Genetic Variability for Net Photosynthesis in Finger Millet (Eleusine coracana Gaertn) Genotypes An Approach to Identify High CER Types

Abstract

AbstractGermplasm lines of finger millet (400 lines) with diverse genetic background were screened to identify high CER and CGR genotypes. Considerable variation was noticed in LA, biomass and all the growth and yield attributes but range in stomatal frequency was relatively less. The difference in plant stomatal number was more due to variation in LA but not the frequency. Since high TDM is a primary criteria for achieving higher grain yield, from amongst the high biomass types, genotypes differing in LA/DM ratios but with similar DM and HI were selected. In six genotypes each from low and high LA/DM group which showed stability across the environment, gas exchange characteristics were studied. The CER in low LA/DM types was 45 per cent higher. A significant negative relationship (r = ‐0.87) exists between CER and LA/DM ratios. Higher net assimilation rate in these genotypes therefore could be attributed mainly due to CER rather than the dark respiration.An approach to identify high CER types with high CGR and low plant conductances from the germplasm lines has been proposed. These conceptual types will have high CGR but with low functional LA, thus low transpiration leaf surface. These conceptual types will have specific advantage under rainfed water limited conditions.