水稻近等基因导入系芽期抗旱性鉴定及抗旱指标筛选

Drought Resistance Identification and Index Screening of Rice Near-Isogenic Introgression Lines at Germinating Stage

为筛选水稻抗旱性鉴定指标并科学鉴定水稻抗旱性,本研究以蒸馏水为对照,采用质量体积比为5%、10%、15%、20%的PEG-6000溶液处理6份川香29B近等基因导入系进行芽期抗旱鉴定,研究模拟干旱对水稻育种材料芽期种子萌发的影响,并探讨芽期抗旱性鉴定指标及筛选抗旱材料。结果表明,轻度水分胁迫对种子发芽抑制作用较小,部分材料表现出促进效应;重度水分胁迫对种子发芽抑制作用明显;对发芽势抑制作用强于发芽率,根长、根干重、剩余种子干重、根芽比在水分胁迫下表现出增长效应,水分胁迫对种子萌发过程中芽的抑制作用强于根,并阻碍了物质的转运利用。相关性分析表明,储藏物质转化率抗旱系数与发芽指数抗旱系数等8个指标呈显著或极显著相关,总体而言,芽长抗旱系数与其他指标抗旱系数相关性强于根长抗旱系数。应用隶属函数法进行抗旱性综合评价,5818(川香29B/ASOMINORI//29B///29B)、川香29B、5819(川香29B/ASOMINDRI//29B///29B)(分别记作C2、C6、C3)综合D值排前三名,综合评价抗旱性较强。在20%PEG-6000溶液处理下,将D值与各指标抗旱系数进行相关性分析,活力指数抗旱系数、根长抗旱系数、储藏物质转化率抗旱系数与D值相关系数分别为0.84、0.78、0.85。综上,储藏物质转化率抗旱系数、活力指数抗旱系数与多数指标抗旱系数显著相关,且与D值显著正相关,储藏物质转化率可作为芽期抗旱性鉴定一级指标,活力指数和D值可作为鉴定二级指标,应用于水稻材料、品种等于芽期进行快速、准确抗旱性鉴定。应用隶属函数法筛选得到抗旱性较强的材料为C2、C6、C3,可进一步应用于抗旱育种,以选育抗旱性品种,并进一步开展抗旱研究。

In order to select drought resistance indexes and scientifically identify drought resistance of rice,6 isolates of Chuanxiang 29 B near-isogenic introgression lines(NIILs)were treated with PEG-6000 solutions with a mass-volume ratio of 5%,10%,15%and 20%for identification of drought resistance at the germination stage,respectively,using distilled water as the control.The effects of simulated drought conditions on germination of rice breeding materials were studied meanwhile,the drought resistance indexes of germination were analyzed,and drought resistance of materials were also screened.The results showed that mild water stress had little inhibitory effect on rice seed germination,but promoted the germination in some lines compared with the control.However,severe water stress significantly inhibited rice seed germination,and in particular,the inhibition of germination potential was stronger than that of germination rate.Root length,root dry weight,residual seed dry weight and root-shoot ratio showed positive response to water stress,which indicated that water stress had a stronger inhibitory effect on buds than roots during seed germination,and hindered the transport and utilization of substances.The correlation analysis showed that there was a significant or extremely significant correlation between the storage material conversion rate drought coefficient and 8 other indexes including germination index drought coefficient while the bud length drought coefficient had stronger correlation with other indexes compared with the root length.In the comprehensive evaluation of drought resistance using the membership function method,the comprehensive D values of 5818(Chuanxiang 29 B/ASOMINORD//29 B///29 B)、Chuanxiang 29 B、5819(Chuanxiang 29 B/ASOMINORI///29 B///29 B)(mark as C2,C6 and C3 ranked top.Under the treatment of 20%PEG-6000 solution,the correlation analysis between D value and drought coefficient of each index showed correlation coefficients of vitality index drought coefficient,root length drought coefficient,storage material conversion rate drought coefficient with D value were 0.84,0.78 and 0.85,respectively.In conclusion,the storage material conversion rate drought coefficient and vitality index drought coefficient were significantly correlated with most of the indexes,and significantly positively correlated with D value.Therefore,the storage material conversion rate drought coefficient could be used as the first-class index for drought resistance identification at the germination stage,while vitality index drought coefficient and D value could be secondary indexes.These indexes could be used for rapid and accurate identification of drought resistance of rice materials and varieties at germination stage.C2,C6 and C3 with strong drought resistance were selected by the membership function method,which could be further applied in drought-resistant rice breeding,to select drought-resistant varieties and carry out drought resistance research further.