Genotypic Differences for Water‐Use Efficiency and Weed Competitiveness in Dry Direct‐Seeded Rice uri icon

abstract

  • Genotypes with improved weed competitiveness and water-use efficiency (WUE) are needed to enhance and sustain productivity in dry direct-seeded rice (DDSR) (Oryza sativa L.). The objective of this study was to investigate the relative performance of selected genotypes under DDSR for yield, WUE, and weed-inflicted relative yield losses in the rainy seasons of 2012 and 2013. Six rice genotypes (two hybrids [US-323 and PAC-837], two cultivars [PR-115 and PR-120], and two advanced breeding lines [CR-2703 and CR-2706]) were grown in a split-split-plot arrangement in a randomized complete block, with soil water potential (10 kPa, well watered; and 20 kPa, stressed) as main plots, weed infestation levels (weed free and partially weedy) as subplots, and genotypes as sub-subplots. Relative grain yield loss among genotypes attributable to water stress had a range of 24-47%; it was lowest for PAC-837 (4.96 and 6.5 Mg ha(-1) at 10 and 20 kPa, respectively) and highest for PR-120 (3.91-7.37 Mg ha(-1) at 10 and 20 kPa, respectively). Similarly, weed-inflicted relative grain yield loss (partially weedy vs. weed free) among genotypes had a range of 10 to 47%; it was lowest for PAC-837 (5.42-6.04 Mg ha(-1)) and highest for US-323 (3.10-5.91 Mg ha(-1)). Weeds reduced WUE in all genotypes (12-46%) except PAC-837. Under weed-free conditions, PR-120 had the highest yield (6.99 Mg ha(-1)) and WUE (0.52 kg m(-3)). Th is study suggested that high yield potential and improved weed-suppressive ability were compatible, and therefore breeding for both traits should lead to strengthened integrated crop management strategies in DDSR.

publication date

  • 2015
  • 2015
  • 2015