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Genetic diversity plays a crucial role in harnessing the potential of crop genotypes for genetic improvement. It helps to identify, preserve, and utilize diverse landraces effectively. This research aimed to assess the level of genetic diversity and traits enhancing genetic variation among 46 brinjal genotypes (Solanum melongena L.) in preparation for a special breeding programme to utilize the potential landraces. Genetic divergence among 46 genotypes of brinjal for eleven characters was assessed using the D² method. The studied genotypes were categorized into eight clusters. Cluster I with 15 genotypes was the largest followed by Cluster IV (14 genotypes), Cluster V (7 genotypes), Cluster VII (4 genotypes), Cluster III (3 genotypes), Clusters II, VI, and VIII with one genotype each. The intra-cluster D² values ranged from 0.00 (Cluster II, VI and VII) to 103.53 (Cluster III). The inter-cluster distances varied from 117.00 to 791.17. Cluster II and Cluster VII had the greatest inter-cluster distance (791.17), followed by Cluster II and VIII (673.41), and Cluster VII and Cluster V had the smallest inter-cluster distance (117.00). Crossing genotypes in clusters with wide inter-cluster distances improves recombinant isolation in segregating generations. The three traits-number of flowers per inflorescence (23.8%), average fruit weight (17.68%) and days to first flowering (16.81%) altogether contribute to 57.8% of the total divergence. The combination of these traits could be useful to produce high-yielding climate resilient varieties from valuable landraces. [ABSTRACT FROM AUTHOR]

A study on heterosis in brinjal was carried out during the year 2019-20 at the Department of Genetics and Plant Breeding, Annamalai University. Seven genotypes were hybridised in full diallel fashion and the resultant 42 hybrids were evaluated along with parents in RBD. The mean squares of the 11 traits revealed significant differences among the entries. The hybrid ICO-345590 x Arka Kusumkar recorded high heterobeltiosis for fruit yield per plant and its associated traits except for fruit grith, fruit length, plant height, and days to first harvest. High standard heterosis was recorded by the hybrid ICO-344674 x ICO-383119 for plant height, ICO-344674 x Arka Kusumkar for days to first harvest, Arka Kusumkar x ICO-345590 for fruit length and ICO-345590 x ICO-545862 for fruit girth. The application of heterosis in brinjal will aid in the production of superior cross combinations, which will help meet the expanding demand for brinjal due to its bioactive properties. [ABSTRACT FROM AUTHOR]

An experiment was conducted with the objective of determining the magnitude of association between seedling vigour index and its component characters. Fifty rice genotypes were evaluated in completely randomized design with three replications. Correlation coefficient analysis of vigour index showed positive and significant association with total seedling length, root length, total seedling dry weight, root dry weight, shoot length, germination percentage and first leaf area under normal condition. Germination percentage, total seedling length, root length, shoot length and first leaf area showed strong and significant positive association with seedling vigour index under cold condition. Thus, these traits could play pivotal role in developing cold tolerant rice. Separation of correlation coefficients into direct and indirect effects of component traits for vigour index revealed that the traits total seedling length and root dry weight exerted maximum positive direct and indirect effect respectively on vigour under normal condition. Under cold stress the traits shoot length and root length exerted maximum positive direct and indirect effects respectively for vigour index. These characters, therefore, are required to be considered during selection for vigour improvement in rice under normal and cold condition in rice. [ABSTRACT FROM AUTHOR]