Physiological response, molecular analysis and water use efficiency of maize (<i>Zea mays</i> L.) hybrids grown under various irrigation regimes

Abstract

With a view to study the effects of irrigation scheduling on the water use efficiency and physiological response and molecular basis of maize hybrids of different maturity groups, a field experiment was conducted at Water Management Research Center (WMRC), Belvatagi, University of Agricultural Sciences, Dharwad, India during 2010-2011 rabi season in Malaprabha Command Area’. The experiment was laid out in split plot design with three replications. The main plot comprised four irrigation levels (0.4. 0.6, and 0.8 irrigation water/cumulative pan evaporation (IW/CPE) ratio and irrigation at critical growth stages of maize) and subplots were three maize hybrids [PEEHM-5 (extra early), PEHM-2 (early) and 900 M gold (full season)] were tested. The results reveal that significantly higher grain yield (P<0.05) was at 0.8 IW/CPE ratio followed by irrigation at critical growth sages of maize. Among the maize genotypes tested, full season 900 M Gold recorded significantly greater grain yield (84.61 q ha^-1) over PEHM-2 (early) and PEEHM-5 (extra-early). The moisture stress due to 0.4 IW/CPE ratio prolonged the days which reached 50% anthesis and 50% silking thus widening the anthesis-silking interval. Significant positive correlations (P<0.05) of maize grain yield with 100 seed weight (r=0.81), cob length (r=0.83), harvest index (r=0.82) and water-use efficiency (WUE; r=0.61) were found. The RWC decreased significantly (P<0.05) from 82.53 to 75.24% with increasing moisture stress on account of variations in the availability of soil moisture in the crop root zone. WUE was significantly low (P<0.05) in 0.8 IW/CPE ratio, despite providing more amount of water which could be attributed to a greater use of water with relatively lesser increase in yield. The present investigation showed that providing four irrigations at critical growth stages of maize hybrids followed by either three or five irrigations seem to have higher WUE. This approach could save water up to 29% with slight reduction of grain yield by 12% over providing full irrigation. Molecular analysis of three hybrids revealed the possibility of introgressing the yield enhancing traits from full season hybrid into early and extra-early hybrids, the latter clustered distinctly with each other. This strategy besides saving water helps tail-end farmers in choosing additional crop for double cropping in the command areas.

Keywords: Maize hybrids, IW/CPE ratio, water use efficiency, grain yield.

African Journal of Biotechnology, Vol 13(29) 2966-2976