Theses

An investigation on the influence of VAM inoculation on nutrient uptake, growth, yield and bacterial wilt incidence of tomato (Lycopersicon esculentum Mill.) was carried out at the College of Horticulture, Vellanikkara during the period 1996 - 2000. The objectives of the study were to select an efficient VAM fungus for improving nutrient uptake, growth and yield of tomato, to explore the possibility of reducing the use of phosphorus fertilizer by VAM inoculation and also to study its influence on bacterial wilt incidence. The survey conducted revealed the natural occurrence of VAM association in tomato at different locations of Kerala. There was variation in VAM colonization and rihzosphere spore count among the locations. Predominant VAM fungi associated with tomato at the survey locations belonged to the genus Glomus. Out of the fifteen native isolates and four standard cultures, Glomus mosseae, Glomus fasciculatum, Glomus intraradices and Gigaspora margarita, the native isolate collected from Eruthempathi (Palakkad District) was found to be the best in improving nutrient uptake, growth and yield of tomato variety, Sakthi. Inoculation of this isolate resulted in increased root colonization, spore count, shoot and root biomass, root volume and yield. It induced seven days early flowering and increased the ascorbic acid content of the fruit. The uptake of nutrients particularly P, K and Ca was improved by the inoculation of this isolate. The pot culture experiment conducted to study the possibility of reducing phosphorus fertilizer due to VAM inoculation showed the superiority of VAM isolate collected from Eruthempathi in improving growth, P uptake and yield. With the increase in dose of P upto 50 per cent, there was a significant increase in root colonization, fresh weights and dry weights of shoot and root and also the yield. No further increase in these parameters was recorded with the increase in dose of P upto 100 per cent. The plants inoculated with the VAM isolates along with 50 per cent P recorded shoot and root biomass and yield significantly superior to that of these parameters recorded by the plants which received full dose of P alone. The results of the field experiment showed that the plants inoculated with VAM had higher root colonization and rihzosphere spore count compared to uninoculated plants. Irrespective of the form of P used the rihzosphere spore count and VAM colonization were less at higher doses of P compared to lower doses. Among the treatments involving super phosphate, the treatment T9 (VAM + FYM + N + 50% SP + K) was significantly superior in improving root colonization, spore count, fresh weight and dry weight of root, root length, shoot P content and yield compared to the package of practices recommendations (T2 - FYM + N + SP + K). Among the treatments involving mussorie rock phosphate, the treatment Tio (VAM + FYM + N + 75% MP + K) was significantly superior to the present package of practices recommendations in its effects on fresh weight and dry weight of shoot and root, root length, shoot P content and yield. The nutrient status of the soil with respect to P_ and K content was improved by the treatment T9 (VAM + FYM + N + 50% SP + K). No significant change in soil P content was observed by the VAM inoculation along with MP. The treatment Tio (VAM+FYM+75%MP+K) recorded the highest soil K content. The field experiment conducted in the wilt sick field revealed that inoculation of selected VAM fungi could reduce the bacterial wilt incidence. Among the three varieties tested viz., Sakthi, BWR-1 and Pusa Ruby, a significant reduction in bacterial wilt incidence due to inoculation of VAM fungi collected from Eruthempathi was recorded by the variety, Sakthi. The inoculated plants of BWR-1 showed only five per cent reduction in wilt incidence. No reduction in wilt incidence was observed in variety, Pusa Ruby.

Theses

Browse

Thesis Type

Type

Author

Date

Subject

Search Results