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Subject: Plant Breeding × End date: 2018 × Start date: 2013 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Breeding cowpea (Vigna unguiculata (L.) Walp.) for resistance to spotted pod borer (Maruca vitrata Fab.)
    (Department of Plant Breeding and Genetics, Vellanikkara, 2018) Ambavane Ajinkya Rajendra; KAU; Jiji Joseph
    Cowpea [Vigna unguiculata (L.) Walp.] is important pulse crop rich in nutrients, especially proteins. This crop is cultivated in the tropics of Asia, Africa and other parts of the world. Nevertheless, the production of cowpea is unable to achieve its summit. One of the prime reasons for this is the infestation of a notorious pest, the spotted pod borer, (Maruca vitrata Fab.; Lepidoptera: Crambidae). Spotted pod borer is one of the most important post-flowering pests of cowpea in the tropics. It is a major lepidopteran pest and damage cause to cowpea by the pest almost always crosses economic threshold level. Hence, the present investigation was conducted in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, Kerala Agricultural University, Thrissur during 2015 to 2018 with the objective of identification and incorporation of resistance against spotted pod borer in high yielding varieties of cowpea and assessment of parental polymorphism at the molecular level Thirty genotypes of cowpea formed the material for the study. These genotypes were subjected to field screening against spotted pod borer. These genotypes were also evaluated for morphological and biochemical basis of resistance. Five selected genotypes from experiment 1 then hybridised with four high yielding genotypes viz., Geethika, Vellayani Jyothika, Lola and Kashi Kanchan following Line × Tester mating design. Twenty F 1 hybrids evaluated for field resistance and the morphological basis of resistance. Progenies of selected F 1 hybrids grown as F 2 populations and evaluated for same parameters as like F 1 s. Thirty genotypes were also subjected to molecular screening by 40 SSR primers. Wide variation was observed in terms of different damage parameters. Ten genotypes viz., Hridya, Palakkadan thandan payar, EC 300039, EC 98668, EC 101216, IC 52110, IC 39945, IC 2918, IC 39922 and IC 39916 recorded total damage below five per cent. Among them, IC 39922 observed to have no flower bud and flower damage, EC 300039, EC 98668, IC 52110, IC 39945, IC 2918 and IC 39916 recorded no flower damage, whereas, Palakkadan thandan payar, IC 39945, IC 2918 and IC 39947 were free from pod damage. The highest damage was recorded in the variety Bhagyalakshmy (48.46 %) followed by variety Lola (30.04 %). Analysis of the morphological basis of resistance to spotted pod borer revealed the negative correlation of trichome density and length on flower bud, trichome density on the pod and pod wall thickness with respective damage parameters. With respect to the biochemical basis of resistance to spotted pod borer, total sugar content, reducing sugar content and non-reducing sugar content of flower bud and pod showed a positive correlation with damage parameters, but the correlation was not significant. However, the total protein content of pod showed a strong and positive correlation with pod damage. Total phenol content of flower bud showed strong negative correlation with damage parameters. Polyphenol oxidase activity in flower bud and pod exhibited a strong negative correlation with damage parameters. The crude fibre content of pod also showed a strong negative correlation with pod damage. In experiment 3, three SSR primers viz., CLM0061, CLM0295 and CLM0300 recorded high polymorphic information content (0.70, 0.71 and 0.76, respectively). Primer CLM0190 observed to have high amplicon size (307.03-415.73 bp). Jaccard’s similarity coefficient was highest between IC 52118 and IC 39916 (0.643) and was lowest between Kashi Kanchan and TVX-944 (0.022). Cluster analysis of SSR data grouped 30 genotypes in 22 clusters, and the 21 st cluster was observed to have more members (3 genotypes). Most resistant genotype, IC 2918, grouped in a separate cluster which proved its diverse nature from other genotypes. Principal component analysis of SSR data placed three yard-long bean genotypes viz., Geethika, Vellayani Jyothika and Lola near to each other in a two-dimensional score plot. The same analysis also formed two clusters with more number of genotypes which placed resistant and susceptible genotypes separately. In field screening of F 1 hybrids, Hybrid 20 observed to have total damage below 5 per cent. Eight hybrids recorded total damage in the range of 5 to 10 per cent. These hybrids were selected for next experiment. Line × Tester analysis of F 1 s revealed Kashi Kanchan, EC 98668 and IC 2918 as a good combiner for resistance against spotted pod borer. Hybrid 5, Hybrid 6, Hybrid 10, Hybrid 11, Hybrid 13, Hybrid 15, Hybrid 16, Hybrid 17, Hybrid 18, Hybrid 19 and Hybrid 20 observed to have desired negative heterosis (mid-parent) for total damage. In F 2 plant screening, Hybrid 1 population recorded low mean for total damage (6.76 %), whereas, the population of Hybrid 3 recorded high mean (12.17 %). Around 100 plants of F 2 generation recorded total damage below ten per cent. Out of them, around 38 plants also registered good yield. These plants should be further evaluated to isolate high yielding resistant segregants.
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    ThesisItemOpen Access
    Diversity analysis in landraces of rice(oryza sativa L.) in Wayanad through morphological and molecular polymorphism study
    (Department of Plant Breeding and Genetics,College of Horticulture, Vellanikkara, Thrissur, 2018) Manjunatha, G A; KAU; Elsy, C R
    The present investigation entitled “Diversity analysis in landraces of rice (Oryza sativa L.) in Wayanad through morphological and molecular polymorphism study” was conducted at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, Thrissur and Regional Agricultural Research Station, Ambalavayal, Wayanad during the period 2015- 2018. The study aimed to collect and characterize the rice landraces of Wayanad at morphological level and also to characterize the popular aromatic genotypes of the area at molecular level. DUS characterization revealed that, all the landraces under the study exhibited presence of leaf collar, absence of anthocyanin colouration of leaf collar, presence of leaf ligule, split shape of leaf ligule, absence of anthocyanin colouration for plant parts like lemma (keel), area below apex of lemma, stem nodes and presence of secondary branching in panicle. Variability was exhibited for majority of characters namely coleoptile colour, basal leaf sheath colour, intensity of green colour of leaf, anthocyanin colouration of plant parts like leaf, leaf sheath, auricles, ligules, lemma apex, area below apex of lemma, distribution of anthocyanin colouration in leaf, pubescence of leaf blade surface, leaf auricles, culm attitude, density of pubescence of lemma, colour of stigma, attitude of flag leaf blade, curvature of main axis of panicle, lemma and palea colour, presence and colour of awns, distribution of awns in panicle, secondary branching in panicle, attitude of branches in panicle, panicle exsertion, leaf senescence, sterile lemma colour, shape, colour and aroma of decorticated grain, gelatinization temperature and lodging nature.Thavalakannan, Mullan puncha and Sugandhamathi exhibited distinct morphological characters. Among the 60 landraces, Kanni kayama, Ambalavayal-1, Kothandan, Onamottan, Thondi-2, Chenthadi, Kannali and Thondi-1 exhibited significantly high grain yield per plant, which was on par with that of Uma and Aathira (high yielding check varieties), indicating the possibility of commercial cultivation of these cultivars. High PCV value than GCV for all the characters under study, indicated the influences of environmental factors on the characters. High heritability and high genetic gain was exhibited by the characters like length of leaf blade, width of leaf blade, stem thickness, stem length, number of tillers per plant, number of panicles per plant, length of panicle main axis, number of spikelets per panicle, number of grains per panicle, seed setting (per cent), 1000 grain weight, grain length, grain L/B ratio, decorticated grain L/B ratio and grain yield per plant, indicating that these characters could be used in crop improvement programmes. Character association studies including correlation and path-analysis revealed that, five characters viz., width of leaf blade, stem length, number of panicles per plant, weight of 1000 grains and decorticated grain width showed both positive correlation and positive direct effect on grain yield per plant. Cluster analysis based on qualitative characters categorized 60 landraces into 11 clusters at 74 percent similarity level. Based on D2 statistics analysis, the landraces were grouped into seven clusters with variable number of landraces in each cluster, indicating wide genetic diversity in the Wayanad landraces. All the inter-cluster distances were higher than the intra-cluster distance, indicating the wider genetic diversity among landraces of different clusters. Molecular characterization of aromatic rice genotypes of Wayanad by SSR (RM) profiling revealed high level of genetic polymorphism among the genotypes studied. Out of 86 SSR markers used for molecular characterization, 44 markers were polymorphic and remaining 42 were monomorphic. Maximum number of amplicons was exhibited by RM247 with five amplicons, followed by RM85, RM251, RM248 and RM493 with four amplicons each. The highest PIC value was exhibited by RM247 (0.90), followed by RM85, RM251 and RM493 with 0.88 PIC value each. Out of 86 SSR (RM) markers, 21 markers distinguished Basmati from traditional aromatic landraces of Wayanad viz., Gandhakasala and Jeerakasala. Seven SSR markers distinguished Gandhakasala from Jeerakasala, whereas 23 markers distinguished Basmati from Jeerakasala. Twenty-two markers distinguished Basmati from Gandhakasala and 23 markers distinguished aromatic group from non-aromatic group. Cluster analysis for molecular characterization revealed maximum similarity coefficient (1.00) within all the Jeerakasala morphotypes and all the Gandhakasala morphotypes. Cluster analysis effectively differentiated Basmati, Jeerakasala, Gandhakasala, Uma and Aathira from each other. Among the five clusters formed, cluster III was the largest one comprising all the 12 Gandhakasala morphotypes, followed by cluster IV with all Jeerakasala morphotypes. Cluster I, Cluster II and Cluster V exhibited one genotype each namely Aathira, Uma and Basmati, indicating their genetic distinctness.
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    ThesisItemOpen Access
    Distant hybridization and compatibility studies in wild orchids
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2018) Seeja, G; KAU; Arya, K
    The present investigation entitled “Distant hybridization and compatibility studies in wild orchids” was carried out with the objective of studying the cross compatibility through distant hybridization in wild orchids and molecular characterization of hybrid seedlings using RAPD/ISSR- markers. The study was carried out at Saraswathy Thangavelu Extension Centre of KSCSTE- JNTBGRI, Puthenthope, Thiruvananthapuram and at College of Agriculture, Vellayan, Thiruvananthapuram. The research work included experiment I, II, III and IV. Experiment I was carried out in two parts as evaluation of parents and hybridization, experiment II was cross compatibility studies of selected species, experiment III was in vitro culture of resultant hybrids and evaluation of seedlings and experiment IV was molecular characterization of hybrids. In experiment I, wild types belonging to different genera/species namely Vanda (Vanda tessellata, Vanda spathulata, Vanda sp.), Rhynchostylis retusa, Spathoglottis (Spathiglottis albida, Spathoglottis unguiculata, Spathoglottis gracilis, Spathoglottis plicata), Aerides ringens and Arundina graminifolia available at the orchid conservatory of Saraswathy Thangavelu Extension Centre of JNTBGRI, Puthenthope, Thiruvananthapuram were selected as parents based on variability in floral characteristics and these were evaluated for various quantitative and qualitative characters. Statistical analysis was carried out in Completely Randomized Design and analysis of variance revealed highly significant differences for all the biometrical characters included in the evaluation. Estimation of components of variance revealed that Phenotypic Coefficient of Variation (PCV) was higher than both Genotypic Coefficient of Variation (GCV) and Environmental Coefficient of Variation (ECV) for all the traits studied. PCV (143.93) and GCV (128.52) were the highest for number of spikes plant-1. Heritability was the highest for flower width (99.06 %) and it was high for all thirteen traits. Genetic advance as percent of mean was high for all the traits studied. It was the highest for number of spikes plant-1 (239.80). Estimated phenotypic correlation coefficient revealed highly significant and positive association between flower length and flower width (0.9519). The highly significant and negative association was obtained between internodal length and days for inflorescence emergence to first flower opening (-0.6896). Similarly genotypic correlation coefficient exhibited highly significant and positive association between flower length and flower width (0.9545) and highly significant and negative association between plant spread and number of leaves plant-1 (-0.9903). Based on this, parents were selected and were crossed in all possible combinations. In Vanda a hybrid evolved from the wild species was available at the centre and it was also crossed with the wild parents to study the cross compatibility of wild species with hybrids. In experiment II, cross compatibility of 152 cross combinations made was studied based on successful capsule setting. Capsule characteristics were recorded. The genus Spathoglottis took only four days for attaining pod setting whereas for the genus Rhynchostylis it was ten days for pod setting. Capsule attained maturity much earlier (30 days) in the genus Spathoglottis but the species Vanda spathulata took more days for attaining capsule maturity i.e., harvesting stage (150-154 days). In experiment III, capsules developed among thirty one cross combinations were subjected to seed culture for rapid germination under in vitro condition and seedling development. Observations regarding seed germination were recorded and seeds of ten crosses exhibited seed greening and initiation of protocorm development. Seeds of seven cross namely one intergeneric hybrid and six interspecific hybrids were developed into seedlings. Evaluation of hybrid seedlings was made based on variability in morphological characters at monthly intervals. The six interspecific hybrids were Spathoglottis unguiculata x Spathoglottis albida (Culture 622), Spathoglottis gracilis Spathoglottis unguiculata (Culture 652), Spathoglottis albida x Spathoglottis unguiculata (Culture 778), Spathoglottis albida x Spathoglottis unguiculata (Culture 1368), Spathoglottis plicata x Spathoglottis unguiculata (Culture 1386), Spathoglottis unguiculata x Spathoglottis plicata (Culture 1388) and intergeneric hybrid was Spathoglottis unguiculata x Vanda sp. (Culture 679). In experiment IV, molecular characterisation of seedlings evolved through the crossing was done based on ISSR analysis to distinguish F1 hybrid seedlings from selfed seedlings and their parents. Percentage of polymorphism between hybrids and parents ranged from 11.99 to 32.97 and these results confirmed that all the seven crossed seedlings tested were F1 hybrids and these were distinct from their relevant parents. The above study revealed that through distant hybridization in wild orchids, one intergeneric hybrid Spathoglottis unguiculata x Vanda sp. and six interspecific hybrids viz., Spathoglottis unguiculata x Spathoglottis albida, Spathoglottis gracilis x Spathoglottis unguiculata, Spathoglottis albida x Spathoglottis unguiculata, Spathoglottis albida x Spathoglottis unguiculata, Spathoglottis plicata x Spathoglottis unguiculata, Spathoglottis unguiculata x Spathoglottis plicata could be obtained and molecular characterization confirmed the hybridity of the intergeneric and interspecific hybrids. Therefore, the intergeneric and six interspecific F1 hybrids evolved through distant hybridization can be carried forward for the development of varieties or can be utilised for genetic improvement programme in future.
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    ThesisItemOpen Access
    Characterization and taxonomic evaluation of landraces of capsicum spp. in Kerala
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2018) Asish, I Edakkalathur; KAU; Minimol, J S
    Capsicum is a unique genus coming under the family Solanaceae. This genus includes nearly 40 species among which five viz. C. annuum, C.chinense, C. frutescens, C. baccatum and C. pubescens are cultivated. Large number of types, the transitory nature of these types, introgressive hybridization and environmental influence make species arrangement in Capsicum a confusing task. Even though Kerala is rich in the diversity of Capsicum, a comprehensive study of landraces available has not yet been carried out. In this background, the present project was carried out with the objective of characterizing the landraces of Capsicum species in Kerala using morphological markers and validating the key for the identification of different taxa using molecular and biochemical markers. Ripened fruit samples of 262 accessions were collected from the different districts of Kerala during December, 2013 to August, 2014. These accessions were planted in augmented block design along with released varieties from Kerala Agricultural University as checks at National Bureau of Plant Genetic Resources, Regional Station, Thrissur. Morphological characterization was done by considering both qualitative and quantitative characters. Numerical Taxonomy and Multivariate Analysis System (NTSYS) software version 2.10 z was used for construction of phenogram based on forty four qualitative characters available in the Capsicum descriptor (IPGRI, 1995). Accessions belonging to three species viz., C. annuum, C.chinense and C. frutescens formed species specific clusters. C. baccatum accessions clustered with C. frutescens. C. chinense accessions were clearly separated and distantly placed from C. annuum accessions revealing genetic dissimilarity between the above two species.. Out of 42 clusters formed at 70 per cent similarity level, 39 are mono-specific clusters. Morphological characterization based on qualitative unit characters aligned 95 per cent of the accessions into species specific clusters. Diversity relationship accessed on the basis of 32 quantitative characters grouped the accessions into 14 clusters. C. annuum accessions formed mono- specific clusters where as C. chinense and C. frutescens accessions grouped together in three different clusters revealing that C. frutescens and C. chinense are inseparably related. C. annuum accessions were found standing as a separated group. C. baccatum accessions clustered along with C. frutescens - C. chinense group. Representative accessions selected from each qualitative cluster along with eight released varieties were analysed using 17 RAPD primers. Dendrogram consisted of eleven mono-specific clusters indicating the ability of RAPD markers to align the genotypes into correct taxa. Clustering of C. annuum accession with C. frutescens (two clusters) and C. chinense (two clusters) as well as clustering between C. frutescens and C. chinense (three clusters) accessions points to the genetic similarity within the annuum complex. C. baccatum accession expressed more similarity with C. frutescens. The genetic background of the annuum complex was further scrutinized with 18 SSR primers among 19 genotypes comprising of eight C. annuum, seven C. chinense and four of C. frutescens accessions. Out of five clusters formed, two were mono-specific C. annuum clusters. Other three clusters composed of both C. frutescens and C. chinense accessions in each clusters. Thus SSR characterization clearly revealed the close genetic similarity between C. frutescens and C. chinense species and this group is distantly placed from C. annuum species. Clustering pattern based on RAPD primers for the above 19 genotypes strongly supported the result of SSR analysis with formation of two major clusters viz., one composed of C. annuum type only and the other major cluster comprising both species viz., C. frutescens and C. chinense. Dendrogram constructed based on RAPD and SSR banding pattern also substantiated above result by forming mono-specific C. annuum clusters and clusters comprising accessions from both species viz., C. frutescens and C. chinese. Both RAPD and SSR analysis points to the close similarity among the released varieties. All the released varieties of C. annuum type are grouped in to the same cluster. Combined analysis based on RAPD and SSR data resulted in the formation of two major clusters viz., first cluster comprising of only released varieties and second of landraces. Compared to separate RAPD or SSR characterization, combined analysis based on RAPD and SSR data more precisely assigned accessions into corresponding species specific clusters and formed mono-specific clusters. At 70 per cent similarity level, combined RAPD-SSR analysis expressed 79 per cent accuracy for allotting accessions to species specific clusters. More number of molecular markers improve the accuracy of species alignment and molecular markers serve a complementary role to assist phenetics. Quantity of ascorbic acid ranges from 81.40 to 327.58 mg per 100g of ripe chilly. The upper limit of capsaicin and oleoresin were 0.87 and 23.5 per cent, respectively. Accessions superior in performance to the check varieties for economic and biochemical characters were identified through the agronomic characterization. Majority of the yield contributing characters exhibited high GCV coupled with moderate to high heritability and high genetic gain revealing wide variability contributed by genetic factors and indicating scope for selection. DNA fingerprinting profile of released varieties and elite accessions were developed using SSR primers. Species specific fingerprinting of C. annuum, C. chinense and C. frutescens species were also made for differentiation of species with SSR primers. Validation of taxonomic key carried out integrating characters viz., spot colour at the throat of corolla, annular constriction at calyx, number of flowers per axil, corolla colour, position of flower at anthesis, leaf shape, margin of calyx at fruiting, fruit to pedicel length ratio and level of main stem bifurcation. SSR primers viz., CAMS-101, CAMS-806 and CAMS-864 as well as RAPD primers viz., OPB-10,OPG-02, OPG-03, OPB-08 and OPA-03 identified as promising in identification and differentiation of cultivated species of Capsicum.
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    ThesisItemOpen Access
    Introgression of mosaic resistance in popular short duration cassava varieties of Kerala through marker assisted selection
    (Deparment of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2018) Darshan, S; KAU; Arya, K
    The present study entitled “Introgression of mosaic disease resistance in to popular short duration cassava varieties of Kerala through marker assisted breeding”was conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, Kerala Agricultural University and Division of Crop Improvement, ICAR- Central Tuber Crops research Institute, Sreekariyam, Thiruvananthapuram, Kerala during the period 2014 - 2017 with the core objective of introgression of cassava mosaic disease (CMD) resistance to short duration varieties of cassava through marker assisted selection (MAS) and to study the inheritance of early bulking nature. The research work was carried out as four experiments. In the first experiment, Five early bulking high yielding lines viz, Sree Jaya, Sree Vijaya, Vellayani Hraswa, CI 889 and 9S 75 and three testers viz, CR 54A3, IMS2-5 and CI 273 with resistance to cassava mosaic disease were selected and planted in a pollination block and crossed in Line x Tester (LxT) design to produce hybrid seeds of 15 F1 combinations. Experiment II was conducted in two parts. Screening of F1 seedlings for CMD resistance and early bulking nature was carried out in the first part of experiment II, where hybrids along with the parents were evaluated. Analysis of variance revealed significant differences among the genotypes for all the traits studied. All the agronomic traits were recorded and inheritance of early bulking and its correlation with other traits were studied. The CMD incidence expressed significant and negative correlation with tuber yield per plant where as significant and positive correlation for all other traits with tuber yield per plant was observed among the F1’s. As a part of experiment II (b), seedlings without the CMD visual symptoms were subjected to multiplex PCR and the results revealed that among the parents Sree Jaya, Sree Vijaya, Vellayani Hraswa expressed presence of Srilankan Cassava mosaic Virus (SLCMV) and Vellayani Hraswa expressed the presence of both SLCMV and Indian Cassava mosaic Virus (ICMV). Among the crosses, Sree Jaya x CR54 A3 (L1x T1), Sree Jaya x IMS2-5 (L1xT2), Vellayani Hraswa x IMS2-5 (L3xT2), CI 889 x CI 273 (L4xT3) expressed the presence of SLCMV. Real time PCR (qPCR) assay for seedlings identified CI 889 (L4), 9S 75(L5), CR 54A3 (T1), IMS2-5 (T2) and CI 273(T3) among the parents and Sree Jaya x CR54 A3 (L1x T1), Sree Jaya x IMS2-5 (L1xT2), Sree Jaya x CI 273(L1x T3) and 9S 75 x CR54 A3 (L5x T1), 9S 75 x IMS2-5 (L5xT2) and 9S 75 x CI 273 (L5x T3) among the crosses as highly resistant, based on viral load present in the DNA sample. Based on the previous report ten CMD resistance linked markers were screened through BSA and five of which SSRY 28, SSRY 44 SSRY 40, SSRY 106 and SSRY 235 were selected. Among the CMD linked SSR markers studied, the maximum polymorphism was elucidated by SSRY 28, SSRY 44 and followed by SSRY 235. SSRY 28 is a strongly linked marker to CMD2 which is a dominant gene conferring resistance among the clones of combinations (L1xT1, L2xT2, L3xT1 and L3xT3) three of five markers revealed alleles associated with CMD2 gene In the third experiment to evaluate the early bulking clones, field was laid out in randomized block design (RBD) with three replications consisting of CMD resistant clones along with parental clones using miniset technique. Analysis of variance revealed significant differences among the genotypes for all the traits. Measurement of heterosis was carried out considering parent Vellayani Hraswa (L3) as check and results revealed that standard heterosis was positive and significant in the combinations Sree Jaya x CR 54A3 (L1xT1) and Sree Jaya x CI 273 (L1xT3) for all the yield contributing traits. The crosses Sree Jaya x CR54 A3 (L1x T1) and Sree Jaya x CI 273 (L1xT3) exhibited negative standard heterosis for CMD. Combining ability analysis showed significant gca, sca variances and gca, sca effects for all the traits. Moreover gca/sca variance ratio indicated preponderance of dominance / non-additive gene action for the inheritance of all traits. Among the lines, Sree Jaya (L1) exhibited positive and significant gcaeffect for tuber yield and yield contributing traits. Among the testers, IMS2-5 (T2) exhibited negative and significant gca effect for CMD. Among the crosses Sree Jaya x CR54 A3 (L1x T1) exhibited positive and significant scaeffect for girth of tuber and stem girth, 9S 75 x CI 273 (L5xT3) exhibited positive and significant scaeffect for tuber yield per plant, CI 889 x CR 54A3 (L4xT1) exhibited negative and significant scaeffect for CMD. In the last experiment, through bulk segregants analysis using 5 SSR markers linked to early bulking in cassava were selected out of 9 SSR markers selected. Among 5 SSR markers of CMD and early bulking nature two SSR markers (SSRY 28 and SSRY 106) associated with resistance to CMD and One SSR marker, ESTs (SSRY) 292 associated to early bulking nature has been identified. Among the crosses, clones from Sree Jaya x CR54 A3 (L1xT1), Sree Jaya x CI 273 (L1x T3) and 9S 75 x CR 54A3 (L5xT1) are being confirmed with CMD resistance as well as early bulking nature.
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    ThesisItemOpen Access
    Stability analysis and molecular characterization of F1 hybrids in brinjal (Solanum melongena L.)
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2018) Kavishetti Vinay, Vishwanath; KAU; Lekha Rani, C
    Stability analysis helps in assessing genotype × environment interaction in order to identify stable genotypes in large multi-environment trials. Therefore the present study entitled “Stability analysis and molecular characterization of F1 hybrids in brinjal (Solanum melongena L.)” was carried out to evaluate ten hybrids along with one check across four locations. The locations selected for trials were College of Agriculture, Vellayani and farmer’s fields at Thiruvalla, Sadanandapuram and Kayamkulam in Kerala. The trial seasons were kharif (2015- 16) and summer (2016-17). The objective was to study the performance of superior hybrids over different locations and seasons from heterotic crosses of brinjal and to confirm the hybridity using SSR markers. Randomized block design with four replications was employed. Stability and adaptability of yield and yield attributing characters of hybrids were analysed by Eberhart-Russell model (1966). Pooled analysis of variance revealed significant differences among the genotypes, environments and genotype × environment interaction for all the characters studied. The indication was that the hybrids responded differently to changes in the environment. Promising hybrids were identified on the basis of stability parameters viz., overall mean, regression coefficient (bi) and deviation from regression (S2di). In kharif season, the hybrid Wardha local × Palakurthi local was observed to be stable and widely adapted to all environments for days to first flowering, number of fruits plant-1, fruit weight, fruit length, fruit girth, calyx length, yield plant-1, yield plot-1 and plant height. The hybrid Wardha local × Swetha was identified as stable with regard to fruit weight, yield plant-1 and yield plot-1. The hybrid Wardha local × Vellayani local was identified as stable for favourable environments with regard to fruit length, yield plant-1 and yield plot-1. The hybrid Surya × Vellayani local was found stable for poor environments with regard to days to first flowering. Stability analysis for the summer season crop also revealed the hybrid Wardha local × Palakurthi local as stable across all environments with respect to days to first flowering, days to first harvest, number of fruits plant-1, fruit weight, fruit length and yield plant-1. Swetha × Vellayani local hybrid was stable across all environments with regard to days to first harvest, fruit weight, fruit length, calyx length, yield plant-1, yield plot-1 and plant height. The hybrid Surya × NBR-38 was found stable with respect to yield plant-1, yield plot-1 and plant height for favourable environments. Qualitative characters viz., total phenols, total sugars and vitamin C content and biotic stress traits viz., shoot and fruit borer infestation and bacterial wilt incidence were recorded for the eleven hybrids in kharif and summer season in all four locations. On the basis of overall mean performance of hybrids, results illustrated that the hybrid Swetha × Vellayani local recorded the highest values for total phenols and the hybrid NBR-38 × Vellayani local recorded the lowest values. Total sugar content was highest in Wardha local × Swetha and NBR-38 × Selection Pooja and lowest in Surya × NBR-38. The hybrid Neelima and Swetha × Vellayani local recorded higher quantity of vitamin C and NBR-38 × Vellayani local and NBR-38 × Selection Pooja recorded the lowest values. The hybrids Wardha local × Palakurthi local, Swetha × Vellayani local and Neelima recorded minimum infestation of shoot and fruit borer and was found resistant to bacterial wilt also. Hybrids and their parental lines were characterized using SSR markers. Among the four markers studied, three markers viz., emb01M15, eme08D09 and CSM31 were found to be polymorphic among the parental lines of respective hybrids viz., Surya × NBR-38, Surya × Vellayani local, NBR-38 × Selection Pooja, Swetha × Vellayani local, Wardha local × Swetha, Wardha local × Palakurthi local, Palakurthi local × Vellayani local and NBR-38 × Vellayani local which could be used for ensuring the genetic purity of respective parental lines and hybrids. F2 families viz., Wardha local × Palakurthi local, Wardha local × Swetha, Wardha local × Vellayani local and Swetha × Vellayani local were selected on the basis of yield performance from F1 for further evaluation. F2 populations revealed that family Wardha local × Palakurthi local and Wardha local × Vellayani local were superior in yield performance and yield attributing characters. The present investigation revealed that the hybrids Wardha local × Palakurthi local and Swetha × Vellayani local were stable and widely adapted over different locations and seasons and the hybridity was confirmed with the SSR markers, emb01M15 and eme08D09.
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    ThesisItemOpen Access
    Induced mutagenesis for delayed flowering and high tillering in guinea grass (Panicum maximum Jacq.)
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2018) Sudrik Bibhishan, Popat; KAU; Mareen Abraham
    The present investigation entitled “Induced mutagenesis for delayed flowering and high tillering in guinea grass (Panicum maximum Jacq.)”, was carried out at College of Agriculture, Vellayani during the period 2014-2017. The major objective of the study was to develop high yielding guinea grass types with delayed flowering and high tillering through induced mutagenesis. The first experiment consisted of evaluation and characterization of germplasm accessions of guinea grass. For assessing genetic variability and diversity, thirty seven germplasm accessions were studied with respect to fourteen morphological and three biochemical characters. ANOVA revealed highly significant differences among the genotypes for all the traits analysed except length of internode. High estimates of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were obtained for green fodder yield, dry fodder yield, leaf stem ratio, weight of seeds hill-1 and gibberellic acid content and high PCV and moderate GCV were obtained for leaf area index, number of tillers hill-1, number of leaves hill-1 and number of panicles hill-1. Moderate values of PCV and GCV were obtained for crude protein content and crude fibre content. High heritability coupled with high genetic advance as percent of mean was observed for number of tillers hill - 1 , leaf stem ratio, weight of seeds hill-1, crude protein content, crude fibre content and gibberellic acid content. High heritability coupled with moderate genetic advance as percent of mean was observed for days to flowering and length of panicle. Moderate heritability coupled with high genetic advance as percent of mean was observed for number of leaves hill-1, number of panicles hill-1 and green fodder yield. Green fodder yield showed significant positive correlation with dry fodder yield and weight of seeds hill -1 at phenotypic level. Green fodder yield showed significant positive correlation with dry fodder yield, weight of seeds hill-1 and crude fibre content at genotypic level. Path coefficient analysis revealed that green fodder yield showed high positive direct effect on dry fodder yield followed by length of panicle, weight of seeds hill-1, plant height and leaf stem ratio. Based on observations four varieties viz. two early flowering (FP-553, MS-4690) and two late flowering (PGG-208, MS- 4600) were selected for further studies. The second experiment included induced mutagenesis using physical mutagens on seeds and slips. The physical mutagen used was gamma rays from 60Co source and the initial trial was for fixing LD50 value. For this, seeds of four varieties viz., FP-553, MS-4600, MS- 4690 and PGG-208 were treated with six doses of gamma rays ranging from 60 to 140 Gy along with control. The effects of gamma rays were studied on different parameters such as germination percent, seedling height and survival in M1 generation. Reduction of germination, seeding height and survival were studied. Accordingly LD50 doses were fixed and three doses 60, 80 and 100 Gy were administered to the seeds of four different varieties and field planting of M1 was done. M1 was evaluated for fifteen morphological characters. Statistical analysis of quantitative characters showed that for an increase in gamma ray doses, a proportionate significant increase for various plant growth parameters was evident. Occurrence of major viable mutants from seedling to adult growth stages varied viz., broad and narrow leaves, paired panicle, early and late maturity, dwarf and tall plants, low and high number of tillers and leaves hill-1, short and long internode. Mutagenesis by gamma ray irradiation was employed to treat slips of four genotypes viz., FP-553, MS-4600, MS-4690 and PGG-208. They were treated with six doses of gamma ray ranging from 20 to 100 Gy along with control for fixing LD50 value. The effects of the irradiation doses were studied on regeneration, survival of shoots and height of plants. Based on LD50 value, three doses 20, 40 and 60 Gy were administered along with control to the different varieties and field planting of M1V1 was done. M1V1 were evaluated for fifteen morphological characters. Most of quantitative characters showed an increase in mean values with increase in doses of mutagen. Analysis of data showed that all characters studied were significantly affected by irradiation at 60 Gy. The third experiment was the study of frequency and spectrum of chlorophyll and viable mutants, mutagenic efficiency and effectiveness in M2 generation while employing the three doses of gamma rays and one control. In general the frequencies of chlorophyll mutations increased in linear fashion at low (60 Gy) and medium (80 Gy) doses and the frequency was erratic at higher (100 Gy) doses. The spectrum of chlorophyll mutants included albina and xantha. The highest frequency of viable mutants was produced at 60 Gy dose. There were variations in the occurrence of major viable mutants during the crop growth period stages viz., broad and narrow leaves, paired panicle, days to maturity, dwarf and tall plants, high and low tillering with variations in number of leaves hill-1, short and long internode, plant height, protein content, fibre content and gibberellic acid content. In the M1V2 generation, the chlorophyll mutation frequency increased in a linear fashion at low (20 Gy) and medium (40 Gy) doses and was erratic at higher doses (60 Gy). The chlorophyll mutant spectrum included albino and xantha. The frequency of these mutants varied with treatments. Superior plants with high green fodder yield as a result of increased number of tillers ranging from 37-42 were observed in 60 Gy populations of MS-4600 and PGG-208 when compared to the control (30-32 tillers). Based on single plant performance, plants which recorded high biomass were identified and M1V2 slips were collected and studied in further generations. The mutagenic treatments were effective in inducing various types of chlorophyll and morphological mutants, such as those with significant change in days to flowering, plant height, leaf mutations (narrow, broad, wrinkled); panicle mutations (twin panicle, compact, spread) and biochemical variations in protein content, fibre content and gibberellic acid content. The fourth experiment was the study of M3 and M1V3 generation. The altered morphological traits were stable as shown by their growth performance in different seasons. The mutagenic treatments were effective in inducing both qualitative and quantitative characters. Tall mutants with delayed flowering, high green fodder and dry fodder yield displayed two fold increase in number of tillers and leaves hill-1 compared to control at 60 Gy irradiation. Considerable variation was observed with regard to leaf stem ratio at 60 Gy from slips. To conclude genetic variability was found to be high among the genotypes of guinea grass. Gibberellic acid content was found to vary with genotypes. Genotypes with late flowering habit had low gibberellic acid content. Gamma rays induced variations in both seeds and slips for plant height, days to flowering, number of tillers hill-1, number of leaves hill-1, green fodder yield, crude protein content and gibberellic acid content at dose of 60 Gy. The study yielded mutants with delayed flowering and high tillering which were found to be stable in growth performance in M3 and M1V3. These stable genotypes could be carried forward to develop better varieties.
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    ThesisItemOpen Access
    Identification of Potential Donors for superior fruit quality traits and genes for resistance to tomato leaf curl virus (ToLCV) In tomato and allied species
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Nadkarni Siddhesh, Raghvehdra; KAU; Jayalekshmy, V G
    The study entitled ‘‘Identification of potential donors for superior fruit quality traits and genes for resistance to tomato leaf curl virus (ToLCV) in tomato and allied species’’ was conducted during the period 2014-2017, in the Department of Plant Breeding and Genetics, Vellayani with an objective of evaluating varieties and allied species of tomato for fruit quality traits and genes for resistance to ToLCV through biochemical analysis and molecular markers and to study compatibility for hybridization and seed set to transfer ToLCV genes to bacterial wilt resistant variety ‘’Anagha’’ from donors of related species. Thirty-four genotypes including allied species of tomato were collected from different sources and studied under four different experiments. First experiment was screening of thirty-four genotypes under natural field condition for tomato leaf curl virus resistance in summer season and scoring for ToLCV by the scale given by Banerjee and Kalloo (1987). Eight genotypes viz., EC 541109 (Solanum pimpinellifolium L.) EC 168283 (Solanum pimpinellifolium L.), IIHR1970 (Solanum peruvianum L.) and LA 2805 (Solanum lycopersicum var. cerasiforme L.), IIHR 2372, IIHR 2200, Vaibhav and Nandi were found to be highly resistant. The scions of these eight highly resistant genotypes were grafted on susceptible root stock with ToLCV symptoms. The scions did not take symptoms after 25 days confirming the resistance of the genotypes. Evaluation of thirty-four genotypes for yield and fruit quality parameters was carried out in field condition during rabi season. The analysis of variance revealed significant difference for all seventeen quantitative and fruit quality attributes. On the basis of mean performance for different yield characters, genotypes viz., Vaibhav, EC 320574, EC 165751, EC 164656 and EC 16786 were superior, whereas genotypes EC 541109, IIHR 2372, Vaibhav and LA 2805 were superior for fruit quality traits. The wild species used in the study had high content of carotene, lycopene and TSS. From coefficient of variation it was evident that the estimates of GCV were higher than the corresponding PCV for all seventeen quantitative attributes indicating the less influence of environment on the expression of these genotypes. The estimates of GCV and PCV were higher for seven characters indicating the existence of high variability in the material studied offering ample scope for selection. Heritability estimates and genetic advance as per cent of mean (GAM) were high for all characters indicating predominance of additive gene action for these characters. Phenotypic and genotypic correlation coefficient analysis with respect to weight of fruits per plant-1 showed positive significant correlation with plant height, number of primary branches plant-1, spread of the plant, number of days to 50% flowering, number of days to first fruit harvest, number of fruits plant-1, weight of fruit and volume of fruit. Path analysis confirmed that direct effect on number of fruits plant-1 expressed highest positive direct effect on weight of fruits plant-1, followed by weight of fruit, spread of the plant, lycopene content, number of primary branches plant-1, number of days to 50% flowering and number of days to first fruit harvest. Molecular markers linked to the three genes Ty2, Ty3 and Ty3a specific to ToLCV resistance were validated with thirty-four genotypes. Genotypes IIHR 2200, Vaibhav and EC168283 (Solanum pimpenellifolium L.) showed the presence of Ty2 gene and genotype IIHR 1970 (Solanum peruvianum L.) showed the presence of Ty3a gene. The identified resistant lines were crossed with ‘‘Anagha’’ the popular bacterial resistant variety with an objective to transfer the resistance. All the seven successful hybrid combinations showed 100% pollen fertility confirming the compatibility of the parents. Evaluation of seven hybrids with parents revealed significant difference for all seventeen quantitative and fruit quality attributes. On the basis of mean performance for different yield and fruit quality traits in hybrids viz., L1 x T1 (Anagha x Vaibhav) showed superiority for characters like weight of fruits plant-1, weight of fruit, volume of fruit, pH of juice and shelf life, L1 x T5 (Anagha x EC 541109) showed superiority for characters like plant height, number of primary branches, lycopene content, TSS %, and carotene content, L1 x T2 (Anagha x Nandi) showed earliness in number of days to 50% flowering and number of days to first fruit harvest, L1 x T4 (Anagha x IIHR 2372) showed superiority for traits like pericarp thickness and vitamin C. Seven hybrids were screened and scored for ToLCV, in natural field conditions. Highly resistant reaction was found in four hybrids viz., L1 x T3 (Anagha x EC 168283), L1 x T5 (Anagha x EC 541109), L1 x T6 (Anagha x IIHR 2200), L1 x T7 (Anagha x LA 2805). This study could identify resistance sources for ToLCV viz., EC 541109, EC 168283, IIHR1970, LA 2805, IIHR 2372, IIHR 2200, Vaibhav and Nandi. The genotypes Vaibhav, EC 320574, EC 165751, EC 164656, EC 16786, EC 541109, IIHR 2372 and LA 2805 which showed superiority in yield and fruit quality traits can be used for breeding for improvement of yield and quality traits. The wild species which are found compatible with cultivated species can be used as donors for quality traits as well as resistance. The hybrid L1 x T1 (Anagha x Vaibhav) with superior yield traits and resistance to ToLCV can be recommended for release after yield trials. Hybrid L1 x T5 (Anagha x EC 541109) an interspecific hybrid with superior fruit quality traits can be recommended for release as cherry tomato after trials. The segregating population of interspecific crosses can be used for further evaluation to locate plant types with good yield, fruit quality along with resistance to ToLCV.
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    ThesisItemOpen Access
    Development of near isogenic lines of rice variety 'uma' for blast resistance genes through molecular marker assisted backcross breeding
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Harikrishnan, P J; KAU; Jayalekshmy, V G
    Blast disease, caused by Magnaporthe oryzae is one of the most devastating diseases in rice and is a great threat to food security worldwide. During kharif season, the disease is prevalent throughout the rice growing areas in India including the southern states of Kerala, Tamil Nadu, Karnataka and Andhra Pradesh. Approximately 100 major blast resistance genes have been reported in rice and hence exploitation of host plant resistance through gene pyramiding can be employed effectively for the management of blast. Developing Near Isogenic Lines (NILs) ie., lines carrying each of the major resistance genes in the background of susceptible recurrent parent is a major step in the pyramiding work to be carried out for developing multi race resistant varieties. So, the present study entitled “Development of Near Isogenic Lines of rice variety „Uma‟ for blast resistance genes through molecular marker assisted backcross breeding” was undertaken at the College of Agriculture, Vellayani Thiruvananthapuram, to develop Near Isogenic lines (NILs) of rice variety Uma for blast resistance genes (Pi1, Pi2 and Pikh) using identified donors through marker assisted back cross breeding. DNA markers closely linked to the blast resistance genes viz., RM527 (Pi2 gene), RM224 (Pi1 gene) and RM206 (Pikh gene) were used for validating marker polymorphism in the identified traditional donors of blast resistance genes viz. PTB21 (Thekkan) with Pi2, PTB7 (Parambuvattan) with Pi1 and Pikh and susceptible recipient parent Uma (MO16). This validation confirmed the absence of genes in the recipient parent, „Uma‟. These polymorphic gene specific markers were used for foreground selection in F1, BC1F1 and BC2F1 plants. Hybridisation was carried out between recipient parent Uma and the two donor parents viz., PTB21 and PTB7 to transfer genes for resistance. F1 plants with heterozygous loci for blast resistance genes specific markers were identified through foreground selection and backcrossed with „Uma‟ the recurrent parent to obtain the BC1F1 generation. The BC1F1 plants were screened with foreground markers and those plants containing the respective resistance genes were identified. Among the plants screened for a particular cross, 12 were found to contain Pi2 gene, 17 had Pi1 gene and 21 plants contained Pikh gene. χ2 test was done with the genotypic data of BC1F1 plants with single genes viz. Pi1, Pi2 and Pikh. Segregation ratio in BC1F1 population from all the crosses except Uma x PTB7 (Pi1) did not show significant deviation from the expected 1:1 ratio suggesting the presence of segregation distortion in the segregants of the cross Uma x PTB7 (Pi1). For the background selection, three parental lines were genotyped with 30 microsatellite loci and the ones polymorphic for Uma and the donors were identified. Twelve markers were found to produce discrete amplicons for distinguishing Uma and PTB21 while 17 markers could distinguish Uma and PTB7. Five of the polymorphic markers were used for background selection in BC1F1 plants with resistance genes of the three crosses. The BC1F1 plants with highest percentage of recurrent parent genome recovery in the three populations were identified. Highest recovery percentage of 70 could be obtained in backcross population of all the three crosses. Morphological data for seven quantitative and one qualitative character (kernel colour) was recorded for the BC1F1 plants with the resistant genes. Euclidean coefficient of dissimilarity was assessed in comparison with the recurrent parent Uma. The Euclidean distance values ranged from 5.9 (A-21) to 21.3 (A-9) in the cross Uma x PTB21 (Pi2), 4.88 (B-8) to 17.8 (B-23) in Uma x PTB7 (Pi1) and from 4.79 (C-34) to 13 (C-15) in case of Uma x PTB7 (Pikh). All the BC1F1 plants with resistance genes were used to raise the BC2F1 generation. The BC2F1 populations of the three crosses were subjected to foreground selection and plants with resistance genes were identified. Background selection was carried out in BC2F1 plants with resistance genes using 12 polymorphic markers in the cross Uma x PTB 21 (Pi2) and 17 markers in plants identified in the BC2F1 of Uma x PTB7 (Pi1 and Pikh). Percentage of recurrent parent genome recovery ranged from 70.83 to 95.83 for the cross Uma x PTB21 (Pi2), 70.59 to 97.06 for Uma x PTB7 (Pi1) and from 61.76 to 94.12 for Uma x PTB7 (Pikh). Euclidean coefficient of dissimilarity was assessed in comparison with the recurrent parent Uma, based on seven quantitative traits (plant height, number of tillers number of productive tillers, panicle length, grain L/B ratio, thousand grain weight and days to maturity) in the BC2F1 plants with resistance genes. The lowest values of Euclidean distance were recorded in the plants A-16-6 (2.24), B-18-2 (3.35) and C-17-3 (4.33) of the three backcross populations respectively. Based on the Euclidean distance and percentage recovery of the recurrent parent genome, five plants were identified from each of the three crosses as potential Near Isogenic Lines (NILs) for the three blast resistance genes Pi2, Pi1 and Pikh. The genotype A-5-1 with a recurrent parent genome recovery of 95.83% and Euclidean distance of 5.55 with Uma was identified as the most potential NIL of Uma for the gene Pi2. Similarly B-27-1 (Euclidean distance – 4.56, % genome recovery - 97.06) and C-17-3 (Euclidean distance - 4.33, % genome recovery - 94.12) were identified as potential NILs for Pi1 and Pikh genes respectively. Selfed seeds (BC2F2) were collected from the identified potential NILs. The present research could identify NILs of Uma for three blast resistance genes viz., Pi1, Pi2 and Pikh with more than 94% recurrent parent genome recovery with two backcrossing through marker assisted selection. This confirms the utility of marker assisted backcross breeding in recurrent parent genome recovery. The NILs can be used in intermating programmes in future to develop pyramided lines of Uma with all the three blast resistance genes (Pi1, Pi2 and Pikh) to ensure high yielding ability and durable broad spectrum resistance to the blast pathogen.