油菜花芽分化与产量结构

FLOWER BUD DIFFERENTIATION OF RAPESEED (BRASS/CA NAPUS L.) AND ITS SEED-YIELD STRUCTURE

采用3—5个不同熟期的甘蓝型油菜品种于出苗后50天至开花前定期对各级生长锥陆续进行解剖观察,探讨油菜花芽分化的规律,以利于育种和栽培研究。甘蓝型油菜品种之间花芽分化始期可相差25天左右。弱冬性品种先分化,一般为出苗后55天至60天,它们达到花芽分化期的温度要求零度以上的总积温为850—880℃,晚熟品种需1000℃左右。油菜花芽分化的顺序为主茎生长锥—主茎腋芽—分枝腋芽。其中,主茎生长锥上的花芽,是先分化出的花芽依次居下位,随生长锥的不断生长,花芽不断分化即形成花序状;主茎腋芽分化以中部最早,上部次之,下部最晚。临花期,上部腋芽的分化强度基本属于同一水平,由它们发育成有效分枝。在8000—9000株/亩的密度条件下,有1/3分化了的腋芽能发育成有效分枝。抽苔期植株的花原基数相当于单株结角数,单株总的花原基数约半数有效。

The researches carried out by the author on flower bud differentiation of some rapeseed varieties maturing at different dates gave the following results. There was a difference of about 25 days in initiation date of flower bud differentiation among these rape varieties. The semiwinter rape varieties developed to the stage of flower bud differentiation 55—60 days after rape emergence. They required a total accumulated temperatures of 850—880℃, however the late-maturing varieties required a total accumulated temperature of about 1000℃.The differentiation sequence of flower buds was as follows: the apieaI cone of main stem differentiated flower buds first, the axillary buds of main stem second and the axillary buds of primary branches last. With the growth of apical cone, the flower bud number increased gradually and an inflorescence formed.On the axillary buds of main stem, the differentiation sequence was as follows: the axillary buds on the middle nodes differentiated flower buds first, those on the upper nodes second and those on the lower nodes last. Most axillary buds on a plant might differentiate flower buds, but only 1/3 of them might develop into effective branches under planting densities of 8000—9000 plants/mu. The number of floral primordia in the peduncle-growing period would be equal to the siliqua number/plant. Half of the total floral primordia per plant were effective.