Dr. R.V.S.K. REDDYRAJEEV KUMAR NAROLIA2016-07-212016-07-212009-11http://krishikosh.egranth.ac.in/handle/1/69127The present investigation was undertaken to estimate the genetic divergence in tomato and to carry out yield component analysis through correlation and path analysis. Fifty five genotypes were sown in a randomized block design with two replications, during rabi 2008-2009 at Vegetable Research Station, Agriculture Research Institute, APHU, Rajendranagar, Hyderabad. The objective of the experiment was to identify divergent genotypes to use as donor parents in hybridization programmes. The D2 analysis was carried out for thirteen characters which partitioned the fifty five genotypes into twelve clusters. The maximum genetic divergence was observed between clusters IX and XII followed by between clusters V and IX. The maximum intra cluster distance was shown by cluster V. The characters viz., acidity content followed by shelf life, plant height, TSS, ascorbic acid content, average fruit weight and number of fruits per plant contributed greatly towards diversity. The clusters showed high genetic divergence that could be effectively utilized in heterosis breeding programme. If a breeding programme is used at improving nutritional characters, then cluster VII showing maximum ascorbic acid that can be utilized in breeding programme. Therefore, a plant breeder may keep in mind the above aspects to obtain superior hybrids and good recombinants. The analysis of variance revealed significant difference for thirteen characters studied suggesting considerable amount of variability exists among the genotypes. Wide range of variability was observed for plant height, number of flower clusters per plant, number of fruits per plant, average fruit weight, ascorbic acid and fruit yield per plant indicating the scope for selection of suitable initial breeding material for further improvement. GA as percent of mean, GCV and PCV values are on par with each other for most of the characters that the influence of the environment on the trait (s) was very very negligible. The values observed are not confounding with the environment. It is a true to the reflection of the homeostasis effect or buffer reaction of the gene. Thus, the true reflection of the trait is exhibited. In a true agreement with the GCV and PCV values in the present investigation for the 12 characters was noticed, indicating additive genetic variance governing the high heritability with genetic advance as percent of mean. Thus a breeder can employ a simple selection process which will be a rewarding one to improve the characters viz., plant height, number of primary branches per plant, number of flowers per cluster, number of fruits per plant, number of flower clusters per plant, average fruit weight, number of locules per fruit, acidity, total soluble solids, ascorbic acid, shelf life and fruit yield per plant. For days to 50 per cent flowering, high heritability with low GA as per cent of mean indicates non additive action controlling the traits. Thus, selection for days to 50 per cent flowering may not be rewarding. From correlation studies it was observed that fruit yield per plant has exhibited highly significant positive association with average fruit weight and shelf life. Path analysis revealed that maximum positive direct effect on fruit yield per plant was exhibited by average fruit weight followed by number of fruits per plant. Therefore, it is emphasized to lay attention on these traits like average fruit weight, number of fruits per plant and shelf life in crop improvement programme of tomato in future. On the basis of the mean performance of the genotypes among traits studied, the following were identified as promising lines for further crop improvement in tomato viz., EC-163611, EC-257580, EC-162508, EC-165749, EC-157568, EC-145622, EC-164863, EC-177393, LE-54, LE-55, LE-59, LE-60, LE-61, LE-63, LE-65 and LE-67.engenetic divergence ,variability ,hybridization programmes ,GCV and PCV ,correlation studies , promising linesThesis