Silicon Nanoparticles and Methyl Jasmonate Enhance Productivity and Nutritional Quality of Vegetable Cluster Bean (Cyamopsis tetragonoloba L.) Under Deficit Irrigation.

Abstract

Cluster bean (Cyamopsis tetragonoloba L.) is usually grown for its high galactomannan content as an industrial crop. Young edible cluster bean pods are also eaten as a nutritious vegetable in many areas. There is little research on the effects of drought on pod yield or the nutritional content of edible cluster bean pods, even with the growing importance of producing vegetable cluster bean in dry and semiarid regions. In this study, the effect of silicon nanoparticles (Si NPs) and methyl jasmonate (MeJA) applied concurrently on the growth performance, pod productivity, and nutritional quality of vegetable cluster bean was evaluated at three irrigation rates. A three-factor experiment was done in a completely randomized block design with three replications under field conditions, with three irrigation rates (100% field capacity, 50% field capacity, and 25% field capacity), three Si NP levels (0, 50, and 100 ppm), and three MeJA levels (0, 20, and 40 μmol L^-1). Drought stress (with irrigation at 25% FC) significantly reduced the growth of the plant, pod yield, crude protein, crude fat, fiber, dry weight, and mineral composition of the edible cluster bean pods. Pod weight reduction of approximately 50% occurred when they were irrigated at 25% FC, compared to pod yield from well-watered plants. The addition of Si NPs and MeJA, when applied together, was able to reduce the adverse effects of low and moderate drought on pod yield and improve the productivity and nutritional quality of the edible cluster bean pods. The combined application of 100-ppm Si-NPs and 40-μmol L^-1 MeJA was the most effective treatment for improving the productivity and nutritional quality of vegetable cluster bean under deficit irrigation. These findings suggest that this combination for cluster bean cultivation under moderate drought conditions after economic feasibility and field-scale validation studies.