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Kerala Agricultural University, Thrissur

The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively. Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively. On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs. In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc. During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU). Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.

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2007 - 20094
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Subject: Plant Breeding × Author: KAU × End date: 2009 × Start date: 2007 × Thesis Type: Ph.D ×
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    ThesisItemOpen 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.
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    ThesisItemOpen 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.
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    ThesisItemOpen 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.
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    ThesisItemOpen Access
    Genetic analysis of resistance to pod borers and yield in yard long bean(Vigna unguiculata subsp.sequipedalis(L.) verdcourt)
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2009) Jithesh, V G; KAU; Radhadevi, D S
    Yard long bean [Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt] known as asparagus bean or vegetable cowpea is one of the important vegetable crops grown in Kerala. The long tender pods are highly nutritious containing carbohydrate, minerals, fibre, calcium, phosphorus, iron and many vitamins. Infestation by pod borers Maruca vitrata (Fab.) and Lampides boeticus (Linn.) which are the most important post-flowering pests of yard long bean. This research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2006-2008 with the objective to study the genetic basis and inheritance pattern of important quantitative and qualitative characters for resistance to pod borers and yield and to formulate a suitable breeding programme for developing varieties resistant to pod borers and with high yield in yard long bean. Fifty genotypes of yard long bean collected from different parts of Kerala were evaluated adopting randomized block design with three replications. Analysis of variance revealed significant differences for almost all the characters. High GCV was observed for pod length, pod weight, pods per plant, pod clusters per plant, pod yield per plant and 100-seed weight, which indicate that there exists high genetic variability and better scope for improvement of these characters through selection. The characters pod clusters per plant, pods per plant, pod yield per plant, pod weight, pod length, seeds per pod and 100-seed weight had high heritability coupled with high genetic advance. In the present study high heritability and low genetic advance was noted for pod breadth and seeds per pod. Yield per plant showed strong positive correlation with pod weight, pod length, pod breadth, seeds per pod and 100-seed weight. The characters pod weight, pods per plant, 100-seed weight, seeds per pod and pod clusters per plant had positive direct effect. Mahalanobis D2 analysis clustered the 50 genotypes in to nine groups. Maximum divergence was shown between the clusters I and VI. Among the seven characters considered pod yield per plant contributed maximum towards divergence. Selection indices were computed based on yield and yield related traits, five genotypes viz; Trailing Red Poded (L1), NS 621 (L2), Ettumanoor local (L3), Vellayanai local (L4) and Palakkad local (L5) with high yield were selected as female parents in the line x tester analysis. The same fifty genotypes were screened for various damage parameters of pod borers by using randomized block design with two replications. All the damage parameters exhibited remarkable variability with respect to different genotypes. Based on all the damage parameters three genotypes with low plant resistant indices namely Kurappunthara local (T1), Kanichar local (T2) and KMV-1 (T3) were selected as testers in the line x tester analysis. Significant variability was present for different morphological and biochemical characters among the 50 genotypes. High coefficient of variation was noticed for number of trichomes on pod wall. High heritability was noticed for all the characters except crude fibre content. The characters peduncle length, trichome number and protein content of pods showing high genetic advance. In line x tester analysis L1 showed high values of gca effect for pods per plant, seeds per pod, pods per cluster, 100-seed weight and pod length. Among the testers T1 showed significant negative gca effects for all the damage parameters for pod borers. In morphological and biochemical traits line L3 showed positive gca effect for peduncle length, trichome number and protein content of pods but L1 for leaf chlorophyll content. Tester T1 showing positive gca effect for all the morphological and biochemical traits. Based on specific combining ability, the crosses L1 x T1, L3 x T1 and L5 x T1, showed maximum sca for yield attributes and minimum for damage parameters. Many of the crosses showed significant positive sca effects for most of the morphological and biochemical traits. The crosses L1 x T1, L3 x T1 and L5 x T1 exhibited significant positive estimates with high magnitude of yield attributes and morphological and biochemical traits indicating considerable heterosis with respect to the important yield characters. Further the relative and standard heterosis exhibited significance in the negative direction for all damage parameters. This results leads to the conclusion that low relative performance of pod borers larvae in these crosses may be due to its trichome number, protein content of pods, leaf chlorophyll content or fibre content which can offer resistance to pod borers in yard long bean and can form the basis for selection of yard long bean genotypes for pod borer resistance or tolerance. The three superior crosses viz., L1 x T1 (Traling Red poded x Kurappunthara local), L3xT1 (Ettumanoor local x Kurappunthara local) and L5 x T1 (Palakkad local x Kurappunthara local) were utilized for generation mean analysis inorder to detect the gene action with regard to the various traits. Presence of epistasis was tested and subsequently interaction effects viz; additive x additive, additive x dominance and dominance x dominance effects were computed. Significance of scale A and B for most of the characters suggested that the simple additive x dominance model was inadequate for defining the inheritance of these characters. Presence of non-allelic interactions was noticed for days to 50 per cent flowering, primary branches per plant and days to first harvest. Hybridization and selection can be resorted to for improving the character of earliness in this crop. The positive significance of dominance x dominance interactions for pod weight points out that a breeding strategy for improving pod weight should be based on direct selection or hybridization and selection for high pod weight. Presence of all three types of digenic interactions was observed for pods per plant and pod yield per plant. The direction of dominance effect and dominance x dominance interactions suggests the presence of non-allelic duplicate gene action for crop duration, main stem length, pod clusters per plant, pod weight and pod breadth in their expression. For damage measurements additive gene action was significant for all the damage parameters. Additive x dominance gene action was significant for peduncle length. The same direction of dominance gene effect and dominance x dominance interactions is an indication of non-allelic complementary gene action in the expression of this character. For leaf chlorophyll content additive gene action was significant for all the hybrids. The L1 x T1 had positive significance in dominance x dominance epistatic interaction for number of trichomes on pod wall. Predominance of additive gene action in a positive direction was observed for protein content but significant additive x dominance interaction in a negative direction. Additive gene effect was significant for crude fibre content of pods. The positive significance of dominance x dominance interactions points out that a breeding strategy for reducing the fibre content should be based on direct selection or hybridization. The result suggest ample scope of improvement of yield through selection based on the characters pod weight and pod length. The genetic analysis for yield and resistance to pod borers brought to light genotypes which could be used as source of resistance. Two superior crosses in which high yield potential and tolerant to pod borers were identified. Less attack of pod borers larvae to these crosses may be due to high values for any of the two characters namely trichome number or crude fibre content coupled with mechanical barriers with restricts their access to pod surface compared to other crosses. The magnitude and direction of the gene effects underlying the pest damage parameters offers a favourable background for the breeder to develop pod borer resistant/tolerant yard long bean genotypes. Presence of additive, dominance and epistatic interactions for all the characters identified indicated that recurrent selection or recombination breeding can be followed for future breeding programme