SUMMARY :Tomato leaf curl virus disease (TLCVD) is a serious problem in cultivation and production of tomato in India. The disease is widespread in tomato during the summer season in South India and autumn in North India. In South India, the incidence of TLCVD in susceptible cultivars increases rapidly from 27 to 90 per cent causing yield losses exceeding 90 per cent.The objective of this study was to screen the two newly synthesized tomato F 1 hybrids viz., CLN 2123A X HN 2 and HN 2 X CLN 2123A to find out the leaf curl virus resistance along with their parents and check varieties/hybrids. The experiment was conducted both under natural epiphytotic condition as well as glass house condition through whitefly mediated inoculation. The experiment was laid out in a Randomized Block Design and replicated thrice. The results revealed that the newly synthesized hybrids CLN 2123A X HN 2 and HN 2 X CLN 2123A registered low level of percent of disease infection under artificial and natural epiphytotic conditions and these varieties showed high values of defense enzymes viz., peroxidase and poly phenol oxidase both under artificial and natural epiphytotic conditions. The same hybrids also registered higher plant height, number of branches per plant, number of fruits per plant and yield per plant under field condition inferred that these two synthesized hybrids are tolerant tomato leaf curl virus. These two newly synthesized hybrids were on par with tomato leaf curl virus resistant check hybrid Lakshmi for tomato leaf curl virus disease incidence.How to cite this article : Sundharaiya, K., Jansirani, P., Karuthamani, M. and Sathish, G. (2017). Evaluation of tomato hybrids for resistance to leaf curl virus. Agric. Update, 12(TECHSEAR-3) : 777-783;

Heterosis breeding can be used to achieve improvement in quantity, quality, and productivity of pumpkin (Cucurbita moschata Duch. ex Poir.). A line × tester mating design was used to study standard heterosis for earliness, yield and yield related characters in pumpkin during 2009-2010. Thirty-six hybrids, developed by crossing 12 lines with 3 testers and a commercial check, 'MPH 1', were evaluated for earliness, yield and yield related characters and indicated presence of heterotic vigor. The hybrid 'Kasi Harit' × 'Avinashi Local' had negative relative standard heterosis for the node at which the first female flower appears, sex ratio, fruit number per vine, flesh thickness and total carotenoid content. Heterosis for days to appearance of the first female flower, days to first harvest, sex ratio, fruit number per vine, flesh thickness and total carotenoid content was in the desired direction in 'Vadhalagundu Local' ×'CO 2'. Estimates of standard heterosis for fruit yield indicated that hybrid 'Kasi Harit' × 'Avinashi Local' had the highest positive value followed by hybrid 'Vadhalagundu Local' × 'CO 2'. These hybrids had high heterosis for most component traits, can be used for exploitation of heterosis and released as promising hybrids after multi location testing.Heterosis is a genetic phenomenon and refers to expression of increased, or decreased, hybrid vigor over the mid-parent (relative heterosis), better parent (heterobeltiosis) and the best commercial variety (standard heterosis) in plant breeding. Hybridization to exploit heterosis commercially, or for selection of promising recombinants in subsequent generations, is the prime objective of heterosis breeding. Heterosis in cross-pollinated crops has the potential to increase yield. Superior recombinants identified in subsequent generations could be evaluated for commercial exploitation as cucurbits do not show inbreeding depression.The search for development of a quick and convenient way of combining desirable characters has assumed greater significance in production of F 1 hybrids in pumpkin (Cucurbita moschata Duch. ex Poir.). However, commercial usefulness of a hybrid would depend on its performance compared to the best commercial variety available. The monoecious character, conspicuous and solitary flowers, large seed number per fruit and wide variability for yield, size and shape of fruit make pumpkin useful for commercial breeding. Though several high-yielding varieties have been developed, the best potential can be achieved by developing hybrids with high yield, earliness and superior quality. A wide range of variability in vegetative and fruit characters is available in genotypes. However, little attention has been paid to its genetic improvement. Hybrid vigor can be substantially increased by crossing genetically diverse inbreds and heterosis obtained from genetic diversity among parents (Sharma, 1994). Previous research on pumkin by Mohanty (A c c e p t e d M a n u s c r i p t 3 3 (2002) heterosis, with different parents and hybrids, has dete...

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Heterosis breeding is a potential tool to achieve improvement in quantity, quality, and productivity of pumpkin. A line x tester mating design was used to study standard heterosis for earliness and yield characters in pumpkin. An investigation was carried out during 2009 to 2010 with twelve lines and three testers at

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A field experiment on effect of harvesting techniques and application of bio-stimulants on growth and yield of curry leaf was conducted at Department of Spices and Plantation Crops, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Periyakulam during 2015. The experiment was laid out in split-split design consisting of three factors, viz., factor -I pruning levels (L 1 -15 cm and L 2 -30 cm), factor -II harvest intervals (H 1 -2 months harvest interval and H 2 -3 months harvest interval) and factor -III foliar applications (N 1 -0.25 per cent ZnSO 4 , N 2 -0.25 per cent FeSO 4 , N 3 -2 per cent seaweed extract and N 4 -0.3 per cent humic acid) constituting sixteen treatment combinations. The results have shown that among the harvesting techniques and bio-stimulants the highest growth characters viz., plant height (127.84 and 124.78 cm at first and second harvest), number of secondary branches (7.01 and 13.67 at first and second harvest), leaflet length (7.21 and 7.26 cm at first and second harvest) and leaflet width (3.94 and 3.98 cm at first and second harvest). It was also observed that yield characters viz., leaf yield per plant (643.50 and 714.21 g at first and second harvest) and leaf yield per hectare (4468.46 and 4959.47 kg at first and second harvest).

to study the effect of bio-stimulants on growth and yield of Black turmeric during 2019 -2020. The experimental design was RBD (Randomized Block Design) consisting of five treatments replicated four times. In this study, different organic substances viz., humic acid, panchagavya, vermiwash and neem cake extract were used. Water spray was considered as control. The present study envisages that spraying of 3% Panchakavya resulted in higher plant height, number of leaves, number of tillers, leaf length and leaf breadth. The estimated fresh rhizome yield of 21.83 t ha -1 was recorded from the treatment of 3% Panchagavya and was significantly differed from other treatments.

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