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1981 - 198911990 - 19965
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Author: Kau × Start date: 1981 × Type: Thesis ×
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    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.
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    ThesisItemOpen Access
    Seasonal fertility of billy goats
    (Department of Animal Reproduction, College of Veterinary and Animal Sciences, Mannuthy, 1995) Ibraheem Kutty, C; KAU; Sudarsanan, V
    Biweekly data on body weight, scrotal circumference, testicular length and diameter and weekly data on semen parameters as volume, colour, pH, consistency, density, sperm concentration, mass activity, initial motility, sperm abnormality, vitality, metabolism and resistance to hyperosmotic medium of seven billy goats were pertaining to four seasons arrived at on the basis of a simultaneously kept daily record of maximum-minimum temperature, humidity and day length. It was statistically analysed to find out that the differences between seasons were significant to be attributed to the environmental variables. Mean body weight, scrotal circumference and testicular length and diameter were 43.62 ± 1.11 kg, 25.08 ± 0.12 cm, 8.57 ± 0.07 cm and 5.32 ± 0.03 cm respectively. There was no significant difference between the seasons except in testicular diameter and they were found to maintain an inverse relationship with day length and humidity. Mean volume, pH, initial motility, sperm concentration, total number of sperm per ejaculate, live sperm per cent, abnormal sperm per cent, MBR time and R value were 0.75 ± 0.04 ml, 6.25 ± 0.02, 73.51 ± 0.98 per cent, 3600 ± 144 millions/ml, 2660.6 ± 133.96 millions, 83.44 ± 0.76, 4.33 ± 0.43, 277.1 ± 14.27 seconds and 84.75 ± 12.39 ml respectively. There was no significant difference between seasons in these parameters except, pH, initial motility, live sperm per cent and R value. They were found to have a significant difference between seasons and were found to maintain either direct or indirect relationship with humidity and day length. Semen on extension with milk antibiotic extender and on storage under refrigeration was found to fast deteriorate rendering it unusable in 24 h. Semen on the day of collection and extension, was used for artificial insemination and result of insemination was found to be independent of the significant or nonsignificant seasonal differences of semen parameters. But, during the period of study, there were two peaks in conception and two peaks in birth corresponding to it. The pattern appeared to be an adjustment of reproduction by the female to the varying food availability and climate with little involvement of the male.
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    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.
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    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).
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    ThesisItemOpen Access
    Effect of different inputs on productivity and quality relations in njavara (Oryza sativa)
    (Department of Agronomy, College of Horticulture, Vellanikkara, 1996) Meera Menon, V; Kau; Potty, N N
    Productivity characteristics of Njavara (Oryza sativa), a medicinal rice variety were investigated based on the results of four separate experiments conducted at the Regional Agricultural Research Station, Pilicode, during 1994-96. The experiments were to study (i) growth and development characteristics (ii) crop weather relations (iii) response to nitrogen, phosphorus and potassic fertilizers and (iv) the effect of integrated nutrient management. Two biotypes of Njavara, the black glumed and golden yellow glumed, were tested in the first two experiments. The black glumed biotype alone was studed in the third and fourth experiments. The first experiment, consisting of the two biotypes as treatments, was conducted in wetland, open upland, heavily shaded upland and partially shaded upland, and pooled analyses of the data were conducted. Treatments of the second experiment which studied the effect of date of sowing on productivity of Njavara included 10 dates of sowing at fortnightly intervals starting from the 15th of May. Combinations of three levels of nitrogen, phosphorus and potassium, each at levels of 15, 30 and 45 kg ha-1 along with a standard and absolute control constituted the treatments of Experiment III. The last trial consisted of two treatments, one exclusively with farmyard manure and another with fertilizer alone, both at 30 kg nitrogen equivalent, two treatments with organic and inorganic manure in different ratios and three combinations of Azospirillum with 25, 50 and 75 per cent of the full farmyard manure dose. The second experiment was conducted in open upland and the third and fourth experiment in heavily shaded coconut gardens. Biometric, nutritional and quality criteria estimated through accepted methodology were used for the evaluation of treatments. An abstract of the results obtained has been presented in the following paragraphs. The results showed that three phases could be distinguished in the growth and development of Njavara. They are a primary phase of absorption and accumulation of nutrients, a grand growth phase of rapid accumulation of dry matter and a diversion phase when the seed and quality develop. Continued growth till harvest gave high yield and dry matter decline in the final phase led to superior quality characteristics. Golden yellow glumed biotype exhibited continuous growth and higher yield of grain. Black glumed biotype manifested dry matter decline in the final phase, leading to lower yield of grain and higher free amino acid content in the grain. Profound influence of cropping situation on yield and quality of grain was observed. Lowest yield of 684 kg ha-1 and highest amino acid content of 0.492 mg g-1 were observed in the uplands and highest yield of 2401 kg ha-1 and lowest amino acid content of 0.203 mg g-1 were observed when Njavara was sown in the wetlands. Viewed on the basis of variation in nutrition in the different situations, the results showed that yield limiting influences were not the deficiency of any element but the excess contents of Mg and Mn at maximum tillering and of P, K, S, Zn and Cu at panicle initiation stages in the plant. This appeared to be a highly significant result in the context of stagnant productivity of crops like rice. Content of free amino acids in the grain appeared to be unique characteristic of Njavara rice. Among the amino acids, sulphur containing amino acids, methionine and cysteine were also present. Possibly, these amino acids are related to the medicinal value of Njavara in the treatment of rheumatic complaints, the symptoms of which resemble thiamin deficiency. Inherently high yield potential of Njavara was expressed in the date of sowing trial. Both the biotypes recorded grain yields of 6000 kg ha-1 when sown on most favourable dates. Weather influence contributed to be highest yield through two ways, firstly, by increasing the total dry matter yield and secondly, by improving the grain-straw ratio. The golden yellow glumed biotype produced higher grain yield than the black glumed biotype. Application of N, P and K fertilizers increased the uptake of all the elements studied. Positive interaction of fertilizer elements on content and uptake of elements was also evident. However, application of fertilizers could influence only the straw yield significantly. One possible reason for the absence of significant improvement of grain yield by fertilizer application appeared to be due to the high levels of application. Even 15 kg ha-1 of N, P and K were found to be excess in shaded situations. Results of the integrated nutrient management studies showed that level of application was more important than the source in affecting the ultimate yield. Farmyard manaure application led to a more balanced development of the components of yield whereas fertilizer source improved only the floret number per panicle. Nutritional management at levels below 15 kg ha-1 N equivalent significantly reduced the yield. Azospirillum did not have any effect in increasing the yield of Njavara. The results of the different experiment brought out the role of soil and atmosphere environment as well as the biotype influence on the yield and contributed to the development of the concept of soil-plant-atmospheric continuum on the technical side. On the pracical side they showed that Njavara is an ideal crop for growing in the first crop season in the uplands in North Malabar when no other crop can be grown and that growing in heavily shaded uplands will give high quality grain. Advantageously, the crop will not require intense management.
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    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.