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ThesisItem Open Access Genetic variability, path analysis and stability parameters in sesame(Department of Plant Breeding, College of Agriculture, Vellayani, 1985) Sverup, John; KAU; Gopinathan Nair, VBiometric analysis in a varietal collection of sesame was undertaken to study the genetic variability, correlations, path analysis and stability parameters. One hundred sesame types were evaluated in replicated trials at Vellayani in uplands during rabi and at Kayamkulam in rice fallows during summer. Genetic variability and correlations were estimated and path analysis worked out independently as both the locations. Location trials for estimating stability parameters were conducted at three places viz. in uplands during rabi at Pattambi and Vellayani and in rice fallows during summer at Kayamkulam. Large values for genotypic coefficients of variation were obtained for characters such as number of capsules on branches, number of capsules perplant, number of capsules on main stem and number of branches during rabi as well as summer. The lowest genotypic coefficient of variation was obtained for number of days to maturity during both rabi and summer. High values of heritability were recorded by seed protein content , seed oil content, height upto first capsule and weight of 1000 seeds under both conditions.ThesisItem Open Access Diallel analysis in rice bean(Vigna umbellata( Thunb.) ohwi & ohashi)(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1999) Preeti, S V; KAU; Radha Devi, D SA diallel analysis in ricebean (Vigna umbellata (Thunb.) Ohwi and Ohashi) was carried out in the Department of Plant Breeding and Genetics, during 1997 - '98. The experimental material consisted of six parental lines and 30 F I hybrids, laid out in Randomised Block Design with three replications. The six parents were 3 LG, 5 LG, 6 LG, 8 LG, 9 LG, and 100 LG obtained from the germ plasm collection maintained at NBPGR, Thrissur. The observations were recorded on yield and yield attributing characters. Significant differences were detected among the mean performance of the genotypes, for all the characters studied. The combining ability analysis carried out by Method I, Model I of Griffing's approach (1956), revealed that the parent, 8LG was the best general combiner for most of the yield attributing traits. Among the crosses, 8LG x 3 LG exhibited outstanding sea for seed yield per plant. The crosses involving 8 LG were found to be good specific combiners. The combinations involving 3 LG and 6 LG also gave good specific combining ability effects. The numerical analysis by Hayman's approach indicated overdominance for almost all characters, which was confirmed by graphical analysis. The dominance of decreasing alleles in the parents was indicated by the negative value of F for all characters except, plant height, length of pods and number of seeds per pod. An almost equal distribution of genes with positive and negative effects was indicated by the ratio of H2 to 4H} for all the characters. The regression coefficient of covarince between parents and their offsprings in each array (Wr) on variance of all progenies in each parental array (Vr) did not- differ from unity, for plant height, length of pods, seed yield, 100 seed weight, days to maturity and protein content, indicating that assumption of non-allelic interaction was satisfactory for these characters. The Vr - Wr graph indicated that the parents were genetically divergent for days to first flowering, number of pods per plant, number of seeds per pod, 100 seed weight, days to maturity, root weight and nodule weight. Manifestation of heterosis was seen for all the characters studied. Among the hybrids, 8 LG x 3 LG was the most outstanding for yield and yield related characters. The crosses, 8 LG x 9 LG, 8 LG x 100 LG, 6 LG x 9 LG, 100 LG x 8 LG and 6 LG x 3 LG also performed better in yield and yield attributing characters. In general, hybrids involving 8 LG and 6 LG were found to be heterotic.ThesisItem Open Access Combining ability in vegetable cowpea(Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Rejatha, V; KAU; Ramachandra Nair, NA 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 cowpeaThesisItem Open Access Induction of polyploidy in kacholam(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1996) Ajithmohan, N K; KAU; Pushkaran, KA trial on induction of polyploidy in Kaempferia galanga L. was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, during the period 1994-'95. A local selection Vellanikkara collected from the genetic stock maintained at AICRP on M & AP was used for the study. The objective was to create variability in kacholam by developing polyploids. The rhizomes of the crop were treated with colchicine for inducing polyploidy. Five concentration of colchicine viz., 0.05, 0.15, 0.25, 0.35 and 0.45 per cent (C2 to C6, C1 being control i.e., 0%) was tried for two time durations viz., four hours and six hours (T1 and T2), the same treatment being repeated on two consecutive days. Two methods of treatment were tried the first (M1) being chemical application in a hole drilled close to the sprouting bud and the second (M2) being the ordinary cotton swab method. Rhizomes with two different stages of bud sprouting were used: (1) with just emerging buds (S1) and (2) buds at an advanced stage of sprouting (S2). The treated rhizomes were planted in the field and their growth was examined. In the end of the crop season, 18 variant plants were identified and they were put to detailed morphological and cytological study in the next growing season. Mitotic study of the parent material confirmed that the chromosome number of kacholam is 55. Of the 18 variants identified one was found to contain 110 chromosomes in the somatic cells. As kacholam is proposed to be a pentaploid the induced polyploid must be a decaploid. The polyploid was obtained from the treatment combination S1M1T1C6. It was characterised by small plant size and reduced vigour. The leaves were thick with reduced size. Stomatal size increased conspicuously with their numbers reduced. The rhizome development was found retarded and the per plant yield was also less. The rhizome morphology was on par with the normal plants. The plant flowered neither in the first season nor in the second. In addition to the polyploid, there other stable variants were obtained from the experiment. They were also characterised by reduced vigour and yield.ThesisItem Open Access Analysis of Maturity related Characters and Identification of Early Maturing Varieties in Groundnut(Department of Plant Breeding, College of Agriculture,Vellayani, 1990) Sunil Kumar, A C; KAU; Sverup JohnWith the intention of identifying suitable superior early maturing genotypes for intensive cultivation in the summer rice fallows of Kerala, a study was conducted for determining the time of optimum physiological maturity of twelve bunch type groundnut genotypes by analyzing the various maturity related component characters in staggered harvests. The twelve test genotypes and the yield and duration checks were staggered harvested at 70, 80, 90, 100 and 110 DAS. The characters that were put to study in each harvest included the height of plant, number and percentage of mature pods, pod yield, 100 pod weight, 100 kernel weight, shelling percentage, percentage of sound mature kernels, haulms yield, harvest index and oil percentage. Analysis of the various parameters in different genotypes indicated that peak pod yield and time of optimum maturity were closely associated with peak performances of components like number of mature pods, 100 pod weight, 100 kernel weight, sound mature kernel percentage and shelling percentage. It was also noted that the genotypes gave fairly high oil percentage at the time of optimum maturity. The genotypes IES 882, IES 883. IES885, ICGS(E) 21, ICGS(E) 52, ICGS(E) 121, Dh(E) 20 and Dh(E) 32 attained optimum physiological maturity at 90 DAS due to attainment of peak values for the various maturity related component characters. A critical appraisal however showed that the genotypes ICGS (E) 52 and IES 883 exhibited significantly superior performance over the remaining genotypes and the yield and duration checks at 90 DAS. The genotypes ICGS (E) 52 and IES 883 may be recommended for intensive cultivation in the summer rice fallows of Kerala owing to realization of high yield and yield attributes, combined with early maturity. ICGS (E) 52 ranked first with a pod yield 12.85 g per plant, 100 pod weight of 88.6 g and 100 kernel weight of 38.1 g. The genotype IES 883 stood second in performance with a pod yield of 12.00 g per plant, 100 pod weight of 88.3 g and 100 kernel weight of 36.2 g. Both the genotypes exhibited appreciably high performance for shelling percentage and sound mature kernel percentage also.ThesisItem Open Access Combining ability for yield and drought tolerance in cowpea(Department of Plant Breeding, College of Agriculture,Vellayani, 1993) Anilkumar, S G; KAU; Sreekumar S G, S GA research programme was carried out at the Department of Plant Breeding, College of Agriculture, Vellayani during 1991 to 92 with five lines, three testers and their fifteen F1s'. The data on sixteen characters were collected and subjected to line x tester analysis for estimating combining ability and gene action in the inheritance of drought tolerance, yield and related characters. Analysis showed that the line DPLC-198 had a positive and significant gca for leaf area index, grain filling period, number of pods per plant, hundred seed weight, grian yield per plant and biological yield. The line IC-38956 showed negative and significant gca for duration upto first flowering and duration upto maturity. The line DPLC-216 had positive and significant gca for grain filling period and hundred seed weight. The line V-240 for number of seeds per pod and VCM-8 for duration upto maturity showed significant gca. The tester C-152 showed significant positive gca for number of seeds per pod, grain yield per plant and biological yield and showed significant gca for duration upto maturity. The tester Chharodi-1 showed significant negative gca for duration upto first flowering and duration upto maturity. The tester Kanakamany showed significant positive gca for grain filling period, hundred seed weight and biological yield. DPLC-198 x chharodi-1 and IC-38956 x C-152 showed significant and negative sca for duration upto first flowering while DPLC-198 x Kanakamany, IC-38356 x Chharodi-1 and VCM-8 x Kanakamany showed significant negative sca for duration upto maturity. Significant negative sca for proline content was recorded by IC-38956 x C-152, V-240 x Chharodi-1 and DPLC-216 x Kanakamany. DPLC-216 x C-152 and DPLC-216 x Kanakamany recorded significant positive sca for filling period. A significant positive sca for number of pods per plant, grain yield per plant and biological yield was recorded by DPLC-198 x C-152. Leaf area index, number of seeds per pod and hundred seed weight which had additive gene action can be improved by selection. Number of pods per plant and proline content had non-additive gene action.Presence of additive and non- additive gene action with preponderance of non-additive gene action was noticed for duration upto first flowering, duration upto maturity, grain yield per plant and biological yield while preponderance of additive gene action was noticed for grain filling period. The characters that are controlled by non-additive genes or predominantly under the control of non-additive gene can be improved by recurrent selection and recombination breeding. Based on the gca estimates the lines DPLC-198 and IC-38956 and the testers C-152 and Chharodi-1 and the hybrids such as DPLC-198 x C-152, DPLC-198 x Chharodi-1, IC-38956 x C-152 and IC-38956 x Chharodi-1 were recommended for further utilization. Exploitation of heterosis normally is not a viable proposition in cowpea in the absence of easy methods of large scale production of hybrid seeds.ThesisItem Open Access Morphological Effect of Gamma Rays and EMS on Winged Bean [Psophocarpus tetragonolobus (L.)](Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1993) Reeja Dharan, S; KAU; Kamalam, NSeeds of winged bean [Psophocarpus tetragonolobus (L.)] variety PT-62 were subjected to induced mutagenesis using six doses of gamma rays (100 to 500 Gy) and six doses of EMS (40 to 200 mM) to obtain information on the extent of genetic variability that can be induced in the M1 generation. The germination percentage was observed to be decreased by both the mutagens, however the effect was more severe with gamma rays in the field study. But gamma rays caused a stimulation of germination and an earlier germination, at all the doses in the laboratory trials. Number of days taken to complete germination was not much affected by either of the mutagens in the field. The growth of root and shoot were reduced by gamma rays linearly with increase of dose and by EMS drastically at its highest dose, however gamma rays showed greater inhibition of shoot growth and EMS caused greater inhibition of root growth. Survival percentage was observed to be reduced by both mutagens, but EMS was of not much effect. Gamma rays caused a stimulatory effect at its lowest dose. Plant height was beneficially affected by gamma rays at the lowest dose and drastically reduced at higher doses. EMS caused not much variation in plant height. Chlorophyll chimeras and morphological variations were mostly observed in gamma rays treated populations. Morphological variations mostly included alteration in number, size and shape of leaves and size and colour of seeds. Earlier flowering was observed in lower doses of gamma rays, but higher doses caused delayed flowering. Days taken to first flowering was not affected by EMS treatments. Both mutagens exhibited not much effect on the number of days to last flowering. However gamma rays treated populations were in reproductive phase for longer period than EMS treated populations. Number of pods per plant and fruit yield per plant were not affected by EMS treatment. But lower dose of gamma rays caused a stimulatory effect, and thereafter a gradual reduction with increase in dose. Weight and length of pod were slightly increased by EMS treatment, and decreased linearly with increase in dose of gamma rays treatment. EMS caused no significant effect on number of seeds per pod, whereas gamma rays showed an inverse relationship with dose. Both the mutagens showed not much variation in hundred seed weight. Greater pollen sterility was induced by gamma rays treatments, but the effect of EMS was not pronounced. An insignificant increase in seed sterility was exhibited by both the mutagens. In the present investigation greater variability for morphological characters was produced by gamma rays than EMS in the M1 generation of winged bean.ThesisItem Open Access Reproductive biology and enzyme studies in ocimum(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1997) Fancy, Parameswaran; KAU; Presannakumari, K TThe present study on "Reproductive biology and enzyme studies in Ocimum spp." was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara during the period 1994-1996 with a view to make a comparative evaluation of the reproductive biology and phosphorylase enzyme activity of different species of Ocimum. The four species of Ocimum viz. O. tenuiflorum, o. gratissimum, o. canum and o. basilicum collected and maintained in the Department were used for the study. The different species of Ocimum varied significantly in the time taken for inflorescence development, completion of anthesis in an inflorescence, number of flowers per inflorescence and distance between verticils. Species level variations were also observed in seed moisture content, seed density, l000-seed weight and seed dormancy period. Flowers of the four selected species were identical in basic structure although there existed variation in size, colour, hairyness and shape of floral parts. Anthesis occurred earlier in o. canum than the other three species. Pollen grains of Ocimum were hexacolpate and reticulate. However, species level difference existed in the size, shape and fertility of pollen grains. No self incompatibility mechanism existed in the four species studied. The floral morphology and protandrous nature makes the species adapted to cross pollination. Insects and ants are the main agents of pollination. Comparison of Sanctum and Basilicum groups revealed that Sanctum group which includes o. tenuiflorum and O. gratissimum required longer time for inflorescence development than Basilicum group which includes o. canum and O. basilicum. Verticils were closer in the inflorescence of Sanctum group than Basilicum group. Sanctum group produced less conspicous flowers with sessile bracts and yellow pollen grains. In this group anther dehiscence occurred in bud stage. Basilicum group produced conspicous flowers with pedicellate bracts and white pollen grains. Anther dehiscence was after flower opening in this group. Dormancy break was sudden in Sanctum group and gradual in Basilicum group. Moisture content of Ocimum seeds was positively related to phosphorylase enzyme activity. Phenol content was negatively related to both moisture content and phosphorylase enzyme activity of the seeds.ThesisItem Open Access 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; KAU; Gopinathan Nair, VA study on genetic divergence, prepotency and inbreeding depression in rubber was undertaken in an effort to identify clones for use as components of polyclonal seed gardens. Forty clones of Indian, Indonesian, Malaysian and Sri Lankan origin were evaluated in a replicated trial at the Rubber Research Institute of India. Genetic variability, correlations and the cause and effect relationships of dry rubber yield and its components were worked out. Genetic divergence was estimated employing the Mahalanobis' D2 techinique. The factors of divergence were identified through principal factor analysis. Twenty promising clones from genetically divergent clusters were subjected to seedling progeny analyses for the estimation of propotency based on performance of their open pollinated seedling progenies and inbreeding depression in the first generation of selfing. Significant clonal variation was revealed in respect of all the physiological, morphological and structural attributes studied as mean values for the fourth year of tapping for the stress period and for the peak yield period. High genetic variability for volume of latex under stress, plugging index under stress, annual mean dry rubber yield and dry rubber yield during the stress and peak periods was indicated by the high estimates of genotypic coefficient of variation. Additive gene effects offering scope for improvement through selection was indicated for dry rubber yield, latex flow rate and volume of latex during the three periods, girth increment rate, annual mean plugging index and plugging index under stress, by the moderate to high heritability estimates along with high genetic advance for these traits. Non- additive gene action was indicated by the high heritability and low genetic advance for dry rubber content during the three periods, girth and bark thickness. At both genotypic and phenotypic levels, annual mean dry rubber yield showed moderate to high positive correlations with dry rubber content and latex flow rate during the three periods, girth, girth increment rate, length of the tapping panel and bark thickness and negative correlations with yield depression under stress and plugging index during the three periods. Dry rubber yield under stress emerged as a more important component than peak dry rubber yield by its higher magnitude of positive direct effect on annual mean dry rubber yield. Latex flow rate during the stress and peak periods and annual mean volume of latex exhibited high positive direct effects on annual mean dry rubber yield while plugging index during the peak yield period, volume of latex under stress and girth increment rate had negative direct effects on annual mean dry rubber yield. The magnitude and direction of the effects of the components on dry rubber yield during the three periods varied indicating these relationships to be under different genetic control. Selection for a high dry rubber yield under stress, annual mean volume of latex and latex flow rate during the stress and peak periods and against a high plugging index during the peak period, volume of latex under stress and girth increment rate would help achieve improvement in annual mean dry rubber yield. Considerable genetic diversity was revealed by the wide range of D2 values and intra and inter cluster distances. The forty clones were grouped into eight genetically divergent clusters irrespective of their country of origin indicating the absence of any relationship between geographical diversity and genetic divergence. Volume of latex, plugging index, latex flow rate, dry rubber content and dry rubber yield contributed more towards divergence than the morphological and structural attributes. Supporting evidence was obtained from principal factor analysis which revealed the yield factor to be the main factor of divergence with respect to the clusters studied. Junveile rubber yield on test tapping, number of latex vessel rows and number of leaf flushes in seedling progenies exhibited high heritability and genetic advance indicating scope for their use as early selection parameters, while girth exhibited high heritability and low genetic advance. These three traits showed significant positive correlations with juvenile rubber yield, of which girth exhibited the strongest association. Juvenile rubber yield, number of latex vessel rows, girth and number of leaf flushes were identified as important traits for being accorded simultaneous emphasis in the computation of performance index and index scores for the determination of recovery of superior seedlings as estimates of prepotency. Nine clones were identified as likely preopotents on the basis of seedling progeny analysis at the age of two years. Selfing resulted in a lower fruit set than open pollination in the clones in general. No significant inbreeding depression was recorded for juvenile vegetative traits and rubber yield in seedlings. Clones PB 28/83, PB 215, RRII 105, AVT 73, PB 217, PB 252, Ch 26, PB 242 and PB 5/51 were identified as likely prepotents from three genetically divergent clusters. They recorded superiority for yield and various yield components. These clones exhibited synchrony in flowering and are suggested as components of a nine parent polyclonal seed garden. For a seven parent seed garden the clones suggested to be excluded are PB 5/51 and PB 242. A polyclonal seed garden comprising these nine or seven clones as components could generate good quality polycross seed material. Appropriate seed garden layouts have been suggested.
