Stay-green quantitative trait loci's effects on water extraction, transpiration efficiency and seed yield depend on recipient parent background uri icon

abstract

  • A stay-green phenotype enhances the adaptation of sorghum to terminaldrought conditions, although the underlying physiological mechanisms leading to theexpression of stay-green remain unclear. Differences in tillering and leaf area at anthesis,transpiration efficiency (TE), water extraction, harvest index (HI) and yield under bothterminal drought and fully-irrigated conditions were assessed in 29 introgression lines(IL) developed targeting stay-green QTLs Stg1, Stg2, Stg3, Stg4, StgA, and StgB in S35background, and 16 IL developed targeting Stg1, Stg3, Stg4, and StgB in R16background. Transpiration efficiency was increased by StgB in the R16 background,whereas there was no effect on this trait in the S35 background. Water extraction wasincreased by Stg1 in the S35 background, whereas there was no effect in the R16background. StgB modified the proportion of water extracted before and after anthesis inthe S35 background. While tillering and leaf area at anthesis were decreased by Stg1 andStg3 in the S35 background, there was no such effect in R16. By contrast, yield dataunder fully-irrigated conditions showed higher tiller grain yield in Stg1, Stg2, and Stg3ILs. While yield differences were mostly explained by harvest index (HI) variation, thesubstantial yield variation unexplained by HI was closely related to TE in the S35background (R2 = 0.29), and more so in the R16 background (R2 = 0.72), while it wasclosely related to total water extracted in the S35 background (R2 = 0.41), but not in theR16 background. These data indicate the potential for several stay-green QTLs to affecttraits related to plant water use and capture. However, they also show that these effectsdepend on the interaction between genetic background and individual QTLs

publication date

  • 2011
  • 2011