The present study had the general objective of comparing KN-1 variety
of cowpea cultivated according to the supply of different Potassium (K+)
solution in a situation of water constraint. The test was carried out in the
experimental garden of the Unit of Training and Research in Health, Life
and Technology (UFR/SVT) in the open air during the rainy period (July
to September) in pots. Three types of solution namely water, Potassium
Dihydrogen Phosphate (KH2PO4 ) and Potassium Nitrate (KNO3 ) were
used to supply the plants. Then, after 6 days, the plants were subjected to
a water deficit by stopping watering in the vegetative phase. At the end of
the water restriction, the morphophysiological and biochemical parameters
were assessed on all the plants. Note that all the plants underwent water
restriction. Our work shows that the different potassium solutions had a positive effect
on the production Root Biomass (RB) (3.093 ± 0.180 g for KNO3
and 2.826 ± 0.146 g for KH2 PO4) and therefore on cowpea adaptation to drought,
compared to control plants (2.671 ± 0.099 g). Plants supplied with potassium
solutions have a lower water potential (-1.528 ± 0.054 MPa for KNO3
and -1.683 ± 0.029 MPa for KH2 PO4 ) than that of control plants (-1.283
± 0.058 MPa). Similarly, RB (p<0,027), chlorophyll A content (p ≤ 0,000)
and nodule mass (p<0,009) of plants were affected by the solution supply
level in the KN-1 variety. Responses to water stress varied depending on the
potassium solution used and the treatment supply level. On the basis of these
results, potassium solutions and the KN-1 variety allow to improve cowpea
production in Burkina Faso.

Cowpea; Potassium; Water deficit; Biomass; Water potential