Evaluation of diverse wheat genotypes for potential biomass production through physiological parameters at seedling stage under controlled environment

Thirty wheat genotypes from UK, CIMMYT and Pakistan were evaluated under controlled environment conditions for their potential biomass production by measuring stomatal conductance (g s ; porometry), leaf photosynthesis (IRGA), carbon isotope discrimination and carbon content (isotope ratio and mass analysis) at Rothamsted Research, Harpenden, UK during 2011.Amongst the dwarf genotypes, Rht2 and Rht3 showed lower stomatal conductance than Seri 32B, Seri 87B and Bathoor-07.For these 5 genotypes and another genotype 'Inqalab' photosynthetic performance was determined by means of IRGA measurements.Of these genotypes Inqalab had the highest photosynthetic activity (A), stomatal conductance (g s ), transpiration (E) and leaf intercellular CO 2 but it also had the lowest water use efficiency (A/g s ) and intrinsic water use efficiency (A/E).Seri-87B had the greatest water use efficiency (A/g s ) and intrinsic water use efficiency (A/E).All the Pakistani genotypes had large stomatal conductances and high 13 C delta (Δ) and thus may be expected to produce high biomass under irrigations and optimum inputs.