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Open Access
Genetic analysis of F2 and F3 generations for yield attributes and resistances to distortion mosaic virus disease in bitter gourd (Momordica charantia L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2003) Sumarani, P; KAU; Arya, K
The research project "Genetic analysis of F2 and F3 generations for yield attributes and resistance to distortion mosaic virus disease in bittergourd (Momordica charantia L.)" was carried out in Department of Plant Breeding and Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara, Thrissur during the period 2002-2003. The major objectives of the study were to understand the genetics of yield attributes and resistance to bittergourd distortion mosaic virus (BDMV) and to identify resistant genotype with desirable yield traits. The whole investigation was grouped into two experiments in Randomised Block Design with three replication. The F2 and F3 generation of three selected crosses and parents were evaluated for yield attributes and resistance to BDMV. Significant variation was noticed for almost all characters except anthesis of male and female flowers. Highest phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for BDMV followed by fruit yield and fruit weight in both generations. High heritability coupled with high genetic gain was noted for fruit weight, fruit yield and coefficient of infection. These characters are controlled mainly by additive genes which rendered scope for direct selection . . High yield was achieved by higher sex ratio, higher fruit weight, long fruit, optimum number of female flowers and low incidence ofBDMV. Based on the results from populations derived from the crosses IC68335 x Preethi and lC 68263B x Preethi as the best genotypes with high yield and resistance to bitter gourd distortion mosaic virus (BDMV) consecutively in both generations.
Open Access
Morphological, Biochemical and Molecular Markers for the Genetic Analysis of Cashew(Anacardium occidentale L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2003) Usha Vani, D; KAU; Jayalekshmy, V G
The research project' Morphological, biochemical and molecular markers for the genetic analysis of cashew' was carried out in the College of Horticulture, Vellanikkara, Thrissur during the period 2000-2002. The major objectives of the study were to fingerprint cashew genotypes based on genetic analysis carried out and the genetic relationship deduced between the morphological, biochemical and molecular parameters studied and also to identify genetically diverse genotypes among those selected for the study to be used in breeding programmes. The study revealed that among the fourteen characters selected i.e., tree height, tree girth, number of primary branches, number of secondary branches, canopy spread, leaf area, number of panicles m", number of nuts m", number of perfect flowers m", apple weight, nut weight, kernel weight, shelling percentage and nut yield, all showed significant variation except number of primary branches. Number of perfect flowers m", number of nuts m", apple weight, nut weight and kernel weight provide a clear seperation of the genotypes. Correlation and path studies revealed tree height and number of nuts m" had significant positive correlation and direct effect on yield. Tree girth showed positive correlation but significant negative direct effect on yield. Number of primary branches showed significant positive direct effect but a significant negative correlation with yield. Apple weight showed significant negative correlation and significant negative direct effect with yield. Genetic divergence studied using Mahalanobis D2 analysis revealed H-1593 to be the most divergent genotype. Cluster' analysis could group them into four clusters. The members of Cluster I (Sulabha, Priyanka and P-3-2) and Cluster II (Mdk-L, AKM-l and K~22-1) were found to be best suited for hybrdisation being the farthest. Biochemical studies on phenol and tannin content could group the twelve genotypes into those with high and low .contents. The genotype H-1593 had the lowest phenol content. Seed storage protein studies could distinguish K-22-1 from all others by a single unique band. Isozyme analysis in cashew showed only high initial rate of reaction. Further studies to standardise the protocol for isozyme studies needs to be done. Molecular studies involved RAPD analysis using four primers which gave 44 amplification products out of which 30 (68.19 per cent) were found to be polymorphic. Two primers OPP-5 and OPP-IO could distinguish varieties Mdk-2 and Mdk-l with amplicons 22 and 25 respectively. Dendrogram constructed based on the study grouped together Kanaka and Dharasree; Mdk-l and Mdk-2 and H-1600 and P-3-2 with the latter two being the closest of all. On comparative study, H-1600 (Damodar) was tied to Dharasree in biochemical studies and with P-3-2 in molecular studies. In morphological studies also, it was placed close to P-3-2 indicating the proximity of Indian accessions with those of South America. Kanaka and Dharasree were tied together both in morphological and molecular studies but both were diverse by pedigree. Similarly, AKM-l and Dhana were placed close together in the three studies both of which were diverse by pedigree. H-1593 and H-1591 were found to be close in molecular and morphological studies. AKM-l and Mdk-l,Bapatla accessions and early flowering varieties, were closer in both morphological and molecular studies. It can be said that pedigree is not completely answerable to variability. The study had revealed a similar trend for morphological and molecular markers in deducing the genetic divergence. Biochemical markers need more refinement so as to get as precise information as has been obtained for the characterisation of the genotypes through molecular studies.
Open Access
Interspecific Hybridisation in Sorghum
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2005) Jithesh, V G; KAU; Suma Bai, D I
A study on ‘Interspecific hybridization in Sorghum’ was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2003-2004 with the objective of developing sorghum-sudan grass hybrids with high fodder yield potential and better quality. Five superior accessions of sorghum viz., GD 65174-1,GD65174-2, GD 65195, GD 65239 and Acc. No. 846 (lines) with high yield potential and better palatability and three accessions of sudan grass viz., Jhansi local, SSG-59-3 and IS-720 (testers) with high tillering ability were crossed in a Line x Tester mating design to obtain 15 hybrid combinations. The lines, testers and their hybrids were evaluated along with a check COFS-29 in a replicated field trial for mean performance, combining ability and heterosis. Observations on plant height, tiller number per plant, stem girth, internodal length, leaf/stem ratio, leaf number per plant, leaf weight per plant, days to 50 per cent flowering, green fodder yield, dry fodder yield, crude protein content, crude fibre content and HCN content were recorded. Significant differences among treatments were observed for all characters. Significant differences among crosses were observed for all characters except tiller number per plant. General and specific combining ability variances and effects were studied. The magnitude of SCA variance alone was significant suggesting the predominance of dominance gene action in controlling these traits. Based on mean performance and gca effects, Acc. No. 846 was identified as the best general combiner among lines and SSG-59-3 among testers. The crosses, GD 65195 x IS-720 and Acc. No. 846 x SSG-59-3 were found to be promising for green fodder yield and its component traits based on mean performance, sca effects and standard heterosis. Hence these crosses can be advanced for further trials for developing superior sorghum-sudan grass hybrid varieties.
Open Access
Genetic improvement of F1 hybrids in anthurium andreanum linden
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2004) Pravin, R S; KAU; Mayadevi, Department of Plant Breeding and Genetics, College of Agriculture
The present study, ‘Genetic improvement of F1 hybrids in Anthurium andreanum Linden’ was undertaken to improve specific commercial characters such as erect, long inflorescence axis, deep blisters of spathe and short downward candles of ten selected F1 hybrids in anthurium. The analysis of variance revealed significant variation among the fourteen genotypes for the seventeen characters studied. This reveals the high genetic potential for the improvement in this crop. Variability studies indicated high phenotypic and genotypic coefficients of variation for the characters number of suckers per plant, pollen fertility and duration of male phase. The characters with high heritability coupled with high genetic advance values were found for characters number of suckers per plant, pollen fertility and pollen size. These characters are therefore controlled by additive gene action and amenable to genetic improvement through selection. Plant height was found to have highly significant positive phenotypic correlation with number of suckers per plant, leaf size, internode length, number of spadices per plant and pollen fertility. Duration of female phase showed positive genotypic correlation with all characters except days to initiation of female phase. The environmental correlations were absent for almost all pairs of characters except for a few characters . Pollen fertility estimated using acetocarmine method indicated that most of the genotypes had low fertility values. ‘PR x FR (1)’ had the highest pollen fertility of 41.67 per cent followed by ‘Liver Red’ (40.67 per cent). Pollen emergence was low in the months from March to June, during which the average maximum and minimum temperatures were relatively high. Pollen emergence was highest during October to December months. A study of five qualitative characters such as colour of young leaf and petiole spathe colour, spathe texture, candle colour and type of inflorescence axis also showed considerable variation among the genotypes studied. Intervarietal hybridization was done to analyse the cross compatibility between 14 varieties (Ten female parents and four commercially important varieties as male parents) based on the percentage of candles bearing fruits, fruit set and seed germination. A total of 23 crosses were attempted based on the availability of receptive spadices and fresh pollen, out of which 12 were found to be successful. Among the 12 successful crosses percentage of candles bearing fruits was 100 per cent for six crosses. Maximum number of 113 fruits was obtained for the cross (‘LR x PR’) x OG followed by [‘FR x MW (1)’] x LR with 88 fruits. The average number of fruits per candles was highest for ‘LR x PR’ and lowest for ‘PR x FR (1)’. The percentage of fruit set was below 50 per cent for all the crosses. The lowest and highest percentage of fruit set was observed for ‘PR x FR (1)’ and ‘LR x PR’ respectively. From the cross compatibility analysis, it was seen that the percentage of fruit bearing candles was highest for the female parents ‘PR x KR’ and ‘PR x MO’ with two crosses each and ‘OG x DT’ with a single cross (100 per cent). The number of fruit per candle ranged from 23 to 113. ‘LR x PR’ had the highest average number of fruits per candle and it was lowest for ‘PR x FR (1)’. The percentage of fruit set was below 50 per cent for all the crosses. The crosses involving ‘LR x PR’ had the highest average percentage of fruit set. The number of days taken for germination varied from four to nine days. The seed germination was highest for the cross (‘PR x FR(1)’) x LR (85.13 per cent). No cross showed 100 per cent survival beyond four to six months. For ‘OG x DT’ with only a single cross the survival percentage was maximum of 90 per cent. Scoring of the compatibility reactions based on the percentage of fruiting candles, fruit set and seed germination on a scale ranging from zero to nine showed the highest compatibility score of eight for the crosses (‘PR x KR’) x AW, (‘LR x PR’) x OG, (‘PR x MO’) x LR and (‘PR x MO’) x AW. Among the ten female parents ‘PR x MO’, ‘LR x PR’ and ‘PR x KR’ performed as the best female parents and among the four male parents ‘Liver Red’ performed as the best pollen parent.
Open Access
Compatibility studies of three way crosses in anthurium andreanum linden
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2003) Premna, Varghese; KAU; Mayadevi, P
The evaluation of morphological characters and compatibility analysis of 14 selected genotypes was undertaken in the present study titled "Compatibility studies of three way crosses in Anthurium andreanum Linden. The analysis of variance revealed significant variation among the 14 genotypes for the 18 characters studied. This reveals genetic potential for crop improvement. Variability studies indicated high phenotypic, and genotypic coefficients of variation for the characters internode length, number of leaves and spadices per plant per year and days from emergence to maturity of leaves. The characters with high heritability coupled with high genetic advance values were leaf area, anthocyanin content and inclination of candle indicating additive gene action. Plant height was found to be positively correlated with number of leaves or spadices per plant per year. Candle length had positive genotypic correlation with position of candle. Pollen fertility ranged from 9.26 per cent in PR x DT to 35.70 per cent in Carre. Pollen emergence was completely absent in the genotype W x LJ during the course of the study. Pollen production was high in the r, cooler months of October to December and was suppressed in the months from March to June. From the cross compatibility analysis, it was seen that the percentage of fruit bearing candles was highest for W x LJ (100.00 %) with two crosses. The cross PR x LR with all the possible four crosses gave a value of 79.15 per cent. The number of fruits per candle ranged from 12 to 120. 00 x KR had the highest average number of fruits per candle and it was lowest for 00 x PR. The percentage of fruit set was below 50 per cent for all the crosses. The crosses involving 00 x KR had the highest average percentage of fruit set. The number of days taken for germination varied from four to nine days. The seed germination was highest (87.30 %) for the cross (00 x KR) x H. No cross showed 100 per cent survival beyond four to six months. For PR x LR with all the possible four crosses, the survival percentage was 56.80 per cent. Scoring of the compatibility reactions based on the percentage of fruiting candles, fruit set and seed germination on a scale ranging from zero to nine showed the highest compatibility score of nine for (00 x KR) x C. The best female parents identified were 00 x KR and PR x LR based on the overall performance.
Open Access
Intra and inter generic hybridization and molecular charatrization in monopodial orchids
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2008) Beena, Thomas; KAU; Lekha Rani, C
A research programme entitled “Intra and inter generic hybridization and molecular characterization in monopodial orchids” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2005-2008 with the objective of undertaking intra and intergeneric hybridization, in vitro embryo culture and molecular characterization in monopodial orchids, as a preliminary step to develop novel hybrids. Fifteen monopodial orchid genotypes comprising of six genera viz., Aranda, Aranthera, Kagawara, Mokara, Renanthera and Vanda, with good cut flower qualities and high demand in the market were selected as parents after initial evaluation. They were evaluated adopting completely randomized design with five replications. Analysis of variance revealed significant differences for almost all the characters studied. Genotypic and phenotypic coefficients of variation were high for thickness of leaf, leaf area and number of aerial roots. High heritability (>70 %) combined with high genetic advance (>70 %) was observed for number of aerial roots, width of leaf, thickness of leaf, leaf area, number of spikes per shoot and number of flowers per inflorescence. Significant positive inter-correlation at genotypic and phenotypic levels was observed for length of flower and width of flower with number of spikes per shoot. The character number of spikes per shoot recorded significant positive correlation with leaf area. Number of flowers per inflorescence was positively correlated with number of leaves per shoot and length of inflorescence. Out of the six genera studied, four viz., Aranda, Aranthera, Kagawara and Mokara, exhibited free-flowering nature. Seasonal flowering was observed mainly from June to December in Vanda, whereas it was confined to two seasons, from February to March and August to October in Renanthera. Inflorescence axis was found to be arching in Aranthera and Renanthera while the rest of the genotypes produced erect inflorescence axis. The 15 parental genotypes were crossed in all possible combinations after preliminary studies on floral biology. A total of 225 cross combinations were attempted including 105 crosses, 105 reciprocals and 15 selfs. Incompatibility reactions were noticed at different stages ranging from flower abscission before the onset of any visible post pollination change to instances where seeds germinated but aborted in culture. Mature green capsules were harvested from 70 combinations at 70 to 90 per cent maturity. Among them 15 combinations did not yield any seeds in the capsule while the remaining 55 combinations were cultured axenically. Among the 55 combinations inoculated in vitro, no germination was obtained from seeds of 12 combinations. Out of the 43 combinations that germinated successfully, seven combinations showed arrested development. Thus out of the total 55 combinations inoculated in vitro 36 combinations developed successfully. These were subcultured three to four times. Seedlings having 2-3 leaves and 2-3 roots were deflasked and planted out. MS half strength was selected as the best basal medium. For improving the in vitro growth of hybrid monopodial orchid seedlings refinement of this medium by supplementing with IAA (8 mg l-1) and NAA (2 mg l-1) was beneficial. Significant differences among the combinations were observed with respect to number of days taken for germination initiation, number of days taken for development of protocorms, chlorophyll, first leaf, first shoot and first root primordia and for deflasking. Significant differences in seedling morphology were observed among the 36 hybrid combinations at deflasking. These were kept in humidity chamber for acclimatization for one month, transferred to net house for hardening and maintained there for further growth. In the present study, RAPD was employed for studying the genetic diversity and for the fingerprinting of 20 monopodial orchid hybrids, making use of arbitrary primers to amplify random DNA sequences in the genome. To identify the promising primers for RAPD analysis, 70 decamer primers of kit A, B, C and D were screened using the DNA of hybrid H-2. Based on the performance in DNA amplification, eight decamer primers were identified for RAPD analysis. Primers that produced highest number of polymorphic bands which were intense and reproducible were selected. They were OPB-07, OPB-15, OPB-l7, OPC-04, OPC-05, OPC-08, OPC-15 and OPD-02. a total of 57 scorable bands (average of 7.125 bands per primer) were generated by the selected eight primers of which six were monomorphic and the remaining 51 were polymorphic (89.47%). The estimation of Jaccard’s coefficients and construction of dendrogram by using UPGMA revealed the presence and extent of genetic similarities among the 20 monopodial orchid hybrids. The overall similarity coefficients ranged from 0.40 to 0.84. Cluster analysis revealed that at 0.69 similarity coefficient, the 20 monopodial orchid hybrids got divided into six groups. Among the 20 hybrids, H-18, H-7, H-13, H-17, H-19 and H-20 stood separately in clusters II, III A, III B, IV, V and cluster VI respectively. This substantiates the moderately broad distribution of genetic variability, which can be attributed to the broad genetic base in their ancestry. Cluster I A contained four hybrids viz., H-1, H-10, H-3 and H-9. This grouping is justified by the presence of a common parent i.e., Arachnis Maggie Oei Red Ribbon in their parentage. Moreover, two common species viz., Arachnis hookeriana and Arachnis flos-aeris are involved in their ancestry. All these support their belonging to the same cluster. The three hybrids such as H-5, H-6 and H-8 fell in cluster I B. RAPD technique is relatively simpler, quicker, less expensive and non-radioactive than other molecular characterization techniques. The results of present investigation proved that it can detect sufficient polymorphisms in genetic distance studies in monopodial orchids. A research programme entitled “Intra and inter generic hybridization and molecular characterization in monopodial orchids” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2005-2008 with the objective of undertaking intra and intergeneric hybridization, in vitro embryo culture and molecular characterization in monopodial orchids, as a preliminary step to develop novel hybrids. Fifteen monopodial orchid genotypes comprising of six genera viz., Aranda, Aranthera, Kagawara, Mokara, Renanthera and Vanda, with good cut flower qualities and high demand in the market were selected as parents after initial evaluation. They were evaluated adopting completely randomized design with five replications. Analysis of variance revealed significant differences for almost all the characters studied. Genotypic and phenotypic coefficients of variation were high for thickness of leaf, leaf area and number of aerial roots. High heritability (>70 %) combined with high genetic advance (>70 %) was observed for number of aerial roots, width of leaf, thickness of leaf, leaf area, number of spikes per shoot and number of flowers per inflorescence. Significant positive inter-correlation at genotypic and phenotypic levels was observed for length of flower and width of flower with number of spikes per shoot. The character number of spikes per shoot recorded significant positive correlation with leaf area. Number of flowers per inflorescence was positively correlated with number of leaves per shoot and length of inflorescence. Out of the six genera studied, four viz., Aranda, Aranthera, Kagawara and Mokara, exhibited free-flowering nature. Seasonal flowering was observed mainly from June to December in Vanda, whereas it was confined to two seasons, from February to March and August to October in Renanthera. Inflorescence axis was found to be arching in Aranthera and Renanthera while the rest of the genotypes produced erect inflorescence axis. The 15 parental genotypes were crossed in all possible combinations after preliminary studies on floral biology. A total of 225 cross combinations were attempted including 105 crosses, 105 reciprocals and 15 selfs. Incompatibility reactions were noticed at different stages ranging from flower abscission before the onset of any visible post pollination change to instances where seeds germinated but aborted in culture. Mature green capsules were harvested from 70 combinations at 70 to 90 per cent maturity. Among them 15 combinations did not yield any seeds in the capsule while the remaining 55 combinations were cultured axenically. Among the 55 combinations inoculated in vitro, no germination was obtained from seeds of 12 combinations. Out of the 43 combinations that germinated successfully, seven combinations showed arrested development. Thus out of the total 55 combinations inoculated in vitro 36 combinations developed successfully. These were subcultured three to four times. Seedlings having 2-3 leaves and 2-3 roots were deflasked and planted out. MS half strength was selected as the best basal medium. For improving the in vitro growth of hybrid monopodial orchid seedlings refinement of this medium by supplementing with IAA (8 mg l-1) and NAA (2 mg l-1) was beneficial. Significant differences among the combinations were observed with respect to number of days taken for germination initiation, number of days taken for development of protocorms, chlorophyll, first leaf, first shoot and first root primordia and for deflasking. Significant differences in seedling morphology were observed among the 36 hybrid combinations at deflasking. These were kept in humidity chamber for acclimatization for one month, transferred to net house for hardening and maintained there for further growth. In the present study, RAPD was employed for studying the genetic diversity and for the fingerprinting of 20 monopodial orchid hybrids, making use of arbitrary primers to amplify random DNA sequences in the genome. To identify the promising primers for RAPD analysis, 70 decamer primers of kit A, B, C and D were screened using the DNA of hybrid H-2. Based on the performance in DNA amplification, eight decamer primers were identified for RAPD analysis. Primers that produced highest number of polymorphic bands which were intense and reproducible were selected. They were OPB-07, OPB-15, OPB-l7, OPC-04, OPC-05, OPC-08, OPC-15 and OPD-02. a total of 57 scorable bands (average of 7.125 bands per primer) were generated by the selected eight primers of which six were monomorphic and the remaining 51 were polymorphic (89.47%). The estimation of Jaccard’s coefficients and construction of dendrogram by using UPGMA revealed the presence and extent of genetic similarities among the 20 monopodial orchid hybrids. The overall similarity coefficients ranged from 0.40 to 0.84. Cluster analysis revealed that at 0.69 similarity coefficient, the 20 monopodial orchid hybrids got divided into six groups. Among the 20 hybrids, H-18, H-7, H-13, H-17, H-19 and H-20 stood separately in clusters II, III A, III B, IV, V and cluster VI respectively. This substantiates the moderately broad distribution of genetic variability, which can be attributed to the broad genetic base in their ancestry. Cluster I A contained four hybrids viz., H-1, H-10, H-3 and H-9. This grouping is justified by the presence of a common parent i.e., Arachnis Maggie Oei Red Ribbon in their parentage. Moreover, two common species viz., Arachnis hookeriana and Arachnis flos-aeris are involved in their ancestry. All these support their belonging to the same cluster. The three hybrids such as H-5, H-6 and H-8 fell in cluster I B. RAPD technique is relatively simpler, quicker, less expensive and non-radioactive than other molecular characterization techniques. The results of present investigation proved that it can detect sufficient polymorphisms in genetic distance studies in monopodial orchids.
Open Access
In vitro multiplication and DNA fingerprinting of selected hybrids and their parents in anthurium andreanum linden
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2007) Yasin Jeshima, K; KAU; Mayadevi, P
Anthurium is the largest genus in the family Araceae, encompassing more than 800 species, native to tropical America, from Mexico, Costa Rica, Cuba to Brazil and Argentina. The spadix is composed of a multitude of flowers, which are perfect having two-carpelled ovary and four anthers. A few commercially grown plants are classified as "rat tail" anthuriums as their inflorescences have a long spadix and a small non-descript spathe. Anthuriums with colourful inflorescences have been grown for cut flowers. With the introduction of compact interspecific hybrids through breeding and the selection of somaclonal variants, the new commercially available types were developed. Propagation is not easy for anthuriums and is considered a long-term crop which will take long time for the propagator to multiply. In light of afore said views, an attempt was made to standardize in vitro multiplication and DNA fingerprinting of selected hybrids and their parents in Anthurium andreanum Linden. The explants after standardizing for the surface sterilization and survival were cultured on selected media with different hormone concentrations to get maximum callus induction. For callus induction the culture flasks were kept in dark at 25˚C and subcultured every third week. Calli were transferred to regeneration medium and embryogenic calli induction medium. Regenerants were selected and placed in rooting medium; further hardened and transferred to the field condition. Preconditioned embryos were suspended in calcium free half strength NN medium supplemented with 1.5 per cent sodium alginate and 0.5 M sucrose. This mixture was dispensed with a micropipette into 0.1 M calcium chloride. Twenty minutes after encapsulation beads were pre cultured on modified half strength NN liquid medium supplemented with 0.75 M sucrose and three per cent DMSO into 100 ml Erlenmeyer flasks for one day without agitation. Beads were then transferred to fresh medium of same composition and incubated in darkness at 4ºC for three days. Beads were desiccated in a sterile laminar air flow chamber. Dehydrated beads were transferred to 4 ml cryo vials and stored at – 80˚C. On rewarming over a water bath at 25˚C, the beads were transferred to culture medium for germination. Surface disinfection treatments were standardized for the different explants, irrespective of the explants and varieties and double sterilization was found to be effective. Among the explants, the highest number of sterile cultures was observed in double sterilization, followed by the treatment with 70 per cent Ethyl alcohol for 20 minutes. Majority of the contamination found in the cultures was due to the presence of systemic infection of Xanthomonas compestris pv dieffenbachiae. This directly influences the percentage of contamination occurred in the culturing condition and the size of explants which also play a major role in creating the bacterial contamination. Candle explants were found to exhibit more systemic infections than other explants and seed explants were found to be free from systemic infections. Leaf explants are highly vulnerable to exhibit systemic infections and are more sensitive; unable to recover even after treatments with antibiotics. The callus cultures exhibiting systemic infections can be recovered by kanamycin 50 mg per litre containing multiplication medium. In most studies of in vitro culture of anthurium, MS medium has been used. In the present study also, it was observed that Nitsch and Nitsch medium was better than MS medium for multiple shoot induction. Nitsch and Nitsch medium is especially suitable for morphogenesis, meristem culture and regeneration. As the genotype showed different nutrient requirements for their survival and growth, the present investigation was planned to standardize the media by screening with modified MS, half strength MS, modified NN and half strength NN medium. Modified NN with activated charcoal and coconut water showed better response. Half strength NN with coconut water and activated charcoal, modified MS with activated charcoal and coconut water and half strength MS activated charcoal and coconut water were also found to support the explants without hindering the survival. Addition of inositol and glycine along with folic acid was found to be essential but the presence of small amount was inefficient. In the present investigation no callus initiation was observed when inositol was reduced to half of the reported quantity. Various treatments were tried for callus multiplication. The maximum fresh weight of callus 4.2458 g was observed in PR X DT inoculated in NN medium with major nutrients at normal strength followed by 4.1325 g in OG X DT for the same composition in NN medium. From the economic point of view NN medium can be recommended for callus multiplication. Among the treatments, combination of 2, 4-D and zeatin was found to be the best. It stimulates callus formation and strongly antagonizes organized development. The low auxin requirement may be due to the high potency of the auxin which was used for callus initiation. The young developing leaf may be a rich source of endogenous auxins due to which lower exogenous application is required. Irrespective of the source of explant all the callus cultures were able to be converted into plantlets by redifferentiation. The number of days taken for regeneration ranges from 55.5 to 82. This variation is due to the varietal difference and difference in hormonal effect. Modified NN with activated charcoal and coconut water along with 22.2 μM BA, 11.42 μM IAA and 4.09 μM biotin was found to produce regenerants. Each genotype is varying with the response to change in media composition in producing somatic embryogenesis. The treatments with MS and modified MS media were found to be insignificant when compared with NN and modified NN media. Among these modified NN was found to be the best one. Within two weeks on embryo development medium, the globular embryos developed a bipolar shape. Embryos at this stage were comprised of cells larger than those at the globular stage. Bipolar embryos had an extended upper region that formed the cotyledon and the epicotyl, and a lower region that formed the radicle.The main difference between the mature embryos of monocotyledons in vitro and in vivo is the absence or presence of suspensor. The presence of single cotyledon which is the terminal structure and the shoot initials present at the sides or hidden creating a heart shape. When the cotyledon starts growing the embryo will have a single cotyledon at the terminal end which is some what cylindrical in shape. In anthurium tissue culture, no special rooting treatments were needed and the shoots developed in vitro were found to develop roots spontaneously even in the absence of additional growth hormones in the supporting medium. The spontaneous root formation was not due to the carry over effect of the hormones supplied in the previous cultures for shoot formation. Irrespective of the supporting medium the shoots were able to form roots even in sterile sand supplied with sterilized compost materials. For in vitro studies Completely Randomized Block Design (CRD) was followed for statistical analysis wherever necessary. Molecular characterization of twelve hybrids and their parents were carried out with RAPD using AP-PCR. Young leaf samples from each genotype were collected for DNA isolation.Young copper coloured leaf tissues were used immediately after collection for DNA extraction. Leaf samples were pre-chilled at -80ºC for half an hour with pestle and mortar and then pulverized in liquid nitrogen by rapid grinding to a fine powder.The frozen powder was used to extract the total genomic DNA using CTAB extraction buffer. The purity of the DNA was analysed by running in 0.8 per cent agarose gel with 1 X TAE buffer. The optimized PCR mixture with 50ng of template DNA for a final volume of 20μl was used in thermal cycling in a PCR machine. The amplified products were run in 1.6 per cent agarose gel with 1X TAE (Tris buffer, Glacial acetic acid and EDTA pH 8.0) buffer. A total of 114 AP-PCR bands were generated by the 25 primers, of which 74.56 per cent were polymorphic (88 bands) and 26 were monomorphic. Ten primers showed high level of polymorphism out of which seven were selected.Seven promising primers were identified for AP-PCR analysis based on performance in DNA amplification, production of highest number of polymorphic bands as well as intense bands and reproducibility viz. OPA 10, OPB15, OPA13, OPB20, OPB6, OPB8 and OPB18 primers were found to produce polymorphism in Anthurium andreanum Linden.A total of 50 scorable bands (average of 7.143 bands per primer were generated by the selected seven primers of which only 8 were monomorphic and the rest were polymorphic. The number of bands ranged form 4 to 11 with an average of 7.143 per primer. The reproducible bands were scored for their presence (1) or absence (0) for all the hybrids and parents. A genetic similarity matrix was constructed using Jaccards’s similarity co-efficient methods. From the cluster analysis based on the dendrogram, TR X MW was found to be extreamly different from the other accessions and its own parents showing the significance of hybridization. The hybrids like OO X KR, PR X DT, OG X DT, FK X LR and PR X MW are not closely related to either of their parents and hybrids were distinguished from others. Some hybrids like LJ X W and PR X MW; PR X LR and FK X DT shows 30 to 39 per cent similarity. This shows there is considerable variability among the genotypes selected and can be further utilized for crop improvement. Confirming that, they were quite different from the other hybrids and varieties. Pair wise genetic distances based on RAPD [(AP-PCR) (Nei and Li Genetic Distance GDNL)] genetic distance co-efficient values for twelve varieties and twelve hybrids ranged from 0.1935 to 0.7037 indicating the wider diversity. The AP-PCR profiles show the relatedness and diversity of the hybrids and varieties. The bands were found within 1.5kb from 100bp. Most of the bands were concentrated between 300bp and 1200bp.
Open Access
Triallel analysis of yield and resistance to anthracnose in chilli ( Capsicum annuum L)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2007) Haridass, A; KAU; Manju, P
. Chilli (Capsicum annuum L.) is an important spice cum vegetable crop grown commercially in India. It is an important constituent of many foods since it adds flavour, colour, vitamin C and pungency. Productivity of the crop remains low mostly due to destructive diseases, of which the most dreaded disease affecting chilli is anthracnose also known as dieback and fruit rot. The best method to tackle the disease is to grow resistant varieties and hence it is essential to breed high yielding anthracnose resistance varieties of chilli. Therefore an investigation was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani to estimate the combining ability and heterosis through diallel pattern and combining ability analysis through general line effect of the first kind ((hi), general line effect of the second kind (gi), two line specific effect of the first kind (dij), two line specific effect of the second kind (sij/sji), three line specific effect (tijk), estimates of genetic components and heterosis by triallel analysis to assess the inheritance pattern of anthracnose resistance, yield and yield component traits, identify the order in which the parents should be combined to obtain maximum effect for a particular character and also to formulate an appropriate breeding programme for improving each trait. Six parents viz., Jwalamukhi (P1), Jwalasakhi (P2), Samkranthi local (P3), Vellayani Athulya (P4), Kidangoor local (P5) and Ujwala (P6) along with their 15 F1 hybrids, and their possible three way cross hybrids was evaluated during 2005-2007. Diallel analysis revealed that the magnitude of gca variance was higher than sca variance suggesting the predominance of additive gene action except for number of seeds per fruit, harvest index and vitamin C. On the basis of per se performance of the parents for different traits, P4 was superior with regard to average fruit weight, fruit length, fruit girth and hundred seed weight while P1 for fruit yield per plant and vitamin C. P6 showed high resistance to anthracnose with high enzymatic activity for anthracnose, phenol, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase along with high capsaicin and oleoresin. The hybrid P1xP6 had highest per se performance for fruit yield per plant and number of fruits per plant, P2xP4 for fruit length, average fruit weight, fruit girth, number of seeds per fruit and hundred seed weight and P5xP6 for duration, incidence of anthracnose, disease intensity, biochemical characters, capsaicin and oleoresin. High values of gca effects were noticed for fruit yield per plant, number of fruits per plant and incidence of anthracnose at 45 DAT and 60 DAT. Highest sca effect was recorded for fruit yield per plant, number of fruits per plant and vitamin C. With respect to mean and general combining ability, P2 was superior for days to first flowering, average fruit weight, fruit girth, fruit yield per plant, hundred seed weight and harvest index while P6 for incidence of anthracnose, disease intensity and all the biochemical characters including capsaicin and oleoresin. Among the fifteen hybrids evaluated with respect to per se, standard heterosis and sca effects, P1xP6 was superior with regard to number of fruits per plant, fruit yield per plant, incidence of anthracnose, disease intensity, phenol, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, capsaicin and oleoresin. In triallel analysis, P4xP6xP1 had highest per se performance for fruit yield per plant, P1xP5xP4 for average fruit weight, fruit length, number of seeds per fruit while P5xP6xP4 had significant per se performance for incidence of anthracnose and high enzyme activity. P6 had the highest general line effect of the first kind (hi) for fruit yield per plant and number of fruits per plant while P1 for days to first flowering, plant height, average fruit weight, fruit length, fruit girth, harvest index and vitamin C. P4 had highest general line effect of the first kind for incidence of anthracnose, disease intensity and for all the enzyme activity. The general line effect of the second kind (gi) was highest in P1 for fruit yield per plant, number of fruits per plant, fruit girth, hundred seed weight and oleoresin while P5 for low incidence of anthracnose, disease intensity and high activity of the enzymes. P6 had highest effect for number of branches per plant, capsaicin, and vitamin C. The two line specific effect of the first kind (dij) was highest in P4xP5 for number of fruits per plant, fruit yield per plant and duration while P1xP6 for incidence of anthracnose, disease intensity and all the enzyme activities. P1 x P2 had highest two line specific effect of the second kind (sij) for fruit yield per plant and number of fruits per plant whereas P4xP6 for incidence of anthracnose, disease intensity, phenol, peroxidase, phenylalanine ammonia lyase and polyphenol oxidase. The two line specific effect of the second kind (sji) reciprocal effect was highest in P5xP4 for fruit yield per plant and average fruit weight while P2xP1 for incidence of anthracnose, disease intensity, phenol, polyphenol oxidase and phenylalanine ammonia lyase. P1xP2xP3 recorded high value of three line specific effect for fruit yield per plant and average fruit weight and P5xP6xP4 for incidence of anthracnose at 60 DAT, phenol, and polyphenol oxidase and phenylalanine ammonia lyase. The hybrid P4xP6xP1 had high relative heterosis and heterobeltiosis for fruit yield per plant. Among the biometrical traits, the relative heterosis was high for fruit yield per plant followed by harvest index and number of fruits per plant whereas heterobeltiosis had maximum per cent for harvest index followed by number of fruits per plant and fruit yield per plant. At 45 DAT the incidence of anthracnose had high relative heterosis and heterobeltiosis. The enzyme polyphenol oxidase had highest heterosis followed by capsaicin and oleoresin for both type of heterosis. From the present investigation several promising three way cross hybrids were obtained with regard to fruit yield, yield attributes and resistance to anthracnose. Some of the promising three way cross hybrids are Jwalamukhi x Kidangoor local x Jwalasakhi, Jwalamukhi x Ujwala x Vellayani Athulya, Jwalamukhi x Ujwala x Kidangoor local, Jwalasakhi x Vellayani Athulya x Kidangoor local, Samkranthi local x Vellayani Athulya x Kidangoor local, Vellayani Athulya x Kidangoor local x Samkranthi local, Vellayani Athulya x Ujwala x Jwalamukhi, and Kidangoor local x Ujwala x Jwalasakhi. These can be directly used as hybrids or can be subjected to selection of superior types in the segregating generation to obtain stable varieties. The estimation of genetic components revealed the predominance of dominance x dominance gene effect for fruit yield per plant, number of branches per plant, number of fruits per plant, average fruit weight, fruit length, fruit girth, harvest index and capsaicin while the remaining traits days to first flowering, plant height, number of seeds per fruit, hundred seed weight, incidence of anthracnose, enzyme activity, phenol, oleoresin and vitamin C had additive x dominance type of epistatic effect. Heterosis method of breeding could be followed for the improvement of the traits which had dominance x dominance type of epistatic effect whereas the traits with additive x dominance component could be improved thereby postponing selection to later segregating generations and following recurrent selection.
Open Access
Stability analysis of selected mutants of coleus (Solenostemon rotundifolius[Poir.] J.K.Morton)
(Department of Plant Breeding and Genetics, College of Horticulture,Vellanikkara, 2003) Shinoj, P; KAU; Mareen Abraham
Stability analysis of fourteen mutants of Coleus comprising of eleven promising mutants, two released varieties and one local cultivar was conducted at four locations in four districts of Kerala, namely, Palakkad, Malappuram, Thrissur and Ernakulam during Khariff, 2001. The selected mutants showed significant differences for many of the economic traits over locations. For increasing the tuber yield in Co le us, selection should be based on low tuber number, low starch content and high protein content. Further the tubers should be white coloured, delicious, non-groovy and smooth. The study revealed that the ideal plant architecture in Coleus should have optimum tuber number, white coloured delicious non-groovy tubers with optimum starch and protein content, good texture and medium flavour. The stability analysis identified mutants '641' and '352' as the most stable high yielding well adapted genotype for many of the economic traits over locations.

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