Selection and characterization of cotton cultivars for dryland production in the south-west of Spain

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

“…Correlation of P n and g s with SCY (Po0.01) and BY (Po0.05 in 2003;Po0.01 in 2004) in W 2 regime reflects strong association of P n and g s with productivity (Lopez et al, 1995). In the present studies, a positive association (Po0.01) between P n and g s under W 2 regime, and the plot of relative reduction in P n against relative reduction in g s across the regimes in 2003 (Po0.05) and 2004 (Po0.001), illustrate significant linear association between these traits.…”

“…This reduction may be attributed to stomatal (reviewed by Chaves, 1991;Cornic, 2000;Flexas et al, 2004) and nonstomatal factors (Ennahli and Earl, 2005;. A higher photosynthetic rate under drought is a decisive factor for higher cotton production (Lopez et al, 1995), and the empirically determined differences in drought tolerance of cotton cultivars can be related to some physiological parameters such as photosynthetic rate and stomatal conductance (Nepomuceno et al, 1998).…”

Cotton

“…The final yield depends on the number of fruits that are set and reach maturity. Differences in boll abscission rates at different nodes, as well as in boll number and boll weight, have been observed among cotton genotypes under drought (Lopez et al 1995). Differences in boll abscission rates at different nodes, as well as in boll number and boll weight, have been observed among cotton genotypes under drought (Lopez et al 1995).…”

“…Differences in photosynthetic behavior under water stress may simply reflect the plants' capacity for water uptake (Lopez et al 1993a). Under dryland conditions, a genotype with the highest photosynthesis under severe water stress was the one that had deeper roots (Lopez et al 1995).…”

“…Under certain conditions, an increase in earliness could be useful as a drought-escape mechanism (Ludlow 1989). However, this trait has not been associated with higher yield under drought (Cook and El-Zik 1993;Lopez et al 1995). The final yield depends on the number of fruits that are set and reach maturity.…”