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Open Access
Combining ability in vegetable cowpea
(Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Rejatha, V; KAU; 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
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 John
With 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.
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 G
A 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.
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, N
Seeds 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.
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, V
A 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.
Open Access
Genetic analysis of productivity in relation to maturity in bunch groundnut
(Department of Plant Breeding, College of Agriculture, Vellayani, 1991) Ramakrishnan, M; KAU; 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.
Open Access
Genetics divergence in bhindi (abelmoschus esculentus (L.) moench)
(Department of Plant Breeding, College of Agriculture, Vellayani, 1993) Bindu, K K; KAU; 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.
Open Access
Genetic variability in guinea grass
(Department of Plant Breeding, College of Agriculture, Vellayani, 1993) Shajan, V R; KAU; Sreekumar, S G
Thirty guinea grass clones were evaluated in a field experiment laid out in an RBD with two replications at the Instructional Farm, College of Agriculture, Vellayani during 1990. Data on nine biometric characters and fodder yield were collected and subjected to analysis of variance and co-variance. Genetic parameters like heritability, genetic advance and correlations were estimated. The path anlysis was done to assess the cause-effect relationship and discriminant function analysis was done to formulate selection index for identifying superior clones. The analysis of variance revealed significant difference with respect to all the characters except dry fodder yield. High genotypic and phenotypic variances were observed for number of panicles per hill, leaf length, and plant height. High phenotypic and genotypic coefficients of variation were observed for number of panicles per hill, weight of seeds per hill and leaf-stem ratio indicating the presence of large amount of genetic variability. High heritability estimates were recorded for the leaf length, number of panicles per hill, protein percentage, leaf-stem ratio, leaf breadth, weight of seeds per hill, number of tillers per hill, plant height and leaf area index. High heritability along with high genetic advance observed for number of panicles per hill, weight of seeds per hill, leaf-stem ratio number of tillers per hill, length, leaf area index and leaf breadth indicates additive gene action and the reliability of these characters during selection. High positive genotypic correlation and significant positive phenotypic correlations of green fodder yield with dry fodder yield, plant height, leaf length and leaf area index indicate that selection based on any one of these characters will result in the improvement of green fodder yield. The yield components showed varying degrees of association among themselves. Correlation studies indicate that selection based on plant height, leaf length and leaf breadth will be effective in the improvement of fodder yield. Path analysis revealed that leaf area index had the maximum direct effect on green fodder yield followed by plant height and leaf-stem ratio. Number of tillers per hill exerted negative direct effect on green fodder yield. Based on the results of variability, correlation and path analysis it can be concluded that selection based on plant height, leaf area index and leaf-stem ratio will be effective for the improvement of fodder yield in guinea grass. A selection index was constructed and by practicing twenty per cent selection, six top ranking clones viz. FR 42, MC 14, FR 559, Mackuenii, FR 550 and MC 16 were identified for use in future breeding programmes.
Open Access
Effect of harvesting time in seednut characters in coconut
(Department of Plant Breeding, College of Agriculture, Vellayani, 1993) Vanaja, T; KAU; Sreekumari Amma, J
On the west coast of India, seednuts are being harvested during the summer months (February to May). The present investigation was mainly to know whether the nuts harvested through out the year can be used for seednut purpose in komadan. An attempt was also made to find out the effect of season on the floral characters in the two varieties. Study on the effect of season on the manifestation of the various floral characters revealed that, in both Komadan and WCT, during February to May there was higher production of bunches having proportionately more female flowers resulting in higher nut yields. The study on mother palm characters revealed that the Komadan variety exhibited superiority over WCT in number of spadices per palm per year, number of nuts per bunch and annual nut yield per palm. Correlation studies in mother palm characters revealed that the principal yield components in Komadan were number of nuts per bunch, number of bunches per season and percentage fruitset, while in WCT, high yields were the resultant effect of number of nuts per bunch, number of female flowers per spadix, number of bunches per season, total number of female flowers and number of spadices. It was also observed that in both varieties when the number of female flowers per spadix increases the retention percentage gets reduced. Most of the correlations between floral and yield traits studied were found to be homogeneous at different times of harvest in both varieties, with more homogeneity in Komadan. Study on the effect of harvesting time on seednut characters revealed that February to May (hot weather periods) is the best period for seednut collection in both WCT and Komadan. This is based on the fact that the important seednut characters like copra content per nut, kernel weight, size of nut, husked nut weight and seednut quality index were found to be at its maximum for nuts harvested during summer months in both WCT and Komadan. The Komadan variety was found to be significantly superior to WCT in four seednut characters viz., weight of kernel, copra content per nut, weight of embryo and volume of nut water. Varietal difference affected only a very limited number of correlations among seednut characters. Most of the inter correlations among seednut characters were found to be homogeneous at different times of harvest in both Komadan and WCT. In both Komadan and WCT, among the seednut characters, weight of kernel was found to be highly correlated with copra content. Oil content was not correlated with any of the seednut characters in Komadan. But in WCT, it was found to be negatively correlated with kernel weight. Among the 15 seednut characters studied, five characters viz., equatorial diameter, weight of unhusked nut, weight of husked nut, weight of kernel and oil content contributed 90 per cent of the total variation explained by the 15 seednut characters on copra content per nut, in both Komadan and WCT. In both Komadan and WCT, the very limited variability for oil content was explained by the 15 seednut characters studied. In Komadan, yield of nuts was negatively correlated with equatorial diameter of nut, weight of unhusked nut and weight of husked nut. But in WCT, yield of nuts was negatively correlated with almost all seednut characters. Based on seednut qualities, hot weather periods (February to May) were found to be the most suitable time for seednut collection in both Komadan and WCT.

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