Browsing by Author "Estelitta, S"

Now showing 1 - 13 of 13

Anatomical and biochemical bases of resistance in banana to yellow sigatoka leaf spot disease
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2001) Saira Banu, V K; Estelitta, S
Banana is an important fruit crop of Kerala, which is commonly infected by yellow sigatoka leaf spot disease caused by Mycosphaerella musicola Leach. Investigations on anatomical and biochemical bases of resistance in . banana to yellow sigatoka leaf spot disease were carried out in the Dept of Plant Pathology and Biochemistry Laboratory of the College of Horticulture, Vellanikkara during 2000-2001. Severity of sigatoka disease was observed maximum 10 the peak monsoon month of July (cool moist period) followed by October (warm moist period) and April (warm dry period) and minimum in January (cool dry period). Maximum growth of M musicola was obtained in the medium potato glucose yeast extract agar (PGYEA) and poor sporulation in the medium banana dextrose agar (BnDA). Red pigmentation was observed in all media tried. The study revealed that the four different groups of banana differed significantly in the various anatomical and biochemical parameters. The resistant variety, Manoranjitham (AAA) was characterised by thickest cuticle and epidermis with inter mediate sized epidermal cells on the adaxial surface and denser pattern of epicuticular wax deposition on the abaxial surface of leaves. Thinner spongy and palisade tissues, maximum number of large and closely placed vascular bundles, thickest lower epidermis and decrease 10 number of stomata/unit area on the adaxial and abaxial surfaces of leaves. The highly susceptible variety, Grand Naine (AAA) showed thinner cuticle, thickened and large sized epidermal cells on the adaxial surface and faint pattern of epicuticular wax deposition on the abaxial surface of leaves. Less number of small and distantly placed vascular bundles, thicker spongy and palisade tissues and maximum number of stomata lunit area on the adaxial and abaxial surfaces of leaves. After pathogen infection the resistant variety Manoranjitham (AAA) showed partial disintegration of spongy mesophyll tissues and the highly susceptible variety Grand Naine (AAA) showed complete disintegration of chloroplast and mesophyll with necrotic vascular bundles. Stomata was found opened during day time and closed during night hours in both healthy and diseased leaves. In the biochemical parameters studied, the resistant variety, Manoranjitham (AAA) possessed higher quantities of total phenol, OD phenol, non reducing and total sugars, protein and peroxidase activity and intermediate values for proline and activity of polyphenol oxidase and lower quantity of reducing sugar. The highly susceptible variety, Grand Naine (AAA) was characterised by higher quantities of reducing sugar and intermediate values for total phenol, non reducing and total sugars and lower quantity of proline, protein, OD phenol and peroxidase and polyphenol oxidase enzyme activities. After pathogen infection, higher quantity of OD phenol, reducing sugar and activity of polyphenol oxidase enzyme was observed in the variety Manoranjitham (AAA) where the content of total phenol, non reducing and total sugars, proline, protein and activity of peroxidase enzyme decreased. The highly susceptible variety, Grand Naine (AAA) exhibited higher quantities of total phenol, reducing sugar, proline and higher activities of peroxidase and polyphenol oxidase enzymes and lower quantities of OD phenol, non reducing and total sugars and protein. The concentrated culture extracts of M musicola In seven different media gave different Rf values.
Cyclea peltata - a new host of phytophthora palmivora (butler) butler
(Kerala Agricultural University, 1996) Estelitta, S; Sukumara Varma, A; Vilasini, T N; Vimi Louis; Raji, P
Field screening of banana germplasm against kokkan disease
(Kerala Agricultural University, 1996) Estelitta, S; Suma, A; Radhakrishnan, T C
Flower bud anatomy of 'kokkan' affected banana
(Kerala Agricultural University, 1993) Estelitta, S; Suma Luckins, A; Babu, C; Mallika, V K
Leaf and sheath blight disease of canna
(Kerala Agricultural University, 1995) Vilasinii, T N; Estelitta, S; Raj, P
Light and fluorescent microscopic studies on kokkan disease of banana (Musa aab Nendran)
(Kerala Agricultural University, 1996) Estelitta, S; Suma, A; Gregory Zachariah; Pradeep, K P
New bacterial wilt of Coleus Vettiveroides Jacob
(Kerala Agricultural University, 1992) Estelitta, S; Beena, S; Koshy Abraham; Ravi, S; Varadarajan Nair, P
New leaf blight of garcinia cambogia desr.
(Kerala Agricultural University, 1996) Vilasini, T N; Estelitta, S; Rajendran Pillai, M V; Nair, P V; Raji, P
Orchid rogangalum keedangalum
(Kerala Agricultural University, 2017) Estelitta, S; Deepthi, K B; Deepa, James; Saneega, K Asokan
Package of practices recommendations: crops 2016
(Kerala Agricultural University, 2016) Estelitta, S
Pigments in kokkan affected banana
(Kerala Agricultural University, 1993) Sarah T George; Estelitta, S; Suma, A; Pradeep, K P
Purification and serology of banana bunchy top virus
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1998) Estelitta, S; Sukumara Varma, A
Banana is one of the major fruit crop in Kerala and is often affected by the bunchytop disease caused by banana bunchytop virus. The disease is easily spread through infected suckers, which are used as the planting materials. Secondary spread is also seen through banana aphid, Pentalonia nigronervosa. Though field level quarantine measures may check the spread of the disease, rapid and convenient methods for the detection and identification of the virus in the suckers as well as in micropropagated plants have not been developed. In this background a study was designed and carried out to purify the BBTV, to produce antisera for developing a serological technique for the pre-symptomatic detection of virus in the planting materials of banana. Studies were also conducted to identify the type of nucleic acid of the virus and its morphology by direct electron microscopy. The study revealed that the disease incidence was maximum during August-November. The virus was not mechanically transmitted and tissue culture plants were the most susceptible planting materials for aphid transmission. Basic studies of virus-vector relationship were also conducted and the adult aphids were found to be effective vectors. In purification studies, among the different portions of banana plants used, the midribs of younger leaves yielded high concentration of the virus. Tissue culture plants yielded more virus concentration than other planting materials. Electron microscopy of the purified BBTV preparation revealed isometric particles of 18-22 nm size. Nucleic acids extracted from both healthy and infected samples were compared. The bands obtained were sensitive to DNase 1 and SI nuclease but not to RNase A, confirming the nucleic acid BBTV as ssDNA. SDS-PAGE analysis of BBTV coat protein revealed that it contained a major protein component of Mr 21000 with Rf value between that of β lactoglobulin (Mr 18400) and α chymotrypsinogen (Mr 25700). Antiserum of BBTV was produced in the rabbit and used for detection of virus specific antigens in different parts of the plant (midrib, petiole, leafsheath and rhizome) by chloroplast agglutination, agar gel diffusion, tube precipitation and ELISA. Among these methods ELISA was found to be highly sensitive for identification of the virus.
Studies on the microflora of stored pepper
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1982) Estelitta, S; Abi Cheeran
With a view to study the microflora in stored black pepper, a research project was carried out at the College of Horticulture, Vellanikkara. It was also aimed at estimating the deterioration of the quality of stored black pepper in terms of its oleoresin, piperine and starch contents due to microbial infection and assessing the role of each micro-organisms in changing the quality of the product. The study revealed that the major chemical constituents of stored black pepper, namely, oleoresin, piperine and starch varied in different grades of black pepper. Slight variations in these quality constituents were observed according to the seasons of storage also. In all the seasons, association of microflora with all grades of black pepper was observed. The species of micro-organisms were not changed during seasons, but the population varied according to grade of black pepper and season of storage. The micro-organisms found were Aspergillus niger, A. candidus, A. nidulans, A. versicolor, curvularia lumata, penicillium citrinum, Fusarium moniliforme, Rhizopus nigricans and Bacterium (gram –ve). There was no growth of microflora in stored black pepper upto 66.8 per cent relative humidity, whereas profused growth was observed at saturation levels of humidity. Only Aspergillus spp. And penicillium citrinum could come up at a lower HUMIDITY LEVEL (75.6 per cent). In three quality constituents of black pepper viz., oleoresin, piperine and starch reduced considerably when the samples were inoculated with different micro-organisms at different levels of humidity. Reduction in the quality constituents was found corresponding to the increase in level of humidity as well as length of incubation period.