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ThesisItem Open 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, VBacterial 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.ThesisItem Open 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, VSesame 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.ThesisItem Open Access Evaluation of the productivity of chilli hybrids(Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Elizabeth Philipose; KAU; Manikantan Nair, PA study was conducted at College of Agriculture, Vellayani, for evaluating the productivity of six intervarietal chilli (Capsicum annuum L.) hybrids obtained by crossing four inbreds in all possible combinations without reciprocals. Since the germination of the combination PR x PCl was poor, the other five hybrids along with four parents were evaluated in a 9 x 3 RED during 1984-85 and 1985-86. Observations on twenty quantitative and five five qualitative attributes were recorded. The statistical analysis included analysis of variance , pooled analysis and the estimation of genetic parameters, correlations among sixteen quantitative traits and three types of heterosis namely relative heterosis, heterobeltiosis and standard heterosisThesisItem Open Access Pollination, pod set and compatibility studies in open pollinated progenies of cocoa var. Forastero(Department of Plant Breeding, College of Horticulture, Vellanikkara, 1984) Madhu, P; KAU; Kumaran, KInvestigations were carried out at the College of Horticulture Vellanikkara, Thrissur, to study the polination , pod set and compatibility aspects of open pollinated progenies of cocoa, var. Forastero. It was found that eventhough cocoa flowered thoughout the year, maximum flower production was between November and April. The flower opening was a slow process starting from 2 to 4 pm and lasting upto 2 to 4 pm on the subsequent day . Maximum stigma receptivity was found between 10 am and 12 Noon. Natural pollination was through the agency of insects. By controlled pollination there was 48 per cent increase in the pod set. Hand pollination by forceps was found to be the best method of artificial pollination. A large number of pod set was not carried to maturity due to the incidence of cherelle wilt. The loss due to Cherelle wilt ranged from 37.04 percent to 70.37 per cent. Most of the trees studied were self-incompatible , while two of them were self compatible. The self - incompatibility in the materials investigated herein could be exploited for production of hybrid pods.ThesisItem Open Access Cross compatibility between abelmoschus esculentus and abelmoschus manihot and hybrid sterility(Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Prabha, P; KAU; Gopakumar, KObservations made during 1985, while conducting a breeding experiment on interspecific hybridization in the genus Abelmoschus of family MALVACEAE, reveal that the virus caused Yellow Vein Mosaic disease susceptible bhindi varieties of the cultivated species esculentus cross readily with the resistant wild/ semi-wild species manihot. Absence of interspecific mating incompatibility is of advantage in programmes of breeding for evolving improved varieties of the crop with built-in-resistance. The first generation hybrids though do not produce viable seeds in profusion, are not totally sterile. The scanty viable seed recovery from the hybrids against the parents is suspected to be due to chromosomal differentation that could have taken place during speciation in the genusThesisItem Open 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, PA 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.ThesisItem Open Access Evaluation of the F2 generation of interspecific hybrids of Abelmoschus with reference to yellow vein mosaic resistance and yield(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1986) Honey Mathews; KAU; Gopimony, RA study was conducted at the College of Agriculture, Vellayani during 1984-85 aimed at evaluating the F2 generation of interspecific hybrids between the yellow vein mosaic susceptible cultivars of Abelmoschus esculantus and the resistant semi-wild species. A manihot for yellow vein mosaic resistance and yield and selecting desirable F2 recombinantsThesisItem Open 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 GA 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.ThesisItem Open Access Genotype X environment interaction, for yield and its component a in sesamum(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1984) Geetha, P; KAU; Gopinathan Nair, VA detailed evaluation of the production potential of 15 multipoded and multiloculed types and varieties available at the Department of Plant Breeding, College of Agriculture, Vellayani, was undertaken to select suitable varieties for the summer rice fallows and robi uplando. The study also aimed at the estimation of genotype x environment interaction, the phenotypic stability of these varieties and the correlations of different characters including seed yield. The field trials were laid out at two locations vis, summer rice « > fallows at Kayamkulam and rabi uplands at Vellayani. The analysis of variance in respect of each character for each location, as well as for both the locations together was done. There was no significant difference between the varieties for number of days to flowering, at both the locations. But they differed significantly for days to maturity, length of pod, number of locules per pod, number of seals per pod, seed yield per plant, weight of thousand seeds and oil content. There was significant difference for height of plants end number of pods per plant in rice fallows and for number of pods per axil in uplands.