Science et changements planétaires / Sécheresse


High diurnal temperatures and cowpea ( Vigna unguiculata (L.) Walp.) productivity in the counter‐season Volume 14, issue 4, OCTOBRE-NOVEMBRE-DÉCEMBRE 2003


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Université de Ouagadougou, Unité de Formation et de recherche en sciences de la vie et de la terre (UFR\SVT), BP 7021 Ouagadougou Burkina Faso <g.zombreuniv‐ouaga.bf> Institut de l‘environnement et de la recherche agricole (INERA), BP 910 Bobo Dioulasso, Burkina Faso.

High diurnal temperatures associated with water deficit during the dry period (March to May), are thought to be limiting factors which impair farming at this period in Burkina Faso. This work aims at looking for cowpea varieties which are adapted to counter‐seasonal cultures. For this purpose, the productivity of five cowpea varieties, e.g. Gorom local, KNl, KVX 61‐1, Bambey 21, TN88‐63, was investigated. Two factors have been applied, the first one at two temperature levels, high temperature and moderate, respectively, and the second factor at four levels corresponding to four watering periods with the same quantity of water in the morning (6 a.m.), midday (12 a.m.), evening (6 p.m.) and three times a day (6 a.m., 12 a.m., 6 p.m.). The impact of these treatments on the temperature in the vicinity of the roots and on growth and reproduction characteristics were assessed. The watering period had an important influence on the temperatures around the roots. Most of growth and reproduction characteristics were affected by high temperatures near the roots. However, all of these characteristics are less affected when the cowpea varieties are watered exclusively in the evenings. The Gorom local variety is the most tolerant to hot thermal shocks. Varieties TN88‐63 and Bambey 21 were susceptible to these stresses.