Effects Of Planting Date, Training Type And Pollination Times On Seeds Yield And Quality In Carrots (Daucus Carota L)

The Effects of planting date, type of training and pollination times on seed yield and quality in carrots were studied in this paper. Also the growth and development of steckling, the yield and quality of seeds from primary umbel and secondary umbel, different position of seed disc at different planting date were compared. The results could be concluded as follows:1 The planting date was the most important factor affecting seed yield of carrot, which did not only influence seed yield per plant significantly but also affected seed germination percent and POD activity significantly. Among three planting dates, February 15 was the best planting date for getting maximum yield per plant, 1000 seed weight, germination percent, germination energy and POD activity-, but March 6 was reverse, and the seed yield, 1000 seed weight and POD activity were all decreased markedly.2 Type of training had effects on seed yield and quality. The seed yields and quality were different due to different training types. Maximum seed yield was obtained when using the training type of 0(first)+8(secondary), while the 1000 seed weight and POD activity were the lowest . Seed had the lowest yield when using the training type of 0(first)+6(secondary), while the weight of 1000 seed, germination percent and germination energy were the highest. When using the training type of "1+3", the seed yield was between "0+8" and "0+6". The 1000 seed weight and germination percent had no significant difference between "0+6" and "l(first)+3(secondary)", but the seeds had the highest POD activity when using the training type of "1+3".3 The effect of pollination times on seed yield and quality was the lowest. Pollination imes had no significant effect on seed yield, 1000 seed weight, germination percent andgermination energy, but had significant effects on seed mean length of incubation time and germination peak value, the seed had the shortest mean length of incubation time and germination peak value when pollinated at 1d interval. Conversely the seeds had the longest mean length of incubation time and germination peak value when pollinated every day.4 The planting date had effects on yield and quality of carrot seeds from different seed umbels and poisons of seed disc, also had effects on the growth and development of carrot steckling. Planting earlier(on January 26 and February 15), the seed yield of primary washigher than that planting latter(on March 6). The 1000 seed weight of primary was higher than that of secondary at different planting dale, and the difference of them was decreased when planting on February 15. The contribution of different umbel layer (outer layer, middle layer and inner layer ) to the seed yield were the outer layer, middle layer and inner layer in turns. The germination percent, germination energy and POD activity of seed from the outer layer were higher than that from middle and inner layer. Planting larter(on March 6), the days from planting to beginning blooming and to mature period were shortened. But the mature period of seed when planting on February 15 was still earlier than that when planting on March 6.