RESUMEN
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.
RESUMO: Foi conduzido um experimento para investigar os efeitos de diferentes regimes de sombreamento [60% (pesado), 30% (moderado) e 0% (controle)] em 25 características associadas às características morfológicas, trocas gasosas fotossintéticas e características agronômicas de feijão alado (Psophocarpus tetragonolobus), leguminosa subutilizada rica em proteínas dos trópicos. Coletivamente, 80% das variáveis estudadas apresentaram diferenças significativas (P<0,05) entre pelo menos dois tratamentos à sombra. O sombreamento mostrou efeito mais pronunciado nas características fisiológicas da leguminosa, pelo que a condutância estomática, a taxa fotossintética e a transpiração diferiram significativamente entre as plantas em todos os tratamentos. Observou-se que as plantas não sombreadas apresentaram crescimento e respostas fisiológicas superiores às plantas sombreadas. Curiosamente, as plantas moderadamente sombreadas exibiram o maior rendimento por planta, que diferiu significativamente das plantas não sombreadas e fortemente das sombreadas. Isso indica que o feijão alado pode se adaptar a cobertura parcial do dossel, tornando-o uma cultura potencial de fixação de nitrogênio que pode ser plantada em conjunto com árvores frutíferas ou oleaginosas em plantações comerciais.
RESUMEN
This study investigated the effects of gibberellin (GA3) on the fruit development, pigmentation and biochemical properties of wax apple. The wax apple trees were rubbing treated with 0, 20, 50 and 100 mgGA3/l under field conditions. The localized application (rubbing) of 50 mg GA3/l significantly increased the fruit set, fruit length and diameter, color development, weight and yieldcompared to the control. In addition, GA3 treatments significantly reduced the fruit drop. With regard to the fruit quality, 50 mg/l GA3 treatment increased the juice content, K+, TSS, total sugar and sugar acid ratio of wax apple fruits. In addition, higher vitamin C, phenol, flavonoid, anthocyanin, carotene content, PAL and antioxidant activities were recorded in the treated fruits. There was a positive correlation between the peel colour and TSS content and between the PAL activity and anthocyanin formation in the GA3-treated fruit. It was concluded that rubbing with 50 mg/L GA3 at inflorescence developing point of phloem once a week from the tiny inflorescence bud until the flower opening resulted in better yield and quality of wax apple fruits and could be an effective technique to safe the environment from excessive spray.