IMPROVEMENT OF DROUGHT AND SALINITY TOLERANCE OF CORIANDER (Coriandrum sativum L.) THROUGH APPLICATION OF MELATONIN

Abstract

Coriander (Coriandrum sativum L.) is one of the most important condiments for culinary purposes.Addressing this issue, there were two experiments were carried out at Hajee Mohammad Danesh Science and Technology University in the Department of Crop Physiology and Ecology from 2023 to 2024 followed by completely randomized design (CRD) with three replications. During the experimental period germination traits, seedling growth, photosynthetic pigments, proline contents and water relations were measured to understand the role of melatonin in mitigating the ill effects of drought and salinity stress of coriander (BARI Coriander 2). The experiment 1 was related to drought stress and the treatments were T1 = Control condition (Tap water + 0 µM MT), T2 = Moderate drought stress (-2 bars) + 0 µM MT, T3 = Moderate drought stress (-2 bars) + 50 µM MT, T4 = Moderate drought stress (-2 bars) + 100 µM MT, T5 = Moderate drought stress (-2 bars) + 150 µM MT, T6 = Higher drought stress (-4 bars) + 0 µM MT, T7 = Higher drought stress (-4 bars) + 50 µM MT, T8 = Higher drought stress (-4 bars) + 100 µM MT and T9 = Higher drought stress (-4 bars) + 150 µM MT. From the results of Experiment 1, it was observed that drought stress plots (T2-T9) showed lower performance in respect of germination, seedling growth and photosynthetic traits compared to control condition (T1). However, the pots treated with MT showed the better results in compared to the no MT-treated pots in artificially created drought conditions. The plants treated with 100 µM MT (T4) revealed that the highest germination traits (Germination percentage, 97%; Mean Germination Time, 14.31 days and Germination rate index, 37.46; Co-efficient velocity of germination,9.15 and Timson germination rate index 17.14); Photosynthetic pigments (chlorophyll a 6.05 mg g-1 FW; chlorophyll b 1.90 mg g-1 FW, total chlorophyll 7.95 mg g-1 FW, and total carotenoids 2.46 mg g-1 FW) and growth attributes (shoot length ,9.29 cm; root length, 10.04 cm ; seedling dry weight, 0.037 mg) traits. Whereas, the lowest germination (Germination percentage, 56%; Mean Germination Time, 13.18 days and Germination rate index,21.71;co efficient velocity of germination 7.04; Timson germination rate index,10.35); Photosynthetic pigments (chlorophyll a ,3.10 mg g-1 FW; chlorophyll b, 1.13 mg g-1 FW, Total chlorophyll ,4.23 mg g-1 FW, and Total carotenoids, 0.85 mg g-1 FW) and growth parameters (shoot length ,7.30 cm; root length, 6.89 cm ; seedling dry weight, 0.016 mg) traits were observed at T9 treatment. On the other hand, highest level of proline was observed in drought stress plots compared to the control (T1) condition. Among all the treatments (T2-T9) under drought condition, the lowest level of proline observed T4.