Morphological Diversity Assessment and Characterization of Cultivated and Indigenous Germplasm of Apple (Malus × domestica Borkh.) in India

Abstract

Apple cultivation is one of the major means of subsistence in the Himalayan region of India. The existence of delicious group of cultivars has a tendency to dominate, resulting in a mono-cropping system. In order to diversify cultivation and extend the harvest season, there is a need to evaluate new cultivars based on physico-chemical attributes of their fruit, which determine the market prices for the same. This needs to be done before the recommendation of new cultivars to farmers for adoption. Exploration of indigenous genetic resources may also help to identify promising selections suitable for cultivation. The present study aimed at assessment of variability and germplasm characterization of forty-eight apple cultivars and indigenous selections in the Bhaderwah region of Jammu & Kashmir (J&K). The study evaluated different morphological characteristics, which showed that growth habit of the genotypes was predominantly spreading (62.5%), followed by upright (33.33%), and drooping (4.17%) forms. Tree vigor was strong (50%), medium (39.58%), and weak (6.25%). Tree height ranged from 3.25 meters (BA-1) to 5.68 meters (BA-19), and leaf area ranged from 22.78 cm² (BA-39) to 41.44 cm² (BA-3). The flowering period ranged from 21 to 25 days. Out of 48 genotypes, 32% were early bloomers, 52% were mid-bloomers, and 16% were late bloomers. Fruit set was as high as 87.57% (BA-4) and as low as 37.89% (BA-19). The PCA and Cluster analysis showed positive correlations among different morphological traits, indicating their potential for direct or indirect selection in breeding programs. The PCA highlighted the most diverse germplasm, which was genotype BA-46 and BA-47, while Cluster analysis grouped the genotypes into distinct groups with Cluster II showing notable variation. Based on the results of this study, it is concluded that there is wide diversity among the germplasm under investigation for morphological traits. Notably, the seedling-origin plants differed markedly from the commercial apple cultivars. It is recommended that these promising seedling strains be considered for further breeding programs to improve apple production and quality in J&K, particularly in the Bhaderwah region.