PG Thesis

Permanent URI for this collectionhttp://localhost:4000/handle/123456789/2

Browse

Subject: search.filters.subject.Biochemical studies

Search Results

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Response of selected banana varieties to root knot nematode meloidogyne incognita (Kofoid and white)
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2015) Neethu, N S; Susannamma Kurien
    Banana, a dessert fruit for millions, otherwise known as “Apple of Paradise” is botanically Musa spp. It is one of the most popular fruits in the world in terms of per capita consumption as well as the most widely traded fruit in the world. Among the various pests and diseases of banana, plant parasitic nematodes constitute one of the major limiting factors to banana production causing extensive root damage and serious economic loss throughout the world. The root knot nematode, Meloidogyne incognita (Kofoid and White) alone causes 31 per cent yield reduction in India (Jonathan and Rajendran, 2000b).Management of this nematode relies mainly on the repeated use of chemical nematicides which has adverse side effect on environment. One of the most effective and economical ways to control plant parasitic nematodes is exploiting host plant resistance. In this context a study entitled “Response of selected banana varieties to root knot nematode, Meloidogyne incognita (Kofoid and White)” was carried out in the Department of Agricultural Entomology, College of Horticulture, Vellanikkara and Banana Research Station (BRS), Kannara during 2014-2015 with the objective of screening selected banana varieties hybrids against M. incognita and to elucidate the biochemical basis of resistance. Twenty five banana varieties from the germplasm collection of BRS, Kannara, comprising of nine exotic hybrids, six Indian varieties, nine exotic varieties and a highly susceptible check (Robusta) were screened for their reaction to M. incognita. Pot culture experiment was conducted at BRS, Kannara in Completely Randomized Design with three replications. Nematodes were inoculated @ one second stage juvenile per gram of soil at forty five days after planting. Monthly observations on the biometric characters viz., plant height, pseudostem girth and number of leaves were recorded from the date of inoculation till uprooting (six months after inoculation). At the time of uprooting, root knot number and nematode population in soil and roots were recorded. Based on the number of galls, indexing was done on 1-5 scale and the banana varieties/hybrids were respectively categorized as highly resistant, resistant, moderately resistant, susceptible and highly susceptible (Gitanjalidevi et al., 2014). None of the varieties were highly resistant whereas, SH–3640 (AAAB) and SH–3436-6 (AAAA) with mean root knot index of 2 were classified as resistant. Nine varieties viz., FHIA-1 (AAB), FHIA-3 (AABB), SH–3436-9 (AAAA), TMB × 5295-1 (AAAB), Udayam (ABB), Dudhsagar (AAB), Manjeri Nendran II (AAB), Big Ebanga (AAB) and Pisang Nangka (AAB) with root knot index of 3 rated as moderately resistant. Seven varieties viz., TMP 2829 (AB), Mysore Ethan (AAB), Sugandhi (AAB), Yangambi Km5 (AAA), Bangrier (ABB), Popoulu (AAB) and Pisang Madu (AA) with root knot index of 4 found to be susceptible and rest of the seven varieties viz., FHIA -17 (AAAA), FHIA -18 (AAAB), Karpooravally Dwarf (ABB), Pisang Ceylan (AAB), Pisang Jari Buaya (AA), Pisang Buntal (AA) and Robusta (AAA) with root knot index of 5 were classified as highly susceptible. To study the biochemical basis of resistance, biochemical components like total phenol content, peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) activity were estimated three months after inoculation based on standard procedures. Biochemical analysis revealed a higher total phenol content and enzymes like polyphenol oxidase, peroxidase, and phenylalanine ammonia lyase in resistant varieties. A significant negative correlation was observed between the biochemical parameters and number of root knots, root knot index and population of M. incognita in root and soil.
  • No Thumbnail Available
    Item
    Biochemical and histopathological alterations due to root-knot nematode, Meloidogyne graminicola in rice (Oryza sativa L.) and varietal reactions
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2015) Darsana V S Lal; Narayana, R
    An experiment entitled “Biochemical and histopathological alterations due to root- knot nematode, Meloidogyne graminicola in rice (Oryza sativa L.) and varietal reactions” was undertaken at Department of Agricultural Entomology, College of Agriculture, Vellayani, during 2013-14. A progressive increase in phenol content, defense enzymes viz. Peroxidase (PO), Polyphenol Oxidase (PPO), Phenylalanine Ammonia Lyase (PAL) from both leaf and root after 45 days of nematode inoculation were observed with increase in inoculum levels. The chlorophyll a and b, NPK content and micronutrients viz. Fe, Cu, Zn and Mn were decreased with increase in nematode population. The plants inoculated with 10,000 J2 showed low pH (5.69) compared to the uninoculated plant and was significantly different from all other treatments. The starch, protein and total sugar content decreased 41.44, 41.89 and 44.95 per cent respectively in plants inoculated with 10,000 J2 compared to uninoculated plants. A progressive decrease in plant growth and yield parameters were observed with increase in population levels of nematode. The maximum reduction in plant height, fresh weight of plant, dry weight of root and dry weight of shoot and the yield parameters like thousand seed weight and number of seeds per panicle were observed in plants inoculated with 10,000 J2. Histochemical studies revealed that an accumulation of polysaccharides, proteins and nucleic acid in epidermal, cortical and stelar region of root progressively increased with increase in population density of nematode. Giant cells were formed near the xylem and phloem cells. The xylem and phloem vessels were disorganized. In studying the varietal reaction of ten popular rice varieties of Kerala against M. graminicola, all the varieties were suceptible to the nematode. Minimum number of galls (51.8) and egg mass (64.60) per plant was observed in the variety Uma and was on par with Pavizham. On the basis of egg mass index, all other varieties were highly susceptible except Uma. The PO and PPO activity of Uma, Karthika, Pavizham and Bhadra were higher than that of TN1 (Suceptible check). In Uma, the nematode population in soil and root was minimum and on par with Karthika and the reproduction rate also minimum in Uma. Based on the results of the study, M. graminicola can be considered as a potential threat to the cultivation of rice. Uma showed better performance against root knot nematode than all other varieties.
  • No Thumbnail Available
    Item
    Morphology and reproductive biology of maramanjal (Coscinium fenestratum (Gaertn.) Colebr)
    (Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 2015) Mithra H Shenoy; Suma, B
  • No Thumbnail Available
    Item
    Selection index and activation of seedling growth in mangosteen
    (Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 2002) Mohamed Yosuf, L; Sajan Kurien
  • No Thumbnail Available
    Item
    Die- back in cashew incited by the tea mosquito bug, Helopeltis antonii Signoret as influenced by wound pathogens and plant biochemicals
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1996) Bindu, N; Pathummal Beevi, S
    Experiments were conducted at the College of Horticulture, Vellanikkara and in the cashew fields at Cashew Research Station, Madakkathara, to ascertain the intensity of shoot die-back symptoms in cashew incited by the TMB bug, Helopeltis antonii in association with the wound pathogens; to evaluate the selected plant products for their feeding detterrency to TMB; to study the variations in the major biochemical factors such as starch, sugars, phenol and OD phenol in the five susceptible and five less susceptible cashew types and the changes in these biochemical factors due to TMB feeding. The predominantly occurring fungus isolated from the necrotic lesions of the TMB affected shoots, panicles and nuts was Colletotrichum gloeosporioides. The involvement of the fungus in the die-back symptom development calls for appropriate modifications in the crop protection strategies particularly for younger cashew plantations. The necessary strategic shifts have been discussed. The role of this fungus in aggravating the seedling die-back when inoculated on the grafts infested by TMB has been established. Emulsions of neem and pongamia oil at 2 per cent and 5 per cent spray caused mortality of adult bug after 12 h of exposure. Significant variations in the biochemical constituents viz., starch, sugar, phenol and OD phenol content were detected in all the ten cashew accessions. Comparatively low starch content was noticed in most of the susceptible cashew types and high in the less susceptible type. The starch content increased during the 6 h followed by significant decrease during 12 and 24 h of infestation by TMB. Low sugar content was found in the less susceptible accessions. The sugar content showed significant decrease during 6,12 and 24 h of infestation by TMB. The phenol and OD phenol contents were lower in the susceptible cashew accessions than the less susceptible accessions. The phenol content showed an increasing trend at 6 h followed by a decrease during 12 h and again an increase during 24 h of infestation by TMB. The varietal variations and the time interval after the TMB infestation seemed to influence the rate of biochemical reaction rather than any specific biochemical changes induced by the interaction of varieties and TMB feeding.