Assessment of Tolerance to Polyethylene Glycol-Induced Water Stress in Phaseolus vulgaris Varieties throughout Early Seedling Stage

Abstract

Aims: Water deficit (WD) has become a major hurdle for worldwide feed production, especially in the context of changing climate. Finding varieties that are more tolerant to drought is key to keeping up productivity in places where water is scarce. This research attempts to assess the influence of WD upon common bean growth. Study Design: The research was carried out according to a fully randomly arranged block scheme involving polyethylene glycol (PEG) concentrations (T0: 0 MPa, T1: -0.9 MPa), varieties (14) and blocks (03). Place and Duration of Study: Faculty of Science of the University of Yaoundé I in the greenhouse. Methodology: The trial was performed using pots, and growth was measured as plant length, n° of leaves, crown diameter and chlorophyll concentrations. Results: The results show that WD had a negative influence on the variables studied. Its influence on bean growth was variety dependent. The representation of PCA individuals and clustering allow us to classify the varieties into three classes: Class 1, consisting of varieties MAC55 and MAC33, which are sensitive to WD; class 2 comprising varieties NITU, Marron, FEB 192, Large white, ECAPAN and GL-22 which are moderately sensitive; and class 3 corresponding to varieties GLP190-S, Dor 701, TY, Mex 142, MUV-6 and PNN which are tolerant to WD. In Marron variety for example, the number of leaves, the plant height and the crown diameter at T0 was double that at T1. WD reduced total chlorophyll content (mg/ml) in varieties MAC55 (0), MAC33 (0), NITU (13.43), Marron (8.68), FEB 192 (8.69), Large white (13.92) and ECAPAN (11.51), but increased it in GLP190-S (22.58), Dor 701 (17.99), TY (19.46), Mex 142 (18.92), MUV-6 (20.06), PNN (20.60) and GL-22 (17.08). Conclusion: Class 3 varieties are therefore recommended to farmers for their tolerance to drought during the growth of common beans.