不同海拔产生的水稻F_(2)群体孕穗期耐冷性遗传相关性分析

Genetic Correlation Analysis of Cold Tolerance at Booting Stage in Rice F_(2)Populations Generated at Different Altitudes

【目的】研究海拔引起的环境温度变化对籼、粳稻细胞质背景下的F_(1)配子基因型选择效应及其对后代分离群体孕穗期耐冷性遗传相关性的影响,以期为水稻耐冷育种提供参考。【方法】以耐冷性极强的粳稻老品种小麻谷和具有籼稻细胞质背景的改良粳稻品种南34为亲本,将在3个海拔条件下产生的正、反交杂合体F_(2)群体种植于海拔2200 m,对其生物学性状间的相关性进行比较分析,并在此基础上对孕穗期耐冷性主要指标小穗育性进行回归分析和通径分析。【结果】产生F_(2)群体的海拔与其各性状间的相关性具有明显效应,该效应受到籼、粳细胞质背景的影响。所有F_(2)群体中实粒数和总粒数对小穗育性都有明显的贡献度,其中实粒数为正向贡献且贡献度最大,总粒数为负向贡献,株高、主穗长和着粒密度等要素也在不同的F_(2)群体中表现出一定的贡献值。【结论】海拔对水稻F_(2)群体孕穗期耐冷性遗传选择具有明显的影响。在水稻耐冷性育种中可选择耐冷性强的亲本进行杂交,将F_(1)杂合体种植于海拔或温度差异较大的不同环境条件下,再将其分离群体种植于低温条件下进行筛选,即能够选择到耐冷性更强的单株。

[Purpose]To study the selection effects of environmental temperature change caused by altitude on F_(1) gamete genotype under the cytoplasmic background of indica and japonica rice and its effects on genetic selection of cold tolerance at booting stage in segregation population,providing reference for rice cold tolerant breeding.[Methods]The correlation of biological characters were analyzed in F_(2)populations generated from reciprocal hybrids at three different altitudes planted at 2200 m altitude.The material parents were Xiaomagu,japonica rice landrace that had strong cold tolerance,and Nan 34,an improved japonica variety that cytoplasm donated by indica rice.On this basis,regression analysis and path analysis were conducted on spikelet fertility,which was a main index of cold tolerance at booting stage.[Results]The altitude of the F_(2)population had a significant effect on the correlation among the traits in the F_(2)population,and this effect was affected by the cytoplasmic background of indica and japonica.The number of filled grains and the total number of grains in all F_(2)populations had a significant contribution to spikelet fertility,among which the number of filled grains had a positive contribution and the contribution was the largest,and the total number of grains had a negative contribution.Factors such as plant height,panicle length and grain density also showed certain contribution values in different F_(2)populations.[Conclusion]F_(2)-generated altitude and cytoplasmic background have obviously effects on genetic selection of cold tolerance at booting stage of F_(2)population in rice.In rice cold tolerance breeding,parents with strong cold tolerance can be selected for hybridization.The F_(1) hybrids are planted under different environmental conditions with large altitude or temperature differences,and then the segregating populations are planted under low temperature conditions for screening.