The effect of exogenous application of salicylic acid and ascorbic acid on forage quality and yield of maize (Zea mays L.) under water deficit conditions

The effects of the foliar application of plant growth regulators (PGRs), salicylic acid (SA) and ascorbic acid (AA) were studied on yield and some qualitative traits of corn silage under drought stress in a field experiment conducted in the Agricultural and Natural Resources Research Center of Khoy in two consecutive years. The experiment was performed in four replications as a split plot in a randomised complete blocks design. Irrigation treatment was in two levels, ir75 and ir150, and the foliar applications of SA and AA at seven levels (100, 200, and 300 ppm, as well as a control treatment). The amount of water consumed in ir75 and ir150 during 10 and 7 times irrigation was 6 000 and 4 200 m3/ha, respectively. Malondialdehyde (MDA) content was increased over the plant growth period in both ir75 and ir150, but with the difference that its range was 3.72 to 12.9 nmol/g FW (fresh weight) under ir75 and 12.5-109.5 nmol/g FW under water shortage conditions. The results show that ir150 decreased plant height, forage yield, ear weight, and nitrogen uptake versus ir75. In plants treated with SA and AA, nitrogen uptake and chlorophyll content increases (45-33%) were observed compared to the control plants under ir75. In most traits, there was no significant difference between AA and SA levels, but plants treated with SA100 showed higher protein yield, dry forage yield, and ear yield.