Mapping of post flowering drought resistance traits in grain sorghum: Association between QTLs influencing premature senescence and maturity

被引：129

作者：

Crasta O.R. ^{[1
,2
]}

Xu W.W. ^{[1
,3
]}

Rosenow D.T. ^{[3
]}

Mullet J. ^{[4
]}

Nguyen H.T. ^{[1
]}

机构：

[1] Plant Molecular Genetics Laboratory, Dept. of Plant and Soil Sciences, Texas Tech University, Lubbock

[2] CuraGen Corporation, New Haven

[3] Texas A and M Univ. Agric. R., Box 219, Lubbock

[4] Dept. of Biochemistry and Biophysics, Texas A and M University, College Station

来源：

Molecular and General Genetics MGG | 1999年 / 262卷 / 3期

关键词：

Drought resistance; Quantitative trait loci (QTLs); Sorghum bicolor (L); Trait-based QTL pyramiding;

D O I：

10.1007/s004380051120

中图分类号：

学科分类号：

摘要：

The identification of genetic factors underlying the complex responses of plants to drought stress provides a solid basis for improving drought resistance. The stay-green character in sorghum (Sorghum bicolor L. Moench) is a post-flowering drought resistance trait, which makes plants resistant to premature senescence under drought stress during the grainfilling stage. The objective of this study was to identify quantitative trait loci (QTLs) that control premature senescence and maturity traits, and to investigate their association under post-flowering drought stress in grain sorghum. A genetic linkage map was developed using a set of recombinant inbred lines (RILs) obtained from the cross B35 x Tx430, which were scored for 142 restriction fragment length polymorphism (RFLP) markers. The RILs and their parental lines were evaluated for post-flowering drought resistance and maturity in four environments. Simple interval mapping identified seven stay-green QTLs and two maturity QTLs. Three major stay-green QTLs (SGA, SGD and SGG) contributed to 42% of the phenotypic variability (LOD 9.0) and four minor QTLs (SGB, SGI.1, SGI.2, and SGJ) significantly contributed to an additional 25% of the phenotypic variability in stay-green ratings. One maturity QTL (DFB) alone contributed to 40% of the phenotypic variability (LOD 10.0), while the second QTL (DFG) significantly contributed to an additional 17% of the phenotypic variability (LOD 4.9). Composite interval mapping confirmed the above results with an additional analysis of the QTL x Environment interaction. With heritability estimates of 0.72 for stay-green and 0.90 for maturity, the identified QTLs explained about 90% and 63% of genetic variability for stay-green and maturity traits, respectively. Although stay-green ratings were significantly correlated (r = 0.22, P ≤ 0.05) with maturity, six of the seven stay-green QTLs were independent of the QTLs influencing maturity. Similarly, one maturity QTL (DFB) was independent of the stay green QTLs. One stay-green QTL (SGG), however, mapped in the vicinity of a maturity QTL (DFG), and all markers in the vicinity of the independent maturity QTL (DFB) were significantly (P ≤ 0.1) correlated with stay-green ratings, confounding the phenotyping of stay-green. The molecular genetic analysis of the QTLs influencing stay-green and maturity, together with the association between these two inversely related traits, provides a basis for further study of the underlying physiological mechanisms and demonstrates the possibility of improving drought resistance in plants by pyramiding the favorable QTLs.

引用

页码：579 / 588

页数：9

共 39 条

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