Divergence in Drought-resistance Traits among Parents of Recombinant Peanut Inbred Lines

Peanut (Arachis hypogaea L.) is often grown in climates of intermittent drought on sandy soils. Plants expressing water-conservative traits would minimize exposure to end-of-season, severe drought. Two traits resulting in conservative transpiration rates (TRs) are limitations on TR with soil drying and with increasing vapor pressure deficit (VPD). This study focused on parents of existing recombinant inbred line (RIL) populations as sources of divergent expression of these two traits. If divergence is found, their derived RIL population could be used in identifying genetic markers. Since both water-conservation traits are laborious to document, a key extension of this study was to explore the possibility of using aquaporin inhibitors as practical tools in marker identification. Tifrunner had a lower soil water threshold for a decline in TR than NC 3033 and N08082olJCT. Tifrunner also had a higher VPD breakpoint than three genotypes, including NC 3033 and N08082olJCT. The difference between Tifrunner and these other two genotypes extended to their response to aquaporin inhibitors. The decrease in TR of Tifrunner when exposed to aquaporin inhibitors was much larger than NC 3033 when treated with silver and N08082olJCT when treated with zinc. This study indicates that an effort to develop drought markers in peanut RIL population should focus on Tifrunner x NC 3033 using the silver inhibitor and/or Tifrunner x N08082olJCT using the zinc inhibitor.