Plant Emergence and t50 Responses of Two Chickpea Cultivar Differing in Seed Coat Colour to PEG-Osmopriming at Sub-optimal Temperature

Abstract

The effect of polyethylene glycol (PEG) priming on seedling emergence was assessed in two cultivars of chickpea (Cicer arietinum L.) differing in testa colour (Kripa-light coloured; DCP 92-3-yellowish brown) at optimal (20 °C) and sub optimal (14 and 30 °C) temperatures using sterilized sand and soil as substrate. PEG primed seeds performed better in sand. In soil, primed Kripa seeds failed to emerge at sub optimal temperatures while unprimed seeds emerged at all temperatures. DCP 92-3 was able to maintain the emergence as that of sand at all temperature but reduced significantly in terms of final emergence and time to reach 50% germination (t50) following osmopriming. Such contrasting performance of osmoprimed seeds in sand and soil may be attributed to decrease in seed tannin content following PEG osmopriming. Kripa and DCP 92-3 had a seed tannin content of 206.4 ± 2.2 and 550 ± 2.2 mg/100 g seed fresh weight respectively, which was reduced to 101.6 ± 2.6 and 394.7 ± 6.1 mg/100 g seed fresh weight following priming. The result suggests using of cultivars with high tannin content when sowing has to be done at sub optimal temperatures.