seed-weight is about 38 g. In the protected field of Zhengzhou（113.65 degrees east longitude and 34.76 degrees north latitude）, it is cultivated from February to June in the spring. The plant growth period is about 100 days, and the fruit growth period is 32 days. In the summer, the plant growth period and fruit growth period are 75 days and 25 days, respectively. The first female flower appears on the 6th to the 10 th node, and the interval between the two neighboring female flowers ranges from 5 to 7 nodes. In order to ensure the fruit quality, the second or the third female flower is selected for fruit-setting normally. This variety shows good resistance to external stresses, such as low temperature and poor light. Importantly, it is somewhat resistant to Fusarium wilt. The fruit has a shelf life of two weeks at room temperature. This variety has wide adaptability and can be cultivated in the main domestic watermelon growing region under protection or in open field. Compared with the field cultivation, protected cultivation can bring more economic benefit. Theyield can reach up 2 715 kg per 667 m2 on average. This variety can be cultivated by means of verticalculture or creeping-culture. For vertical-culture, one or two vines can be remained. The optimum planting density for single vine is 2 200 plants per 667 m2, while the density for double vines is 1 800 plants.For creeping-culture, the optimum planting density is 800 plants per 667 m2, and two to three vines can be remained. As the mini-watermelon is small in size, the management of irrigation and fertilization is important. The water should be provided at low frequency but in sufficient amount every time from seedling stage to stretch tendril period in order to build strong root system. During flowering period, the water must be controlled strictly. Exceeded water and fertilizer is avoided during the fruit swelling period, and irrigation should be stopped one week prior to harvest. The fertilization is mainly used in base fertilizers including manure and N, P, K compound fertilizers. Additional fertilizer can be supplied with water once during the fruit swelling period.