Seed priming with putrescine improves the drought resistance of maize hybrids

Maize productivity is severely hampered owing to looming water deficit worldwide. Exogenous use of polyamines, especially putrescine, is of vital significance in alleviating the adversities of drought in crop plants. This study, consisted of two independent experiments was conducted in a glasshouse. In experiment I, conducted to screen the maize hybrids for drought resistance, maize hybrids Pioneer 30-Y-87, Pioneer 31-R-88, Pioneer 32-W-86, Pioneer 3025 and Pioneer 3062 were sown in 8 kg soil and compost (1:1) filled pots maintained at 80, 60, 40 and 20% water holding capacity (WHC) from sowing till crop harvest. Performance of maize hybrid Pioneer 31-R-88 was better in terms of seedling biomass, leaf area and leaf water status, so was selected as drought resistant; whereas, performance of Pioneer 30-Y-87 in terms of these traits was poor and was designated as drought sensitive. In experiment II, potential of putrescine seed priming in improving the drought resistance of maize was evaluated. Seeds of maize hybrids (selected from experiment I) Pioneer 30-Y-87 (drought sensitive) and Pioneer 31-R-88 (drought resistant) were soaked in water (control) or aerated solution of putrescine (0.1, 0.01 and 0.001 mM) for 10 h. Seeds were thoroughly rinsed, re-dried near to original weight with forced air and then sowed in 10 kg soil-filled earthen pots maintained at 80 and 40% WHC designated as well-watered and drought stress, respectively. Drought stress hampered the seedling emergence, reduced the seedling biomass and disrupted the plant leaf water status. Nonetheless, putrescine application improved the plant biomass components and leaf water status under well-watered and drought conditions. However, seed priming with 0.1 mM putrescine was the most effective in this regard. Similarly, both the maize hybrids differed significantly for seedling emergence, seedling vigor, leaf area and leaf water relations; however, maize hybrid Pioneer 31-R-88 performed better than the hybrid Pioneer 30-Y-87 both under well-watered and water deficit conditions. In conclusion, seed priming with 0.1 mM putrescine can effectively improve the drought resistance in hybrid maize.