Response of selected okra [Abelmoschus esculentus (L.) Moench] cultivars to root knot nematode meloidogyne incognita (Kofoid and White)
| dc.contributor.advisor | Susannamma Kurien | |
| dc.contributor.author | Chandini, S M | |
| dc.contributor.author | KAU | |
| dc.date.accessioned | 2020-02-13T07:32:45Z | |
| dc.date.available | 2020-02-13T07:32:45Z | |
| dc.date.issued | 2017 | |
| dc.description | PG | en_US |
| dc.description.abstract | Okra [Abelmoschus esculentus (L.) Moench] is an important vegetable crop, popularly known as “bhendi” or “lady’s finger” in India. It is grown in three seasons in the tropical and subtropical regions throughout the world. The nutritional, medicinal and industrial value of okra fruits makes it a promising vegetable crop globally. Pests and diseases are the major limiting factors for okra cultivation. Among them plant parasitic nematodes are the most serious. Root-knot nematode, Meloidogyne incognita is one of the most economically damaging genera of plant parasitic nematodes which causes 31 per cent of yield loss in India (Jain et al., 2006). Several methods have been developed for the management of the nematode. Use of chemical nematicides is the most effective, which brings about 80 per cent reduction in nematode population. Host resistance is an important component of integrated nematode management. Use of cultivars resistant to M. incognita is one of the best alternatives, which is specific, environmentally safe and economically feasible. In this context, a study entitled “Response of selected okra [Abelmoschus esculentus (L.) Moench] cultivars to root knot nematode, Meloidogyne incognita (Kofoid and White)” was carried out in the Department of Agricultural Entomology, College of Horticulture, Vellanikkara during January 2016 to October 2016, with the objective of screening selected okra cultivars against M. incognita and to elucidate the biochemical basis of resistance. Thirty okra cultivars comprising twenty one accessions from NBPGR Regional Station, Thrissur, eight released varieties and a highly susceptible check (Arka Anamika) were screened for their reaction to root knot nematode M.incognita. Pot culture experiment was conducted in Completely Randomized Design with three replications and 30 treatments. Okra plants were inoculated with M.incognita @ one second stage juvenile per gram of soil after two weeks of seed germination. Biometric characters like plant height, number of leaves, number of flowers, number of fruits and fruit weight were recorded at fortnightly intervals from the time of inoculation till uprooting. Shoot weight, root weight, root knot number and nematode population in soil and roots were also recorded when the plants were uprooted i.e. three months after inoculation. Significant reductions in all the biometric parameters were observed over their respective controls in all the cultivars. The per cent decrease in these parameters were higher in highly susceptible and susceptible cultivars than moderately resistant cultivars. Based on the number of galls per 10 g roots, indexing was done on 1-5 scale and the okra cultivars were categorized as highly resistant, resistant, moderately resistant, susceptible and highly susceptible (Devi et al., 2014). None of the cultivars were highly resistant or resistant whereas four cultivars viz., IC 117238, IC 117251, IC 111507 and Varsha Uphar with root knot index 3 were classified as moderately resistant. Seven cultivars viz., Manjima, IC 111536, IC 117260, IC 111500, IC 111247, IC 469689 and IC 111517 were found to be susceptible with root knot index 4. Rest of the nineteen cultivars viz., Aruna, Kiran, Anjitha, Salkeerthi, Susthira, Arka Anamika, Pusa Sawani, IC 218900, IC 112457, IC 329360, IC 045819, IC 117308, IC 117228, IC 111525, IC 111514, IC 329357, IC 282275, IC 305634 and IC 045515 were classified as highly susceptible with root knot index 5. Biochemical parameters like total phenol, peroxidase (PO), total sugar and reducing sugar of both control and inoculated roots of okra cultivars were estimated at three months after inoculation based on standard procedures to analyze the biochemical bases of resistance. An increase in total phenol and peroxidase activity was noticed in moderately resistant cultivars than susceptible cultivars whereas total sugar and reducing sugars were higher in highly susceptible cultivars. Correlation analysis showed a significant negative correlation between total phenol content and peroxidase activity with number of root knots, root knot index and population of M. incognita in root and soil. A significant positive correlation of total sugar and reducing sugar was recorded with number of root knots, root knot index and population of M. incognita in root and soil. The present study revealed that IC 117238, IC 117251, IC 111507 and Varsha Uphar were moderately resistant. Hence these cultivars could be utilized as resistant sources for further breeding programmes. Field trials in sick plots also need to be conducted to study the field performance of the moderately resistant cultivars. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810142990 | |
| dc.keywords | Okra, Root-knot nematode, Meloidogyne incognita, Pathogenicity, Inoculum levels, Germplasm, Brinjal, Tomato, Peroxidase | en_US |
| dc.language.iso | en | en_US |
| dc.pages | 94 | en_US |
| dc.publisher | Department of Agricultural Entomology, College of Horticulture, Vellanikkara | en_US |
| dc.sub | Agricultural Entomology | en_US |
| dc.subject | null | en_US |
| dc.theme | selected okra cultivars to root knot nematode | en_US |
| dc.these.type | M.Sc | en_US |
| dc.title | Response of selected okra [Abelmoschus esculentus (L.) Moench] cultivars to root knot nematode meloidogyne incognita (Kofoid and White) | en_US |
| dc.type | Thesis | en_US |