Effects Of Environmental And Genetic Factors On Starch Properties Of Rils On Rice

Starch as the most important component in rice endosperm.Its species,content and molecular structure are closely related to rice quality traits.Starch properties are not only regulated by genetic factors such as characteristics of Indica and Japonica rice,but also closely related to environmental conditions.So far,there have been few studies on the interaction effects between genetic and environmental factors.In this study,the F10 generation inbred line population after indica rice cultivar Shennong 265 and japonica rice variety Luhui 99 is selected as experimental material.We also explore the effects of genetic background and environmental factors on starch properties,map QTLs that regulate starch properties in different environments,explore the differences in starch synthase genotypes,and analyse the relationship between starch properties,Fi and other quality traits and taste quality in four typical rice-growing areas of China.The main results are as follows:1.Apparent amylose(AAC),long-branched amylopectin(Fb3)and resistant starch(RS)are showed as Shenyang>Sichuan>Shenzhen>Jiangsu,while short-chain amylopectin(Fa)content is Shenyang<Sichuan< Shenzhen <Jiangsu,the higher the content of AAC,Fb3 and RS,the lower the content of Fa.The starch characteristics are significantly correlate with most environmental factors.The contents of AAC,Fb3 and RS are positively correlate with the illumination time,day and night temperature difference,nighttime temperature,and negatively correlate with the daily average temperature,daytime temperature,nighttime temperature,relative humidity of the air and nighttime humidity.The content of Fa is negatively correlate with the illumination time,day and night temperature difference,nighttime temperature,and positively correlate with daily average temperature,daytime temperature,nighttime temperature,air relative humidity,and nighttime humidity.2.In the content of AAC and Fb3 in Shenyang,Pre-japonica > Intermediate > Pre-indica type,In the content of Fa,Pre-indica > Pre-japonica,intermediate type,In the content of RS,Pre-japonica,intermediate >Pre-indica type;In the content of Fa in Jiangsu area,intermediate > Pre-japonica > Pre-indica type,In the content of RS,Pre-indica > Pre-japonica,intermediate type.Under the Indica-Japonica properties,the difference in starch properties don't reach a significant level in Sichuan and Shenzhen area.3.Under the four environmental conditions,the QTLs of three AACs are identified and distributed on chromosomes 1,4 and 7,with a contribution rate of 11.58% to 15.55%.The QTLs of three Fa are located on chromosomes 4,6,and 7,with a contribution rate of 5.92% to 8.18%;the QTLs of six Fb3 are located on chromosomes 1,3,4,5 and 6,with a contribution rate of 0.96% to 22.23%;the three QTLs control resistant starches,the contribution rate is 6.39%-12.68%.No sites are found in all four environments.4.The three important starch synthase genotypes are SBE3,SSIIIa and UGP1 involved in this study.Among them,SBE3 and UGP1 don't reach significant levels,SSIIIa shows Pre-indica > Pre-japonica type,and the intermediate type is unobvious.The three starch synthase genotypes show a significant differences with the starch characteristics of rice based on the characteristics of the parent starch.Among which the SBE3 and UGP1 genotypes don't reach significant levels,but the SSIIIa genotype,intermediate mixed content of AAC and Fb3 are significantly higher than the parents.The Fa content is significantly lower than the parent.5.The content of AAC is significantly positively correlate with chalkiness and grain width,and extremely significantly negatively correlate with crude protein,and negatively correlate with taste value.The content of Fa is significantly negatively correlate with chalkiness,grain width and gel consistency,extremely significantly positively correlate with grain length-width ratio and alkali elimination and negatively correlate with viscosity and equilibrium.The content of Fb3 and RS are extremely significantly positively correlate with chalkiness,grain width and gel consistency,extremely significantly negative with grain length-width ratio and alkali elimination,and positively correlate with equilibrium.The correlation between starch properties and grain length,alkali elimination in Jiangsu is significant.The correlation between starch properties and taste quality in Shenyang and Sichuan reach extremely significant levels.The correlation between starch properties and viscosity and hardness/viscosity ratio in Jiangsu is significant.6.The Fi shows a significant positive correlation with the brown rice rate in Jiangsu and Shenzhen,and a significant negative correlation with the polished rice rate.The correlation with the whole polished rice rate and grain width shows a extremely significant negative correlation in all four regions.shows a extremely significant positive correlation with chalkiness,grain length and grain length-width ratio in Jiangsu,Sichuan and Shenzhen,only shows a positively correlation with crude protein in Jiangsu,shows a significantly negatively correlation with appearance,balance and taste,shows a significantly positively correlation with hardness in Jiangsu and Sichuan,shows a negatively correlation with viscosity in four regions.Finally shows a significantly positively correlation with hardness/viscosity ratio in Sichuan and Shenzhen.