中国常用水稻保持系及恢复系开花灌浆期耐热性评价

Thermal Resistance of Common Rice Maintainer and Restorer Lines to High Temperature Stress During Flowering and Early Grain Filling Stages

以我国常用的15个水稻保持系和26个丰产性较好的恢复系为材料,于主茎见穗当天起连续15d进行高温胁迫处理(9:00-15:00,39～43℃),研究花期高温胁迫对水稻保持系和恢复系结实特性的影响。结果表明,根据高温胁迫指数,可把水稻品种分为热钝感型、耐热型、不耐热型和热敏感型等4个类型。其中,水稻保持系K22B、博白B和V20B为热钝感型材料,Ⅱ-32B、中浙B和中9B为热敏感型材料;水稻恢复系明恢63耐热性最强,其次为R207和P929,P62-2-2、R8006和P51等耐热性最弱。进一步分析表明,高温胁迫指数与水稻在自然条件下结实率、空壳率和秕谷率之间相关不显著,但与胁迫环境下结实率和空壳率的相关性均达极显著水平。花期高温胁迫致使水稻保持系和恢复系结实率下降,空壳率大幅度上升。

Fifteen common rice maintainer lines and 26 high-yielding restorer lines were used to evaluate their thermal resistance and fertility during flowering and early grain filling stages. The rice plants were subjected to high temperature stress at 39-43℃ for 1-15 d from main stern flowering. Based on the high temperature stress index, they were divided into thermal resistant lines, semi thermal resistant lines, semi thermal sensitive lines and thermal sensitive lines. Therefore, the maintainer lines K22B, Bobai B and V20B belonged to thermal resistant lines, whereas Ⅱ -32B, Zhongzhe B and Zhong 9B to thermal sensitive lines. The rice restorer line Minghui 63 had the highest thermal resistance, followed by R207, P929, and the lowest thermal resistant P62 2-2, R8006 and P51. The correlation analysis indicated that the high temperature stress index was not significantly correlated with seed setting rate, abortive grain rate, unfilled grain rate under natural conditions, but significantly correlated with seed-setting rate and unfilled grain rate under high temperature stress. This indicated that high temperature stress occurred during flowering early grain filling stage mainly decreased the seed setting rate and significantly increased the unfilled grain rate in both rice maintainer and restorer lines.