Assessment of Genetic Divergence Based on Qualitative and Quantitative Characters among the Hundred Sweet Potato (Ipomoea batatas L. Lam.) Accessions

Abstract

Sweet potato is an important starchy root crop and assessment of genetic diversity among germplasm accessions is essential for identifying superior genotypes for yield improvement and breeding programs. The present study was conducted at the Research Farm of Tirhut College of Agriculture, Dr. Rajendra Prasad Central Agricultural University, Dholi, Bihar-848125, India, during the Rabi season of 2022-23. The experimental site is located at 25.99°N latitude, 85.60°E longitude and an altitude of 52.12 m. A total of 100 distinct sweet potato accessions were evaluated using an augmented block design comprising four blocks and two check varieties, focusing on 13 qualitative and 12 quantitative morphological traits. The study aimed to assess genetic diversity and identify key traits influencing yield. Significant variability was observed across all traits, indicating a broad genetic base. Principal component analysis revealed that the first three components accounted for 99.47% of the total variation, with the first component alone contributing 87.37%, highlighting the predominance of yield attributes. Mahalanobis’s D² analysis grouped the accessions into eight distinct clusters, with maximum inter-cluster distance observed between clusters IV and VIII (103.72), suggesting high genetic divergence and scope for good combining ability. Cluster mean analysis identified superior clusters for tuber yield per plant and its contributing traits viz. number of tubers per plant and average tuber weight, while trait contribution analysis indicated that number of tubers per plant had the highest influence on genetic divergence. Qualitative trait assessment grouped accessions into two major clusters further confirmed substantial morphological diversity particularly in tuber shape, skin colour and flesh colour, which are important for market preference and nutritional quality. Overall, the study identifies key traits and genetically diverse accessions that can be strategically utilized for developing high yielding, nutritionally enriched and climate resilient sweet potato cultivars.