| To study the growth and development characteristics of no-tillage direct seeding of rape under different
seeding rates in the Dongting Lake plain, the growth stage, partly biological characteristics, grain yield components and
grain yield of no-tillage direct seeding of rape with variety of Fengyou682 (Brassica napus L. ) were investigated by
seeding rate 2.25 kg/hm2 (T1), 3.00 kg/hm2 (T2), 3.75 kg/hm2 (T3) and 4.50 kg/hm2 (T4) The results showed that the growth
process of T3 and T4 were earlier and whole growth period was shortened than that of the T1 and T2, and the whole growth
period of rape with T3 and T4 was shorten about 1-2 days than that of T1 and T2, respectively. The plant height, diameter
of opening, largest leaf length, largest leaf width, total number of leaves, number of green leaves, thickness of root crown were decreased with the seeding rate increasing，and those characteristics of T1 were higher than those of other treatments.The chlorophyll content of leaves in different parts of the rape plant was varied with different seeding rate as the order: T1〉T2〉T3〉T4 at flowering stage. And the dry weight of stem and leaf, leaf area, leaf area index decreased with the seeding rate increasing. The plant height, length of main inflorescence, effective branches of secondary branches per plant, effective pods of main inflorescence, effective pods per plant, pod number, grain yield per plant with T1 were higher than those of other treatments. There was significant difference in the rape yield for T1, T2, T3 and T4. That was, the sequence of rape yield with different seeding rates was T2〉T4〉T3〉T1. The rape yield of T2 increased by 12.9%, 8.2% and 7.2% compared with T1, T3 and T4, respectively. The results also indicated that the suitable amount of seeding application was 3.00 kg/hm2 for gaining high grain yield of rape. |
