Variability in photosynthetic traits is associated with biomass accumulation and grain yield in basmati rice germplasm

Rice productivity has reached a plateau, and further yield improvement can be possible by exploiting the physiological traits. Higher grain yield and biomass production are important agronomically desired targets for a successful breeding program. A field study was conducted using mini core collection of 135 basmati rice germplasm to analyze variability in growth, photosynthetic and gas exchange traits, and yield parameters. Eleven diverse morphological and physiological traits under standard agronomic practices were scored in the study. At 50% flowering, plant samples were analysed for growth traits. Photosynthetic and gas exchange traits of the fourth leaf from the top were measured. Most of the growth and photosynthetic traits showed variability among the rice genotypes, and the magnitude of variability among them was quite large. The shoot biomass varied between 8 to 95 g hill −1 and tiller number were 5 to 22 tillers hill −1 across the genotypes. Similarly, grain weight was observed in the range of 1.16–25.16 g per plant. Photosynthesis rate ranged between 6 to 26 µmol CO 2 m −2 s −1 and transpiration rate from 3 to 10 mmol H 2 O m −2 s −1 among basmati rice germplasm. There was a strong positive correlation between shoot biomass and days to flowering and between gas exchange traits, while photosynthesis rate showed no correlation with shoot biomass and grain yield. The study suggests that the variability in diverse morphological and physiological traits and their correlation with grain yield can be useful as selection criterion for breeding high yielding basmati rice cultivars.