Effects of shading on the growth, development and yield of winged bean (Psophocarpus tetragonolobus)

Abstract

An experiment was conducted to investigate the effects of different shading regimes [i.e., 60% (heavy), 30% (moderate), and 0% (control)] on 25 traits associated with the morphological features, photosynthetic gas exchange and agronomic characteristics of winged bean (Psophocarpus tetragonolobus), an underutilized protein-rich legume from the tropics. Collectively, 80% of the studied variables displayed significant differences (P<0.05) between at least two shade treatments. Shading generally showed most pronounced effect on the physiological traits of the legume, whereby the stomatal conductance, photosynthetic and transpiration rate differed significantly among plants for all treatments. The non-shaded plants were observed to have superior growth and physiological responses than the shaded plants. Interestingly, the moderately shaded plants exhibited the highest yield per plant, which significantly differed from the non-shaded and heavily shaded plants. This indicated that winged bean can adapt to partial canopy cover, making it a potential nitrogen-fixing cash crop which can be planted together with fruit or oil trees in commercial plantations.

Yield Response and Physiological Adaptation of Green Bean to Photovoltaic Greenhouses

“…Other previous trials on common bean showed an increase of both SLA and LAR as a bean acclimation feature due to the reduced irradiation ( Worku et al, 2004 ). Recent experiments on winged bean under shading nets observed that the lower light intensity contributed to delay flowering and that moderately shaded plants with 30% shading nets achieved higher yield than non-shaded plants ( Raai et al, 2020 ). However, the common shading applied using shading nets or during intercropping is considerably different from the shading of a PVG, which is higher and persistent, since opaque PV panels shade the direct radiation completely.…”

Shading Effects on Leaf Gas Exchange, Leaf Pigments and Secondary Metabolites of Polygonum minus Huds., an Aromatic Medicinal Herb

“…The measurements of photosynthesis rate (A), leaf temperature (Tleaves), transpiration rate (E), and stomatal conductance (Gs) were obtained by a closed infra-red gas analyser LICOR 6400 Portable Photosynthesis System (IRGA, Licor Inc., Lincoln, NE, USA). The measurements used an optimal condition set of 400 µmol mol −1 CO 2 flux, 30 °C standard cuvette temperature, and PAR of 1200 µmol m −2 s −1 [ 70 ]. Leaf gas exchange measurements were carried out between 10:00 a.m. to 11:00 a.m., on the third fully expanded leaves from the plant apex.…”

Effects of Shading and Nitrogen Fertilizer on Growth and Physiology of Gandarusa (Justicia gendarussa Burm. F.)

“…The evaluation of gandarusa growth also showed a decrease in plant height, number of leaves, and number of branches. Raai et al (2020) reported a decrease in the height and number of leaves and branches of Psophocarpus tetragonolobus due to shading and nitrogen fertilizer treatment. Lu et al (2021) also reported that light deficiency inhibited plant growth by directly affecting photosynthesis, phytohormone transduction, stress-related transcription factor, and R genes that are responsible for the immune system in Magnolia sinostellata.…”