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Agronomic drought tolerance indicators in three cowpea varieties cultivated in Senegal and Niger |
Science et changements planétaires / Sécheresse. Volume 12, Number 4, 259-66, Décembre 2001, Notes de recherche
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 Résumé
Article gratuit
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Author(s) : Benoît SARR, Omar DIOUF, Macoumba DIOUF, Harold ROY-MACAULEY, Casimir BROU |
Summary : In spite of the fact that cowpea (Vigna unguiculata (L.) Walp.) is one of the most drought-tolerant crops, its production in the dry Sahel environment is affected by the water deficit that usually occurs during its growth cycle. Using agronomic criteria, this work aims at comparing the degree of sensitivity to water deficit of the early maturing, erect cowpea varieties and of the late maturing, semi-erected or crawling varieties. The effect of severe water deficit applied from the vegetative phase until the beginning of flowering was studied during the dry season in 1999 at Bambey (Senegal). The agronomic observations were focused on soil water status, on the development of the vegetative parts and on root growth, yield and yield components. The sensitivity of the varieties to water stress was assessed using a water stress index (Is) and a water use efficiency (WUE) parameter for the pods, grains and the total biomass productions. The results obtained showed that the early maturing Bambey 21 variety was more sensitive to drought than the other varieties. This sensitivity was shown by a very high Is for the grains (0.61) and pods (0.54) and by a WUE for grain production lower under stress (3.27 kg. ha- 1.mm- 1) than under optimal water conditions (6.41 kg ha- 1.mm- 1). Simple regression between grain yield and various field crops parameters (phenology, development, and yield components) showed that the preservation of the number of grains per square meter is an interesting criteria of drought tolerance in the niebe. These parameters appear to be useful indicators of drought tolerance. At the plant population level, the results obtained could serve to define drought tolerance criteria relevant to varietal selection. |
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