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ThesisItem Open Access Flower bud differentiation in clove, Eugenia caryophyllus (Sprengel) Bullock & Harrison(Faculty of Agriculture, Department of Horticulture, College of Agriculture, Vellayani, Trivandrum, 1989) Pauline Lina, Edwin; KAU; Vasanthakumar, KInvestigations on flower bud differentiation in clove were carried out at College of Agriculture, Vellayani from August, 1936 to December, 1987. Bearing clove trees (seven years old) at the Instructional Farm attached to the college were utilized for the study. The plant specimens were stored in FAA (Formalin-acetoalcohol) and then dehydrated through tertiary butyl alcohol - iso propyl alcohol series. The specimens were Infiltrated and embedded In paraffin wax (m.p. 58-60'C) and sectioned In a rotary microtone. The sections were then de-waxed, stained and examined for the anatomical features and photoalerogra- phed. The weather parameters and the nutritional factors recorded daring the period of study and those during sixteen fortnights prior to differentiation, were correlated with the data on flower bud differentiation. Significant positive correlation was obtained between the maximum temperature during the sixth to tenth fortnights before differentiation and the percentage of flower buds differentiated. Sunshine hours during ninth to twelfth fort night prior to differentiation showed a positive correlation with the percentage of flower bud differentiation.ThesisItem Open Access Variability studies on certain T X CDO F, hybrids of coconut (Cocos nucifera L)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1987) Sreelatha, P C; KAU; Kumaran, KInvestigations conducted on variability in 14 F1 parental combinations of T X CDO coconut hybrids at the KADP farm attached to the College of Horticulture, Vellanikkara revealed no significant difference between pollen parents in their contribution to the progenies in any of the 17 characters studied, unlike the female parents. The number of spadices was found to be highly correlated with the number of buttons set followed by the number of functional leaves and number of female flowers produced. The fourteen parental combinations were grouped into three clusters using Mahalanobis’ D2 analysis. Clusters I and II were the most divergent ones. Production of spadices and female flowers were found to be high during March, April and May and absent during October, November and December. Heavy rain during active female phase was found to affect setting of button adversely. Fertility and viability of pollen were found to be very high except during April and May due to high temperature.ThesisItem Open Access Induction of genetic variability in guinea grass (Panicum maximum Jacq.) Var.Makuenii(Department of Agricultural Botany, College of Agriculture, Vellayani, 1989) Rani, N; KAU; Vijayagopal, P DGuinea grass (Panicum maximum J.) being a facultative apomicts under continuous vegetative propagation carry very little variability. The cross incompatibility also restricts attempts to produce variability through conventional methods of plant breeding. The main objective of the study is to induce variability through mutations in guinea grass variety Makuenii using gamma rays at four doses ranging from 15 Krad to 30 Krad and EMS at four concentrations ranging from 0.25 percent to 1.00 percent. The effect of the mutagens in M1 and M 1 V1 generations were studied. The observations in the M1 generation indicated that germination of seeds was progressively reduced with increase in the dose of mutagens. The survival and early growth of seedlings were adversely affected by the mutagen treatments. The seedlings appeared to suffer from the transplanting shock as indicated by high mortality of the plants in the field. Higher doses of mutagens induced height reduction. However the tillering ability of the plants did not seem to have been affected but higher doses of mutagens inhibited flowering initiation. Pollen sterility in M1 generation exihibited dose dependence. A few chlorophyll chimeras were observed in the M1 generation. Morphological abnormalities induced dwarf, tall, semi open and open types with leaf and inflorescence modifications. The means of M1 V1 clones exhibited both positive and negative shifts from the population means with respect to plant height. Treatments 20 Kard gamma rays and 0.25% EMS caused positive shifts in the means of girth at internode and leaf area index. Certain clones were identified to have higher green fodder yield than the control. These clones also had higher girth at internode and higher leaf area index. The study revealed that variability with respect to plant height, girth at internode, leaf area index and green fodder yield can be induced by mutations using appropriate doses of gamma rays and EMS. A medium dose of 20 Krad gamma rays and a relatively lower dose of 0.25 percent EMS were found to induce more useful variations.ThesisItem Open Access Relative biological effectiveness of gamma rays and ethyl methane sulphonate on cardamom varieties(Department of Agricultural Botany, College of Agriculture, Vellayani, 1987) Benney Joseph; KAU; Kamalam, NThe direct effect of 60 Co-gamma rays and ethylmethane sulphonate (EMS) on three varieities of cardomom namely Malabar, Mysore and Vazhukka was studied during the course of present investigation. The experiment was carried out at the Department of Agricultural Botany, College of Agriculture , Vellayani during the year1985-1986. Dry seeds were exposed to gamma rays at dose levels ranging from 10-70 kR at 10 kR interval and the pre-soaked seeds for 16 hours were treated with EMS concentrations ranging from 0.25 % to 1.75% at an interval of 0.25%. Soaked seeds were also exposed to gamma rays with 10 and 20 kR. The experiment was laid out in RBD with two replications. Direct effect of the mutagens was assessed by analysing the effect of various growth metrices like number of days taken to start germination , number of days taken to complete germination from the date of sowing and also from the date of first sprout, rate of germination , germination percentage, survival percentage, growth rate based on plant height , leaf number, leaf area and tiller number , frequency of chlorophyll deficient plants and cytological effects. The data collected were analysed statistically . Since sufficient population was not available at higher doses of both the mutagens they were not considered for growth metric analysis.ThesisItem Open Access Genetic resource evaluation of groundnut (Arachis hypogaea L.) for resistance to tikka leaf spot(Division of Agricultural Botany, College of Horticulture, Vellanikkara, 1989) Sajikumar, T A; KAU; Achamma OommenThe research project " Genetic resource evaluation of groundnut Arachis hypogaea L.) for resistance to tikka leaf spot was carried out at the College of Horticulture, Kerala Agricultural University, Vellanikkara, during 1988-89. Two hundred and fifty six groundnut genotypes available in the Department of Agricultural Botany were made use of for the study. A susceptible variety- TMV 2- was used as control. A field screening study was conducted with the 257 genotypes during July- November 1988, in arandomised block design with two replications. Disease rating was done with the aid of a diagramatic chart and the groundnut accessions were grouped into different categories such as immune, highly resistant, resistant, moderately resistant , moderately susceptible, susceptible and highly susceptible , based on the percentage of infection on leaves . Out of the 257 genotypes used for screening studies, four genotypes were moderately susceptible , 197 susceptible and 56 highly susceptible to tikka leaf spot. None of the varieties was immune highly resistant or moderately resistant.ThesisItem Open Access Karyomorphology, Pollen sterility and seedset in Vetiver (Vetiveria zizanioides (Linn) Nash.)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1989) Mini, K S; KAU; Viswanathan, T VInvestigations on karyomorphology, pollen sterility and seedset in Vetiveria zizanioides were undertaken using eleven cultivars of Vetiver, including North Indian type, South Indian type and one hybrid. The observations on plant morphology indicated no clearcut morphological features employable for exact identification of North Indian and South Indian types of Vetiver. The somatic chromosome number was observed constant in all cultivars ie. 2n = 20. However, the different cultivars differed cytologically with respect to chromosomal characters like size and shape, total chromatin content and meiotic configurations during different stages of division. Presence of meiotic abnormalities like bridges and laggards were observed in all cultivars with highest frequency in O D V - 4. This cultivar also showed high percentage of pollen sterility. A direct relationship between meiotic abnormalities and pollen sterility was noticed. Studies on seedset pattern of different cultivars revealed very low set, mostly nil upon selfing, while all the cultivars produced fairly high quantity of seeds upon open pollination.ThesisItem Open Access Intra and inter varietal variability analyses in cardamom (Elettarla cardamomum Maton)(Department of Agricultural Botany, College of Agriculture, Vellayani, 1987) Gopal Radhakrishnan; KAU; Chandramony, DThe present investigation was conducted at the Cardamon Research Station, Pampadumpara to obtain Information on the magnitude of genetic variability In the population and the extent to which the desirable characters are heritable. Four popular cultivars viz. Malabar, Mysore, Vazhukka and PV-1 of two age groups three and six year old planted at the above station were used for the study. Observations were made on height of tillers, number of productive tiliers/plant, number of leaves/tiller, number of panicles/plant, number of capsules/panicle, fresh weight of capsules/plant, dry weight of capsules/plant, hundred capsule weight, capsule volume, number of seeds/capsule, length of panicle, number of nodes/ panicle and Internodal length In the panicle. The data collected was subjected to studies on genetic variability, estimation of genetic parameters, correlation and path coefficient analysis. Variability analysis revealed that significant differences exsisted among the varieties for eight of the thirteen morphological characters studied. They were number of productive tillers/plant, height of tillers, number of panicles/plant,internodal length in the panicle, number of capsules/panicle, capsule volume, fresh and dry weight of capsules/plant. The variability within the varieties was not significant.ThesisItem Open Access Demand and supply of agricultural credit - a case study of Madakathra Panchayath(Faculty of Agriculture, College of Co-operation and Banking, Mannuthy, 1989) Renuka S, Menon; KAU; Ramachandran, UThe study viz – ‘The Demand and Supply of Agricultural Credit – A case study of Madakathara Panchayath’ has been carried out to assess the total credit requirements for paddy and other seasonal crops and to assess the extent of credit applied by different credit agencies so as to estimate the credit gap. Hundred farmers consisting ten percent of the population in Madakathara Panchayath were selected at random for detailed survey. Percentage analysis of the cost of cultivation and credit supplied for paddy banana and tapioca revealed that in the case of borrowers from co-operatives, the credit gap was 54.89 per cent, 52.10 per cent and 88.90 per cent for the size classes 1.5 to 2.5 acres, 2.5 acres to 5.0 acres and 5 acres and above, respectively. Commercial banks were not giving loans for paddy cultivation. In the case of banana, as far as borrowers from co-operative are concerned, it was noticed that there was a large credit gap for the size classes 5 acres and above followed by 1.5 to 2.5 acres and below 1.5 acres. In the case of borrowers from commercial banks, the credit gap was just 14.32 per cent for the size- class below 1.5 acres, but there was over financing for the remaining size-classes ranging from 23 per cent to 71 per cent. Only co-operatives provided finance for tapioca and over financing existing for all size- classes. It was thus observed that credit availability is a major constraint on farms cultivating paddy and banana.
