No abstract

No abstract

Black pepper is highly sensitive to water deficit stress especially during summer, resulting in significant losses in yield; therefore, strategies aimed at enhancing water stress tolerance are essential. Melatonin improves stress tolerance in plants; however, its method of application and optimum concentration in black pepper under water deficit stress remains unclear. Therefore, we conducted a two pot culture experiment during March and April, 2022 (var. Panniyur-1) to investigate the effects of foliar-sprayed and root-irrigated melatonin (50, 100 and 150 µM L-1) on the recovery per cent and physiological mechanism under water stress. The treatment details were, WW - Well-watered; WS - Water stressed; FM50 - Waterstress+50µM Melatonin (Foliar spray); FRM50 - Water stress + 50µM Melatonin (Foliar spray + Soil drenching @ 50ml/plant);  FM100 - Water stress + 100µM Melatonin (Foliar spray); FRM100 - Water stress + 100µM Melatonin (Foliar spray + Soil drenching @ 50ml/plant); FM150 - Water stress + 150µM Melatonin (Foliar spray); FRM150 - Water stress + 150µM Melatonin (Foliar spray + Soil drenching @ 50ml/plant). The melatonin-induced enhanced stress tolerance could be attributed to improved recovery %, leaf relative water content, photosynthetic pigments, activity of antioxidant enzymes (SOD, POD, and CAT), and ultimately significantly relieved the inhibitory effects of water stress on leaves. After rehydration, melatonin-treated plants recovered more quickly than untreated plants. In addition, melatonin counteracted the water stress induced accumulation in proline content. Overall, the results of this study demonstrated that melatonin at 100 µM L-1 (Foliar spray and root irrigation) significantly alleviated the adverse effects of water deficit stress compared untreated plants. In addition, application of exogenous melatonin combined with root and foliar application is superior than foliar spraying alone.

An experiment was conducted at University of Horticultural Sciences, Bagalkot, Karnataka, during Kharif 2016 and 2017 to study effect of ajwain (Trachyspermum ammi L.) varieties and nitrogen levels on its plant growth and yield attributes in semi-arid tropics of Northern Karnataka. The experiment was laid out in a split plot design with three replications by keeping varieties in main plots (Ajmer Ajwain 1, Ajmer Ajwain 93, Lam Selection 1, Lam Selection 2 and Local cultivar) and nitrogen levels in sub plots (50, 75, 100 and 125 kg/ha). The growth and yield attributes were significantly higher in improved varieties compared to local cultivar. Ajmer Ajwain 1 recorded highest plant height (81.82 and 80.56cm), number of secondary branches (52.36 and 50.98), plant spread (72.66 and 50.98cm), number of umbels/plant (177.15 and 171.88), number of umbellate/umbel (11.81 and 11.65), seed yield (14.44 and 14.26 q/ha, during both year, respectively), which was on a par with Lam Selection-1 (13.93 and 13.56 q/ha, respectively). Earliest 50 per cent flowering was observed in Ajmer Ajwain 93. Application of nitrogen up to 125 kg/ ha significantly increased growth and yield attributes which were on a par with 100 kg N/ha. Maximum seed yield g/plant, seed yield q/ha and essential oil yield kg/ha were recorded with 125 kg N/ha. Earliest 50 per cent flowering was observed under 50 kg N/ha application. Ajmer Ajwain1 and Lam Selection 1 were found better with an optimum dose of 100 kg N/ha.

No abstract