Sorghum stay-green QTL individually reduce post-flowering drought-induced leaf senescence

Harris, K. and Subudhi, P.K. and Borrell, A. and Jordan, D. and Rosenow, D. and Nguyen, H. and Klein, P. and Klein, R. and Mullet, J. (2007) Sorghum stay-green QTL individually reduce post-flowering drought-induced leaf senescence. Journal of Experimental Botany, 58 (2). pp. 327-338.

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Sorghum is an important source of food, feed, and biofuel, especially in the semi-arid tropics because this cereal is well adapted to harsh, drought-prone environments. Post-flowering drought adaptation in sorghum is associated with the stay-green phenotype. Alleles that contribute to this complex trait have been mapped to four major QTL, Stg1-Stg4, using a population derived from BT × 642 and RT × 7000. Near-isogenic RT × 7000 lines containing BT × 642 DNA spanning one or more of the four stay-green QTL were constructed. The size and location of BT × 642 DNA regions in each RT × 7000 NIL were analysed using 62 DNA markers spanning the four stay-green QTL. RT × 7000 NILs were identified that contained BT × 642 DNA completely or partially spanning Stg1, Stg2, Stg3, or Stg4. NILs were also identified that contained sub-portions of each QTL and various combinations of the four major stay-green QTL. Physiological analysis of four RT × 7000 NILs containing only Stg1, Stg2, Stg3, or Stg4 showed that BT × 642 alleles in each of these loci could contribute to the stay-green phenotype. RT × 7000 NILs containing BT × 642 DNA corresponding to Stg2 retained more green leaf area at maturity under terminal drought conditions than RT × 7000 or the other RT × 7000 NILs. Under post-anthesis water deficit, a trend for delayed onset of leaf senescence compared with RT × 7000 was also exhibited by the Stg2, Stg3, and Stg4 NILs, while significantly lower rates of leaf senescence in relation to RT × 7000 were displayed by all of the Stg NILs to varying degrees, but particularly by the Stg2 NIL. Greener leaves at anthesis relative to RT × 7000, indicated by higher SPAD values, were exhibited by the Stg1 and Stg4 NILs. The RT × 7000 NILs created in this study provide the starting point for in-depth analysis of stay-green physiology, interaction among stay-green QTL and map-based cloning of the genes that underlie this trait

Item Type: Article
Author Affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
Subjects: Crop Improvement
Crop Improvement > Plant Breeding
Divisions: Sorghum
Depositing User: Syamala
Date Deposited: 23 Feb 2011 17:50
Last Modified: 23 Feb 2011 17:50
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