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.