Characterisation of Tomato (Solanum lycopersicon Mill.) Genotypes for Morphological and Disease Resistance Traits through Cluster Analysis
Uppuluri Tejaswini *
Department of Seed Science and Technology, UAS, GKVK, Bangalore, India.
Parashivamurthy
Department of Seed Science and Technology, UAS, GKVK, Bangalore, India.
R. Siddaraju
Department of Seed Science and Technology, UAS, GKVK, Bangalore, India.
K. Vishwanath
Department of Seed Science and Technology, UAS, GKVK, Bangalore, India.
T. M. Ramanappa
Department of Genetics and Plant Breeding, UAS, GKVK, Bangalore, India.
K. N. Srinivasappa
Department of Horticulture, UAS, GKVK, Bangalore, India.
N. Nagaraju
Department of Plant Pathology, UAS, GKVK, Bangalore, India.
*Author to whom correspondence should be addressed.
Abstract
The characterization of germplasm is crucial for breeding and developing improved seed varieties. In this study, seed material was collected from M/s. Noble Seeds Pvt. Ltd., Yelhanka, focusing on genotypes with varying resistance to Tomato Leaf Curl Virus (ToLCV). The research was conducted during the Kharif seasons of 2021 and 2022 in Kestur Village, Doddballapura. Morphological characterization was performed according to DUS guidelines set by PPV&FRA, assessing 20 qualitative and 22 quantitative traits. The genotypes were grown in a randomized complete block design for reliability. Multivariate cluster analysis was employed to group the genotypes based on the morphological traits assessed, enabling the identification of patterns and relationships among them. This analysis facilitated the formation of distinct clusters, highlighting the genetic diversity and similarities among the genotypes, which are crucial for targeted breeding strategies. Through multivariate cluster analysis, two main clusters (A and B) were identified, each further divided into two sub-clusters (C and D). Overall, 66.67% of the 30 genotypes (20 in total) were grouped in Cluster E, while 5 genotypes were placed in Cluster C, 3 in Cluster D, and only 2 in Cluster F. The analysis revealed that NBLTM-22 and NBLTM-11 exhibited the highest variation between them, while genotypes within clusters demonstrated greater similarity.
These findings underscore the importance of genetic diversity in breeding programs, highlighting that closer proximity in clustering correlates with trait similarity among genotypes. This information can guide further breeding efforts aimed at developing ToLCV-resistant varieties.
Keywords: Tomato genotypes, characterization, cluster analysis, Ty gene and ToLCV resistance