Screening Determination Methods Of Rice Plumule Ratio And Study On Related Characteristics Of Embryo Soft Rice

Rice nutrition is closely related to human health.With the improvement of people’s living standard,the development of rice has changed from quantity type to quality type.For consumers,rice quality includes both taste and nutrition.Rice taste is mainly determined by amylose content,soft rice with low amylose content tend to has good palatability,but the differences in taste between strains and the related formation mechanism are still worth comparing further in order to select the optimal strain.From the point of nutrition,germ-remained rice greatly improving the rice nutrition because it retains nutrient-rich embryo,so the selection for germ-remained rice become a direction of functional rice breeding,but in breeding practice,the determination of plumule ratio,the plumule ratio influence factors,the analysis of the causes of leaving embryo,the stability of germ-remained rice,and the regulation direction of germ-remained rice problems yet to be further clarified.Therefore,this study selects japonica rice varieties（or strains）that participated in regional trials in Liaoning province and the new material--embryo soft rice,which research group selected that combine with germ-remained rice and soft rice as material,aiming at the above problems are unclear start research,and draw the following conclusions:1.Semi-embryo method is the best method for determining of plumule ratio,this method not only has strong discrimination ability,but also saves time and effort.2.The plumule ratio is positively correlated with the grain thickness and negatively correlated with the aspect ratio.However,only the grain width is significantly negatively correlate with the plumule ratio among the embryo soft rice strains.The others grain shape traits have nothing to do with the plumule ratio,and it is speculated that the plumule ratio may be mainly controlled by genetic factors.3.The protein content of the embryo soft rice is about 8%,and that of other varieties is about 6%,the nutritive composition of the embryo soft rice is significantly higher than that of other japonica rice.4.The embryo structure and embryo shape of embryo soft rice and non-germ-remained rice exist significant difference,embryo soft rice compared with non-germ-remained rice,the ratio of germ inward growth depth and outward growth range of embryo soft rice is bigger（inside range of embryo/outside range of embryo）.The embryo morphology of embryo soft rice has a round shape,and embedded deeper in endosperm.The embryo length is negatively correlated with the plumule ratio,and the embryo width and embryo depth are positively correlated with the plumule ratio.There is a significant negative correlation between embryo length and plumule ratio in embryo soft rice strains.5.Yangengruanyu 1 of embryo soft rice new variety that nutritional quality and taste quality are greatly influenced by region,but almost keep the rule that 80%plumule ratio,protein content is higher,apparent amylose content is lower,Yangengruanyu 1 taste quality is still superior to Shendao 6 even planting in the other area,above all,Yangengruanyu 1 has regional stability.There is an opposite interaction between variety and environment on RVA spectrum.The plumule ratio is controlled by genetic and environmental factors,and the interannual stability is good.6.The superior grain width and grain thickness of the embryo soft rice increased,and the two traits have negative and positive effect on the plumule ratio of the embryo soft rice,therefore,there is no regularity in the effect on the plumule ratio.There are no significant difference in the Fa’s distribution rate that the short branch of amylopectin（5≤DP≤12）and the protein content between the superior and inferior grains of embryo soft rice.The apparent amylose content of superior grain is lower than that of inferior grain,and the distribution rate of Fb₃（37≤DP≤58）is higher than that of superior grain.The whole texture characteristics of the embryo soft rice are expressed as superior grain’s elasticity,guminess,balance is greater than that of inferior grain,the elastic force is smaller than the inferior grain,and other texture characteristics are not regular.Apparent amylose content was negatively correlated with tack force,positively correlated with elasticity index,protein content was negatively correlated with first cycle hardness,drawing length,Springiness,chewiness,positively correlated with elasticity;Fa was negatively correlated with Springiness.Superior grain taste quality is better than inferior grain.