| In this study,a widely used in production and water-saving rice variety Hanyou 73 was used as a control,Y Liangyou 1,Liangyou 336,Xiangwanxian 13,and four two-line hybrid rice combinations(6WSH1136/Yuehesimiao,764S/R412,N111S/X7H004,N111S/X7H008)were used as materials.PEG-6000 was used to simulate the drought environment in the germination period of the tested varieties.The drought resistance of varieties was evaluated by analyzing the difference of drought resistance among different characters at germination stage.At the same time,greenhouse pot culture was used to treat the varieties from the whole growth stage,booting stage,full heading stage and milk stage.The effects of drought treatment in different periods on yield traits,rice quality and Starch RVA characteristics of the tested varieties were analyzed,and the drought resistance of the varieties was evaluated comprehensively.It provides a reference for screening and breeding water-saving and drought resistant rice varieties.The main results are as follows:(1)Using 15% PEG-6000 to simulate drought stress environment,9 growth indexes of8 rice varieties were analyzed.The results showed that there was a significant positive correlation between the fresh weight of buds and the dry weight of buds,a significant negative correlation with the ratio of root to shoot and a very significant positive correlation between the fresh weight of roots and the dry weight of roots,a significant negative correlation between the dry weight of buds and the ratio of root to shoot and a very significant positive correlation between the dry weight of roots and the ratio of root to shoot and a very significant positive correlation between the dry weight of roots and the germination rate,a very significant positive correlation between the dry weight of roots and the germination index,and a very significant positive correlation between the germination index and the germination rate.The comprehensive index of drought resistance was calculated by principal component analysis and subordinate function method.The drought resistance at germination stage rank of tested varieties was N111S/X7H018 >N111S/X7H004 > Hanyou 73 > Xiangwanxian 13 > 6WSH1136/Yuehesimiao > 764S/R412> Liangyou 336 > Y Liangyou 1.Two indexes,root dry weight and germination rate,were selected as drought resistance identification indexes of rice seeds at germination stage.(2)By using pot culture in greenhouse,8 rice varieties were subjected to drought stress from four different periods,and the effects of drought stress on yield traits were analyzed.The results of variance analysis showed that there were significant differences in total grains per panicle,seed setting rate,1000 grain weight and theoretical yield per hole among different treatments,and there were also significant differences among varieties and treatments of seed setting rate and 1000 grain weight.Seed setting rate,1000 grain weight and theoretical yield per hole of the tested varieties would be significantly reduced as long as drought stress was applied at milk ripening stage;and the longer the drought stress was,the greater the effect on seed setting rate and theoretical yield of single hole.Drought resistance index represents the drought resistance ability of varieties and the drought resistance index of tested varieties ranked as N111S/X7H004 > Hanyou 73 > 6WSH1136/Yuehesimiao >Liangyou 336 > N111S/X7H018 > 764S/R412 > Y Liangyou 1 > Xiangwanxian 13.(3)By using pot culture in greenhouse,6 rice varieties were subjected to drought stress from four different periods,and the effects of drought stress on rice quality traits and Starch RVA characteristics were analyzed.The results of variance analysis showed that there were significant differences in brown rice rate,milled rice rate,head rice rate,rice grain length,length width ratio,chalkiness degree,chalky grain rate,gel consistency,amylose content,peak viscosity,hot viscosity,breakdown,final viscosity,setback,gelatinization temperature and consistency among different treatments;and there were significant differences in head rice rate,grain length,grain width,length width ratio,chalkiness degree,chalky grain rate,gel consistency,peak viscosity,hot viscosity,breakdown,final viscosity,setback,peak time,gelatinization temperature and consistency among varieties and treatments.The Milling quality and amylose content of the tested varieties would be significantly reduced,and the chalkiness and chalky grain rate of the tested varieties would be significantly increased as long as drought stress occurred at the milk stage.The effect of drought stress at other stages on rice quality traits was not significant compared with that at milk stage.Principal component analysis and subordinate function method were used to calculate the comprehensive indexes of rice quality traits under drought stress at milk stage.Analysis shows that the drought resistance of rice quality traits of all tested varieties from milk stage was 6WSH1136/Yuehesimiao > 764S/R412 > Hanyou 73 > N111S/X7H004 >N111S/X7H018 > Liangyou 336... |
PDF Full Text Request