Effect of drought stress induced by polyethylene glycol (PEG) on germination indices in corn (<i>Zea mays</i> L.) hybrids

Abstract

Drought stress is one of the most important environmental factors in reduction of growth, development and production of plants. Germination is one of the main growth stages and success in this stage is dependent on moisture content of soil at time of planting. This study examined germination characteristics of seven corn hybrids under five levels of osmotic potential (0, -3, -6, -9 and -12 bar) by polyethylene glycol (PEG) 6000 using a factorial experiment based on a completely randomized design with three replications. Results indicated that water potential significantly reduced germination percent (71.2%), germination rate (24.2%), root length (60%), shoot length (89.8%), seedling length (71.2%) and seed vigour (91.7%). The mean germination time and root/shoot length ratio increased with decrease in the osmotic potential of PEG solution. Hybrid K3651/1×K166B produced the highest germination percent, germination rate, root length, seedling length and seed vigour, hence this hybrid was the most tolerant hybrid to drought stress.

Key words: Corn, drought stress, early growth, germination, PEG.