Multivariate Analysis of Morpho-physiological and Biochemical Traits in Barley Genotypes under Heat Stress

The experiment was conducted during the December-April, 2022–23 and 2023–24 at the Barley Research Area of the Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar, Haryana, India to estimate the genetic variation and association among 22 morpho-physiological and biochemical traits in 51 barley (Hordeum vulgare L.) genotypes under heat stress conditions using principal component analysis. The trials were carried out in randomized block design with three replications having plot size of 2.5x0.46 cm². The results revealed highest coefficients of variation for 1000-grain weight followed by number of grains spike^-1 and plant height, implies the significance of traits for genetic improvement, while the low variation observed for days to maturity and transpiration. The PCA results revealed that the first eight principal components (PCs) accounted for 71.5% of the total variation. The first principal component (PC1) explained 19.5% of the total variation and also showed strong association with grain yield plant^-1, biological yield, SPAD, 1000-grain weight, NDVI 1, number of tillers plant¹, total soluble sugars and photosynthetic rate. The genotypes BH 19–44, BH 1029, BH 946, BH 1039, EIBGN-1, EIBGN-48, Lakhan, NBGSN-1, NBGSN-9 and RD 2907 exhibited strong yield potential under heat stress, highlighting their adaptability to adverse conditions. Further, the association of PC1 and PC2 with productivity and stress tolerance traits, respectively serve as key indicators for breeding selection. Hence, the study reflected substantial genetic variability among the barley genotypes studied and demonstrated the utility of principal component analysis in understanding and evaluating complex traits.