Studying the genetic basis of drought tolerance in sorghum by managed stress trials and adjustments for phenological and plant height differences

Sabadin, P.K. and Malosetti, M. and Boer, M.P. and et al, . (2012) Studying the genetic basis of drought tolerance in sorghum by managed stress trials and adjustments for phenological and plant height differences. Theoretical and Applied Genetics, 124 (8). pp. 1389-1402.

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Managed environments in the form of well watered and water stressed trials were performed to study the genetic basis of grain yield and stay green in sorghum with the objective of validating previously detected QTL. As variations in phenology and plant height may influence QTL detection for the target traits, QTL for flowering time and plant height were introduced as cofactors in QTL analyses for yield and stay green. All but one of the flowering time QTL were detected near yield and stay green QTL. Similar co-localization was observed for two plant height QTL. QTL analysis for yield, using flowering time/plant height cofactors, led to yield QTL on chromosomes 2, 3, 6, 8 and 10. For stay green, QTL on chromosomes 3, 4, 8 and 10 were not related to differences in flowering time/plant height. The physical positions for markers in QTL regions projected on the sorghum genome suggest that the previously detected plant height QTL, Sb-HT9-1, and Dw2, in addition to the maturity gene, Ma5, had a major confounding impact on the expression of yield and stay green QTL. Co-localization between an apparently novel stay green QTL and a yield QTL on chromosome 3 suggests there is potential for indirect selection based on stay green to improve drought tolerance in sorghum. Our QTL study was carried out with a moderately sized population and spanned a limited geographic range, but still the results strongly emphasize the necessity of corrections for phenology in QTL mapping for drought tolerance traits in sorghum.

Item Type: Article
Additional Information: We acknowledge financial support from the Embrapa Macroprograma 1 (Orygens Project) and 2 (CerealSeca Project). This work was partially-funded by the CGIAR Generation Challenge Programme (GCP) including project IBP 2.2.1 to FVE and MM. We are also thankful to the Fundac¸a˜o de Amparo a` Pesquisa do Estado de Minas Gerais (FAPEMIG) for a post-doctoral fellowship granted to PKS and FFC and to The National Council for Scientific and Technological Development (CNPq) for support to JVM, CTG and AAFG.
Author Affiliation: Embrapa Maize and Sorghum, Rod. MG 424, Km 65, Sete Lagoas, MG 35701-970, Brazil
Subjects: Crop Improvement
Divisions: Sorghum
Depositing User: Mr Siva Shankar
Date Deposited: 18 Dec 2012 05:26
Last Modified: 18 Dec 2012 05:26
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