Genotypic variation for drought tolerance in cotton (Gossypium hirsutum L.): Leaf gas exchange and productivity

摘要: Although water-limited environments are detrimental to cotton growth and productivity worldwide, identification of (Gossypium hirsutum L.) genotypes that less sensitive drought may improve in prone areas. The objective the study was assess genotypic variation for tolerance varieties using physiological attributes as selection criteria, determine relationship with traits. association target traits (photosynthetic rate (Pn), stomatal conductance (gs), transpiration (E)) under well-watered (W1) (W2) regimes analyzed 32 public cultivars/bred lines two field experiments conducted during normal growing seasons 2003 2004. Seed yield (SCY) biological (BY) were markedly affected W2 regime all cultivars except outstanding performance CIM-1100 RH-510 proving their superiority other tolerance. Conversely, FH-901, FH-634, FH-2000 high yielding W1 regime; however, exhibited a sharp decline regime. A positive correlation between SCY BY water stress (r=0.44 2003; r=0.69 2004) indicates is also primary determinant genetic improvement environment SCY. Pn, gs, E significantly reduced by stress. Substantial gas exchange existed among cultivars. (P<0.01) observed gs both years indicating prevalence control transpiration. Pn major role effects regulating leaf photosynthesis conditions. correlated (P<0.05 P<0.01 level these associations not significant These findings demonstrate effective be useful criterion breeding programs improving environments. Moreover, suggests