1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)

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    Phenotyping of tomato germplasm for root knot nematode resistance
    (Department of Plant Breeding, College of Agriculture, Vellayani, 2020) Bikkasini Mythri; Jayalekshmy, V G
    The present study entitled “Phenotyping of tomato germplasm for root knot nematode resistance” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2018-2020, with the objective to screen tomato germplasm including released varieties of KAU for root knot nematode resistance through artificial screening. The study comprised of two experiments. In the first experiment, collection, identification and multiplication of Meloidogyne incognita (Kofoid and White, 1919) Chitwood culture for artificial inoculation was performed. Root knot nematode infested root and soil samples were collected from tomato plants in the Department of Nematology, College of Agriculture, Vellayani. Root knot nematode females, egg masses and juveniles were extracted from the samples and identified. The collected soil samples upon identification are then inoculated to healthy seedlings for multiplication and maintained as pure source of inoculum. The second experiment was screening of tomato germplasm for root knot nematode resistance using thirty seven tomato genotypes (including released varieties of KAU) which were evaluated in Completely Randomized Design with three replications. Fifteen days after transplanting the seedlings, hatched juveniles were inoculated @ 2000 juveniles plant-1. Observations were recorded for number of larvae in 5 g root, root-knot count in 5 g root, number of females in 5 g root, number of egg masses in 5 g root, average number of eggs in egg mass and nematode population in 200 cc soil. Reproductive potential was assessed by calculating reproduction factor. Weight of root and shoot were recorded. Analysis of variance was found to be significant for all the parameters observed. PNR – 7 recorded lower for number of larvae and egg masses in 5 g root. EC – 165700 recorded higher for root knot count and number of females 5 g root-1. IIHR – 2868 recorded lower and EC – 165700 recorded higher for number of nematodes in 200 cc soil as well as reproduction factor. Root knot indexing was done using the method given by Heald et al. (1989). The genotypes were categorized on a root knot index scale of 0-5 using total root knots in root system (0 – highly resistant, 1 – resistant, 2 – moderately resistant, 3 – moderately susceptible, 4 – susceptible and 5 – highly susceptible). The study revealed the lack of resistance in all the genotypes. No genotype was found to be highly resistant, resistant or moderately resistant. Vellayani Vijai was found to be moderately susceptible with a root knot index of 3 and EC – 160855 was susceptible with a root knot index value of 4, while all other genotypes in the study were highly susceptible. Vellayani Vijai can be forwarded further for fruit yields under nematode infected fields. Genotyping can also be performed to check for the presence of gene Mi conferring resistance to M. incognita.
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    Combining ability in vegetable cowpea
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Rejatha, V; Ramachandra Nair, N
    A 6 x 6 diallel analysis was conducted at the Department of Plant Breeding, College of Agriculture, Vellayani, during 1990, aimed at analysing the combining ability, gene action and heterosis of six vegetable cowpea (Vigna unguiculata var-sesquipedalis) lines collected from the germplasm maintained in this department. The experiment I consisted of crossing the six parental lines in all possible combinations, without reciprocals. The material for experiment II consisted of the six parental lines and fifteen hybrids. They were grown in a Randomised Block Design with three replications.The combining ability analysis was carried out based on method 2 under model I as suggested by Griffing (1956). The treatments showed significant differences in most of characters except number of pods/plant and fruit yield/plant. The variance due to general combining ability was significant and higher in magnitude than specific combining ability for the characters days to flowering, mean weight of pod, mean length of pod, number of seeds/pod, length of internode and seed/pod ratio. It was found that the parent selection 104 and selection 145 were the best general combiners for most of the characters studied. The parent selection 129 was the best general combiner for earliness. The hybrids selection 145 x selection 129 was the best specific combiner for mean weight of pod and number of seeds/pod. The hybrid selection 145 x kurutholapayar was the best specific combiner for earliness. The significance of g.c.a. and s.c.a. variances for most of characters indicate the importance of additive and non-additive gene action in controlling the inheritance of these characters. But additive gene action played a major role suggesting that improvement could be made through selection. Heterosis was calculated over mid and better parental values. Maximum positive heterosis was found for the character fruit yield/plant. Since considerable heterosis was evident in most of the characters, heterosis breeding can be attempted in cowpea
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    Genetic divergence, prepotency and inbreeding depression in para rubber (Hevea brasiliensis Muell. Arg.)
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Kavitha Mydin, K; Gopinathan Nair, V
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    Genetic analysis of productivity in relation to maturity in bunch groundnut
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1991) Ramakrishnan, M; Gopinathan Nair, V
    A preliminary evaluation of 63 bunch type of groundnut revealed that the genotypic coefficient of variation was highest for number of immature pods per plant which indicated the maximum genetic variability for the trait and lowest for oil content which indicated low variability for the trait. High heritability along with moderate genetic advance was obtained for shelling percentage and 100 kernel weight which showed the importance of additive genes in their control. A maturity index was formulated and on its basis the 63 types were classified in to three groups namely, extra early, early and medium. In the extra early group, 100 pod weight and 100 kernel weight were important components for pod yield. In the early group. Number of mature pods per plant, shelling percentage and 100 kernel weight were important components for pod yield. In the medium group, number of mature pods per plant, shelling percentage and 100 kernel weight were important components for pod yield. For oil yield in all the three groups, pod yield and shelling percentage were the important components. Line x Tester analysis with six extra early types as lines and three high productive types as testers indicated predominance of sca variance over gca variance indicating pre ponderance of non – additive gene action over additive for the traits studied. Chico was the best general combiner for earliness and TMV 2 was the best general combiner for pod yield. High yielding extra early recombinants were selected at 80 days after sowing from the 18 Fz populations for further testing and selection.
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    Yield and its components in groundnut under partial shade in coconut garden
    (. Department of Plant Breeding, College of Agriculture, Vellayani, 1988) Rajasree, M R; Gopimony, R
    . A study on the parameters of variability, heritability and genetic advance and correlation of pod yield with other components were undertaken in thirtyone varieties of groundnut to select genotypes having good yield and adaptability under partially shaded conditions of coconut gardens. The study was conducted during kharif 1987 at the Department of Plant Breeding, College of Agriculture, Vellayani, by raising the varieties in a randomised block design with four replications. Analysis of variance revealed significant differences among varieties for the characters like plant height, first date of flowering , flowering duration, pod yield per plant on fresh weight basis, pod number per plant, mature to immature pod ratio, pod yield per plot on fresh and dry weight basis, 100 pod weight, 100 kernel weight, shelling percentage, halum yield per plant and per plot on fresh and dry weight basis, harvest index, photosynthetic efficiency at reproductive phase, leaf area index at reproductive phase and Cercospora leaf spot disease score. Analysis of variance for chlorophyll-a, b and total pigments revealed that there was no significant difference among the varieties with respect to chlorophyll pigment content. Analysis of variance for shade intensity measured in each plot during vegetative and reproductive phase indicated the presence of uniform shade in the experimental field. High genotypic and phenotypic coefficients of variation, heritability and genetic advance were observed for hundred pod weight and mature to immature pod ratio, suggesting the reliability of these characters during the selection programme for the improvement of this crop. Correlation analysis of dry pod yield per plot with twentyfour characters revealed that fresh pod yield per plot, fresh and dry pod yield per plant, pod number per plant, halum yield per plot on fresh and dry weight basis, harvest index and photosynthetic efficiency during reproductive phase showed relatively high genotypic correlation with dry pod yield per plot. The study indicated that for selecting an ideal plant type of groundnut for partially shaded conditions we have to look for the tallest, earliest flowering and vegetatively maximum vigorous individual plant.
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    Genetics divergence in bhindi (abelmoschus esculentus (L.) moench)
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1993) Bindu, K K; Manju, P
    A study was conducted in the Department of Plant Breeding, College of Agriculture, Vellayani during the period 1991-93. The main aim was to estimate the magnitude of genetic divergence in a collection of bhindi varieties to select suitable ones for use as parents for developing commercial hybrid varieties. The estimation of genetic parameters of important economic characters, the association among these characters, direct and indirect effects and D2 values were undertaken. Seventy genotypes of bhindi were evaluated in a RBD with three replications. The genotypes showed significant differences in most of the characters studied except fruiting phase and leaf axil bearing the first flower. Genotypic coefficient of variation was maximum for weight of fruits per plant and minimum for days to first flowering. Heritability estimate was maximum for length of fruit while it was minimum for leaf axil bearing the first flower. Genetic advance as percentage of mean was maximum for weight of fruits per plant. High hertibility coupled with high genetic advance was recorded for length of fruit, leaf area, weight of single fruit, height of the plant and weight of the fruits per plant. At genotypic level yield per plant showed positive correlation with all the characters studied. Path coefficient analysis at genotypic level revealed that the number of fruits per plant, weight of single fruit and number of branches exhibited high direct influence on yield. The study indicated that the model for selection of high yielding varieties of bhindi should be based on the number of fruits per plant, weight of single fruit and number of branches. D2 analysis revealed that the 70 genotypes were grouped into six clusters. Cluster I, II, III, IV, V and VI contained fifty seven, four, three, two, three and one genotypes respectively. The maximum divergence was obtained between clusters II and VI and the minimum between clusters I and IV. The intra cluster distance was maximum in cluster III and minimum in cluster IV. In future breeding programme for the development of heterotic hybrids parent may be selected from cluster II and VI for hybridization.
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    G x E interaction in the F6 generation of wide crosses of rice (Oryza Sativa L.)
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2003) Vidhu Francis Palathingal; Kanakamani M T
    The present study 'G x E interaction in the FG generation of wide crosses of rice (Oryza sativa L)' was carried out under the Department of Plant Breeding and Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara. The study was carried out for 20 characters in nine rice cultures at three locations viz., Mannuthy, Pattikkad and Adatt. The experiment estimated the variability, heritability, correlation, path coefficients and stability for the characters. High variability and heritability was noticed for most of the yield characters. The estimates of variability and heritability vaired widely between locations indicating the preponderance of the environment Correlation and direct and indirect effects of the characters on yield also differed between the environments indicating the profound influence oflocation on the character. Stability analysis revealed that among the rune nee cultures studied, culture C 26T(b) was found to be stable over locations for most of the yield traits. Culture C 26T(b) had maximum grain yield and was stable for most of the yield contributing characters like height of plant at harvest, number of productive tillers, number of spikelets per panicle, number of grains per panicle, number of days for physiological maturity, 1000 grain weigh! and grain yield. C 26T(b) showed superior and stable performance in the hill tracts of Pattikkad, Kole land of Adatt and at Mannuthy Stability parameters indicated C 80 as the next stable culture. C 80 was stable for the characters total number of tillers, days to 50 per cent flowering, hulling percentage, milling percentage and amylose content.
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    Potential for drought tolerance in cowpea
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1989) Magie Mereena; Sreekumar, S G
    A research programme was carried out at the department of plant breeding, College of Agriculture, Vellayani, Trivandrum during 1988 with sixteen varieties of cowpea for studying the potential for drought tolerance. The date on twentysix characters and soil moisture percentage in different plots were collected and subjected to analysis of variance/covariance. The genetic variability and correlations were estimated for the characters contributing to drought tolerance, yield and its components. The path analysis was conducted using yield as the effect and seven components contributing to drought tolerance as causes. Analysis of variance for twentysix characters revealed that significant differences existed among varieties for all the characters except for root spread at vegetative period. The analysis of variance for soil moisture percentage showed no significant difference among experimental plots indicating uniform soil moisture status in all the plots. High genotypic coefficient of variation, moderate to high heritability and high genetic advance was shown by characters such as leaf area index at vegetative, flowering and harvest periods, number of pods per plant, hundred grain weight, and proline content. Harvest index also had moderately high heritability and genetic advance. This indicates the reliability of the above components during selection programmes for the improvement of yield. Grain yield per plot showed positive genotypic correlation with leaf area index at vegetative and flowering period, root spread at harvest period, number of pods per plant, root/shoot ratio at vegetative period, grain filling period, and plant height at maturity. Path analysis revealed that harvest index and leaf area index at vegetative period had maximum positive direct effect on yield. Based on the studies on variability, correlation and path analysis it can be concluded that a plant type. Suited to drought conditions should be early flowering with deep and wide spread root system, high root/shoot ratio and leaf area index at vegetative period, low proline content, few number of stomata, long grain filling period and medium duration resulting in the production of more number of pods per plant and high harvest index. The cowpea varieties UPC-124, DPLC-198 and DPLC-216, satisfying the above plant type can be considered as drought tolerant.
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    In vitro mutagenesis in rice (oryza sativa L.)
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2005) Ambika Rajendran, R; Dijee Bastian
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    Genetic analysis of yield and leaf curl virus resistance in chilli (Capsicum spp.)
    (Department of Plant Breeding, College of Agriculture, Vellayani, 2010) Anandhi, K; Abdul Khader, K M
    Pepper fruits (Capsicum spp.) are among the most consumed vegetables as fresh green or red and dried whole or ground forms in the world for its pungency. Leaf curl virus is an important biotic stress transmitted by the vector, Bemisia tabaci. Controlling the vector can be the only way to manage the disease and results in only partial control of disease. The incidence of disease is more in summer season and makes the cultivation uneconomical. There is an immediate need to develop leaf curl resistant varieties especially for summer cultivation. Hence the present investigation was undertaken at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2007-2009 with the objective of estimating the combining ability, heterosis and gene action involved in the inheritance of yield and leaf curl virus resistance. Five resistant C. frutescens accessions Mangalapuram Local, Thavanur Local, Kayamkulam Local, Mavelikkara Local and Nenmara Local were crossed in L x T pattern with three high yielding susceptible varieties Jwalamukhi, Jwalasakhi and Vellayani Athulya and 15 F1s were produced and evaluated along with the parents in randomized block design. Analysis of variance revealed highly significant genotypic difference for all the characters studied. The observations recorded were plant height (cm), number of branches, number of days to first flowering, plant spread (cm), duration of flowering (fruiting span), number of fruits per plant, fruit length (cm), fruit width (cm), pedicel - fruit ratio, fruit colour at intermediate stage, green fruit yield per plant (g), average fruit weight (g), number of seeds per fruit, hundred seed weight (g), duration of crop, vector population and virus disease scoring. Higher estimates of PCV and GCV were recorded for vulnerability index and green fruit yield per plant. High heritability coupled with high genetic advance were exhibited for days to first flowering, duration of flowering, number of fruits per plant, green fruit yield per plant, number of seeds per fruit, duration of crop and vulnerability index. Combining ability analysis showed that the line Mavelikkara Local and Nenmara Local were alone good general combiners for fruit yield along with leaf curl resistance. Four hybrids viz., Mavelikkara Local x Jwalasakhi, Nenmara Local x Vellayani Athulya, Kayamkulam Local x Jwalamukhi and Thavanur Local x Jwalamukhi exhibited significant sca effect for fruit yield. Considering per se performance, standard heterosis and sca effect two hybrids Mavelikkara Local x Jwalasakhi and Nenmara Local x Vellayani Athulya were found to be superior. Generation mean analysis was carried out using six-parameter model. Six generations viz. P1, P2, F1, F2, B1, B2 were built up among the crosses Mavelikkara Local x Jwalasakhi and Nenmara Local x Vellayani Athulya. Presence of additive, dominance and epistatic interaction for all the characters indicated that hybridization or recombination-breeding programme can be followed for future breeding.