No abstract

Paucity of research on the development of tomato hybrid having desirable post harvest/or processing quality in the tropics compel to undertake this study. Therefore, the present investigation was undertaken to identify potential donors and crosses, to study the extent of heterosis and dominance behaviour, and to ascertain the genetic control of fifteen yield components and post harvest quality traits through line x tester mating design in tomato. Non-additive gene action controlled all characters studied, suggesting heterosis breeding for their improvement. Among parental lines, CLN2777-G’ and ‘FEB-2’ were the best general combiners for yield and processing traits and could be utilized further in tomato breeding programme. Crosses (‘CLN2768-A x A.C.AFT’ and ‘CLN2777-G x FEB-2’) showing high specific combining ability and yield involved parents showing high general combining ability for fruit yield per plant and other horticultural traits. All 9 F1 hybrids had significantly higher number of fruits per cluster and number of fruits per cluster over both mid-and better-parental values, while for the other traits, hybrids expressed average heterosis in both directions. The maximum extent of heterobeltiosis (53.56%) was found in lycopene content of fruit followed by number of fruits per cluster (32.59%) and fruit yield per plant (31.77%). The performances of the hybrids illustrated the presence of various degrees of dominance effects i.e., partial to overdominance /or no dominance. We could able to improve processing quality in spite of yield in the cross (‘CLN2777-G x FEB-2’) which can substantially make a dent for processing industry in the tropics.

Brinjal has immense potential for the development of desirable recombinants for export trade through heterosis breeding. Therefore, half-diallel mating design involving six optimally diverse parents was used to determine heterosis, dominance reaction, combining ability, and gene action for eleven quantitative traits in brinjal. The predictability ratio revealed overwhelming response of non-additive gene action for conditioning of all the studied traits, suggesting that heterosis breeding could be used for their improvement. The maximum extent of significant heterobeltiosis in desired directions was recorded for total sugar content of fruits (105.10 %) followed by marketable fruit yield per plant (91.77 %), number of marketable fruits per plant (85.86 %), and fruit borer infestation (-77.54 %). The study identified three outstanding brinjal hybrids (Gujrat Brinjal Round 9 BCB-10, Gujrat Brinjal Round 9 10 BRR Var-2, and BCB-10 9 10 BRR Var-2) having all the desirable traits for export. The hybrids also exhibited various degrees of dominance effects in the inheritance of marketable fruit yield and other desirable traits.

Selection of parental lines for considering export trade in hybridization programme is a new approach in brinjal breeding. Eight quantitative characters were taken to estimate genetic variation and relationships among twenty seven genotypes of round fruited brinjal, and to identify potential donors for the development of recombinants suitable for export. Analysis of variation revealed considerable level of variability among the genotypes. High broad sense heritability (˃80 %) and genetic advance as per cent of mean (˃20 %) were observed for the maximum number of traits under study. Among the yield components, only number of marketable fruits per plant showed positive and significant correlation (r = 0.771 and 0.725 at genotypic and phenotypic level, respectively) with marketable fruit yield per plant. However, number of marketable fruits per plant (1.24) followed by average fruit weight (0.834) ex-hibited maximum positive direct effects on marketable fruit yield per plant suggesting to give emphasis on these traits while imposing selection for amenability in fruit yield of round fruited brinjal. Principal component analysis showed the amount of variation by principal components 1 to 4 viz., 26.75, 49.98, 69.81 and 84.28 %, respectively. Divergence analysis based on various yield component traits grouped 27 brinjal genotypes into nine main clusters. Dendrogram based on hierarchal clustering grouped genotypes based on their yield component traits rather than their geographic origin. Based on averages and principal component analysis, six genotypes (BCB-30, Deshi Makra, Gujrat Brinjal Round, 09/BRBWRes-3, BCB-10, 10/BRRVar-2) appeared to be promising donors for use in export oriented breeding programme.