Tania Seth

Breeding Eggplant for Higher Productivity and Bacterial Wilt Tolerance

Eggplant (Solanum melongena L.) has the potential for improvement through heterosis breeding, which can be further utilized for development of desirable recombinants. A Line × Tester mating design was used to determine heterosis over better parent, combining ability, and gene action for 11 characters in eggplant. Crosses showing high specific combining ability (sca) and yield involved parents showing high general combining ability (gca) for fruit weight, fruit diameter, or fruit length. Two hybrids, ‘VNR-218’ × ‘BCB-11’ and ‘Arka Nidhi’ × ‘KS-331’ were selected on the basis of their per se (mean) performance: heterosis and the sca effects. These hybrids could be used commercially due to high yield and low percentage disease index (PDI) values for bacterial wilt disease. The preponderance of nonadditive gene action was evident for control of all characters studied. Parental lines and hybrids were categorized according to disease reaction. Average large vessel area of stems and roots of the hybrids was negatively correlated with PDI. Larger vessel area in the vascular bundle needs to be considered in the selection of hybrids for resistance to bacterial wilt disease.

Heterobeltiosis, potence ratio and genetic control of processing quality and disease severity traits in tomato

Five inbred lines of tomato were crossed in a half diallel fashion to estimate the combining ability, mode of gene action, extent of heterobeltiosis and dominance effects in the inheritance of fruit yield, processing qualities and disease severity traits. A preponderance of non-additive gene action was detected for all studied characters except fruit weight, indicating that heterosis breeding is an appropriate strategy for their improvement. Maximum heterobeltiosis was observed for the percent disease index (PDI) of tomato leaf curl viruses (ToLCV), followed by the number of locules per fruit, PDI of early blight, fruit yield per plant, lycopene content of fruit, vitamin C content of fruit, total soluble solids content of fruit and acidity content of fruit. Partial- to over-dominance effects were involved in the inheritance of the studied traits. Three lines (CLN 2777E, BCT-115 and CLN 2777F) were identified as potential donors. We recommend that two hybrids (CLN 2777 F × CLN 2777 E and CLN 2777E × Ailsa Craig fulgens) would be appropriate for commercial use following further evaluation of their traits, as they exhibit desirable horticultural traits, particularly in the tropics.

Evidence of Economic Heterosis and Genetic Control of Fruit Yield and Yellow Vein Mosaic Virus Disease Severity Traits of Okra

Evidence of Economic Heterosis and Genetic Control of Fruit Yield and Yellow Vein Mosaic Virus Disease Severity Traits of Okra) Ten diverse genotypes of cultivated and wild species were crossed in half diallel fashion to produce 45 F1 hybrids to determine mode of gene action, extent of economic heterosis and dominance effect, and to estimate combining ability for eight quantitative traits. Predictability ratio revealed overwhelming response of non-additive gene action for controlling fruit length, number of fruits per plant, and fruit yield per plant; additive gene effects for days to 50% flowering, while both additive and non-additive genetic control for node number at first flowering, fruit weight, fruit girth, and PDI of YVMV disease. Appropriate breeding strategies for improvement of studied traits are highlighted here. Significant standard heterosis over two commercial hybrids, Shakti and Abantika was comparatively lower in magnitude for fruit yield per plant (4.62 % and 17.59 %, respectively) and higher in magnitude for PDI of YVMV disease (-71.28 % and -72.28 %, respectively). Partial- to overdominance effects were involved in the inheritance of the studied traits. BCO-1 and 11/RES-6 were identified as potential donors for future use. The study could able to identify an outstanding hybrid (BCO-1 × Arka Anamika) having high tolerance both under field and artificial conditions. This hybrid would definitely make a room in okra growing zones of the tropics after critical testing..