Genotypic variation in diverse bread wheat (Triticum aestivum L.) for photosynthesis related traits, biomass and yield in response to low phosphorus stress

Phosphorus (P) is an indispensable nutrient for plant growth and development. Deficiency of P adversely affects photosynthesis, biomass accumulation and yield potential in wheat. We evaluated 103 diverse bread wheat (Triticum aestivum L.) genotypes under low P (LP) and optimum P (OP) conditions in terms of photosynthetic traits, biomass, and yield. Results revealed that under LP, transpiration rate (E) significantly increased while net assimilation or photosynthetic rate (A), stomatal conductance (g_s), instantaneous-water use efficiency (IWUE), biomass, yield, and harvest index (HI) decreased. The LP stress tolerant and sensitive genotypes were identified using principal component analysis (PCA) ranking values of genotypes based on the relative values of six most contributing traits. Further, hierarchical cluster analysis also validated the variability among the genotypes and grouped P stress-tolerant and sensitive genotypes into distinct clusters. The P stress-tolerant genotypes exhibited a relatively lesser reduction in photosynthetic rate, g_s, yield, and HI as compared to P stress-sensitive genotypes in response to LP. Our results substantiate the genetic potential inherent in Indian bread wheat genotypes, which can be used as donors in breeding programs to develop P-efficient wheat varieties.