Hybrid rice performance in environments of increasing drought severity uri icon

abstract

  • Hybrid rice provides an option for achieving high yield potential under favorable conditions, but the performance of hybrids under drought stress has not yet been fully evaluated. This study explored the feasibility of using hybrid rice technology in drought-prone tainted lowland fields. Hybrid lines, parental inbreds, and cultivated varieties as checks were screened for yield potential in well-watered fields and for drought resistance in drained fields at different stress levels. Nineteen out of 45 hybrid lines showed a yield advantage (on average 20%) over check lines in the three well-watered environments. Classifications of drought stress levels were based on the yield reduction relative to the well-watered environments, with moderate, severe, and very severe stress levels resulting in 54%, 77% and 89% reductions in yield, respectively. The relationship between yield advantage of hybrids and drought severity differed among lines: some hybrids showed more of an advantage under severe drought, whereas others had a greater yield advantage under moderate stress. Some hybrids did not perform as well as parents under drought. In general, the harvest index of hybrids was greater than those of inbred parents and checks, and showed strong correlation with grain yield in the different stress environments. Total dry matter yield of hybrids was correlated with improved yield in all stress environments during dry seasons, and some drought-tolerant hybrids also showed greater tillering efficiency and thousand-grain weight. Twenty-four selected hybrid lines were divided into seven clusters on the basis of yield trends across different drought stress environments. Among the hybrid rice lines, one cluster including IR81954H, IR81955H, and IR81956H stood out as combining high yield potential in both well-watered and drought stress environments. Hybrid IR81954H showed an 8% yield advantage over other hybrids across all studies, as well as stable yield in all the stress environments having an average yield advantage of 22% over other hybrids averaged across drought environments. These results highlight the variability among hybrids in their drought response, and the need for screening of hybrids and parents under drought stress conditions. (C) 2011 Elsevier B.V. All rights reserved.

publication date

  • 2012
  • 2012
  • 2012