Appearance and cooked rice elongation are key quality traits of rice. Although some QTL for these traits have been identified, understanding of the genetic relationship between them remains limited. In the present stu...Appearance and cooked rice elongation are key quality traits of rice. Although some QTL for these traits have been identified, understanding of the genetic relationship between them remains limited. In the present study, large phenotypic variation was observed in 760 accessions from the 3 K Rice Genomes Project for both appearance quality and cooked rice elongation. Most component traits of appearance quality and cooked rice elongation showed significant pairwise correlations, but a low correlation was found between appearance quality and cooked rice elongation. A genome-wide association study identified 74 QTL distributed on all 12 chromosomes for grain length, grain width, length to width ratio, degree of endosperm with chalkiness, rice elongation difference, and elongation index. Thirteen regions containing QTL stably expressed in multiple environments and/or exerting pleiotropic effects on multiple traits were detected. By gene-based association analysis and haplotype analysis, 46 candidate genes, including five cloned genes, and 49 favorable alleles were identified for these 13 QTL. The effect of the candidate gene Wx on rice elongation difference was validated by a transgenic strategy. These results shed light on the genetic bases of appearance quality and cooked rice elongation and provide gene resources for improving rice quality by molecular breeding.展开更多
Development of hybrid rice with high yield and grain quality is a goal of rice breeding.To investigate the genetic mechanism of heterosis for rice milling and appearance quality in indica/xian rice,QTL mapping was con...Development of hybrid rice with high yield and grain quality is a goal of rice breeding.To investigate the genetic mechanism of heterosis for rice milling and appearance quality in indica/xian rice,QTL mapping was conducted using 1061 recombinant inbred lines(RILs)derived from a cross of the xian rice cultivars Quan 9311B(Q9311B)and Wu-shan-si-miao(WSSM),and a backcross F_(1)(BC_(1)F_(1)) population developed by crossing the RILs with Quan 9311A(Q9311A),combined with phenotyping in two environments.The F_(1) hybrid(Q9311A×WSSM)showed various degrees of heterosis for milling and appearance quality.A total of 142 main-effect QTL(M-QTL)and 407 pairs of epistatic QTL(E-QTL)were identified for five milling and appearance quality traits and grain yield per plant(GYP)in the RIL,BC_(1)F_(1) and mid-parental heterosis(H_(MP)) populations.Differential detection of QTL in three populations revealed that most additive loci detected in the RILs did not show heterotic effects,but some of them did contribute to BC_(1)F_(1) trait performance.Unlike heterosis of GYP,single-locus overdominance and epistasis were the main contributors to heterosis for milling and appearance quality.Epistasis contributed more to the heterosis for milling quality than to that for appearance quality.Three(four)QTL regions harboring opposite(consistent)directions of favorable allele effects for GYP and grain quality were identified,indicating the presence of partial genetic overlaps between GYP and grain quality.Three strategies are proposed to develop hybrid rice with high yield and good grain quality:1)pyramiding favorable alleles with consistent directions of gene effects for GYP and grain quality at the M-QTL on different chromosomes;2)introgressing favorable alleles for GYP and grain quality into the parents and then pyramiding and fixing these additive effects in hybrids;and 3)pyramiding overdominant and dominant loci and minimizing or eliminating underdominant loci from the parents.展开更多
The demand for high quality rice represents a major issue in rice production. The primary components of rice grain quality include appearance, eating, cooking, physico-chemical, milling and nutritional qualities. Most...The demand for high quality rice represents a major issue in rice production. The primary components of rice grain quality include appearance, eating, cooking, physico-chemical, milling and nutritional qualities. Most of these traits are complex and controlled by quantitative trait loci （QTLs）, so the genetic characterization of these traits is more difficult than that of traits controlled by a single gene. The detection and genetic identification of QTLs can provide insights into the genetic mechanisms underlying quality traits. Chromosome segment substitution lines （CSSLs） are effectivetools used in mapping QTLs. In this study, we constructed 154 CSSLs from backcross progeny （BC3F2） derived from a cross between ＇Koshihikari＇ （an Oryza sativa L. ssp. japonica variety） as the recurrent parent and ＇Nona Bokra＇ （an O. sativa L. ssp. indica variety） as the donor parent. In this process, we carried out marker-assisted selection by using 102 cleaved amplified polymorphic sequence and simple sequence repeat markers covering most of the rice genome. Finally, this set of CSSLs was used to identify QTLs for rice quality traits. Ten QTLs for rice appearance quality traits were detected and eight QTLs concerned physico-chemical traits. These results supply the foundation for further genetic studies and breeding for the improvement of grain quality.展开更多
Improving grain quality, which is composed primarily of the appearance of the grain and its cooking and milling attributes, is a major objective of many rice-producing areas in China. In the present study, we conducte...Improving grain quality, which is composed primarily of the appearance of the grain and its cooking and milling attributes, is a major objective of many rice-producing areas in China. In the present study, we conducted a marker-based genetic analysis of the appearance and milling quality of rice （Oryza sativa L.） grains using a doubled-haploid population derived from a cross between the indica inbred Zhenshan 97 strain and the japonica inbred Wuyujing 2 strain. Quantitative trait locus （QTL） analysis using a mixed linear model approach revealed that the traits investigated were affected by one to seven QTLs that individually explained 4.0%-30.7% of the phenotypic variation. Cumulatively, the QTL for each trait explained from 12.9% to 61.4% of the phenotypic variation. Some QTLs tended to have a pleiotropic or location-linked association as a cause of the observed phenotypic correlations between different traits. Improvement of the characteristics of grain appearance and grain weight, as well as an improvement in the milling quality of rice grains, would be expected by a recombination of different QTLs using marker-assisted selection.展开更多
基金funded by the National Key Research and Development Program of China (2016YFD0100301)Project for Cultivating New Transgenic Varieties (2016ZX08009003-004)+2 种基金the Agricultural Science and Technology Innovation Program and the Cooperation and Innovation Mission (CAAS-ZDXT202001)Open Fund of Hubei Collaborative Innovation Center for Grain Industry (HCICGI2020-06)the National Natural Science Foundation of China (U19A2025 and 31870229)。
文摘Appearance and cooked rice elongation are key quality traits of rice. Although some QTL for these traits have been identified, understanding of the genetic relationship between them remains limited. In the present study, large phenotypic variation was observed in 760 accessions from the 3 K Rice Genomes Project for both appearance quality and cooked rice elongation. Most component traits of appearance quality and cooked rice elongation showed significant pairwise correlations, but a low correlation was found between appearance quality and cooked rice elongation. A genome-wide association study identified 74 QTL distributed on all 12 chromosomes for grain length, grain width, length to width ratio, degree of endosperm with chalkiness, rice elongation difference, and elongation index. Thirteen regions containing QTL stably expressed in multiple environments and/or exerting pleiotropic effects on multiple traits were detected. By gene-based association analysis and haplotype analysis, 46 candidate genes, including five cloned genes, and 49 favorable alleles were identified for these 13 QTL. The effect of the candidate gene Wx on rice elongation difference was validated by a transgenic strategy. These results shed light on the genetic bases of appearance quality and cooked rice elongation and provide gene resources for improving rice quality by molecular breeding.
基金funded by the Key Research and Development Project of Hainan Province(ZDYF2021XDNY128)the Hainan Yazhou Bay Seed Lab Project(B21HJ0216)+1 种基金the Agricultural Science and Technology Innovation Programthe Cooperation and Innovation Mission(CAAS-ZDXT202001)。
文摘Development of hybrid rice with high yield and grain quality is a goal of rice breeding.To investigate the genetic mechanism of heterosis for rice milling and appearance quality in indica/xian rice,QTL mapping was conducted using 1061 recombinant inbred lines(RILs)derived from a cross of the xian rice cultivars Quan 9311B(Q9311B)and Wu-shan-si-miao(WSSM),and a backcross F_(1)(BC_(1)F_(1)) population developed by crossing the RILs with Quan 9311A(Q9311A),combined with phenotyping in two environments.The F_(1) hybrid(Q9311A×WSSM)showed various degrees of heterosis for milling and appearance quality.A total of 142 main-effect QTL(M-QTL)and 407 pairs of epistatic QTL(E-QTL)were identified for five milling and appearance quality traits and grain yield per plant(GYP)in the RIL,BC_(1)F_(1) and mid-parental heterosis(H_(MP)) populations.Differential detection of QTL in three populations revealed that most additive loci detected in the RILs did not show heterotic effects,but some of them did contribute to BC_(1)F_(1) trait performance.Unlike heterosis of GYP,single-locus overdominance and epistasis were the main contributors to heterosis for milling and appearance quality.Epistasis contributed more to the heterosis for milling quality than to that for appearance quality.Three(four)QTL regions harboring opposite(consistent)directions of favorable allele effects for GYP and grain quality were identified,indicating the presence of partial genetic overlaps between GYP and grain quality.Three strategies are proposed to develop hybrid rice with high yield and good grain quality:1)pyramiding favorable alleles with consistent directions of gene effects for GYP and grain quality at the M-QTL on different chromosomes;2)introgressing favorable alleles for GYP and grain quality into the parents and then pyramiding and fixing these additive effects in hybrids;and 3)pyramiding overdominant and dominant loci and minimizing or eliminating underdominant loci from the parents.
基金Supported by the Ministry of Science and Technology of China(2006AA10Z1F7 and 2007AA10Z187)the Chinese Academy of Sciences(KSCX1-YW-03)the National Natural Science Foundation of China(30821004)
文摘The demand for high quality rice represents a major issue in rice production. The primary components of rice grain quality include appearance, eating, cooking, physico-chemical, milling and nutritional qualities. Most of these traits are complex and controlled by quantitative trait loci （QTLs）, so the genetic characterization of these traits is more difficult than that of traits controlled by a single gene. The detection and genetic identification of QTLs can provide insights into the genetic mechanisms underlying quality traits. Chromosome segment substitution lines （CSSLs） are effectivetools used in mapping QTLs. In this study, we constructed 154 CSSLs from backcross progeny （BC3F2） derived from a cross between ＇Koshihikari＇ （an Oryza sativa L. ssp. japonica variety） as the recurrent parent and ＇Nona Bokra＇ （an O. sativa L. ssp. indica variety） as the donor parent. In this process, we carried out marker-assisted selection by using 102 cleaved amplified polymorphic sequence and simple sequence repeat markers covering most of the rice genome. Finally, this set of CSSLs was used to identify QTLs for rice quality traits. Ten QTLs for rice appearance quality traits were detected and eight QTLs concerned physico-chemical traits. These results supply the foundation for further genetic studies and breeding for the improvement of grain quality.
基金国家重点基础研究发展计划(973计划)，国家自然科学基金，Foundation on Ministry of Education in China
文摘Improving grain quality, which is composed primarily of the appearance of the grain and its cooking and milling attributes, is a major objective of many rice-producing areas in China. In the present study, we conducted a marker-based genetic analysis of the appearance and milling quality of rice （Oryza sativa L.） grains using a doubled-haploid population derived from a cross between the indica inbred Zhenshan 97 strain and the japonica inbred Wuyujing 2 strain. Quantitative trait locus （QTL） analysis using a mixed linear model approach revealed that the traits investigated were affected by one to seven QTLs that individually explained 4.0%-30.7% of the phenotypic variation. Cumulatively, the QTL for each trait explained from 12.9% to 61.4% of the phenotypic variation. Some QTLs tended to have a pleiotropic or location-linked association as a cause of the observed phenotypic correlations between different traits. Improvement of the characteristics of grain appearance and grain weight, as well as an improvement in the milling quality of rice grains, would be expected by a recombination of different QTLs using marker-assisted selection.
