Effect of abscisic acid concentrations and stages of spray on maize growth, seed yield and germination at late planting

Abstract

           A field experiment was carried out in Al-Hajjaj district- Salah Al-Din Governorate, during the autumn season of 2021. The experimental design was randomized complete block design (RCBD) in three replications. It had three ABA concentrations of 0, 9 and 12 mg L-1 that sprayed on plants at 4 and 8 leaves and at the beginning of flowering. Results indicated that a concentration of 12 mg L-1 was superior in shortening the number of days from sowing until 50% of tasseling (male flowering) 38.33 days and silking (female flowering) 41 days. The same concentration recorded the highest stem diameter of 2.47 cm, seeds number per ear 682.89 seed ear-1, 1000 seed weight 373.77 g, single plant yield 165.64 g and seed yield 11.04 tons ha-1, protein content 9.80% and ash percentage 1.39%. However, control recorded the highest germination percentage and speed of 95.89 and 64.80, respectively. Spraying ABA at 4 leaves was superior in recording the least number of days from planting until 50% of tasseling 38.50 days and silking 43.55 days and also excelled in giving the highest stem diameter 2.35 cm. However, foliar application of ABA at the beginning of flowering showed the highest means of number of seeds per ear 664.99 seed ear-1, 1000 seed weight 361.80 g, single plant yield 158.70 g, seed yield 10.57 tons ha-1, protein percentage 10.03%, and ash percentage 1.36%. Hence, foliar spray at 4 leaves recorded the highest mean 84.81 of germination speed.