Effect of short-term waterlogging applied at various growth phases on growth, development and yield in Vigna unguiculata

Abstract

The effects of short-term waterlogging during the vegetative, reproductive and total growth phases were investigated in four cultivars of cowpea (Vigna unguiculata L. Walp) in relation to their controls in a pot experiment conducted at the University of the West Indies, St. Augustine, in 1989. All cultivars were able to recover completely and produce near to normal yields, when waterlogging was confined to the vegetative period. Recovery growth was affected in cultivars waterlogged during the total growth phase and the plants were significantly smaller (P < 0·05) in vegetative dry matter (60–80% of the size of their respective controls) even at maturity. Recovery growth was affected, to a greater extent, in cultivars possessing a small mainstem[ratio ]branch ratio. Yield development in the waterlogged plants was affected by accelerated leaf senescence and consequent reduction in the reproductive period. As a result, yields in all the cultivars tested were significantly smaller (P < 0·05) than their respective controls and varied between 54 and 60% of the controls. Plants waterlogged during the reproductive phase were not significantly different (P < 0·05) in vegetative dry matter from the controls, but showed root degeneration and accelerated leaf senescence in all but one cultivar (Local Red). Yield reduction, however, was significant (P < 0·05) only in IT-83S-898. Possible criteria for selecting plants tolerant to waterlogging are discussed.