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Open Access
Standardisation of selection criteria for cocoa hybrids
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1998) Raji Varghese; KAU; Pushkaran, K
Investigation on standardisation of selection criteria for cocoa hybrids was conducted at Cadbury-KAU Co-operative cocoa Research Project (CC RP) Farm of Kerala Agricultural University, Vellanikkara during 1994-96. Twenty nine hybrids grown under Progeny Trial I and their 18 parents maintained in CYT-I were used for the study. The influence of seedling height and girth on yield was more pronounced in the case of seedlings one year after sowing than with those of 4 mas, 5 mas and 6 mas. The vegetative vigour measured by the height and diameter of trunk was found to be better correlated with precocity. The correlation coefficients of pod characters viz., length, width and weight of pods, number of beans, wet bean weight and pericarp thickness and seed characters viz., length, width, thickness and dryweight worked out between hybrids and female parents showed significant relationship in the case of pod length (r = 0.649) and number of beans (r = 0.606). But with mid parental value, the hybrids showed high correlation for the characters pod length, pod weight, number of beans, seed length, seed width and seed thickness (0.65, 0.45, 0.86, 0.70, 0.76 and 0.70 respectively). Heritability estimated by regressing offspring on female parent was high for the characters pod width, seed length and seed width (0,7, 0.64 and 0.78 respectively). Among the 29 hybrids studied, the hybrid H-4 of the cross GI 10.3 x GVI 54 was found to be promising in terms of both pod and wet bean yield. With the seedling characters of hybrids taken one year after sowing, a multiple regression equation for wet bean yield was fitted as: Y = 43 + 0.195 x1 + 3.70 X2 Where, x1 and X2 are height and girth of one year old seedlings respectively. This can be taken as a seedling selection criteria for cocoa hybrids.
Open Access
Genetic analysis of segregating generations of irradiated interspecific hybrids in okra (Abelmoschus spp.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1997) Sophia John; KAU; Manju, P
A study* was. conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during l996-'97 to estimate the extent of variability generated in the f 2M? and F3M3 generations as a result of hybridisation and hybrid irradiation of the interspecific hybrids between A. s esculenins and A. manihot and also to isolate high yielding yellow vein mosaic disease resistant lines from among the segregating generations In the l-^M-, generation, the irradiated treatments were found to be late flowering and had more number of leaves per plant, flowers per plant and fruits per plant Irradiation was found to increase pollen sterility and was maximum in 10 kR However seed set was lower for the irradiated treatments. Average fruit weight and weight of fruits per plant was maximum in plants belonging to the treatment 20 kR. Fruit length and girth were found to increase with increasing radiation doses. Number of ridges per fruit, fruiting phase and plant duration were higher in the irradiated treatments when compared to 0 kR and was maximum in 40 kR Plant height was highest in the treatment 30 kR Irradiation was found to increase YVM disease incidence and fruit and shoot borer incidence and it was maximum in 30 kR among the irradiated treatments. However a few high yielding YVM disease resistant plants resembling the cultivated parent were also observed in 30 kR ■Genotypic coefficient of variation, heritability and genetic advance were high for number of branches per plant and number of seeds per fruit in all the irradiated treatments in F2M2. High heritability with high genetic advance were observed for leaf number, number of flowers per plant, Iruits • ' per plant and pollen sterility in 20 kR and 30 kR. Significant positive * . correlation of number of leaves per plant, flowers per plant and fruits per plant with weight of fruits per plant and also among themselves was observed in all the irradiated treatments in F2M0. Average fruit weight and fruit yield A* • 0 per plant were positively correlated in treatments 0 kR, 10 kR, 40 kR, P, and P2. % In F3M3 the irradiated treatments were found to be late flowering and had more number of leaves, branches, flowers and fruits per plant. Pollen sterility was lower for the irradiated treatments, when compared to the unirradiated treatment and was lowest in 30 kR. However the number of seeds per fruit was more in 30 kR compared to the other treatments excluding parental treatments. Irradiation was found to decrease average fruit weight but fruit yield per plant was more for the irradiated treatments due to the larger number of fruits and was maximum in 40 kR. Length of fruit increased with increasing radiation doses. Significant differences among the irradiated treatments were not observed with respect to number of ridges per fruit. Irradiation was found to increase the fruiting phase as well as plant duration. Plant height was maximum in 10 kR when compared to all the other treatments. Yellow vein mosaic disease incidence was high in the cultivated parent and the higher dose radiation treatments viz , 30 kR and 40 kR. From the present study *a few recombinants which resembled the cultivated parent, with high yield and YVM disease resistance could be isolated from 30 kR, which suggested that 30 kR could be ideal radiation dose for evolving high yielding YVM disease resistant lines in okra. Fruit and shoot borer incidence was highest in the cultivated parent and was also high in 30 kR. High to moderately high genotypic coefficient of variation was observed.lor number of branches per plant, leaves per plant, flowers per plant, fruits per plant, weight of fruits per plant and number of seeds per fruit in all irradiated treatments in F3M3. High heritability and genetic advance were observed lor number of fruits per plant, weight of fruits per plant, flowers per plant and pollen sterility in all the irradiated treatments. Number of leaves per plant, flowers per plant and fruits per plant were positively correlated with fruit yield per plant in all the treatments while average fruit weight had significant positive correlation with fruit yield per plant in 0 kR, P, and P2 in the F3M3 generation. As a future line of work, high yielding, YVM disease resistant plants assembling the cultivated parent which have been isolated from the treatment 30 kR will be further evaluated for a few more generations and if found superior and YVM disease resistant it will finally be developed into a YVM disease resistant variety.
Open Access
Genetic analysis of high yielding rice varieties of diverse origin
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1998) Vanaja, T; KAU; Luckins, C Babu
The research project 'Genetic Analysis of High Yielding Rice Varieties of Diverse Origin' was carried out in the College of. Horticulture, Kerala Agricultural University, Vellanikkara, Thrissur during the period 1995-'98. The major objectives of the study were to understand the genetic architecture of high yielding rice varieties of diverse origin so as to evolve appropriate breeding methodology, to isolate promising lines having the new ideotype concepts from the segregating generations and to identify alternative source of cytoplasmic male sterile system suitable to warm humid climatic conditions experienced in Kerala. The study, about components of heritable variation revealed that the characters, number of panicles m-2 number of tertiary branches panicle-1, yield ha-1, spikelet sterility percentage and alkali spreading value exhibited high broad sense heritability coupled with high expected genetic advance and high genotypic coefficient of variation. High broad sense heritability and high expected genetic advance coupled with moderate genotypic coefficient of variation were manifested by the characters, namely, height of plant at harvest, second uppermost internodal length, length of flag leaf, ratio of vegetative phase to reproductive phase, number of spikelets panicle-1 number of grains panicle-1, LIB ratio of grain, milling percentage, amylose content, volume expansion ratio and water uptake. '1 Correlation studies revealed that the principal yield determining components in rice are harvest index, number of tertiary branches panicle-1 number of panicles m-2 number of grains panicle-1 number of spikelets panicle-1. ratio of vegetative phase to reproductive phase, 1000 grain weight, number of days to 50 per cent flowering, number of days to harvest and spikelet sterility percentage. While selecting genotypes for higher yield potential, emphasis should be given for comparatively long vegetative period, short period from panicle initiation to 50 per cent flowering and long ripening period. A selection model was formulated consisting of the characters, namely, yield ha-1 harvest index, number of days to harvest, number of tertiary branches panicle-1 ratio of vegetative phase to reproductive phase and number of grains panicle-1 Cluster analysis revealed that there was no parallelism between geographical distribution and genetic diversity. The 56 genotypes representing different eco-geographical regions were grouped into nine clusters based on genetic distances. Combining ability studies showed that both additive and non-additive gene effects were important, with predominance of non-additive gene action, for all the characters except for 1000 grain weight, second uppermost internodal length and height of plant at harvest. The varieties Vytilla3, Mahsuri, Mattatriveni and Karthika were identified as good general combiners. The varieties Mahsuri, Karthika, Vytilla 3, Mattatriveni and IR62030-18-2-2 showed pronounced cytoplasmic effect on yield and various yield contributing characters. The crosses Vytilla 3 x Mattatriveni, Mahsuri x Vytilla-3 an,d Mahsuri x Mattatriveni are recommended for recombination breeding. The crosses Vytilla 3 x IR36, Vytilla 3 x IR60133-184-3-2, PK3355-5-1-4 x Bhadra, Vytilla 3 x Mattatriveni, Karthika x Bhadra, PK3355-5-1-4 x Karthika and PK3355-5-1-4 x IR620'30-18-2-2 are recommended for heterosis breeding. The cytoplasm of Vytilla 3 (an improved saline tolerant variety of Kerala) was identified as an alternative source for cytoplasmic male sterility in rice, suitable to warm humid tropical climate, experienced in Kerala. The varieties IR36 (international check) and Hraswa (extra short duration high yielding variety of Kerala) are the proposed maintainer lines. Mattatriveni is the proposed restorer line for the proposed IR36 'A’ line and Hraswa 'A’ line. The generation mean analysis using six parameter model revealed that both additive and non-additive gene effects played an important role in the inheritance of yield and important yield components, with predominance of dominance, additive x additive and dominance x dominance type of gene effects. Results of inbreeding depression indicated absence of reduction in vigour in the F2 generations for yield and all other yield attributes. Investigation on pattern of inheritance of kernel colour revealed that kernel colour in rice is a complex qualitative character. Each red and white colour may be separately controlled by two or more sets of genes having both inhibitory and duplicate type of gene interactions with predominance of inhibitory type gene interaction. From 22F2 generations, seven early stabilized promising lines and 26 promising segregants were selected. Two early stabilized lines were found to possess most of the ideotype features proposed by IRRI with preferable cooking quality characters. Their further evaluation and multiplication are being carried out at the Agricultural Research Station, Mannuthy, Kerala Agricultural University. By hybridization, it was possible to successfully transfer the non sticky nature and red kernel colour of Mattatriveni to a high yielding Taiwan variety whose kernel is white and sticky on cooking. The gene action studies revealed that there is ample scope for yield improvement in rice both through pedigree breeding and heterosis breeding. As yield and yield components were found to be under the control of all the three types of gene actions namely, additive, dominance and epistasis, intercrossing of early segregating generations derived from multiple crosses seems to be the best suited method of breeding for yield improvement in rice. Future line of studies suggested 1. Conversion of the already obtained cytoplasmic male sterile F1 crosses to fully sterile CMS lines by repeated back crossing with the respective recurrent parents. 2. Screening from the segregating populations of these cytoplasmic male sterile crosses for 100 per cent cytoplasmic male sterile lines. 3. Confirmation of the restoring ability of the proposed Mattatriveni 'R' line and identification of other restorers. 4. Incorporation of the sterile cytoplasm of Vytilla 3 into other elite genotypes other than IR36 and Hraswa. 5. Screening for cytoplasmic male sterile system in other saline tolerant lines. 6. Screening of promising segregants selected, for high yield and quality with multiple resistance to pest and diseases, for developing varieties suited to various climatic and soil conditions of Kerala.
Open Access
Combining ability in bhindi (Abelmoschus esculentus (L) Moench)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1995) Rajani, B; KAU; Manju, P
The study was carried out in the Department of Plant Breeding and Genetics, College of Agriculture , Vellayani during 1994-95 to estimate the combining ability of six genetically divergent parental strains of bhindi and their 30 F1 hybrids obtained by crossing the six parents in a diallel pattern. The magnitude of heterosis and nature of gene action governing the yield of fruits and other important yield attributes was also elicited through Hayman's numerical and graphical approach. The combinig ability analysis by the Method 1 of Griffing's (1956) approach revealed that the parent P4 (NBPGR/TCR 864) was the best general combiner for yield and a few yield related characters. Among the hybrids P1 X P4 (NBPGR/TCR 893 x NBPGR/TCR 864) exhibited outstanding s.c.a effects for yield. Non addictive gene action was found to govern days to first flowering number of flowers per plant, length of fruit, girth of fruit, weight of single fruit, weight of fruits per plant and number of seeds per fruit while the remaining characters were governed by addictive gene action.
Open Access
Genetic analysis of seed dormancy and productivity in groundnut (Arachis hypogaea L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1997) Tessy Joseph; KAU; Namboodiri, K M N
Investigations on genetic analysis of seed dormancy and productivity in groundnut (Arachis hypogaea L.) were carried out in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara from 1992-95. The objective of the study was to find out the gene effects of biometric traits and seed dormancy in groundnut, so as to suggest appropriate breeding methodology and parental combinations to evolve domant, high yielding and early manuring varieties. The findings of the study are briefed below. Evaluation of 28 genotypes (14 domant and 14 non domant) for two seasons revealed that wide range of variability existed among them. Donors for specific traits were identified . The genotypes were also genetically diverse and could be grouped into four clusters. The line x tester analysis with three lines and five testers revealed that additive gene effects governed most of the characters except pod yield and number of mature pods , for which , non addictive gene effects were important. To harness both the types of gene effects pedigree method followed by selection in advanced generations will be fruitful.
Open Access
Combining ability for biological nitrogen fixation traits and yield components in blackgram (Vigna mungo (L.) Hepper)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1998) Beena Thomas; KAU; Sreekumar, S G
The research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1995-96. The objective was to assess the general and specific combining abilities and gene action involved in the inheritance of biological nitrogen fixation traits and yield components in blackgram, as a preliminary step for developing high yielding varieties with good biological nitrogen fixation capacity. The five lines, three testers and their 15 combinations were evaluated in a replicated field experiment and data on twelve characters were collected and subjected to line x tester analysis. The best general combiners for important biological nitrogen fixation traits were COBG305 and Pant U19 among lines and T9 among testers. The hybrid combination Pant U19 x T9 was the best specific combiner for these characters. In the case of number of pods and grain yield per plant, among. lines WBG-13 and among testers T9 were the best general combiners. The hybrids, LBG 17 x VBN 1 and WBG 13 x AKU4 were the best specific combinations for these traits. Considering the mean performance, sea effect and standard heterosis percentage Pant U 19 x T9 was identified as the best hybrid combination for nodule weight and nitrogen content at 50 per cent flowering. Regarding yield, the best hybrid was WBG 13 x AKU4. These superior combinations can be utilized further for developing improved blackgram varieties.
Open Access
Heterosis and combining ability in greengram (Vigna radiate (L.) Wilczek) for biological nitrogen fixation and yield
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1998) Bhadra, K; KAU; Wilson, D
The research programme was carried out in diallel manner at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, Thiruvananthapurarn during 1996-98. The objective was to assess the general and specific combining abilities and gene action involved in the inheritance of biological nitrogen fixation traits and yield attributes in green gram. The study was conducted in a diallel model in a replicated field experiment using seven varieties of greengram, out of them four were high yielders and three with good nitrogen fixing capacity. Seven parents and twenty one hybrids were also raised in pots with seven replications to study the nodulation efficiency of hybrids and parents. Analysis of variance revealed highly significant differences among the genotypes for all the characters. Except for nitrogen content at 50% flowering and harvest index, gca effects were not significant, for all the other characters both gca and sea effects were significant. The additive to dominance ratio indicated a preponderance of non-additive gene action for all characters except number of secondary roots and weight of nodules. The combining ability analysis revealed that NDM-88-14 was the good general combiner with respect to important nitrogen fixation traits where as P-9333 was the best general combiner with respect to yield and 2 other yield attributes. P-9333 x NDM-88-14 was the best specific combiner for nitrogen content. P-9333 x IIPRM-3, IIPRM-3 x LGG-444 and P-9333 x COGG-902 were the best specific combiners for yield and yield attributes. Combining the mean performance, sca effects and heterobeltiosis P-9333 x NDM-88-14 was identified as the good hybrid combination for nitrogen fixation traits. Re~arding yield, the hybrids P-9333 x IIPRM-3, P-9333 x COGG-902 turned out to be outstanding. Therefore, these hybrids can be utilized for crop improvement programme.
Open Access
Genetic evaluation of F4 and F5 generations of irradiated interspecific hybrids in okra(Abelmoschus spp.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1998) Anu Mary, C Philip; KAU; Manju, P
A study was undertaken in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1997-98 for the genetic evaluation of the F 4 and F 5 generations of irradiated interspecific hybrids between A. esculentus and A. manihot with the objective of isolating high yielding yellow vein mosaic disease resistant lines from the segregating generations. The families in the F 4M4 generation were found to be late flowering and recorded higher mean values for number of leaves, number of branches, number of flowers and number of fruits per plant compared to the cultivated parent. The fruit yield per plant was higher than the parents inspite of the reduction noticed in average fruit weight. The families recorded lesser values for fruiting phase and duration and higher values for plant height. The crude fibre content of the fruits, yellow vein mosaic incidence and shoot and fruit borer infestation were lower in the families. This provided scope for the selection of several high yielding and YVM disease resistant types from the F 4M4 generation Number of flowers per plant and incidence of YVM disease recorded high phenotypic and genotypic coefficients of variation. High heritability and genetic advance were observed for leaf number and weight of fruits per plant. Fruit yield per plant had high positive correlations with leaf number, number of branches, number of flowers and fruits per plant and plant height. Hence effective selection can be done for these characters for yield improvement. In the F sMs generation, the families were early flowering and recorded increase in leaf area, pollen sterility and number of branches per plant. The families also recorded higher mean values for leaf number, number of flowers and fruits per plant and plant height compared to the parents. The fruit yield per plant, average fruit weight and number of seeds per fruit were higher in the F sMs families. The fruiting phase and duration recorded an increase while the crude fibre content of fruits, incidence of YVM and incidence of shoot and fruit borer recorded lower mean values. Incidence of YVM disease had the maximum phenotypic and genotypic coefficients of variation. High heritability and genetic advance were observed for yield of fruits per plant. Weight of fruits per plant was significantly and positively correlated with leaf number, number of branches, number of flowers and fruits per plant, average fruit weight and plant height. Selection based on these characters will be effective in improving the yield of the crop. At the same time, high variation noted for YVM disease incidence offers more scope for selection based on disease incidence, in the process of selection for high yielding disease resistant types.
Open Access
Genetic variability and correlations in nine divergent varieties of coconut
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1998) Sindhumole, P; KAU; Ibrahim, K K
An experiment was conducted at Instructional Farm, College of Horticulture, Vellanikkara during 1995-96 on nine coconut varieties viz., West Coast Tall x Choughat Yellow Dwarf, West Coast Tall x Gangabondam, Laccadive Ordinary x Gangabondam.West Coast Tall, Philippines, Jawa, Cochin China, New Guinea and Laccadive Ordinary, Significant varietal variance was absent among several characters, Economic characters showed the highest genotypic coefficient of variation (16 to 22%). Among the vegetative and reproductive characters, heritability was maximum for petiole length (52%) followed by the economic characters percent oil content and nut yield (45% each). Among the four reproductive characters studied for seasonal variability viz" spadix length (SL), branches spadix' (BS), female flowers spadix" (FF) and fruit set (FS), FF showed the maximum variation, FF andFS had been low during the rainy months, SL was markedly reduced during the winter months, Phenotypic correlation coefficients were generally lower than genetic SInce environmental correlation was either less in magnitude or in opposite direction in relation to the genetic, Genotypic correlations were mostly negative where vegetative characters were involved and positive for other pairs, Only nut yield among the four economic characters was correlated with both vegetative and reproductive characters, Other economic characters were dependent only on vegetative characters. Similarly step-down regression revealed that only vegetative characters were retained in the final model for all the economic characters except nut yield. Vegetative characters also showed higher direct effects than reproductive characters on the variability of economic characters. Trunk height generally produced highest direct effects on the economic characters, but was modified by the indirect effects to large extent except in the case of oil content (%). Correlation, regression and path analyses suggested that reproductive characters had less effect on economic characters when all the characters were recorded during the 'same year. This may possibly be due to genotype x season (year) interaction for the reproductive characters.

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