PG Thesis
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Item Rootstock evaluation and grafting studies in brinjal (Solanum melongena L.)(Department of Vegetable Science, College of Horticulture, Vellanikkara, 2019) Sadanand Kumabar; Narayanankutty, CThe 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.Item Entomopathogenic fungi for the management of banana rhizome weevil (cosmopolites sordidus germer)(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Varsha Vijayan; Anitha, NThe study entitled “entomopathogenic fungi for the management of banana rhizome weevil, Cosmopolites sordidus Germer” was conducted at College of Agriculture, Vellayani during 2015-17. Objective of the study was to evaluate the biocontrol potential of entomopathogenic fungi for the management of banana rhizome weevil. Adults and grubs of the rhizome weevil were collected from Thiruvananthapuram district and were observed for infestation by entomopathogenic fungi. From the infected adult weevil, Fusarium solani (Mart.) Sacc. was isolated and its pathogenicity was proved on adults and grubs of C. sordidus. Pathogenicity studies with entomopathogenic fungi Metarhizium anisopliae (Metchnikoff) Sorokin (Ma4), Beauveria bassiana (Balsamo) Vuillemin (Bb5), Beauveria bassiana (ITCC6063), Purpureocillium lilacinum (Thorn) Samson (ITCC6064) and F. solani were carried out on adults and grubs of C. sordidus. Grubs of C. sordidus treated with M. anisoliae (Ma4) caused mortality at 24 Hours after treatment (HAT) and white mycelial growth initiated two days after death which later changed to green color. In case of adults, mortality occurred 72 HAT. B. bassiana treated on grubs of C. sordidus caused mortality at 24 HAT and developed pink color after three days and later white cottony mycelial growth was observed on body. On adults, death occurred 72 HAT and extensive mycelial growth covered the body except the dorsal elytra after four days of treatment. P. lilacinum when treated on grubs caused mortality at 48 HAT and produced pink color one day after death and white mycelia covered the body. In adults, mortality initiated four days after treatment and extensive mycelial growth was observed on dorsal and ventral side. At 48 HAT, F. solani caused mortality of grubs of C. sordidus and produced brown color on shrunken grubs which later changed to creamy white stiff grubs. All the tested fungi were found to be pathogenic to both adults and grubs of C. sordidus. Under laboratory conditions the effective spore concentrations of the fungi were found out by testing different concentrations on adults and grubs. M. anisopliae (Ma4) @ 1.29×108 spores mL-1recorded 100 per cent mortality of grubs at 168 HAT. On adults M. anisopliae @ 2.1×108 spores mL-1 recorded 35 per cent mortality. B. bassiana (Bb5) @ 1.2×108 spores mL-1 when treated on grubs caused 95 per cent mortality at 216 HAT. Whereas in adults, B. bassiana caused 40 per cent mortality @ 2.5× 108 spores mL-1. P. lilacinum @ 1.9×108 spores mL-1 recorded 85 per cent mortality at 192 HAT when treated on grubs. At a spore concentration of 2.1×108 spores mL-1 P. lilacinum caused 30 per cent mortality. B. bassiana (ITCC6063) and F. solani caused less than 50 per cent mortality of both grubs and adults of C. sordidus. Evaluation of entomopathogenic fungi for the management of C. sordidus under field conditions was done by conducting three pot culture experiments; viz. rhizome dip method, prophylactic soil drenching and curative soil drenching. The study revealed that spore suspension of M. anisopliae @ 108 spores mL-1 when applied as rhizome dip method was more effective with least damage in rhizomes (10.83 per cent), lowest number of tunnels (0.49) and the least number of live immature stages (0). In the prophylactic soil drenching, spore suspension of M. anisopliae @ 108 spores mL-1 was found to be effective with least rhizome damage (14.16 per cent), number of tunnels (1.08) and number of live immature stages (1.25) followed by its talc formulation with a rhizome damage, number of tunnels, and immature stages of 14.16 per cent, 1.16 and 0.66 respectively. In curative soil drenching, spore suspension of M. anisopliae recorded least rhizome damage (10 per cent) and was statistically on par with talc formulation of M. anisopliae and B. bassiana @30 g L-1 (12.49 per cent). Soil drenching given as curative treatment was more effective than the prophylactic method. Talc formulation of Ma4 and Bb5 was equally effective when applied as curative soil drenching. To conclude, isolate F. solani was isolated from the cadaver of C. sordidus. F. solani, NBAIR isolates viz. M. anisopliae (Ma4) and Beauveria bassiana (Bb5) and local isolates available in department of Agricultural Entomology B. bassiana (ITCC6064), P. lilacinum (ITCC6064), were identified to be pathogenic to grubs and adults of C. sordidus. In laboratory conditions, M. anisopliae @ 108 spores mL-1 was found to cause 100 per cent mortality of grubs. Curative application by soil drenching of talc formulation of M. anisopliae and B. bassiana 108 spores mL-1 @ 30g L-1 was found to be effective for the manangement of C. sordidus.