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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Differential adoption of plant protection technology by farmers of Kerala - a critical analysis(Department Of Agricultural Extension, College Of Agriculture, Vellayani, 1995) Meera, B; KAU; Thyagarajan Nair, GIndian agriculture has undergone intensive farming with the introduction of high yielding varieties of crops. Adoption of improved technology and management practices for boosting up production of food grains have resulted in serious pest and disease complexes warranting intensive and extensive use of plant protection chemicals. A number of limitations and adverse side effects such as pest resistance to pesticides, pesticide residues, health hazards, environmental pollution and ecological imbalance have been identified recently. The components of plant protection technology were taken to study the differential adoption in important crops like paddy and vegetables by the farmers and explained the variations in their cognitive, affective and connative components of behaviour with a selected set of independent variables. The study analysed the indigenous practices of plant protection being followed by farmers and also their perception about the impact of pesticides on environmental aspects. The major constraints experienced by the farmers in the adoption of plant protection technology along with the suggestions to overcome the same were also studied. The study was undertaken in two districts of Kerala viz., Thiruvananthapuram and Alappuzha. A sample of 120 farmers each from the two districts was selected and the total sample size for the study was 240.The data were collected using an interview schedule and analysed using suitable statistical techniques. There was significant difference among the farmers of Thiruvananthapuram and Alappuzha districts with regard to their knowledge about chemical and cultural methods of plant protection. Majority of farmers of both the districts belonged to low knowledge group. The farmers of both the districts were ignorant about biological, physical and integrated methods of plant protection methods. Majority of the farmers of both the districts possessed favourable attitude towards chemical method of plant protection. The farmers of Alappuzha district were significantly higher adopters of plant protection methods than the farmers of Thiruvananthapuram district. Majority of the farmers of both the districts belonged to low perception category with regard to their perception about the utility and practicability of plant protection methods. Crops yield index and scientific orientation emerged as significant independent variables in the correlation and multiple regression analysis with regard to the farmers of both the districts. The practices, viz., controlled application of nutrients for reducing pest and disease attack in paddy and use of ‘thulsikeni’ in ‘pandals’ to trap and kill fruit flies in vegetables were judged as the most effective and scientifically rational practices adopted by farmers. The farmer’s perception about the impact of pesticides on environmental aspects was very low and majority of them belonged to low perception category. The constraint ‘untimely supply and high cost of imputs’ was the most important constraint experienced by the farmers of Thiruvananthapuram district, while ‘lack of proper drainage facilities’ was the most serious constraint experienced by the farmers of Alappuzha District. The most important suggestion given by the farmers to overcome the constraints was to ‘develop simple and more compatible plant protection technologies’ and the most important suggestion given by the experts to overcome the constraints experienced by the farmers was to ‘impart adequate training to farmers as well as extension workers on IPM practices’. The strategic model developed by integrating the salient findings of the present study, emphasized the importance of popularizing effective plant protection technology among the farmers in ecologically sensitive rice and vegetable production systems in Kerala.ThesisItem Open Access Genetic analysis of biological nitrogen fixation traits and yield components in cowpea (Vigna unguiculata (Linn). walp)(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1995) Sreekumar, K; KAU; Manikantan Nair, PA study on the parameters of variability, correlations, path-coefficients, combining ability, gene action and heterosis in cowpea was undertaken at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1991 to 1993. Fifty three genotypes of cowpea collected from different sources were planted in a field experiment for the estimation of variability, correlation and path coefficient. Eleven biological nitrogen fixation characters, viz., number of days to flower, length of primary root, number of secondary roots, number of nodules in the primary root, number of nodules in the secondary roots, total number of nodules, weight of effective nodules in the primary root, weight of nodules in the secondary roots, total weight of nodules, nitrogen content in the plant at 50 per cent flowering and plant dry weight and six yield characters, viz., grain yield per plant, length of pods, number of pods per plant, number of seeds per pod, weight of 100 seeds and seed protein content were considered for this study. The ten selected varieties/types from the initial evaluation trial were crossed in a line x tester model, keeping the three high nitrogen fixing types and three high yielding types as lines (total six lines) and two low nitrogen fixing and two low yielding types as testers (total four testers). The F1’s along with their parents were compared in a field experiment and combining ability, gene action and heterosis were estimated. The study of combining ability and gene action were confined to six biological nitrogen fixation characters, viz., number of days to 50 per cent flowering, weight of nodules in the primary root, total weight of nodules, weight of effective nodules, dry weight of the plant and nitrogen content per plant and six yield characters, viz., length of pod, number of seeds per pod, number of pods per plant, hundred seed weight, seed protein content and grain yield per plant. The analysis of variance revealed that a considerable amount of variation among the varieties was present with respect to the characters under study. Characters like number of days to flower, total nodule weight, nitrogen content per plant, weight of 100 seeds and seed protein content had recorded narrow relative magnitude of difference of phenotypic and genotypic coefficient of variation along with high heritability estimate. Moderate magnitude of difference of PCV and GCV along with moderate heritability was recorded for the characters viz., number of nodules in the primary root, number of nodules in the secondary roots, total number of nodules, weight of effective nodules in the primary root, weight nodules in the secondary root, length of pods and number of pods per plant. Plant dry weight and grain yield registered a wider difference of PCV and GCV along with low heritability indication the greater influence of environment over these two characters. Genetic advance as percentage of mean was found to be high for the characters like number of nodules in the secondary roots, weight of effective nodules in the primary root, weight of nodules in the secondary roots, total nodule weight, number of pods per plant and 100 seed weight and moderate for number of nodules in the primary root, total number of nodules and grain yield. Low genetic advance was recorded by number of days to flower, plant dry weight, nitrogen content per plant, length of pod and seed protein content. Hence characters such as number and weight of nodules in the primary root, number and weight of nodules in the secondary roots, total number and weight of nodules, number of pods per plant and weight of 100 seeds may be controlled by additive genes whereas days to 50 per cent flowering, nitrogen content in plant, length of pod and seed protein content may be controlled by non-additive genes. Correlation coefficients were workedout at the genotypic and phenotypic levels. Based on the genetic correlation of characters studied, it was understood that high nitrogen fixing genotypes may not be high yielders because of the antagonistic relationship between grain yield and total nitrogen per plant. Weight of nodules in the primary root and total nodule weight were positively correlated with the nitrogen content in plant. Hence genotypes which was able to form effective large nodules on the primary root system seems to be a better nitrogen fixer. Number of days to 50 per cent flowering had negative genotypic correlation with grain yield. Hence an early flowering genotype may be better yielder than a late flowering type. Weight of hundred seeds and seed protein content exhibited very strong negative correlation indicating that small seeded genotypes may be better with respect to protein content. Grain yield recorded positive phenotypic and genotypic correlation with number of pods per plant. Path coefficient analysis at the genotypic level revealed that total number of nodules had the highest positive direct effect on nitrogen content per plant followed by weight of effective nodules in the primary root and weight of effective nodules in the secondary root. Highest positive direct effect was recorded for length of pod with grain yield. The combining ability analysis revealed that both additive and non-additive gene actions were important for all the characters under study. However GCA and SCA variance ratio which was less than unity for all the traits under study indicated the predominance of non-additive gene action in the inheritance of these traits. Considering the combining ability effects, VCP 4 was found to be the best general combiner for most of the biological nitrogen fixing characters and V 322 was the best general combiner for the grain yield. The cross combination of V 27 x C 152 and V 271 x Co Vu 85020 showed the best performance with respect to sea for the character number of days to 50 per cent flowering while VCP 4 x C 152 for weight of nodules in the primary root and nitrogen content in plant. DPLC 210 x PTB 2 recorded high sea for total weight of nodules, weight of effective nodules, dry weight of the plant and number of pods per plant, on the other hand Co Vu 358 x C 190 recorded high sca for length of pod, number of seeds per pod and seed protein content. The cross combination V 322 x C 190 exhibited high sca for hundred seed weight and V 27 X C 152 for grain yield per plant. Marked heterosis was observed in many cross combinations for most of the characters studied and pronounced heterotic expression was obtained for weight of nodules in the primary root, total weight of nodules, weight of effective nodules, dry weight of the plant at 50 per cent flowering, number of pods per plant and grain yield. It was already established that these characters are predominantly governed by the non – additive gene action. Hence the heterotic vigour expressed by the hybrid combination with respect to these characters are justified. Since the biological feasibility for the exploitation of heterosis is not economical as a plant improvement programme in this crop, genetic improvement of these trait can be brought about more effectively through combination breeding involving genetically diverse and high combining parants.ThesisItem Open Access Incorporation of resistance to fruit cracking in a bacterial wilt resistant genetic background in tomato(Department of Olericulture, College of Horticulture, Vellanikkara, 1995) Sadhan Kumar, P G; KAU; Rajan, SAn investigation on “Incorporation of resistance to fruit cracking in a bacterial wilt resistant genetic background in tomato” was undertaken in the Department of Olericulture, College of Horticulture, Vellanikkara during the period from January, 1991 to March, 1994. The findings are succinctly mentioned below. Evaluation for bacterial wilt resistance revealed that Sakthi and LE 79 – 5 are consistently resistant to bacterial wilt. Four addition sources of bacterial wilt resistance were identified viz., LE 214, CAV – 5, LE 415 and LE 382 – 1. Resistances to bacterial wilt in these lines was governed by recessive genes. Screening for resistances to fruit cracking resulted in the identification of fifteen tomato genotypes which were found to be resistant to both radial and concentric cracking. Resistances to concentric fruit cracking in these lines were found to be dominant. All the bacterial wilt resistant genotypes had a higher content of total phenols, O.D. phenol and ascorbic acid than the susceptible line pusa Ruby. The crack resistant varieties had a higher content of insoluble solids and pectin, lower content of acidity, total sugar and reducing sugar in fruits, thick fruit skin and pericarb as compared to susceptible variety. The elasticity of skin was also higher in crack resistant genotypes. Crack resistant varieties had a compact arrangement of parenchymatous cells when compared with crack susceptible variety. The resistant lines had a thicker cuticle also. The F1 S developed by line x tester crossing were susceptible to bacterial wilt. All the same, they were resistant to both radial and concentric fruit cracking indicating dominant gene action for crack resistance. The F2 segregants with combined resistance to both bacterial wilt and fruit cracking were selected for further improvement.ThesisItem Open Access Characterisation and evaluation of the dwarf cattle of Kerala(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1994) Girija, C R; KAU; Sosamma, IypeThe native cattle of Kerala have been treated as non descript animals always eventhough they possess some special features. The dwarf cattle often called as Vechur were very popular in Central Travancore until 35 years back. With the emergence of the crossbred population of cattle the traditionally reared local cattle have gradually suffered genetic erosion. Under this circumstance, the present work was undertaken to characterize and evaluate the germplasm of local dwarf cattle of Kerala by studying (a) the karyotype and morphology of chromosomes using G-banding (b) the population structure by means of gene frequencies of different blood proteins (c) the growth and production performance. The characterization and the evaluation would help in finding out the genetic differences of the dwarf cattle which will help in deciding about the conservation of their germplasm as a reserve for the future. The dwarf cattle maintained under the ICAR scheme on “Conservation of germplasm of Vechur cattle of the coastal area and the dwarf cattle of the high ranges of Kerala” formed the material for the study. The characterization and evaluation was carried out through the cytogenetic, immunogenetic and polymorphism studies as well as through the description of the growth and production traits. Karyotype analysis was carried out using peripheral blood leukocyte culture technique described by Halnan (1977) and Halnan (1989) with suitable modifications. G-banding of chromosomes were done by the method described by Thiagarajan (1993). Blood protein polymorphism systems such as Haemoglobin and transferring were studied by poly acrylamide gel electrophoresis in horizontal dimension. (Gahne et. al. 1977) with suitable modifications. The statistical analysis of the growth and production data were done as suggested by Snedecor and cochran (1967). The diploid chromosome number of the dwarf cattle was found to be 60, with 29 pairs of autosomes and one pair of sex chromosomes. All the autosomes and the ‘Y’ chrosome were acrocentric. The X chromosome was submetacentric. The relative length of the autosomes ranged from 1.757 to 5.431 per cent. The relative length of the X and Y chromosomes were found to be 5.591 per cent and 2.875 per cent respectively. In the karyological array, the X chromosome occupied the first position. The X chromosome was biarmed and the arm ratio and centromere index obtained were 2.182 and 0.314 respectively. The karyotype and morphometric measurements resembled the finding in Bos indicus group of cattle. The G-banding pattern of chromosomes revealed 72 regions and 314 G-bands. The Y chromosome had 7 G-bands in the ‘q’ arm which resembled the ‘q’ arm of Bos taurus described in the international system for cytogenetic nomenclature of domestic animals. There were two haemoglobin variants HbA and HbB and three phenotypes viz. HbAA, ,HbAB and HbBB , in the population. The heterozygocity was found to be 0.4815. The population was found to be in genetic equilibrium with respect to the Haemoglobin locus. Six transferring phenotypes controlled by three alleles TfA, TfD and TfE were observed. The frequency of TfE (0.359) allele in the dwarf cattle was as high as the frequency of the allele reported in the zebu cattle. The absence of transferring variants like TfF, TfH, TfN and TfG and higher frequency of TfE allele are probably indicative of the genetic isolation of the population from exotic breeds. The absence of TfB and TfF allele which is present in Gir, Hariana, Kankrej, Kangayam, Ongole, Red Sindhi, Sahiwal and Tharparkar also indicates that the dwarf cattle has not inherited genes from the above cattle breeds. The body weights and measurements of calves at birth studied showed that the male calves had a higher body weight (12.55 ± 0.31 kg with a CV of 7.86 per cent) than female calves (10.78 ± 0.40 kg with a CV of 15.02 per cent). The same trend was observed with regard to the birth body measurements also. The heart girth measurement and body weight showed a positive correlation from birth to the 24th fortnight. There is a 100 per cent increase in the birth weight by the 5th fortnight and a three-fold increase by the 10th fortnight. The average daily gain in weight for the four periods I e., fortnights 0-6, 7-12, 13-18 and 19-24 were 0.160 ± 0.011, 0.167 ± 0.018, 0.212 ± 0.011 and 0.139 ± 0.015 respectively for female calves and 0.188 ± 0.023, 0.145 ± 0.016, 0.116 ± 0.025, 0.242 ± 0.049 kg respectively in male calves. During the period from birth to 6th fortnight the growth rates in males and females were similar. The gain in body weight per day during the periods from 7 to 12th and 13 to 18th fortnight was comparatively less for males but the trend reversed during the period of fortnights for 19 to 24th. The average body weights of adult females and males were 126.90 ± 3.56 kg (CV 16.39%) and 210 ± 15.75 kg (CV 14.95%) respectively. The body measurements such as length, heart girth and height (in cms) in females were 97.5 ± 1.12 (CV 5.85%), 115.60 ± 1.32 (CV 5.82%) and 87.53 ± 0.82 (CV 4.82%) respectively. The corresponding figures in males were 111.5 ± 3.77 (CV 6.76%), 146.0 ± 2.92 (CV 3.99%) and 107.5 ± 1.35 (CV 2.50%) respectively. The average body weights and measurements were lesser than those reported in other Indian breeds and crossbred cattle. The total lactation milk production performance of the dwarf cattle was 471.68 ± 38.72 kg (CV 45.29%) in an average lactation length of 217 ± 16.50 days (CV 32.20%). The average daily yield was 2.17 ± 0.11 kg (CV 29.48%). The dwarf cattle attained a peak yield of 3.71 ± 0.16 kg (CV 21.5%) in 23.23 ± 1.703 days (CV 37.38%). The milk production performance eventhough was lesser than crossbreds or some recognized Indian breeds, the milk production in comparison with the body size was reasonable. Considering the morphology of the Y chromosome, the Hb as well as Tf polymorphism and their allelic frequencies, it is to be summarized that the stock of dwarf cattle of Kerala maintained at Kerala Agricultural University is genetically isolated from the other cattle breeds of the country and world. The body size and milk production of the cow indicates its suitability for a farmer who requires milk just for home consumption. The study strongly confirms the necessity of conservation of the dwarf cattle of Kerala which is the smallest variety available in India and perhaps in the world itself.ThesisItem Open Access Farmer-labourer relationship in rice production systems -a case study(Department Of Agricultural Extension, College Of Agriculture, Vellayani, 1995) Ramanathan, S; KAU; Thyagarajan Nair, GThe study was undertaken with the objective of analyzing the farmer – labourer relationship in paddy production systems. The study was conducted in two districts of Kerala namely, Thiruvananthapurm and Alapuzha representing two distinctly different paddy production systems. Dyadic approach was used in the conduct of the study and altogether 150 farmer – labourer dyads were selected, 75 dyads each from the selected districts using random sampling. The farmer – labourer relationship was measured with the help of a scale developed for the study having 33 items. A pilot study was conducted for the selection of items to be included in the scale. The response for the items was obtained on a 5 point continuum with bipolar adjectives at the extreme ends as in the case of semantic differential technique. The data on farmer – labourer relationship and on 11 common variables, 7 farmer – related variables and 4 labourer – related variables were collected using a structured interview schedule. The relationship dimensions identified empirically were ‘facilitation’, ‘empathy’, ‘equity’, ‘tolerance’, ‘guidance’, ‘recognition’, ‘economic’, ‘social’ and ‘priority’. In general, a little more than half of the farmer – labourer dyads had high relationship. Like wise, in case of relationship dimensions such as facilitation, equity, tolerance, guidance, social and priority majority of the dyads came under high group. There was no significant difference between the overall relationship of the two study districts and among the three union membership categories. However, there was significant difference between the labourer categories with male labourers having significantly higher relationship than their female counterparts. The dimension – wise performance of farmer – labourer dyads on the whole was in the order of ‘tolerance’, ‘economic’, ‘empathy’, ‘recognition’, ‘social’, ‘guidance’, ‘priority’, ‘facilitation’ and ‘equity’. While there existed a vast dissimilarity in the relationship performance of dimensions of the two study districts, the two labourer categories and the three union membership categories were in agreement with regard to dimension – wise relationship performance. The socio – economic and psychological factors namely, management orientation, persuasiveness, gregariousness, education, ability to handle conflicts and labour use efficiency put together contributed significantly to the relationship of farmer – labourer dyads and explained 68 per cent of the variation in the relationship of farmer – respondents. In case of labourer – respondents, the variables participation in decision making with farmers, employment days and education were observed to be significantly contributing to the farmer – labourer relationship and explained 20 per cent of variation in the relationship.ThesisItem Open Access Partial substitution of muriate of potash by common salt for cassava (Manihot esculenta crantz) in oxisols of Kerala(Department of Soil Science & Agricultural Chemistry, College of Agriculture, Vellayani, 1995) Sudharmai Devi, C R; KAU; Padmaja, PField experiments were carried out in the College of Agriculture, Vellayani during 1991 to 1994 to study the possibility and extent of substitution of K of Muriate of Potash with the Na of common salt in Cassava variety M4 used as the test crop. Substitution of K was tried at 4 levels viz. 25, 50, 75 and 100 per cent of the recommended dose. Muriate of potash, replaced by wood ash and a combination of KHCO3 and NaHCO3 (eliminating chlorine source) also were included in the experiment. Plant growth characteristics like plant height and number of leaves did not vary significantly as a result of substitution. The maximum LAI was observed in the case of 50% K as MOP + 50% Na as CS treatment at all the growth stages. An increase in chlorophyll content was observed with NaCl substitution. In the early growth stages there was no significant variation in the production of roots, but at the later stages there was significant difference in this aspect. The root volume at 2 MAP varied significantly between treatments. In general, there was an increase in total weight of plant with NaCI substitution upto 50% and thereafter a decrease with higher levels of substitution, at all growth stages. Significant treatment difference could be observed in tuber yield in both the years of the experiment. T3 (50% MOP +50% CS) registered the highest tuber yield and T5 the lowest. The bulking rate and Utilisation Index also differed significantly among treatments. The cooking quality of the tubers from T3 was as good as that of T1. Significant differences could be observed in total sugars, reducing sugars and sucrose content of fresh tubers under different treatments. With increasing levels of substitution, the content of total sugars increased. Sucrose content was found to increase with Na application upto 75% substitution of K by Na. Significant variation was observed in the crude protein, total amino acid and free amino acid content of tubers. Hydrocyanic acid, total phenols and crude fibre also differed significantly between treatments. The keeping quality studies revealed that tubers from T3 could be stored fresh up to 35th day in moist soil, whereas tubers from T1 could be stored only upto 12th day, without deterioration. Enzyme studies revealed significant difference in the activity of starch synthesising enzymes, but NRA at 6 MAP was not affected by different treatments. The uptake of N was highest in T1 and P and K in T3. Na uptake by T1 which received no Na was generally higher than other treatments receiving Na. Ca and Mg uptake also differed significantly between treatments. Changes in soil organic carbon, available P, available K and available Mg were statistically significant between treatments but that of Ca was significant only from 4 MAP onwards. Yield of tubers was positively and significantly correlated to the uptake of N, P, K, Na, Ca and Mg. Yield at harvest was positively and significantly correlated to the root weight and root volume and also to the bulking rate at 2 MAP. Path coefficient Analysis revealed that the maximum direct effect on yield was contributed by the drymatter of roots at 2 MAP. From the results, it can be concluded that in soils having low to medium status of K, the K of MOP can be substituted up to 50% by Na of commonsalt in cassava without affecting the quality and quantity of tubers.ThesisItem Open Access Bionomics of pareuchaetes pseudoinsulata rego barros (lepidoptera:arctiidae) and its interaction with the siam weed chromolaena odorata king and robinson (asteraceae)(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1995) Lyla, K R; KAU; Abraham, C CStudies were undertaken on the biology, morphometrics, feeding habits, factors affecting fecundity and fertility of Pareuchaetes pseudoinsulata King and Robinson (Arctiidae : Lepidoptera) and also the plant response of the weed host Chromolaena odorata L. at the College of Horticulture, Vellanikkara during 1990 – 1993. The morphometrics and morphology of the various immature stages and adults have been described. The total life-cycle of P. pseudoinsulata took a total of 46.75 days and the various developmental stages lasted for 5.5 days in eggs, 21.30 days for larvae (seven instars) 1.5 days for pre-pupa and 10.15 days for pupae at a mean ambient temperature of 28.40 C. In feeding trials to assess the relative preference of tender, mature, semi yellow and yellow leaves of C. odorata, it was found that the I instar larvae showed district preference to tender leaves as compared to mature leaves. The I and II instar larvae did not feed on semi-yellow and yellow leaves and they died of starvation when these types of leaves were offered for feeding. Consumption indices decreased as the age of larvae advanced and thus early instars consuming all the types of leaves recorded high indices. The rate of increase in larval weight gain was higher in later instars (VI and VII). Caterpillars feeding on mature, semi-yellow and yellow leaves showed higher Relative Growth Rate during IV to V stage, but during I to II stage, a high RGR was seen on larvae which fed tender leaves. Yellow. leaf diet for late instar larvae adversely affected their development and adult emergence. Highest fecundity was recorded when the parental sex-ratio of moths was kept at 1:1 level followed by 1:2 ratio and 2:1 in that order. Egg production and viability were significantly higher at 250 C and 75 per cent RH as compared to 300 C and 60 per cent RH. Adult food did not show any influence on fecundity but in respect of improvement of egg viability the treatments were advantageous. Total nitrogen content in leaves was maximum on the sixth day of release of four larvae per cage. Leaf nitrogen showed a declining trend when the larval load per plant was increased from the eighth day of release onwards. Soluble nitrogen content in leaves showed an increasing trend with increase in larval load per plant, but this however failed to reach significant levels. Chlorophyll content in leaves got reduced significantly at increased larval population loads and with passage of time of confinement. The natural enemies of P. pseudoinsulata consisted of avian fauna, spiders and ants and parasitoids. Predatory species of ants recorded in association with the insect included Lioponera sp. Oecophylla smaragdina Fabr. Solenopsis sp.and Monomorium sp. Occasionally NPV infection occurred in the laboratory as well as in field cultures causing substantial mortality. The implications of the various findings in reorienting the biocontrol strategies involving P. pseudoinsulata against C. odorata have been discussed.ThesisItem Open Access Influence of cover crops on growth of rubber and on soil fertility status(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1994) Sushama Kumari, K R; KAU; Alice, KurienThe study was conducted in Ottapalam taluk (Palakkad district, Kerala state) to make a comparative evaluation of two cover crops (pueraria phaseoloides and Mucunna bracteata) with respect to yield of biomass, leaf litter addition , nutrient composition , soil enrichment through added nutrient , competition , soil enrichment through added nutrient , moisture regime of the soil and its impact on growth of rubber . The salient findings of study are summarized below. Mucuna bracteata recored higher biomass on per hectare basis than pueraria phaseoloidies . The status of nutrients N, p and k were higher in Mucuna bracteata than pueraria phaseoloides and the difference was much evident in the case of N content. Calcium and magnesium were found to be high in pueraria phaseolodies. The leaf litter from the cover crop was quantified and found that the mucuna bracteata produced higher leaf little (2324.09 kg ha -1) Compared to pueraria (1205.72 kg ha-1). Content of organic carbon, available p and available K in the soil at two depths (0-15 cm and 15-30 cm ) was higher in plots cover-cropped with M. bracteata than other three plots cover-cropped with P. phaseolodies, inter -cropped and those with natural cover. The availability of magnesium was found to be highest in plots inter -cropped with banana . M. bracteata recorded lowest magnesium status of the soil and this can be attributed to the higher up take due to high biomass production . Any sort of the cropping whether cover-cropping or inter-cropping helps to improve the nutrient status of soil and conserve the moisture. The area under natural cover recorded the lowest moisture content during both the months. P. phaseoloides was found to be the most efficient with regard to moisture conservation and recorded the highest moisture content during April and may. Cover –cropping or inter-cropping was found to augment the growth of rubber and maximum girth increment was observed for Mucuna bracteata covercropped plots. The study also revealed that in general Mucuna bracteata was much superior to pueraria phaseolodies with regard to biomass production , and addition of major nutrients to the soil . The low moisture content in Mucuna cover-cropped plots demands further investigations to arrive at definite conclusions regarding the competition for soil moisture between rubber and the cover crop.ThesisItem Open Access Effect of cover crops on nutrient dynamics in the rubber plantations(Department of Agronomy, College of Agriculture, Vellayani, 1995) Prathapan, K; KAU; Sreedharan, CThree field experiments were conducted at Bethany Estate, Mukkampala, Kanyakumari District from February 1991 to October 1993 to study the effect of cover crops on the nutrient dynamics in immature, mature rubber plantation and an open area. In Experiment I there were two cover crops viz. Pueraria phaseoloides and Mucuna braceata and five levels of NPK viz. 0:0:0, 0:30:30, 10:30:30, 0:60:60 with one year old RRII-105, replicated thrice and statistically laid in RBD. In Experiment II there was one cover crop Mucuna sp alone with five levels of NPK as above with 8 years old RRII-105 replicated 4 times and statistically laid in RBD. In Expt. III there were 10 microplots, with both cover crops. N, P, K, Ca, Mg content of both Hevea and cover crops were increasing as the crops growth progressed. Fertilizer application to cover crops improved the Hevea leaf nutrient content than the absolute control. Among the levels 10:30:30 was found optimum. Mucuna was found better than Pueraria in increasing the Hevea leaf nutrient content. Girth increment was better with 10:30:30. This was found to be optimum under both experiments. More height increment was observed in this level, as well as in cover cropped treatments when compared to absolute control. Biomass production of cover crops were maximum at 10:60:60 followed by 10:30:30 under both experiments. Biomass production, root weight and length were higher in Mucuna and it was found increasing as the crop growth progressed. Nodule count was higher in Pueraria and the fresh weight of nodule per plant was higher in Mucuna as the size of its nodule was found bigger. Soil Moisture retention capacity was found higher under cover cropped plots at both shallow (0-30cm) and deeper (30-60cm) soil depths at-0.033 and -1.5 Mpa pressures than control. Pore space and aggregation percentage were improved whereas bulk density decreased. Among the levels of NPK 10:30:30 was found optimum in improving the soil physical properties. The percentage of improvement was found greater at shallow depth of soil than deeper. Soil moisture content during summer months were improved in the cover cropped area. The soil moisture in than the top soil (0-30cm) was lesser than the bottom soil (30-60cm) in Pueraria grown plots. This trend was reverse in the case of Mucuna. Growing of cover crops improved the microbial population of bacteria, fungi and phosphate solubilising organisms. The level 10:30:30 was found optimum for the better microbial activity. 10:30:30 was found optimum for better yield and Latex Flow Characteristics. Covercropping has increased the latex yield by 15-20%. 10:30:30 was optimum for better leaf litter production of Hevea. In cover cropped plots the leaf litter production was higher and wintering was delayed by 26-30 days over the control. This has enhanced 10 additional tapping days. Girth is positively correlated with cover crop biomass, nutrient uptake, soil available nutrients, soil moisture contents and Hevea leaf nutrient contents. Strongest correlation for girth was found with Hevea leaf N content, and uptake of N by cover crops, suggesting the importance of foliar diagnosis. Yield was negatively correlated with Mg content of soil.
