Stay-green expression in early generation sorghum [Sorghum bicolor (L.) Moench] QTL introgression lines uri icon

abstract

  • Reduced leaf senescence (stay-green) has been demonstrated to improve tolerance of post-Xowering moisture stress in grain sorghum. A number of quantitative trait loci (QTLs) associated with staygreen have been identiWed in sorghum, to facilitate transfer of this trait into adapted genetic backgrounds. This study reports initial evaluations, in both well watered and post-Xowering stress environments, following partial introgression (BC2F3/BC1F4 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 Xowering (a distinctive trait of the donor parent) and a greater percentage green leaf area during the latter part of grain Wlling, 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 Wlling was related to agreater relative grain yield in two of three post-Xoweringmoisture deWcit 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-Xowering stress environments in which this was measured (r2 = 0.42, P < 0.05). Thus the study provided useful evidence that the marker-assisted backcross transfer of staygreen QTLs from B35 into an adapted, but senescentbackground has the potential to enhance tolerance of post-Xowering drought stress in sorghum

publication date

  • 2010
  • 2010