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2020 - 20234
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Subject: Nematology × Start date: 2020 × Type: Thesis × Thesis Type: M.Sc ×
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Now showing 1 - 4 of 4
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    ThesisItemOpen Access
    EVALUATION OF DAMAGE CAUSED BY ROOT KNOT NEMATODE AND ITS SURVIVAL IN TUBEROSE DURING STORAGE OF BULB
    (2023) Arandhara, Babyshree; Gogoi, B. B.
    In the present investigation on evaluation of damage caused by root knot nematode and its survival in tuberose during storage of bulbs, it was observed that all growth parameters of tuberose were affected with corresponding increase in inoculum levels. Plant showed gradual increase in number of galls, egg masses and final nematode population in the soil with increase in population levels of root knot nematode from 20 to 10,000 nematode per pot. Reproductive rate was found to be maximum at lowest inoculum and minimum at highest inoculum of 10,000 M. incognita per kg soil. In the investigation on survival of root knot nematode during storage of bulb, the study of stored planting material (bulbs of tuberose) reveled that all the stages of root knot nematode were present within the bulbs. J2 were found within the bulb and also in between the layers of bulbs. J3, J4 and adult females were found in the bulb tissue. Some adults were also found to be aggregate in between the layers of bulb tissue. There was a reduction in nematode population (56.91%) during the storage period of 6 months. Egg masses within the bulb were brownish in colours, protected by gelatinous matrix and the bulb tissue. The egg masses attached to the basal portion of the bulbs were deep orange colour. The change in colour of egg masses attached to the basal portion of the bulbs during the storage period might be due to drying and tanning of the gelatinous matrix may be due to low moisture for an extended period of time. Germination percentage of the stored bulb was recorded to be 70%. There was 30% reduction in germination of stored bulb due to heavy nematode infestation and drying of bulbs in storage. When infected stored bulbs were replanted in pots with sterilized soil, survival and transmission of nematode to the new crop was confirmed by the developed symptoms (gall and egg mass formation) on roots.
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    ThesisItemOpen Access
    GRAFTING FOR THE MANAGEMENT OF ROOT KNOT NEMATODE, Meloidogyne incognita IN BRINJAL
    (AAU, Jorhat, 2021) Prasanth, Polimera; Bhagawati, B.
    An attempt was made for the management of root knot nematode, Meloidogyne incognitain brinjal through grafting. Thirteen Solanum species were screened against M. incognita. Of these, S. torvum and S. khasianum showed resistant and moderately resistant reactions against M. incognita and remaining species showed highly susceptible reactions against M. incognita. S. torvum and S. khasianum were taken as rootstocks. Liliya and Kokila were taken as scions. Highly susceptible and cultivated hybrids, Liliya and Kokila were grafted on resistant rootstock S. torvum and onmoderately resistant rootstock S. khasianum. Cleft graftingmethod was adopted for grafting. The highest success rate of grafting was recorded on S. torvum× Liliya, followed by S. torvum× Kokila. Liliya and Kokila grafted on S. torvum showed maximum reduction in number of galls, egg masses per root system, final nematode population and rate of reproduction with increased number of fruits per plant, fruit weight, fruit yield per plot and total fruit yield per ha followed by Liliya and Kokila grafted on S. khasianum. Delayed flowering and fruiting was observed in grafted plants as compared to non grafted plants.
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    ThesisItemOpen Access
    Approaches for management of Meloidogyne incognita in Pulse crops
    (AAU, Jorhat, 2022) Zonunpuii, Maria; Das, Debanand
    Investigation were carried out under Net House condition to evaluate the reaction of eight chickpea germplasm, ten pea germplasm and forty six lentil germplasm along with their respective susceptible checks for resistance against Meloidogyne incognita. All eight germplasm of chickpea screened were found to be either susceptible or highly susceptible to M. incognita. None of the germplasm were found to be resistant to M. incognita. Among ten germplasm of pea, two germplasm viz., IPFD-99-13 and IPFD-12-2 were found to be resistant, two germplasm were found to be moderately resistant, and the rest six germplasm were found to be either susceptible or highly susceptible. Out of forty six lentil germplasm screened, only one germplasm (IPL 81) was found to be resistant, seven germplasm were found to be moderately resistant, while the rest thirty eight germplasm were found to be either susceptible or highly susceptible to M. incognita. Study on the bio-intensive management of M. incognita on black gram with bio-agents viz., Bacillus marisflavi, Bacillus altitudinis, Bacillus subtilis, Trichoderma viride, Verticillium lecanii and Pseudomonas fluorescens showed significant increase in plant growth parameters including root nodulation with corresponding decrease in number of galls per root system, egg masses per root system, and final nematode population over untreated control. The treatment with soil application of Pseudomonas fluorescens @ 1x108 cfu/ml enriched in vermicompost @ 20 g/m2 was found to be the most effective in enhancing plant growth parameters, number of nodules per root system and reducing number of galls per root system, egg masses per root system and final root-knot nematode population in soil. Nonetheless, all the treatments significantly decreased number of galls, egg masses and final nematode population in soil.
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    ThesisItemOpen Access
    Morphological and morphometric variations of Hoplolaimus and Helicotylenchus
    (AAU, Jorhat, 2020-08) Venkadesh, G; Das, Debanand
    Investigations were carried out to study the morphological and morphometric variations of genera Hoplolaimus and Helicotylenchus in relation to host plants and geographical locations of Assam. Total of 163 soil samples were collected from Rice, Maize, Banana, Mango, Jackfruit, Citrus, Pea and Tea, and from different geographical locations viz., Jorhat, Kokrajhar, Sivasagar, Kamrup, Lakhimpur, Dhemaji, Nagaon and KarbiAnglong district of Assam. The populations of both genera under survey were identified as Hoplolaimus columbus, Hoplolaimus indicus, Helicotylenchus crenacauda and Helicotylenchus dihystera. In the study no morphological variations have been observed in genera Hoplolaimus and Helicotylenchus in relation to both host plants and geographical locations. Results of morphometric characters showed that body length, a ratio, oesophagus length, b ratio, oesophageal gland overlapping length, bʹ ratio, ABW, MB, V, Vʹ, stylet length, SE and Pp (only in Hoplolaimus) were regards as least variable characters and considered highly stable in relation to host plants for genera Hoplolaimus and Helicotylenchus. The c ratio, number of tail annules and Pa of females were least variable characters; while, tail length and cʹ ratio were moderately variable characters in Hoplolaimus columbus. The c ratio, cʹ ratio, number of tail annules and Pa of females were regarded as moderately variable characters; while, tail length of females was regarded as highly variable character in Hoplolaimus indicus. In males of H. indicus, tail length, c ratio, cʹ ratio and Pa were regarded as least variable characters; while, bursa of males was regarded as moderately variable character. The tail length, c ratio, cʹ ratio and O of females were regarded as moderately variable characters in relation to host plants of Helicotylenchus dihystera. Influence of geographical locations on morphometric characters revealed that the body length, a ratio, oesophagus length, b ratio, oesophageal gland overlapping length, ABW, MB, V, Vʹ, stylet length and Pp (only in Hoplolaimus) were least variable characters and considered highly stable characters in relation to geographical locations for genera Hoplolaimus and Helicotylenchus. The bʹ ratio, c ratio, cʹ ratio, SE and number of tail annules were least variable characters; while, tail length and Pa of females were moderately variable characters in Hoplolaimus columbus. The bʹ ratio, c ratio, cʹ ratio, SE, number of tail annules and Pa of females were moderately variable characters; while, tail length of was highly variable character in females of Hoplolaimus indicus. In males of H. indicus, bʹ ratio, tail length, SE, Pp, spicule length and gubernaculum length were least variable characters; while, c ratio, cʹ ratio, Pa and bursa of males were moderately variable characters. In case of Helicotylenchus crenacauda the bʹ ratio and SE of females were regarded as least variable characters; while, tail length, c ratio, cʹ ratio and O of females were moderately variable characters. The bʹ ratio, tail length, c ratio and SE of females were regarded as least variable characters; while, cʹ ratio and O of females were regarded as moderately variable characters in relation to geographical locations of Helicotylenchus dihystera.