EFFECT OF DIFFERENT CONCENTRATIONS OF GR24 AS SEED PRIMING TREATMENT ON PHYSIO-CHEMICAL AND YIELD RELATED ATTRIBUTES OF MAIZE (ZEA MAYS) HYBRIDS UNDER DROUGHT STRESS

Climate change increases the intensity of drought stress throughout the world. Drought stress poses serious threat to global food security by effecting the yield of field crops. In current experiment, maize hybrids (HY-1898, FH-1046) were used to analyze the effectiveness of GR24 as seed priming strategy under drought stress (60% field capacity). Two levels of drought stress (control and 60% field capacity) were used in this experiment. Seeds of maize hybrids were soaked for 16 h in four concentrations of GR24 (control, 0.001, 0.01 and 0.1 mg L-1). After 48 days of sowing data were collected which showed that net CO2 assimilation rate and stomatal conductance were increased by GR24 priming in both maize hybrids while transpiration rate (E), sub-stomatal carbon dioxide concentration (Ci), water use efficiency (A/E) and Ci/Ca ratio remained unresponsive. Chlorophyll b, total chlorophyll, chlorophyll ratio and carotenoids concentrations considerably improved by seed priming with GR24 except chlorophyll a. Leaf ascorbic acid and total phenolics were also increased by seed priming with synthetic analogue of strigolactones (GR24). Glycinebetaine (GB) showed significant results while leaf free proline showed non-significant result in both maize hybrids by GR24. Yield parameters of both maize hybrids revealed that GR24 has positive effect on number of seeds per cob and number of seeds per plant under both regimes. In conclusion, seed priming with GR24 improved the drought tolerance in both maize hybrids.