Detection and validation of stay-green QTL in post-rainy sorghum involving widely adapted cultivar, M35-1 and a popular stay-green genotype B35

BMC Genomics

Jagannatha Vishnu Patil²  Seetharama Nadoor²  Murali Mohan Sabbavarapu²  Madhusudhana Ragimasalawada²  Nagaraja Reddy Rama Reddy¹ 

[1] ICAR-Directorate of Medicinal and Aromatic Plants Research (DMAPR), Anand, Gujarat 387 310, India;Marker-assisted selection Lab, ICAR-Directorate of Sorghum Research (DSR), Rajendranagar, Hyderabad 500 030, India

关键词: Marker assisted breeding;    Quantitative trait loci;    Post-flowering drought tolerance;    Sorghum;    Stay-green;   

Others  :  1128447
DOI  :  10.1186/1471-2164-15-909

 received in 2014-04-03, accepted in 2014-09-24,  发布年份 2014

【 摘 要 】

Background

Sorghum [Sorghum bicolor (L.) Moench] is an important dry-land cereal of the world providing food, fodder, feed and fuel. Stay-green (delayed-leaf senescence) is a key attribute in sorghum determining its adaptation to terminal drought stress. The objective of this study was to validate sorghum stay-green quantitative trait loci (QTL) identified in the past, and to identify new QTL in the genetic background of a post-rainy adapted genotype M35-1.

Results

A genetic linkage map based on 245 F₉ Recombinant Inbred Lines (RILs) derived from a cross between M35-1 (more senescent) and B35 (less senescent) with 237 markers consisting of 174 genomic, 60 genic and 3 morphological markers was used. The phenotypic data collected for three consecutive post-rainy crop seasons on the RIL population (M35-1 × B35) was used for QTL analysis. Sixty-one QTL were identified for various measures of stay-green trait and each trait was controlled by one to ten QTL. The phenotypic variation explained by each QTL ranged from 3.8 to 18.7%. Co-localization of QTL for more than five traits was observed on two linkage groups i.e. on SBI-09-3 flanked by S18 and Xgap206 markers and, on SBI-03 flanked by XnhsbSFCILP67 and Xtxp31. QTL identified in this study were stable across environments and corresponded to sorghum stay-green and grain yield QTL reported previously. Of the 60 genic SSRs mapped, 14 were closely linked with QTL for ten traits. A genic marker, XnhsbSFCILP67 (Sb03g028240) encoding Indole-3-acetic acid-amido synthetase GH3.5, was co-located with QTL for GLB, GLM, PGLM and GLAM on SBI-03. Genes underlying key enzymes of chlorophyll metabolism were also found in the stay-green QTL regions.

Conclusions

We validated important stay-green QTL reported in the past in sorghum and detected new QTL influencing the stay-green related traits consistently. Stg2, Stg3 and StgB were prominent in their expression. Collectively, the QTL/markers identified are likely candidates for subsequent verification for their involvement in stay-green phenotype using NILs and to develop drought tolerant sorghum varieties through marker-assisted breeding for terminal drought tolerance in sorghum.

【 授权许可】

   
2014 Rama Reddy et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

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