胡蘿蔔疏花對種子生產之影響

Effect of Umbel Thinning on Seed Production of Carrot

1.胡蘿蔔放任不疏花，種子產量雖多，大小不一，形質甚差，又花期甚長，管理不便，種子收穫後調理，諸多困難。2.疏花後，可促使抽苔吐蕾整齊，花輪大小一致，花期縮短，種子成熟期提早20～30天。3.疏花後，可增加種子整齊度及千粒種子重量，以及收穫後種子調理上之便利，但單株種子產量減少，為其缺點。4.一輪、三輪疏花處理，過份抑制植株生長發育，影響種子產量甚大，不合實用。五輪、七輪、九輪、十一輪疏花處理，對種子產量減少有限，但種子整齊度增加，千粒種子重量均比對照區增加50%以上。5.在本試驗中，適當密植時，可自然抑制第三、四次分枝之發生，及種子成熟時，免去倒伏之現象。

In seed production, carrot (Variety 黑田五寸) plant grown on rich soil without umbel thinning usually produce more than 300 umbels per plant. Though seed yield was higher, and the flowering period was prolonged, but the size and appearance of seeds were variable. Therefor cause difficulties in both field management and handling of seeds after harvest. This paper reports of umbel thining on seed yield and qualities. It was found that with proper thinning, that was 5, 7, 9, or 11 flowering branches were left on each plant, seeds matured 20~30 days earlier, the weight of one thousand seeds was heavier and the seeds were better in appearance. It was also found that close planting also prevented the formation of third and fourth branches and hence less lodging.