Grain size is one of the most important agronomic components of grain yield. Grain length, width and thickness are controlled by multiple quantitative trait loci （QTLs）. To understand genetic basis of large grain sh...Grain size is one of the most important agronomic components of grain yield. Grain length, width and thickness are controlled by multiple quantitative trait loci （QTLs）. To understand genetic basis of large grain shape and explore the beneficial alleles for grain size improvement, we perform QTL analysis using an F2 population derived from a cross between the japonica variety Beilu 129 （BL129, wide and thick grain） and the elite indica variety Huazhan （HZ, narrow and long grain）. A total number of eight major QTLs are detected on three different chromosomes. QTLs for grain width （qGW）, grain thickness （qGT）, brown grain width （qBGW）, and brown grain thickness （qBGT） explained 77.67, 36.24, 89.63, and 39.41% of total phenotypic variation, respectively. The large grain rice variety BL129 possesses the beneficial alleles of GW2 and qSW5/ GW5, which have been known to control grain width and weight, indicating that the accumulation of the beneficial alleles causes large grain shape in BL129. Further results reveal that the rare gw2 allele from BL129 increases grain width, thickness and weight of the elite indica variety Huazhan, which is used as a parental line in hybrid rice breeding. Thus, our findings will help breeders to carry out molecular design breeding on rice grain size and shape.展开更多
Field resistances of nine accessions of common wild rice （Oryza rufipogon Griff.） and one rice variety （IR24） were evaluated by using nine strains of bacterial blight pathogen （Xanthomonas oryzae pv. oryzae） fro...Field resistances of nine accessions of common wild rice （Oryza rufipogon Griff.） and one rice variety （IR24） were evaluated by using nine strains of bacterial blight pathogen （Xanthomonas oryzae pv. oryzae） from the Philippines. IR24 was highly susceptible to all the strains, and six common wild rice accessions resisted all the nine strains, with a resistance frequency of 67%. The accessions Yulin and Wanning were only susceptible to PXO280 and PXO71, respectively. The accession Gaozhou was susceptible to the three strains PXO79, PXO99 and PXO339, whereas resistant to the other six strains. It could be concluded that there is at least one resistance gene in each common wild rice accession. The functional markers of the genes xa5, xa13, Xa21 and Xa27 were used to detect the presence of these resistance genes in the nine tested wild rice accessions, and it was found that four wild rice accessions contained heterozygous xa13. Among the nine common wild rice accessions, five were homozygous for Xa27 and three homozygous for xa27, and the accession Laibin contained neither xa27 nor Xa27. In addition, there were no xa5 and Xa21 in all of these accessions.展开更多
基金supported by grants from the National Basic Research Program of China(2013CBA01401)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA08020108)the Platform Construction Programs of Key Laboratory and Engineering Technology Research Center,Department of Science and Technology of Hainan Province,China(ZDZX2013023)
文摘Grain size is one of the most important agronomic components of grain yield. Grain length, width and thickness are controlled by multiple quantitative trait loci （QTLs）. To understand genetic basis of large grain shape and explore the beneficial alleles for grain size improvement, we perform QTL analysis using an F2 population derived from a cross between the japonica variety Beilu 129 （BL129, wide and thick grain） and the elite indica variety Huazhan （HZ, narrow and long grain）. A total number of eight major QTLs are detected on three different chromosomes. QTLs for grain width （qGW）, grain thickness （qGT）, brown grain width （qBGW）, and brown grain thickness （qBGT） explained 77.67, 36.24, 89.63, and 39.41% of total phenotypic variation, respectively. The large grain rice variety BL129 possesses the beneficial alleles of GW2 and qSW5/ GW5, which have been known to control grain width and weight, indicating that the accumulation of the beneficial alleles causes large grain shape in BL129. Further results reveal that the rare gw2 allele from BL129 increases grain width, thickness and weight of the elite indica variety Huazhan, which is used as a parental line in hybrid rice breeding. Thus, our findings will help breeders to carry out molecular design breeding on rice grain size and shape.
基金supported by the Project of the National Ministry of Science and Technology,China (Grant No.2006AA10Z1C8)the Knowledge Innovative Program of the Chinese Academy of Sciences (Grant Nos.KSCX-YW-N-009-02 and KSCX1-YW-03)+1 种基金the National Basic Research Program of China (Grant No.2009CB126004)the Natural Science Foundation of Hainan Province,China (Grant No.309019)
文摘Field resistances of nine accessions of common wild rice （Oryza rufipogon Griff.） and one rice variety （IR24） were evaluated by using nine strains of bacterial blight pathogen （Xanthomonas oryzae pv. oryzae） from the Philippines. IR24 was highly susceptible to all the strains, and six common wild rice accessions resisted all the nine strains, with a resistance frequency of 67%. The accessions Yulin and Wanning were only susceptible to PXO280 and PXO71, respectively. The accession Gaozhou was susceptible to the three strains PXO79, PXO99 and PXO339, whereas resistant to the other six strains. It could be concluded that there is at least one resistance gene in each common wild rice accession. The functional markers of the genes xa5, xa13, Xa21 and Xa27 were used to detect the presence of these resistance genes in the nine tested wild rice accessions, and it was found that four wild rice accessions contained heterozygous xa13. Among the nine common wild rice accessions, five were homozygous for Xa27 and three homozygous for xa27, and the accession Laibin contained neither xa27 nor Xa27. In addition, there were no xa5 and Xa21 in all of these accessions.
