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Physiological, biochemical and agronomical responses of cowpea (Vigna unguiculata (L.) Walp.) genotypes to water deficit in greenhouse and field conditiions

Hamidou F., Zombre G., Diouf O., Guinko S., Braconnier S.. 2005. In : 2nd International Conference on Integrated Approaches to Sustain and Improve Plant Production Under Drought Stress, Rome, Italy, September 24 -28, 2005. s.l. : s.n., 22 p.. InterDrought II. 2, 2005-09-04/2005-09-28, Rome (Italie).

Five genotypes of cowpea, Gorom local, KVX61-1, Mouride, Bambey 21 and TN88-63 differing in their susceptibility to water stress were experienced in greenhouse and field to study their agrophysiological and biochemical responses to water deficit at flowering stage. Effect of this stress on leaf water potential ([psi]f), gas exchanges, foliar proline and starch contents, vitality index (SFI), canopy temperature, yield and its components was assessed during the pot culture and/or the field trial. In pot culture, water deficit increased significantly the proline content (from 0.35 to 1.96 mg g-1 DM in mean) of the five genotypes while gas exchanges and starch content decreased (respectively from 19 to 2.25 [mu]mol CO2 m-2 s-1 of net photosynthesis and from 61.28 to 17.47 mg g-1 DM in mean). SFI decreased significantly for the five genotypes. Gorom local, Mouride, KVX61-1 and TN88-63 decreased significantly their [psi]f (from -0.55 to -0.92 MPa in mean) while Bambey 21 maintained it (from -0.4 to -0.43 MPa). In field conditions, drought stopped gas exchanges of Gorom local, KVX61-1, Mouride and Bambey 21. KVX61-1 and Bambey 21 showed the highest decrease of SFI. The yield and its components were more affected for Bambey 21 (> 60%) which accumulated the lowest proline quantity (0.44 mg g-1 DM). Our results revealed that adaptative responses of genotypes to water deficit in greenhouse can be different from that in field. Furthermore, the effect of water deficit on the physiological and biochemical parameters could explain the agronomical responses notably in the field. (Texte intégral)
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