Tropicultura (Jan 2001)
Réponses agro-physiologiques et efficacité d'utilisation de l'eau chez le maïs (Zea mays L. - cv. Synthetic-C) soumis au déficit hydrique
Abstract
Agrophysiological Responses and Water Use Efficiency of Maize (Zea mays L. - cv. Synthetic-C) in Water Deficit Conditions. Senegal is known to have very tow rainfall with high probability of drought occurring du ring crop development. The study on the growth of maize under water deficit conditions aimed at characterising its agro-physiological responses and the evaluation of its water use efficiency (WUE). A water deficit was applied respectively during the vegetative phase (T1), at flowering start (T3) and both during the vegetative phase and at flowering start (T2) with a period of rewatering between these two phases. For the control (TO) water was applied by irrigation to maintain optimal water conditions for growth. The amount of water to complete (in low rainfall conditions during the cycle) was determined by measuring "bac" evapotranspiration and using crop coefficient (Kc) for maize during the different phases. The results show that Synthetic-C variety was sensitive to water deficit during the flowering phase. Actually, the relative water content (RWC), leaf water potential and crop water stress index (CWSI) were less sensitive to water deficit during the flowering phase than during the vegetative phase. These parameters showed a higher rate of decrease during the vegetative phase. On the other hand, gazeous exchanges [stomatal conductance (Gs) and transpiration (Tr)] were found to be more sensitive to water deficit during the reproductive stage. Moreover, significantly low grain yield and WUE were observed during this phase of development. However, on the basis of physiological parameters and productivity, Synthetic-C showed a good capacity to resume its physiological activities after rewatering during the vegetative phase, similar to a good plasticity of the control.
