Evaluation of Physiological Response and Yield Function to Bio-fertilizer and Potassium Consumption in Melon (Cucumis Melo L.) Under Water Deficit Conditions.

Tarbat-e Jam is one of the major areas of melon production. Recent droughts and shortage of water have reduced melon yield. In this research, the role of nitroxin bio-fertilizer and potassium on mitigating the adverse effects of drought stress on melon yield was evaluated during the years of 2019 and 2020. This experiment was designed as a split-plot factorial with three replicates based on a randomized complete block design. The factors in the split-factorial design including: irrigation (I), bio-fertilizer (B) and Potassium (K). Irrigation levels (I100, I80, and I60) were kept at 60%, 80%, and 100% of crop evapotranspiration. The Nitroxin was used as seed coating (B1) and none seed coating (B0). The highest proline content and electrolyte leakage were obtained in I60 whit combination of B0 and K0. The highest and the lowest value of CAT activity were obtained in I60 + B0 and K2+B1 treatments respectively. The highest peroxidase activity was achieved in the I60. The seeds inoculated with nitroxin and Potassium application significantly decreased POD activity. Relative water content and total chlorophyll were decreased under drought stress but they increased significantly by using bio-fertilizer and potassium. The highest TSS was obtained in the K2 and in the I80+B1 treatment. Potassium application increased the yield significantly. The highest and lowest yields were recorded in the I100+B1 and I60+B0 respectively. In this research, the use of bio-fertilizer and potassium moderated the effect of drought stress and reduced its negative effects, and the yield improved under drought stress.