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ThesisItem Open Access Genetic variability and correlation studies in cocoa (Theobroma cacae L.)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1983) Gregory Zachariah; KAU; Kumaran, KInvestigation on the generic variability and correlation studies in cocoa were undertaken in the Department of Agricultural Botany, College of Horticulture, Vellanikkara during the period from July 1980 to August 1981 in a well established cocoa garden at Alpara in Trichur district, to elucidate information on the extent of variability and the degree of association existing among the 26 important plant, pod and bean characters, in a group of 135 cocoa tress, variety Forastero. Considerable variability was noted among all the characters of the sexually reproduced population of cocoa trees. Number of flowers per unit length on the trunk, number of pods per tree per year, weight of pod, volume of pod and wet weight of beans per pod showed maximum variability. Shell percentage and seed index manifested considerable variability among the bean characters. Phenotypic coefficient of variation (P.C.V.), genotypic coefficient of variation (G.C.V.) and heritability were estimated for 7 pod and bean characters. Both (P.C.V.) and (G.C.V.) were highest for attributes such as thickness of pod husk, number of beans per pod and weight of pod. Moderately high heritability was observed for weight of pod, thickness of pod husk and number of germinated beans. Volume of beans showed the lowest heritability. Yield from trees was found to be positively correlated with 6 of the characters studied, while number of germinated beans per pod and pod value were negatively correlated with yield. Out of the eight characters, pod value had the maximum contribution to yield. Number of pods per tree per year was found strongly associated with yield. Seed index and trunk girth also were positively and significantly correlated with yield. Phenotypic (rp) correlations among seven characters indicated that number of beans per pod was positively correlated with weight of pod. Positive correlations were also established between volume of beans and wet weight of beans per pod. Among the seven characters observed for genetypic (rg) correlations, wet weight of beans showed positive correlation with diameter of the pod and pod weight. Positive phenotypic as well as genotypic correlations were established in the case of wet weight of beans per pod with number of beans per pod and volume of beans. Number of beans per pod in turn, showed positive correlation with weight of pod at both levels. From the present studies it was evident that characters like diameter of pod, wet weight of beans per pod, number of beans per pod, number of germinated beans per pod, volume of pod, volume of bean, pod value, number of cushions on trunk, trunk girth, number of pods per tree per year and seed index have direct influence on the yield of cocoa. These traits can be considered while selecting cocoa trees for using in breeding programmes.ThesisItem Open Access Effect of herbicides of cell division sterility and yield in rice(Division of Agricultural Botany, College of Agriculture, Vellayani, 1981) Kishore Kumar, K; KAU; Mercy, S THerbicides have become a very important tool for weed control and research in this line has been progressing ever since their invention. Studies on the possible damages which herbicides cause at the chromosomal level have been undertaken under laboratory conditions by many workers. But only a few studies have been on this aspect under field conditions. This study was done with the aim of finding the extent of chromosomal aberrations and consequent deterioration of yield attributes in rice caused by the application of five selective herbicides. Observations on the herbicidal influence on weed population have also been taken. From this study it has been found that herbicides do cause chromosomal changes during cell division. Pollen mother cell studies revealed that highest number of chromosomal abnormalities occur in 2,4-D and nitrofen treatments when applied at a dose of 1kg and 1.5 kg a.i. per hectare, eighteen days after transplanting. Such abnormalities caused pollen sterilityand consequent spikelet sterility leading to reduction in yield . These parameters showed significant positive correlation.ThesisItem Open Access Correlation and path coefficient analysis in guinea grass (Panicum maximum Jacq.)(Department of Agricultural Botany, College of Agriculture, Vellayani, 1983) Sreenivasan, E; KAU; Kamalam, NA study was undertaken at the Department of Agricultural Botany, College of Agriculture, Vellayani, to determine the character association for yield and quality of green fodder and their degree of association and relative influence on yield in guinea grass. Twenty four diverse varieties of guinea grass were selected for the study and laid out in randomised block design with three replications. Observations were made on nine morphological characters and four chemical attributes and the data collected were subjected to variability studies and correlation analysis. Five morphological characters which showed highly significant genotypic correlation with green fodder yield were considered for path coefficient analysis in order to separate the total correlation of these characters with green fodder yield into direct effects and indirect effects via. other characters.ThesisItem Open Access Incompatibility studies on sweet potato (Jpomoea batalas (L) Lam)(Division of Agricultural Botany, College of Agriculture, Vellayani, 1983) Padma Kumar, A; KAU; Chandramony, DIn a study conducted on the flowering and natural fruit setting in sweet potato (Ipomoea batatas (L.) Lam). It was observed that varietal difference did exist for the above trait. Of the thirty varieties screened for compatibility/incompatibility reactions, only one variety viz. S.378 was found to be self-compatible. Except 2, 4-D treatment and end of season pollination, all the other methods including bud pollination, surgical techniques, application of sugar solution etc failed completly to break the self - incompatibility barrier in sweet potato. The success of 2, 4-D treatment , which resulted in fruit set in 13 varieties might be due to its effect on increasing the flower life by preventing floral absisaion.ThesisItem Open Access Formulation of a key for identification of the different types of pepper, Piper nigrum L.(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1982) Kanakamany, M T; KAU; Luckins, C BabuThe studies reported herein were carried out in the Department of Agricultural Botany, College of Horticulture, Vellanikkara, during the year 1980-82 with a view to formulating a key for identification of different varieties of pepper. From the germ plasm collection maintained in the Pepper Research Scheme of the College, 45 types of uniform age were earmarked. Observations on twentyeight quantitative and seventeen qualitative characters were recorded from all the fortyfive types and the variability among the types was assessed. The study revealed that the material was highly variable with reference to many of the characters.ThesisItem Open Access Biometrical studies in banana(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1982) Rosamma, C A; KAU; Narayanan Namboodiri, K MStudies were undertaken with forty eight banana varieties belonging to five different genomic groups at the Banana Research Station, Kannara and Department of Agricultural Botany, College of Horticulture, Vellanikkara during 1981-82 to estimate the extent of genetic variability, association among the selected characters and its partition into direct and indirect effects through path coefficient analysis. Selection indices were worked out to estimate the efficiency of selection through discriminant function over straight selection or vice versa.ThesisItem Open Access IC divergence in coconut(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1982) Balakrishnan, P C; KAU; Narayanan Namboodiri, K MA study was conducted at the Regional Agricultural Research Station, Pilicode and in the College of Horticulture, Vellanikkara during 1981-82 with the objectives of assessing the extent of variability present in the 24 cultivars of coconut maintained in the germplasm collection at Pilicode and to assess their genetic divergence using Mahalanobis D2 statistic. All the 24 cultivars were planted during 1924-25, and hence were of the same age group and were receiving the same management practices. Observations on 17 economic characters were recorded from 120 palms at the rate of 5 palms per cultivar. Four observations at quarterly intervals were recorded during the 12 month period of study. The data were subjected to relevant statistical analyses and the results were interpreted.ThesisItem Open Access Selection parameters in groundnut(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1984) Radhika, C; KAU; Gopinathan Nair, VForty divergent varieties of groundnut belonging to the hunch and serai-spreading groups were subjected to preliminary evaluation in summer rice fallows and kharif uplands. Studies on the various aspects like variability, heritability, stability and correlations were undertaken, A selection index was also formulated and the superior, stable varieties for the two locations were identified. The varieties were found to differ significantly for the various characters like number of days to maturity, number of primary branches per plant, height of plants, number of mature pods per plant, number of immature pods per plant, number of pegs per plant, weight of haulms per plant, fresh weight of mature pods per plant, dry weight of mature pods per plant, 100-pod and kemal weights and shelling percentage in rice fallows. In uplands, the varieties differed significantly for the number of days to flowering, number of days to maturity, number of primary branches per plant, height of plants, number of mature pods per plant, number of pegs per plant, weight of haulms per plant, 100-pod weight, 100-kemal weight and shelling percentage. Pooled analyses were done for the various characters to determine the influence of environment on them. It was found that number of days to flowering, number of days to maturity, number of primary branches per plant, number of mature pods per plant, number of immature pods per plant, number of pegs per plant, weight of haulms per plant, fresh weight of mature pods per plant, 100-pod weight and shelling percentage were influenced by environment to various degrees. But height of plants, dry weight of mature pods per plant and 100-kemal weight were found to have stable performance.ThesisItem Open Access Physiological basis of degeneration in root (wilt) affected coconut palm(Department of Agricultural Botany, College of Agriculture, Vellayani, 1983) George Tharakan, P A; KAU; Abraham, A TSeveral studies on the different physiological aspects of the root (vd.lt) disease have "been carried out and conclusions have been drawn* The present study comprised of estimation of protein, non protein amino acids and cytokinins v“ ' from root, leaf and developing nut from healthy-, apparently healthy and root (wilt) affected coconut palm. The chlorophyll content of leaves was also estimated. The results of the biochemical analysis including a bioassay in the case of cytokinins show that in the root (wilt) affected coconut palms there are alterations or deviations in normal metabolic activities from that of the healthy palms Earlier work done has shown several abnormalities in the physiological functions. The present study has revealed a deficiency of cytokinin, one of the important plant hormones or growth regulator, in the root (wilt) affected palm in addition to reduction in protein and chlorophyll contents. The sites of synthesis of hormone (ie. root tips) are damaged, together with the impairment of the translocation system.