Conference Proceeding

Harnessing the Potential of Efficient Isolates of Fungi as Biocontrol Agents against Apple Root Rot-An Emerging Threat to Apple Industry in Kashmir Valley

Dr. Baby Summuna

Two hundred and twenty two VAM isolates were isolated from the rhizosphere of apple, pear and cherry crops from the four districts of Kashmir valley viz., Srinagar, Ganderbal, Baramulla and Shopian. During the study 29 species of VAM were identified, besides 16 could be identified only upto genus level. The identified VAM belonged to 7 genera. Glomus species was the most common and predominant VAM fungus in the soils of study sites with 57.72 per cent of frequency isolation, followed by Acaulospora (22.82%), Scutellospora (8.05%) and Septoglomus (4.69%). The VAM isolates, isolated from different host viz., apple, pear and cherry rhizosphere, and evaluated on maize revealed variable behaviour of isolates with respect to plant growth improvement and enzyme activities. Mycorrhizal root colonization in inoculated plants was in the range of 17.78 to 65.15 per cent. The root colonization by VAM isolates from cherry, apple and pear rhizosphere was 23.2 to 65.2, 19.8 to 53.1 and 17.8 to 61.5 per cent, respectively. The root phosphatase was in the range of 3.30-40.66 m mol PNP/g fresh root weight as compared to 3.66 m mol PNP/g fresh root weight in uninoculated control. The soil phosphatase activity varied from 3.23-30.73 m mole PNP /g soil in VAM inoculated plants as compared to uninoculated control. Amongst the isolates, Glomus geosporum (isolate SSC9), Acaulospora rehmii (isolate SHC17), Glomus diaphanum (isolate SBA21) and Gigaspora decipiens (isolate GBC34) proved significantly superior and selected to assess their efficacy in improving apple plant growth and suppressing root rot pathogen. The root rot pathogen, Dematophora necatrix R. Hartig, was isolated from infected samples of apple plants and pathogenicity proved as per Koch’s postulates. Trichoderma viride Pers. was isolated from the rhizosphere of apple trees by dilution plate method. Five most efficient VAM species were assessed on apple cv. Red Delicious for their impact on plant height, girth, leaf area, leaf number, root rot index, root phosphatase activity, soil phosphatase activity and soil N and P under polyhouse conditions along with T. viride in presence and absence of root rot pathogen. The apple seedlings inoculated with G. geosporum showed maximum increase in growth parameters and phosphatase activity, followed by A. rehmii, G. diaphanum, G. decipiens and A. bireticulata. The soil N and P was also maximum in the plants inoculated with G. geosporum as compared to uninoculated control. The unicoculated control (without pathogen) showed the highest values of plant height, girth, leaf area and leaf number in apple plants. VAM inoculation reduced root rot incidence in apple by 8.36 to 41.44 per cent. Inoculation of T. viride showed a significant reduction in controlling root rot of apple by 35.23 per cent and also improved plant height, girth and leaf area but showed a non-significant effect on leaf number.

Published: 08 November 2017

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Copyright: © 2017 Dr. Baby Summuna. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.