Studies On Key Technique Of Increasing Crossbreed Seed Quality And Yield Of Bare Kernel Pumpkin

Bare kernel pumpkin has kernel but no shell, It is rare in nature. Its kernel is controlled by a pair of recessive genes, and the seed hasn't shell when this pair of gene serves as the recessive homogeneity. Because of the convenience and enriched nutrition, It is received warm welcome both at home and abroad and has prosperous market foreground.This experiment was performed from 3,2003 to 6,2004 at the bare kernel pumpkin hybridization base of Jiuquan fanning and forestry science and technology school of Suzhou, Jiuquan, Gansu. Through field experiment, the reasons that the lower purity of female parent and male sterility, and the influences of temperature and density on the level of male sterility and the effects of different medicaments preventing and curing models on powdery mildew in bare kernel pumpkin systems was observed. It can provide theory basis for the improvement of seed quality and yield of bare kernel pumpkin hybridization. The main results as follows:1. The purity of female parent is not high (purity < 95%= chiefly because of the inadequate purification generations during inbreeding seed selection, which leads to the instability of main properties, and the unconformity of genotype. It is suggested to cultivate the self-mating system of high purity as quickly as possible by adding purification generations and shortening the time of female parent purification, et al. The yield of the cenospecies propagated by the female parent which purity is 95% and used to produce his commercial seeds is lower than cogenetic female parent.). The problem of purity < 95%= cenospecies still need to be explored further.2. Contrasting male parents of big melon of different year and region and seeding time with that of small melon of bare kernel pumpkin, It Is considered that the female flower can normally bloom after male flower of the later flowered 4-9 days that male flower was sterile and It Is a kind of physiology genetic characteristic.3.Planting density has influences on the level of male sterility of small melon. The bigger of the Planting density, the longer of the male sterility time and the more of the invalid male flowers on per plant. The sterile male flowers go through 11 days when the density was 25cm X 90cm, were longer 1 and 2 days than that when density were 35cm×90cm and 40cm×90cm respectively. The mean sterile male flowers on per plant of 25cm row spacing are 8.7cm, more 1.3cm and 2.2cm than that of 35cm and 40cm respectively. The ideal density is served as 40cm×90cm.4.The higher of the temperature from the male parent sowed to flower, the shorter of the time of invalid male flowers flowering.5.Through the powdery mildew preventing and curing model contrast, two models that was considered as excellent were selected out: Lime sulfur + high aliphatic film or using Lime sulfur of different density independently in fixed time, quantity and ordering spurts. They are worth to spread and apply in cross-bred seed production of bare benevolence pumpkin.