QTL Detection For Rice Traits Using Chromosome Segments Substitution Lines

With the improvement of people’s living standards rice cultivation technology,the requirement of rice yield and quality is more and more high.Digging rice genetic resources and analyzing the genetic basis of the important traits of rice can provide the basis for the genetic improvement of rice yield and quality,which has important theoretical and practical significance.In four sowing environments,This study using the constructed chromosome segment substitution lines contained 112 families,the donor parent is N22 and recurrent parent is 9311,to investigate 11 rice traits,including plant height,heading date,panicle length,panicle number,grains per panicle,yield per plant,1000 grains weight,seed setting ratio,grain length,grain width and grain length-width ratio.Using QTLIciMapping 4.0,combined with 112 CSSLs phenotype and genotype,to analysis genetic effect,the main results are as follows:1、In four different environmental conditions,forty-four QTLs which decided eleven QTLs important traits of rice were detected.In which twelve QTLs decide plant height,five QTLs decide heading date;There were nine QTLs associated with ear traits,that decided the panicle length,panicle number and grain per panicle respectively for two,four and three;The seven QTLs related to thousand grains weight,four QTLs seed setting ratio and one for yield per plant;Also anmong grain shape traits,there were 2,4 and 1 QTL respectively determine grain length,grain width and length width ratio.2 、 According to the results of analysis,multi-substitution segments have the characteristic of “pleiotropism” and “multigenic effect”.Fragment RM7389,RM336 and RM1335 both controled plant height and 1000 grain weight two traits,RM1335 was also associated with panicle length,seed setting rate and grain length;The latter was also related to the grain width and the effective panicle number;RM248 was both related to the length and width ratio,seed setting rate,and the heading date.3、The analysis also shows that there are epistatic interaction phenomena between all eleven traits in their respective substitution segments.The epistatic phenomena between substitution related to plant height and heading date were more complex,which both had 16 pair of substitution segments’ epistasis were detected,The number of epistatic was little difference between the remaining related traits’ substitution segments.Besides a handful of the epistatic effect between substitution segments were main effect,most of the rest were micro effect interaction.it could explain small phenotypic variation,but they could influence the expression of traits through interaction effect.4、In this study,we also found that the interaction phenomena related to traits between environment and substitution segments.In the forty-four substitution segments related to eleven traits,eleven for plant height,two for panicle length,one for yield per plant and four for grain width.Substitution segments can not be detected repeated in all four sowing environments.Seven substitution segments for 1000 grain weight were detected,only one substitution segment could be detected in both three sowing environments,only one substitution segment could be detected in two environments for the seed setting ratio and panicle number traits,while three segments for heading date were detected in two environments.