Principal Component Analysis in Kodo Millet (Paspalum scrobiculatum) under Salt Stress Conditions

Abstract

The study was carried out in a polyhouse using germination trays to examine the impact of salt stress on seedling growth and germination across 42 Kodo Millet genotypes. Conducted at the Research Farm of RVSKVV, Gwalior, the experiment followed a Completely Randomized Design (CRD) with three replications. To minimize variability and maintain uniform conditions, a standardized growing medium composed of compost, vermiculite, and cocopeat in a 1:1:1 ratio was employed. Salt stress levels were assessed using NaCl solutions at concentrations of 50 mM, 100 mM, 250 mM, and 500 mM. In this study, two principal components with eigen values greater than one collectively accounted for 72.2% of the total variability among the analyzed traits. The first principal component (PC1) contributed the most, explaining 63.05% of the variation, while the second principal component (PC2) explained 9.15%. PC1 was primarily associated with traits such as days to emergence, final germination percentage, shoot length, seedling length, shoot fresh weight, root fresh weight, total fresh weight, total dry weight, and proline content. In contrast, PC2 was dominated by traits such as root length, vigor index, chlorophyll a, and chlorophyll b. The scores for PC1 ranged from 0.002 to 3.795 for positive values and -7.521 to -0.034 for negative values, while PC2 scores ranged from 0.061 to 2.894 for positive values and -2.687 to -0.089 for negative values. Scree plot and biplot collectively highlighted the major contributors to variability and their interrelationships under the salt stress condition in kodo millet genotypes.