Studies On Seed Producing Technology And Evaluation Of Seed Quality In Cucumber 'Jihuanggua No.1'

To find an effective way in producing high quality and yield seeds of cucumber 'Jihuanggua No.1',a series of experiments were proceeded in the experimental field of Jiyuan Agricultural Scientific Research Institute from March 2006 to September 2008. Influence of different sowing times,planting densities,fertilizer components and chemical castration on the seeds qualities of inbred line 'J11',the parent of 'Jihuanggua No.1',was studied.The main results are list below.1.Sowing time showed significant influence on the seed yield of 'Jihuanggua No.1'.The best sowing time in the North Henan Province should be at the end of March.The fruit number per unit area,seed number and seed yield were significantly higher than in other treatments.Seed thousand-grain weight was significantly higher than other treatments, except the treatment sowing at middle of March.No significant influence of sowing time on vigor of germination,germinating capacity and conductivity were found.2.Planting densities significantly influenced the seed yield of 'Jihuanggua No.1'.The feasible density should be at 82 500 plant per hm².Seed yield was significantly higher than other treatments except the density of 75 000 plant per hm².In a specific density range, fruit number showed a positive correlation with planting density,but seed thousand-grain showed a negative one.3.Fertilization also significantly influenced the seed yield of 'Jihuanggua No.1'.The best seed yield,720.01 kg per hm²,when fertilized with an N,P,K component ratio of 2:2:2 (N240kg·hm^-2 + P180kg·hm^-2 + K280 kg·hm^-2),was 52.67 percent higher than the none-fertilization treatment.The fruit numbers per unit area and leaf areas showed positive correlations with K and N fertilizer ratios,respectively.No significant influence of fertilization on vigor of germination,germinating capacity and conductivity were observed.4.The net photosynthesis rates(Pn) of functional leaves were significantly influenced by fertilizaitons.The highest Pn,18.72μmol·m^-2·s^-1,when fertilized with an N,P,K component ratio of 3:2:2(N360kg·hm^-2 + P180kg·hm^-2+K280 kg·hm^-2),was significantly higher than any other treatment and 85.71 percent higher than the none-fertilization treatment.The N contents accounted for most of the Pn changes.5.Chemical castration using ethephon was also studied.The best combination was 4 times treatment with 400mg·kg^-1 ethephon when the seedling had two leaves.Considering the restraining effect of ethephon on plant growth,4 times treatment with 300mg·kg^-1 ethephon when the seedling had one leaf or 4 times treatment with 300mg·kg^-1 ethephon when the seedling had two leaves also could have reasonable effects.6.Seed producing of cucumber 'Jihuanggua No.1' in mountainous area when the previous crop was cabbage,combining with chemical castration using ethephon,had a seed yield of 533.60 kg·hm^-2.And it showed higher seed yield and better seed qualities than in plain.7.A technical specification on seed production of cucumber 'Jihuanggua No.1' in spring and summer was consequently established.It will offer an effective technical support for cucumber seed productions.