Effect of Water Stress on Morpho-physiological Trait of Some Accessions of Bambara Groundnut [Vigna subterranea (L). Verdcourt]

Background: The cultivation of Bambara groundnut in arid zones, such as the Sahelian regions of Cameroon, has received scant attention despite its nutritional and agronomic potential. The Sahelian regions of Cameroon are classified as part of the arid zones of the world, characterized by a rainy season of approximately three to four months in duration. Nevertheless, the cultivation period of Bambara groundnut is approximately four to six months, a duration that hinders its cultivation. The objective of this study is to assess the impact of water stress on the morpho-physiological traits of select Bambara groundnut accessions cultivated in the Sahelian regions of Cameroon. Methods: The experiment was executed in accordance with the fisher bloc design, employing four replicates. The water stress was induced using distilled water in pot experiments to monitor thirteen (13) morphological traits and six (06) physiological traits. Result: The results demonstrated significant variability among the accessions under water stress. Accession V2 exhibited the greatest resistance, characterized by diminished leaf areas and reduced stomatal number. The findings demonstrated a consistent increase in relative water content, accompanied by a decrease in water loss and transpiration. This observation suggests a reduced response to stress. The genetic material of the accession exhibited a range of morphological responses. The considerable impact of water stress was evident on the 100-pod weight produced per accession. Accession V1 exhibited a significant response to water stress, resulting in the production of the smallest pods (22 g). Accession V2 demonstrated the least susceptibility to the 100-pod weight (26 g), exhibiting the highest weight among the other accessions. The evaluation of the 100 seeds’ weight revealed that accession V2 exhibited a significantly higher seed weight compared to the other accessions. The grain yield in the accession V2 was higher for both sites (65.39±1.15 and 65.72±0.50). Principal component analysis demonstrated a positive correlation between stress and the weights of 100 pods and seeds (r = 0.956). The results obtained underscore the capacity of accession V2 to adapt to the environmental conditions prevalent in the Sahelian regions of Cameroon.