Hydritic Stress Tolerance Indices for Four New Varieties of Cotonnier (Gossypium Hirsutum)

Water stress is a major limiting factor for cotton production in the Cameroon cotton-growing zone. The aim of this study was to evaluate water stress tolerance indices and classify cotton varieties (Gossypium hirsutum) to identify those best adapted to drought conditions. The experiment was conducted in a greenhouse at IRAD Maroua, in a Sudano-Sahelian climate. Five cotton varieties were studied under two water regimes: normal conditions (ETM) and water stress (total deprivation of water for six days). The stress tolerance indices assessed included: stress sensitivity index (SSI), stress intensity (SI), stress tolerance index (STI), stress tolerance (TOL) and yield stability index (YSI). The results show significant variability between varieties in terms of their tolerance to water stress. IRMA A2188 and IRMA H2062 stand out for their yield stability and resilience to stress, while IRMA F2181 and IRMA Q302 are more sensitive, with a sharp reduction in yield under drought conditions. Correlation analysis reveals that STI and YSI are reliable indicators for identifying tolerant varieties. The study proposes a classification of varieties into three groups: (i) resistant varieties (IRMA D2139 and IRMA H2062), (ii) susceptible varieties (IRMA F2181 and IRMA Q302), and (iii) intermediate varieties (IRMA A2188). These results are essential for guiding breeding programs to improve the resilience of cotton to water stress.