Alfalfa(Medicago sativa L.)is the most widely grown forage legume crop worldwide.Yield and plant height are important agronomic traits influenced by genetic and environmental factors.The objective of this study was to...Alfalfa(Medicago sativa L.)is the most widely grown forage legume crop worldwide.Yield and plant height are important agronomic traits influenced by genetic and environmental factors.The objective of this study was to identify quantitative trait loci(QTL)and molecular markers associated with alfalfa yield and plant height.To understand the genetic basis of these traits,a full-sib F1 population composed of 392 individuals was developed by crossing a low-yielding precocious alfalfa genotype(male parent)with a high-yielding latematuring alfalfa cultivar(female parent).The linkage maps were constructed with 3818 single-nucleotide polymorphism(SNP)markers on 64 linkage groups.QTL for yield and plant height were mapped using phenotypic data for three years.Sixteen QTL associated with yield and plant height were identified on chromosomes 1 to 8.Six QTL explained more than 10%of phenotypic variation,representing major loci controlling yield and plant height.One locus on chromosome 1 controlling yield traits had not been identified in previous studies.Three QTL co-located with other QTL(qyield-1 and qheight-7,qheight-5 and qyield-4,qheight-6,and qyield-6).With further validation,the markers closely linked with these QTL may be used for marker-assisted selection in breeding new alfalfa varieties with high yield.展开更多
Alfalfa(Medicago sativa L.)is the most important legume forage crop worldwide with high nutritional value and yield.For a long time,the breeding of alfalfa was hampered by lacking reliable information on the autotetra...Alfalfa(Medicago sativa L.)is the most important legume forage crop worldwide with high nutritional value and yield.For a long time,the breeding of alfalfa was hampered by lacking reliable information on the autotetraploid genome and molecular markers linked to important agronomic traits.We herein reported the de novo assembly of the allele-aware chromosome-level genome of Zhongmu-4,a cultivar widely cultivated in China,and a comprehensive database of genomic variations based on resequencing of 220 germplasms.Approximate 2.74 Gb contigs(N50 of 2.06 Mb),accounting for 88.39%of the estimated genome,were assembled,and 2.56 Gb contigs were anchored to 32 pseudo-chromosomes.A total of 34,922 allelic genes were identified from the allele-aware genome.We observed the expansion of gene families,especially those related to the nitrogen metabolism,and the increase of repetitive elements including transposable elements,which probably resulted in the increase of Zhongmu-4 genome compared with Medicago truncatula.Population structure analysis revealed that the accessions from Asia and South America had relatively lower genetic diversity than those from Europe,suggesting that geography may influence alfalfa genetic divergence during local adaption.Genome-wide association studies identified 101 single nucleotide polymorphisms(SNPs)associated with 27 agronomic traits.Two candidate genes were predicted to be correlated with fall dormancy and salt response.We believe that the alleleaware chromosome-level genome sequence of Zhongmu-4 combined with the resequencing data of the diverse alfalfa germplasms will facilitate genetic research and genomics-assisted breeding in variety improvement of alfalfa.展开更多
基金The authors thank the reviewers for their valuable comments on this manuscript and gratefully acknowledge the financial support for this study provided by grants from the Collaborative Research Key Project between China and EU(granted by the Ministry of Science and Technology of China,2017YFE0111000)the China Forage and Grass Research System(CARS-34)+1 种基金the Agricultural Science and Technology Innovation Program of CAAS(ASTIP-IAS14)the National Natural Science Foundation of China(31772656).
文摘Alfalfa(Medicago sativa L.)is the most widely grown forage legume crop worldwide.Yield and plant height are important agronomic traits influenced by genetic and environmental factors.The objective of this study was to identify quantitative trait loci(QTL)and molecular markers associated with alfalfa yield and plant height.To understand the genetic basis of these traits,a full-sib F1 population composed of 392 individuals was developed by crossing a low-yielding precocious alfalfa genotype(male parent)with a high-yielding latematuring alfalfa cultivar(female parent).The linkage maps were constructed with 3818 single-nucleotide polymorphism(SNP)markers on 64 linkage groups.QTL for yield and plant height were mapped using phenotypic data for three years.Sixteen QTL associated with yield and plant height were identified on chromosomes 1 to 8.Six QTL explained more than 10%of phenotypic variation,representing major loci controlling yield and plant height.One locus on chromosome 1 controlling yield traits had not been identified in previous studies.Three QTL co-located with other QTL(qyield-1 and qheight-7,qheight-5 and qyield-4,qheight-6,and qyield-6).With further validation,the markers closely linked with these QTL may be used for marker-assisted selection in breeding new alfalfa varieties with high yield.
基金supported by the National Natural Science Foundation of China(Grant Nos.31971758 to QY and 32071865 to RL)the Collaborative Research Key Project between China and EU(Grant No.2017YFE0111000)+2 种基金the China Agriculture Research System of MOF and MARA(Grant No.CARS-34)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(Grant No.ASTIP-IAS14)the Key Projects in Science and Technology of Inner Mongolia,China(Grant No.2021ZD0031)。
文摘Alfalfa(Medicago sativa L.)is the most important legume forage crop worldwide with high nutritional value and yield.For a long time,the breeding of alfalfa was hampered by lacking reliable information on the autotetraploid genome and molecular markers linked to important agronomic traits.We herein reported the de novo assembly of the allele-aware chromosome-level genome of Zhongmu-4,a cultivar widely cultivated in China,and a comprehensive database of genomic variations based on resequencing of 220 germplasms.Approximate 2.74 Gb contigs(N50 of 2.06 Mb),accounting for 88.39%of the estimated genome,were assembled,and 2.56 Gb contigs were anchored to 32 pseudo-chromosomes.A total of 34,922 allelic genes were identified from the allele-aware genome.We observed the expansion of gene families,especially those related to the nitrogen metabolism,and the increase of repetitive elements including transposable elements,which probably resulted in the increase of Zhongmu-4 genome compared with Medicago truncatula.Population structure analysis revealed that the accessions from Asia and South America had relatively lower genetic diversity than those from Europe,suggesting that geography may influence alfalfa genetic divergence during local adaption.Genome-wide association studies identified 101 single nucleotide polymorphisms(SNPs)associated with 27 agronomic traits.Two candidate genes were predicted to be correlated with fall dormancy and salt response.We believe that the alleleaware chromosome-level genome sequence of Zhongmu-4 combined with the resequencing data of the diverse alfalfa germplasms will facilitate genetic research and genomics-assisted breeding in variety improvement of alfalfa.
