Loading...
Theses
Browse
8 results
Search Results
ThesisItem Open Access Cytogenetic studies on intervarietal hybrids of sesamum (Sesamum indicum L.)(Department of Agricultural Botany, College of Agriculture Vellayani, Trivandrum., 1984) Chandramony, D; KAU; Krishnan Nair, NThesisItem Open Access Induced mutations in banana var. Nendran(Department of Agricultural Botany, College of Agriculture, Vellayani, 1990) Radha Devi, D S; KAU; Krishnan Nair, NThe present investigations was carried out in the Department of Agricultural Botany, College of Agriculture, Vellayani during 1985-88 and in the plant tissue culture Laboratory attached to the Department of Plantation Crops, College of Horticulture, Vellanikkara, Thrissur during 1986-88. The project was taken up to standardise the techniques for induced mutagenesis in-vitro and in-vitro in banana (Musa paradiciaca L.) var. nendran and aslo to analyse the direct effect of 60 Co gamma rays on growth and bunch characters in the vM1 and vM3 generations. One, two and three months old suckers of various sizes (after removal of 25 to 75 per cent of the pseudostem) were exposed to 1.0, 1.5, 2.0, 2.5 and 3.0 kR gamma rays. For in-vitro mutagenesis, isolated shoot tips were exposed to 0.50, 0.75, 1.00, 1.25 and 1.50 kR gamma rays. Ex-vitro analysis of five plants per treatment per exposure was done in the vM1 generation for various growth, bunch and fruit characters.ThesisItem Open Access Studies on heterosis and combining abilities with respect to important economic traits in Capsicum annuum, L.(Division of Agricultural Botany, College of Agriculture, Vellayani, 1981) Manikantan Nair, P; KAU; Mary, K GeorgeSixty three varieties of Capsicum annuum representing different agroclimatic regions of the country constituted the base material of the study. Based on yield potential , adaptability and tolerance to leaf curl complex disease, thirty varieties were selected for subsequent studies. Comprehensive genetic studies including estimation of genetic parameters, cause effect relationship by path coefficient analysis, genetic divergence by Mahalanoble D2 statistic and a nine parent diallel analysis to causes the combining ability, to unravel the pattern of inheritance and also to examine the level of heterosis manifested with respect to eighteen economic characters including four nutritiveand quality attributes namely Vitamin A, Vitamin C, Capsaicin and Oleoresin content were conducted during the year 1976-79. Analysis of plot means exhibited highly significant differences among varieties except for Capsaicin content. The high degres of variability in economic attributes offers scope for recombining desirable genes from different varieties.ThesisItem Open Access Biometric analysis of yield and certain yield attributes in the para rubber tree: Hevea Brasiliensis Muell. Arg.(Department of Agricultural Botany, College of Agriculture, Vellayani, 1984) Markose, V C; KAU; Mary, K GeorgeThe para rubber tree, Hevea brasiliensis, is the commercial source of natural rubber. Introduced into the Far East in 1876, from Brazil, commercial cultivation started in India during 1902. The tree has a gestation period of six to seven years. A large number of clones have been evolved through ortet selection and through hybridisation, which show variability for different characters. The present study was undertaken to estimate (1) productivity (2) yield pattern (3) variability (4) correlations (5) effect of yield attributes (6) genetic diversity of twenty clones, and (7) early growth vigour of open pollinated seedlings of selected clones.ThesisItem Open Access Genetic analysis in red gram (Cajanus cajan L.)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1990) Achamma Oommen; KAU; Narayanan Namboodiri, K MThe research project "Genetic analysis in red gram" was carried out in the College of Horticulture, Kerala Agricultural University, Vellanikkara, Trichur during the period 1985-90. A 5 x 5 diallel cross, excluding reciprocals conducted in red gram revealed the predominance of additive gene effect for all the characters except days to first flowering. The combining ability analysis showed PLA-550 as the best general combiner; and the F 1 of the cross UPAS-120 x I.C. 15708 to have good specific combining ability. Negative heterosis over both the parents was exhibited by UPAS-120 x I.C. 15708 and PLA-550 x PLA-600 for days to first flowering and days to maturity which showed that early maturing segregants could be obtained from these crosses. The same crosses showed relative heterosis for yield also. The analysis of generation means by using six parameter model revealed the importance of both additive and dominance gene effects in the expression of most of the characters. Additive x additive and dominance x dominance effects showed influence in the expression of the characters. Among the components of variances dominance variance was higher for most of the characters. Heritability in narrow sense was found to be low. Number of clusters per plant and number of pods per plant were highly correlated with yield in parents, F 1 's and F2's. As the yield and yield components in the present study were under all the three types of gene action viz., additive, dominance and epistasis, reciprocal recurrent selection procedure seems to be the best suited method of breeding for improvement of this crop.ThesisItem Open Access Seed germination and tissue culture studies in orchids(Division of Horticulture, University of Agricultural Sciences, Bangalore, 1982) Ramachandran Nair, S; KAU; Foja SinghThesisItem Open Access Genetic studies in brlnjal with relation to bacterial wilt resistance(Department of Agricultural Botany, College of Agriculture, Vellayani, 1983) Gopimony, R; KAU; Krishnan, Nair NThesisItem Open Access Genetic studies in red gram (Cajanus cajan L.)(1988) Radhakrishnan, V VThe research project “Genetic studies in red gram (Csjsnus csjsn h. Mill sp.)* wae carried out at the College of Horticulture, Kerala Agricultural University, Vellanikkara, Trichur during the period 1983-86. The genetic diversity studies among the 112 genotypes of red grans obtained from NBPGR, Vellanikkera and THAU, Coimbatore during 1963-84 showed that the genotypes of the same place of origin fell into different clusters while those of diversified origin fell into seme cluster. All the genotypes studied were grouped into five clusters. Based on both the inter and intr©cluster distances 20 genotypes representing the broad spectrum of variability were selected and raised during 1965-86. The values estimated for phenotypic coefficient of variation and genotypic coefficient of variation showed that number of clusters per plant, number of pods per plant and seed yield possessed high estimates. Number of days from sowing to 50 per cent flowering and seed yield have exhibited high heritabllity coupled with moderately high genetic gain estimate* indicating the involvement of additive gene effect* Ku:ber of days from sowing to harvest and height of plant at harvest, have high or moderately high estimates of heritability together with low values of genetic gain indicating the action of non-additive genes. In nine out of ten cases there has been significant positive correlation between component characters and seed yield both in the phenotypic and genotypic levels, however the correlation of hundred seed weight with seed yield was not significant both at phenotypic and genotypic levels* Intercorrelaticna studies have shown that characters exhibiting significant association with seed yield per plant were also highly intercorrelated indicating that these characters can be simultaneously improved. Path coefficient analysis showed that number of poda par plant, hundred seed weight, number of primary branches at harvest, number of secondary branches at harvest and length of pod bearing branches had high positive direct effects on seed yield in th at order* The residual effect wea 0*07227 indicating that about 93 per cent of the variation in yield were contributed by the ten components considered in path coefficient analysis. The selection index formulated with characters like seed yield, number of pods per plant and hundred seed weight showed an efficiency of 8.4 per cent over direct selection and it includes 57 per cent of the factors determining the yield. Hence it is suggested for isolating superior genotypes. A comparison of different genotypes based on the index value has revealed the superiority of the genotypes NSPGR-XX-EC—10046-1 and HBPGR-124-PLA-345-1 over others. The study paved the way for understanding the source of variability for various factors contributing to yield, the degree of diversity among the genotypes, on the association between yield and its components and between themselves, and helped to formulate selection index for selecting superior genotypes.
