PRIMING OF MAIZE SEED WITH GIBBERELLIN (GA3) TO TOLERATE DROUGHT STRESS. 1. GERMINATION AND SEEDLING VIGOUR

Abstract

A factorial experiment was carried out under laboratory conditions in 2017 at the postgraduate laboratories at the College of Agricultural Engineering Sciences, University of Baghdad. The experiment aimed to study the response of maize cultivars seed (Baghdad3, Fajr1, Almaha and Sara) to be primed with GA3 (soaking seed in 300 mg L-1 for 24 hours) to tolerate drought stress (-5, -8, and -11 bar) in germination stage. Complete randomize design (CRD) with four replications was used according to factorial experiments. Data statistical analysis was done and mean were compared using the least significant difference at 5% probability. The simple correlation analysis was done between the studied traits: germination ratio at final count, lengths of root and plumule, seedling dry weight, root to plumule ratio, seedling growth rate and seedling vigour index. The results showed the analysis of variance indicates significant differences in the effect of tri-interaction between cultivars, seed priming and drought stress. The treatment of tri-interaction (Baghdad3 × primed seed × -5) significantly  exceeded the rest of the treatments by giving the highest average of germination ratio at the final count (89.0%) and did not differ significantly with the same treatment at the osmotic potential of -8 or -11 bar. The treatment of tri-interaction (Almaha × primed seed × -5) significantly exceeded the rest of the treatments by giving the highest average length of root (6.2 cm) and the highest mean of seedling vigour index (876.5). It can be conclude that there is a role for genotypes and seed priming process to tolerate drought stress to somewhat extent. Therefore, it can be recommend planting one of the two cultivars of Baghdad3 or Sara after priming their seed to improve their performance under conditions of drought stress or not