Principal component analysis of exotic lettuce varieties in North Bank plain zone of Assam

Lettuce (Lactuca sativa L.) is a widely cultivated leafy vegetable known for its nutritional value and culinary uses. Although its cultivation is expanding in India, there has been limited research on identifying varieties suited to the agro-climatic conditions of Assam, particularly in the North Bank Plain Zone. This study evaluated genetic divergence among seven exotic lettuce genotypes using Principal Component Analysis (PCA), based on 20 quantitative morphological and physiological traits. The experiment was carried out during the rabi season of 2018-2019 at the Biswanath College of Agriculture, Assam Agricultural University, in a Randomized Block Design with three replications. PCA results revealed that the first four principal components, each with eigenvalues exceeding one, accounted for 93.66% of the total variation. The first principal component alone explained 57.20% of the variance and was largely influenced by traits such as plant height, canopy spread, leaf dimensions, head diameter, and fresh head weight. These traits emerged as major contributors to variability among genotypes. The study highlights the utility of PCA in simplifying complex trait data and identifies key parameters for selecting high-yielding lettuce varieties adaptable to Assam’s growing conditions.