Stay-green expression in early generation sorghum [Sorghum bicolor (L.) Moench] QTL introgression lines.
Reduced leaf senescence (stay-green) has been demonstrated to improve tolerance of post-flowering moisture stress in grain sorghum. A number of quantitative trait loci (QTLs) associated with stay-green have been identified in sorghum, to facilitate transfer of this trait into adapted genetic backgrounds. This study reports initial evaluations, in both well watered and post-flowering stress environments, following partial introgression (BC<sub>2</sub>F<sub>3</sub>/BC<sub>1</sub>F<sub>4</sub> generations) of four stable stay-green QTLs (StgB, Stg1, Stg3 and Stg4) from donor parent B35 to senescent variety R 16. The majority of the introgression lines had higher leaf chlorophyll levels at flowering (a distinctive trait of the donor parent) and a greater percentage green leaf area during the latter part of grain filling, than did R 16, indicating that the stay-green QTLs were expressed phenotypically in the R 16 background. None of the QTL introgression lines achieved the same level of stay-green as B35, however. Maintenance of a greater relative green leaf area during the latter half of grain filling was related to a greater relative grain yield in two of three post-flowering moisture deficit environments in which the materials were evaluated (r² = 0.34 in 2004–2005 and r² = 0.76 in 2005–2006), as was a direct measure of leaf chlorophyll in one of the post-flowering stress environments in which this was measured (r² = 0.42, P
Kassahun, B.; Bidinger, F.R.; Hash, C.T.; Kuruvinashetti, M.S. Stay-green expression in early generation sorghum [Sorghum bicolor (L.) Moench] QTL introgression lines. Euphytica (2010) 172 (3) 351-362. [DOI: 10.1007/s10681-009-0108-0]