QTL Analysis Of Source-sink Related Traits In Rice

The yield genetics has always been an important job for rice breeding researchers.The formation mechanism of yield is essentially the process of interaction among source,sink and flow.In recent years,molecular technology developed rapidly,and the molecular marker-assisted breeding has become one of the ways for breeders to cultivate new varieties with high yields.Through molecular marker-assisted selection,they can quickly find the elite strains that carry the genes of the target traits,and speeding up the breeding process.In this study,the female parent-Guangluai4?indica?and the male parent-Toyonishiki?japonica?were used to construct a recombinant inbred line containing 166 lines.And the analysis about correlation and QTL of the source characters?sword leaf,inverted two leaf character?and sink characters?panicel traits?in F₇,F₈ and F₉ were carried out.The aim is to find the new dominant QTL locus that regulate the characteristics of the source and sink and provide resources for further molecular assisted breeding.The main results are as follows:1.In this study,the Mapchart was used to construct the genetic map of recombinant inbred lines from Guangluai4/Toyonishiki.As well as a total of 150 markers were used,which were covered the 1062.08cM of rice genome,with an average distance of 7.08CM.2.The correlation analysis showed that there was a significant correlation between panicle weight and grain length,grain width and other ear traits,but not with grain thickness and unfilled grain number per panicle;There was a significant correlation between panicle length and spikelet number and grain length but not with the grain width for three years;The correlation between grain shape traits and solid grain number,unfilled grain number,spikelet number were not significant;The correlation between grain length and grain width and grain thickness was not significant,but the correlation between grain width and grain thickness was significant;The correlation between leaf length and leaf width was not significant,and the correlation between leafs length or leafs width at different leaf positions was significant.Correlation analysis of panicle and leaf traits showed that except the ratio leaf length to width had little effect on spike weight,all other leaf traits had great influence on panicle;The panicle length was negatively correlated with the leaf and positively correlated with other leaf traits;Except the ratio of length to width,the other traits of leave have great influence on number of spikelet per panicle;The effect of leaves on the grain length is significant,but the effect on the grain width is insignificant,and the effect on the grain thickness can not be inherited stably;In addition,the leaves have little effect on the 1000-grain weight and seed setting rate.3.In this study,I used ICI Mapping to locate 18 characters of rice.A total of 65 QTLs were found,37 of which were major QTLs with a contribution rate of 15.05%-62.69%.In the two years,there were 5 co-localized to the same locus,namely qPL8 and qPL11-2,which regulate panicle length;qBG6-1,which regulates the number of unfilled grains;qGL3,which regulates grain length;and qSLL9,which regulates the length of the inverted two leaf.The synergistic alleles were all from the female parent-Guangluaisi,of which qGL3 was mapped as the major effect QTL for two years,the contribution rates are 23.01%and 24.17%.4.In this study,I used network2.0 to locate the QTLs for 18 traits in rice and obtained18 additive QTLs with the contribution rate of 1.9%-8%.There are 6 relocations with ICI Mapping:qPL11-2 regulats panicle length;qBG2-1 regulats the grain number;qGT3 regulats the grain thickness;qSLA12-1 regulats the area of the inverted two leaf;qSR1-1 and qSR11-1regulats the length width ratio of inverted two leaf.5.Network2.0 was used to locate the epistatic QTL of 18 traits in rice.And 16 pairs of epistatic QTL were obtained,including 1 additive×additive epistatic QTL and 15 pairs of non-additive×non-additive epistatic QTLs.The epistatic contribution rate is 2.23%-8.91%.6.Through comprehensive analysis,we found four hot spots with concentrated distribution of QTLs.There were 10 QTLs controlling leaf traits between RN8111-ID1 on chromosome 1;4 QTLs controlling the leaf between RM1687-RM1155 on chromosome 4;RM1985-RM585 on chromosome 6 regulats the grain length,unfilled grain number,the number of spikelets and the area of the sword leaf;RM19-RM7119 on chromosome 12regulats panicle weight,leaf length and leaf area.The clustered distribution of genes may be caused by multiple effects,tight linkage,or gene overlap.