Rootstock evaluation and grafting studies in brinjal (Solanum melongena L.)

Abstract

The present investigation was conducted at Agricultural Research Station, Mannuthy and Centre for Hi-Tech Horticulture and Precision Farming, Vellanikkara, Thrissur during the year 2018-2019 with the objective to evaluate ten available rootstocks comprising of Surya, Haritha, SMI, SM2, SM3, SM116, SM398, Solanum sisymbrifolium, Sokmum torvum KAUl, Solanum torvum TNAUl for resistance to bacterial wilt in both field evaluation and artificial Inoculation and to study the field performance of grafted brinjal plants on bacterial wilt resistant rootstocks. In the field trials Solanum sisymbrifolium was highly susceptible to bacterial will with 96.6% wilt incidence whereas SM398 (40% PDI), SM2 (40% PDl), SMI (23.3% PDI), Solanum torvum KAUl (16.6% PDI) and Solanum torvum TNAUl (20% PDI) were found moderately resistant to bacterial wilt. Genotypes such as Surya, Haritha, SM3 and SM1I6 found highly resistant to bacterial wilt even when spot planted with susceptible check genotype Pusa Ruby which showed 100 percent wilt incidence. The PDI in check genotype Pusa Ruby ranged from 86.67 per cent to 100 per cent. Solanum sisymbrifolium spot planted with Pusa Ruby took minimum number of days to wilt incidence (23.40 days) whereas SM398 took maximum days to will (32.3 days). Under artificial inoculation the genotype Solanum sisymbrifolium exhibited 73.33 per cent will incidence along with the susceptible check Pusa Ruby which exhibited 86.6 per cent wilt incidence and both the genotypes were classified as susceptible to bacterial wilt. All other genotypes viz,, Surya, Haritha, SM 1, SM2, SM3, SM 116, SM398, Solanum torvum KAU1 and Solanum fon'um TNAUl did not show any wilt incidence under artificial inoculation and were resistant to bacterial wilt. Solanum sisymbrifolium took more number of days to wilt (16.81 days) when compared to the susceptible check Pusa Ruby (9.77 days). The root dip method recorded highest PDI in both susceptible genotype Solanum sisymbrifolium (86.67%) and the susceptible check Pusa Ruby (100%) when compared to media drenching and stem injection methods and the number of days to wilt incidence was also the lowest in root dip method (11.70 days) followed by stem inoculation (12.25 days) and media drenching (26.50 days). Significant differences were observed with respect to plant height, plant spread, stem girth, number of primary branches, fruits per plant, fruit length, fruit girth, average fruit weight, yield per plant, total phenolic, dry matter, number of wilted plants, root length and root spread among ail the rootstocks used when compared to non-grafted control and all the grafted plants produced significantly better performance for all the above parameters irrespective of the rootstocks used. Maximum yield per plant (6.69 kg), number of fruits per plant (94.80), plant spread, stem girth, number of primary branches, fruit lengtli (22.22 cm), root length (63.65 cm) and root spread (87.05 cm) were recorded when cullivar Haritha was used as a rootstock. The highest plant height, fruit girth (10.97 cm) and average fruit weight (78.00 g) were recorded on SMI 16 rootstock. Highest dry matter content was found in fruits of grafted plants of SM398 (11.12%) and the total phenolic content was the highest when SM3 (113.30 mg/l OOg) was used as rootstock. Maximum numbers of wilted plants were observed in non-grafted control. The perfonnance of non-grafted control plants was poor for all the above characters studied. Grafting did not significantly influence earliness, duration of the crop or number of harvests or total soluble solids content of fruits in brinjal. It had no significant effect on incidence of other pests on the crop except for bacterial wilt. From above studies it could be summarised that spot planting could be used as an effective tool for screening brinjal genotypes against bacterial wilt. Grafting technology could be successfully utilised in brinjal not only for bacterial wilt resistance but also for obtaining higher productivity. Haritha was found to be best rootstock for grafting in brinjal as it recorded significantly higher yield per plant, number of fruits per plant, plant spread, stem girth, number of primary branches, fruit length, root length and root spread followed by SMI 16 rootstock which recorded the highest plant height, fruit girth and average fruit weight.