Physiological and Molecular Screening of High Temperature Tolerance in Okra [Abelmoschus esculentus (L.) Moench]

Okra is a vegetable crop adapted to summer temperatures, but heat stress has been shown reduce its growth and productivity. We measured physiological traits of 104 okra genotypes in response high temperature, augmented by the molecular characterization selected identify parents for crossing. Genotypes were exposed short shock (45 °C, 4 h) controlled environment, followed assessment chlorophyll fluorescence (Fv/Fm, Fv′/Fm′) stomatal conductance (gs). DNA was isolated from all using modified CTAB method with additional PVP RNase, amplification 8 polymorphic SSR markers used generate dendrogram. This preliminary screening identified 33 less than 50% genetic similarity contrasting Fv′/Fm′ gs responses. More detailed measurements (Fv/FmFv′/Fm′, gs, photosynthesis (A), efficiency open reaction centre (ΦPSII), electrolyte leakage (EL)) conducted after exposure 45 °C 6 h compared control (30 °C). EL did not significantly increase treatment; contrast, there significant genotype treatment effects observed photosynthetic parameters (A, ΦPSII, gs). In conclusion, cell membranes remained unaffected periods stress, whereas ranking differences (∆) between heat-treated plants (∆Fv′/Fm′, ∆Fv′/Fm′, ∆A, ∆ΦPSII, ∆gs) indicative sensitivity heat.