DI Li-Chao, ZHANG Yong-Jiang, LIU Lian-Tao, SUN Hong-Chun, ZHU Xiu-Jin, LI Cun-Dong
Bt-transgenic cotton plants with two different sowing dates were treated normally (CK), or by removing one(R1), two (R2) or three basal fruiting branches(R3) to study the effects of early fruiting branch removal on growth, development and senescence processes in a two-year experiment. The results showed that the removal of early fruiting branches delayed the process of growth and development(there was no difference between R1 and CK in the total number of fruiting branches, but R2 and R3 were significantly lower than CK), but had no obvious effects on the total fruiting nodes. Early fruiting branch removal significantly increased the LAI and dry matter accumulation in plants of the first sowing date over two years(R1, R2 and R3 increased the dry matter weight on average by 13.5%, 17.5% and 19.0%, respectively, compared with CK), but there was no significant difference in plants of the second sowing date. For plants of the first sowing date, early fruiting branch removal significantly decreased the abscission and rotten boll rates and promoted seed yield over the two year period. R1, R2 and R3 decreased the abscission rate by 5.9%, 6.4% and 9.5%, respectively, and rotten boll rate by 3.8%, 3.1% and 4.3%, and the R1 and R2 treatments enhanced the seed cotton yield by 9.6% and 8.1%, respectively. There was no significant yield increase in plants of the second sowing date; there was even a decrease for some treatments.