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19875
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Subject: Plant Breeding × Author: KAU × End date: 1987 × Start date: 1987 ×
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    ThesisItemOpen Access
    Heterosis for yield and resistance to bacterial wilt in brinjal
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1987) Jameela Thomas; KAU; Gopinathan Nair, V
    Bacterial wilt of brinjal (Solanum malongena L.) caused by Pseudomonas colanacearum E.F Smith is a serious threat to brinjal cultivation all over India. Most of the commercial varieties are highly susceptible to this disease and hence unsuitable for cultivation in wilt endemic areas. Farmers in many places have been forced to abandon cultivation due to heavy incidence of bacterial wilt. Fine cross combinations were made between three resistant varieties (Pusa purple cluster, SM-6 and SMI-10) as ovule parents and each of three commercialbut susceptible varieties (Black beauty, Puma purple long and Puca purple round) as pollen parent , with a view to combine the wilt resistance of the former and high yield potential of the latter. The bacterial pathogen causing wilt in brinjal was isolated. Based on the cultural and physiological characters it was identified as Pseudomonas solanaecearum.
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    ThesisItemOpen Access
    Cross compatibility between Sesamum indicum L. and S. malabaricum
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1987) Lali, K S; KAU; Gopinathan Nair, V
    Sesame is most valued annual oilseed crop of Kerala. Lack of varietieswith resistance to drought and diseases is the main problem confronting sesame cultivation in the state. The wild species Sesamum malabaricum shows tolerance to drought and most of the diseases. But this wild species appears to be non compatible with the cultivated S. indicum. An investigation was therefore undertaken to study cross compatibility between these two species. Eleven adapted varieties of S. indicum were crossed reciprocally with S. malabaricum. Capsule set was normal in direct as well as reciprocal crosses. In general it was more in reciprocal crosses . In general it was more in reciprocal crosses than in direct crosses. In spite of normal capsule set , these crosses failed to produce any normal seed. The seeds were either medium shrivelled or highly shrivelled. Failure normal seed development in a wide range of crosses confirm that these two species are noncompatible.
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    ThesisItemOpen Access
    Studies on genetic parameters and association of yield and its components in short duration tapioca varieties (Manihot esculenta Crantz-)
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1987) Rekha, V R; KAU; Manikantan Nair, P
    A study was conducted at the Department of Plant Breeding, College of Agriculture, Vellayani during January to June 1986 with eight varieties of tapioca to identify suitable medium duration variety for wet land. Study of variability in the population, association among characters and determination of direct and indirect influence of different component characters on yield formed part of the objectives. Genotypic coefficient of variation was maximum for number of branches followed by number of leaves retained at harvest and utilization index. High heritability was manifested by total number of leaves per plant, number of leaves retained at.harvest, single tuber weight and utilization index; Quality attributes registered low estimates for heritability.and genetic gain. High heritability accompanied by high genetic gain for cassava mosaic, leaf spot disease and mite attack indicate^that the feasibility of reducing the incidence of this pest and disease is remote through selection in the present varieties. At genotypic level yield showed significant positive correlation with length and girth of tuber, single tuber weight and utilization index. Sparsely branching plant type can be advantageously utilized for adopting closer spacing and thereby enhancing yield.
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    ThesisItemOpen Access
    Induced mutagenesis for earliness in groundnut (Arachis hypogaea L.)
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1987) Gigi, K John; KAU; Sreekumar, S G
    A research programme was carried out to induce earliness in the promising groundnut variety EC.119704 by irradiating uniformly dried kernels witlri gamma rays at five doses viz., 10, 20, 30, 40 and 50 krads. In the M-| generation, germination, survival, plant height and pollen fertility were estimated. In the M 2 generation, studies on chlorophyll mutations (frequency, spectrum and segregation ratio), viable mutations (frequency and spectrum) and economic mutants were carried out. Mutagenic effectiveness and efficiency were also estimated. Germination and survival in the generation were found to decrease with Increasing doses. But the lowest dose of 10 krad stimulated germination and the higher doses retarded germination. The length of root and shoot decreased with increasing dose. The inhibition of root was more pronounced. Plant height recorded on 15th, 30th and 45th days was found to decrease with increasing doses. Pollen fertility showed an inverse relationship with the dose of gamma rays. Chlorophyll chimeras and morphological abnormalities were also observed.
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    ThesisItemOpen Access
    Model for selecting black gram (Phaseolus mungo Roxb.) varieties for yield and adaptability under partial shade
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1987) Geetha, Philip; KAU; Gopimony, R
    A study on the parameters of variability, correlation and path coefficient were undertaken in twenty black gram varieties to formulate a model for selecting varieties having good yield and adaptability under partial shade. The study was conducted at the Department of Plant Breeding, Vellayani during May to November of 1986. The varieties showed significant differences in most of the characters studied. Genotypic coefficient of variation was maximum for Cercospora leaf spot disease (rating) and minimum for days to pod harvest initiation. High heritability estimate was observed for days to pod harvest initiation. Genetic gain was maximum for Cercospora leaf spot disease (rating). LAX at blooming and LAX at harvest recorded high heritability and high genetic gain indicating the presence of additive gene action. Days through which pod harvest continued, plant height and number of branches per plant showed moderate to high heritability and*genetic gain. At the genotypic level seed yield showed high positive correlation with days to 50 per cent flowering, days to pod harvestinitiation, number of nodes per plant, number of pod clusters per plant, number of pods per plant and number of seeds per pod. Path coefficient analysis projected days to pod harvest initiation, days through which pod harvest continued, number of pods per plant and 100 seed weight as the traits exerting high positive direct effect on seed yield. Days to 50 per cent flowering plant height, number of nodes per plant, number of branches per plant and length of root also exerted positive direct effect on yield. The study indicated that the model for plant selection in black gram under partial shade should be of taller ones with more number of branches, nodes and pods per plant.