“九二O”对株两优02制种母本茎秆性状及倒伏指数的影响

Effects of GA3 on stem characters and lodging index of female parent in seed production of combination——Zhuliangyou02

在株两优02制种母本株1S见穗15%、25%、35%、45%、60%5个时期均分别喷施"九二O"(GA3)8、12、16、20g/(667m2),研究了茎秆性状的变化及其与抗折压力、倒伏指数的关系.结果表明,对株1S喷施"九二O"后倒伏部位一般在倒四、倒三节间的下部50%以内区域;株高、地上部分鲜重和倒二、倒一节间长与倒伏指数均呈极显著正相关,倒四节和倒三节间长与抗折压力呈负相关,与倒伏指数呈一定的正相关;倒四、倒三节间茎壁厚度与抗折压力呈一定程度的正相关,与倒伏指数呈一定的负相关;倒四、倒三节间茎粗与抗折压力及倒伏指数均呈一定程度的正相关.通径分析表明,增加倒四、倒三节间茎粗及茎壁厚度对提高株1S茎秆抗折压力有较明显的正向作用.株1S系列组合制种,在母本见穗指标达35%时喷施"九二O"8g/(667m2)或见穗指标达45%时喷施"九二O"8～12g/(667m2),既能较好地改善母本异交态势,又能较好地控制稻秆倒伏.

Spraying GA3 8, 12, 16, 20 g per 667 m^2 when ZhulS has 15%, 25%, 35%, 45%, 60% hills to heading, the changes of stem characters and their relationship with the breaking resistance and lodging index were studied.The main inclusions as follows： the lodging of ZhulS usually occurs with in the fifty percent area below the middle line of the fourth or the third node after spraying GA3.The height of plant, biomass per plant, and length of the first and the second internodes were correlated to the lodging index at 1% level of significance. The internode＇s length of the fourth and the third nodes were negatively correlated to the breaking resistance and positively correlated to the lodging index at some extent; the basal internode walls of the fourth and the third nodes were positively correlated to the breaking resistance and negatively correlated to the lodging index at some extent; the culm thickness of the fourth and the third nodes were positively correlated to the breaking resistance and lodging index. The path analysis showed, it could augment the breaking resistance by increasing the culm thickness, the basal internode wall of the forth and third node. It could result in lower lodging index and better situation of female outcrossing by spraying GA3 8g per 667 m^2 when Zhul S has 35% hills to heading or 8- 12 g per 667 m^2 when 45% hills to heading.