Thumbnail Image

Theses

Browse

Reset filters
Author: Kau × End date: 2012 × Type: Thesis × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    ThesisItemOpen Access
    Plant parasitic nematodes associated with pineapple in Kerala
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1981) Hamza Koya, C P; KAU; Venkitesan, T S
    As a part of the studies on the occurrence of plant parasitic nematodes associated with pineapple in Kerala, a survey was carried out in different agro climatic regions of the Kerala State and it was found that R. reniformis occurred in more than 76 per cent of the locations sampled. Helicotylenchus spp. were recorded in about 50 per cent of the locations. The other plant parasitic nematodes detected in association with the crop included Meloidogyne spp., Creconemoides spp., Pratylenchus spp., Hoplolaimus and Hemicyclophora occurred in very low population densities. A new species of Helicotylenchus closely resembling H. digitatus ( Hussain and Siddique, 1964) but differing with respect to spear knob characters and location of excretory pore has been reported to be associated with the crop. The pot culture trial with M. incognita indicated that this nematode could not induce pathogenic effect on the cv kew even at the highest inoculum levels of 10,000 larvae per 7.5 kg soil during the period of 180 days.
  • Thumbnail Image
    ThesisItemOpen Access
    Foliar diagnosis, yield and quality of ginger(zingiber officinale ROSCOE) in relation to nitrogen, phosphorus and potassium
    (Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1978) Johnson, P T; KAU; Jose, A I
    A field experiment was carried out at the Instructional Farm, attached to the College of Horticulture, Vellanikkara during 1977 – 78 to study the effect of graded doses of nitrogen, phosphorus and potassium on the growth, yield and quality of ginger and also to develop suitable foliar diagnosis techniques in relation to these nutrient elements. The treatments comprised of three levels each of nitrogen (40, 80 and 120 kg N/ha), Phosphorus (30,60 and 90 kg P2 o5/ha) and potassium (40,80 and 120 kg k2o/ha). The experiment was laid out in a 33 factorial experiment in randomised block design confounding the affect of interaction NP2K2 totally. The results revealed that among the morphological characters studied, only the height of tiller and total dry matter of the plant were markedly influenced, while other characters like number of tillers and number of leaves per tiller were not effected. Of the fertilizer treatments, nitrogen at 80 kg/ha significantly affected these two characters, while the effect of phosphorus and potassium were not significant. Application of nitrogen at 80 kg/ha significantly increased the rhizome yield of the crop, while the levels of phosphorus and potassium employed failed to influence the yield. Uptake of nitrogen and phosphorus by the plant was significantly influenced by the application of nitrogen at the rate of 80 kg/ha, whereas the graded doses of phosphorus and potassium had no significant influence in this respect. The uptake of potassium on the other hand was not influenced by any of the fertilizer treatment introduced. The total period of growth put under observation appeared divisible into three phases with respect to the development of aerial tissues namely, a phase of active vegetative growth (90th to 120th day after planting); a phase of slow vegetative growth (120th to 180th day) and a phase approaching senescence (180th day to harvest). The pattern of the rhizome development followed the same trend as that of the aerial tissue, but instead of a final phase of insignificant growth, the development of rhizome continued till harvest. The uptake of nitrogen, phosphorus and potassium progressively increased with advancing period of group growth. There was marked uptake of these nutrients by the plant during the period of active plant growth (90th to 120th day after planting). The uptake of nitrogen, phosphorus and potassium in leaf and pseudostem progressively increased upto 180th day and then decreased while their uptake in rhizome steadily increased till harvest. The content of nitrogen phosphorus and potassium was highest in the top most leaves and continuously decreased with increasing number of the leaf position, when the leaves are numbered from top to bottom of the tiller. In consideration of the stability of nutrient level with leaf positions and sensitivity or correlation with varying doses and uptake, the group of 5th to 12th leaves appeared to be the best suited for foliar diagnosis of N, P and K status of the crop. The period between 90th to 120thday after planting was recommended as the optimum period for the detection and amendment of the nutrient status of the crop. The graded doses of nitrogen, phosphorus and potassium and their interaction failed to influence the percentage oleoresin content of ginger.
  • Thumbnail Image
    ThesisItemOpen Access
    Influence of storage on the quality of selected pulses
    (Department of Home Science, College of Agriculture, Vellayani, 1995) Bhanu Lekha, T; KAU; Prema, L
    Blackgram, greengram, horsegram and cowpea were the pulses commonly cultivated in Kerala. Area under cultivation was in the range of 21 cents to 1 acre and 10 to 90 kg of pulses were harvested every time. Pre harvest loss of crops were mainly due to insect attack. Conventional methods of pretreatments such as sundrying and sand mixing were administered. Prior to storage, for seed material, fungicide and insecticide were also used. Quantitative, qualitative and organoleptic changes such as weight loss, colour change texture change, inferior taste and discolouration due to storage were reported by the farmers. Forty five godowns were selected for the large scale storage study. Space facilities of the godown decided the number of pulses stored and duration of storage. Every month pulses were procured from Tamilnadu, Karnataka, Uttar Pradesh, Maharashtra and Madhya Pradesh. Prior to storage, pretreatments such as sparying DDVP, sweeping and dusting DT were administered. Infected pulses were sold as cattle feed and as manure or sold at subsidredrate for human consumption. Decrease in protein content, and volume expansion in all the pulses stored under large scale as well as farm level storage were noticed. While increase in no-protein-nitrogen, uric acid, moisture, cooking time, water uptake, percent hydration coefficient, damaged fraction, percent weight loss fungal contamination and bacterial contamination were observed in all the pulses irrespective of storage containers, storage period and level of storage.
  • Thumbnail Image
    ThesisItemOpen Access
    Vertical movement of nitrogen in major rice soils of Kerala
    (Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1995) George Abraham, T; Kau; Pushkala, S
    An experiment was conducted at the College of Agriculture, Vellayani, to assess the leaching and runoff losses of applied fertilizer nitrogen in typical, major rice growing soils of kerala, with varying physical and chemical properties. Undisturbed vertical columns were used for the leaching study. The runoff study was conducted as a pot experiment using surface soil samples. The study revealed that the Onattukara soil recorded the highest leaching loss of applied nitrogen (56.10%). Kayal soil showed the lowest leaching percentage of 24.21. The quantity of leachate collected per unit time was also found to be the maximum in the case of Onattukara soil (185.51 ml/hr) and least in the case of Kayal soil (155.60 ml/hr). Correlation studies revealed that the leaching loss of nitrogen was negatively correlated with organic matter (-0.5593), cation exchange capacity (-0.4560), clay (-0.5864), bulk density (-0.3213) and water holding capacity (-0.5544). The leaching loss was positively correlated with the quantity of leachate collected per unit time (+0.8876). In the case of Onattukara and kole soils, the loss of nitrogen through leaching was observed till the fifth day. For Kari soils, the loss stopped completely by the 10th day. The Karappadam and Pattambi soils showed leaching till the 15th day. However, in the case of Kayal soils, the leaching loss continued through the whole period of the study. In all cases, maximum amount of leaching occurred during the first five days after fertilizer application and after that the loss was in negligible quantities. In the case of runoff study also, Onattukara soil showed the highest runoff loss of applied nitrogen (40.41). The least loss was shown by karappadam soil (15.70%). The runoff loss was found to decrease with increase in number of days. Even though, Karappadam soils showed the lowest runoff loss of applied nitrogen, it had the highest percentage difference in runoff loss (77.8%) and the least was shown by Onattukara and Pattambi soils (63.5%). Correlation studies revealed that the runoff loss of fertilizer nitrogen was found to be negatively correlated with the oprganic matter (-0.1248), cation exchange capacity (-0.0324), clay (-0.4135), water holding capacity 9-0.6723) and bulk density (-o.4659).
  • Thumbnail Image
    ThesisItemOpen Access
    Investigations on mosaic disease of bitter gourd
    (Department of Plant Pathology, College of Agriculture, Vellayani, 1994) Purushothaman, S M; Kau; Rajagopalan, B
    Bitter gourd mosaic virus disease commonly occurring in Kerala was investigated. The symptoms appeared as typical mosaic mottling with dark green and light green patches. Diseased plants were severely stunted and produced only a few flowers and fruits. Transmission studies showed that the virus could be transmitted through mechanical means, grafting and by aphid vectors. The virus was found to be transmitted by the aphids aphis gossypii Glov., Aphis malvae Koch., Myzus persicae Sclz. And aphis craccivora Koch. Among the four species of aphids, A. gossypii and A. malvae were found to be the most efficient vectors. Investigations on the physical properties of the virus revealed that the virus had a thermal inactivation point between 50 and 600C, dilution end point between 1:1000 and 1:10000, longevity in vitro between 12 and 24 h at room temperature (28 - 300C) and 48 and 72 h at 100c. The minimum acquisition feeding and inoculation feeding period of the vector A. malvae were found to be 30s and I min respectively. But the percentage of transmission was maximum when an acquisition feeding period of 30 min and inoculation feeding period of 2 h were given. Influence of starvation before acquisition and inoculation feeding period proved that pre – acquisition starvation for 2 h produced maximum infection but post- acquisition starvation decreased the per cent infection. The vector could retain the virus for I h only. A single aphid could transmit the virus to healthy test plants, but maximum percentage of transmission was obtained with 10 aphids. Host range studies showed that the virus was restricted to the members of the family Araceae, Chenopodiaceae, Cucurbitaceae, Musaceae, Polygonaceae and Solanaceae. Datura metal acted as a symptomless carrier of bitter gourd mosaic virus. Serological studies showed that bitter gourd mosaic virus is related to cucumber mosaic virus, pumpkin mosaic virus and snake gourd mosaic virus. Varietal screening showed that all the varieties and collections were susceptible to biter gourd mosaic virus infection, but the variety Arka Harit and the collections 87 green long 1 C 68234, 61 white medium 1C 45358 and 177 green medium 1C 68324 were least susceptible. Studies on estimation of loss revealed that early infection of bitter gourd plants by the virus significantly reduced the number of leaves, leaf area, intermodal length, thickness of vines, length of vines, number of branches, number of flowers, number of fruits and other fruit characters viz., length of fruits, girth of fruits, weight of fruits and total yield of fruits.