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2011 - 2019202020 - 20232
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Subject: Plant Breeding × Author: KAU × Start date: 2011 × Thesis Type: Ph.D ×
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    Genetic diversity analysis for nutrient efficiency and identification of nutrient responsive genes in cassava (Manihot esculenta Crantz)
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2023-02-10) Swathy Sivan; KAU; Arya, K
    The present study entitled “Genetic diversity analysis for nutrient efficiency and identification of nutrient responsive genes in cassava (Manihot esculenta Crantz)” was carried out in the Department of Plant breeding and Genetics, College of Agriculture, Vellayani and Division of Crop Improvement, ICAR-CTCRI, Sreekariyam, during 2019-2022. The study was undertaken to screen and characterize N and K-efficient genotypes in cassava and identify the traits contributing to nutrient efficiency and study their gene expression. Thirty genotypes of cassava comprising of landraces, released varieties and pre-release accessions from ICAR-CTCRI and KAU were taken for the study. Field evaluation was done to identify low input nutrient efficient lines where analysis of variance revealed significant difference among the genotypes for all the characters studied except the girth of tuber. High GCV, PCV, heritability and genetic advance were observed for traits like tuber yield, N and K efficiency, plant height, number of leaves, number of branches, stem N and K content. Tuber yield was positively correlated to N and K efficiency, plant height, leaf and stem weight, stem girth, mean weight of tubers, number of nodes, girth and length of tubers, while negatively correlated to tuber starch and dry matter content. Path analysis showed that tuber length gave highest positive direct effect on yield followed by number of tubers, number of leaves, tuber starch content, plant height and nitrogen efficiency. Diversity studies grouped the genotypes into eleven clusters and the characters that gave the maximum contribution to divergence were tuber dry matter content, N and K efficiency. Root studies on thirty genotypes revealed that root traits like number of nodal roots, basal roots, adventitious roots, storage roots and root length displayed significant positive correlations with N and K efficiency. Evaluation of five highly nutrient efficient genotypes at the three levels of fertilizers (0%, 25% and 50% of the recommended dose of fertilizers) showed overall significance for traits like plant height, the number of leaves retained, stem weight per plant, girth of the stem, tuber yield, length of tuber, stem K content, tuber K content, total N and K uptake, N and K efficiency. The highest yielder was KBH 18 followed by 8S501-2. Maximum N efficiency was observed for KBH18 followed by 15S409, while maximum K efficiency was recorded for 8S501-2 followed by 15S409. Results showed that from 0 to 25 % there is an escalation in tuber yield as well as N and K efficiency, while the values at 25 and 50% are on par. All the selected four genotypes showed significant superiority over the K efficient check variety – Sree Pavithra – in terms of tuber yield, N efficiency and K efficiency. The study identified nine nutrient responsive genes in cassava which includes NRT1, NRT3, NLP1, GPT2, AMT1, TAR2 for nitrogen and KUP3, KUP4, KUP8 for potassium. Expression studies done using these genes in contrasting genotypes for N and K efficiency raised under field conditions showed significant upregulations and downregulations in their expression for efficient and less efficient genotypes. Allele mining for allelic variations in contrasting genotypes (15S409 and Export kappa) for two genes (AMT2 and NTR3) didn’t show much significant variation. Although SNP differences were observed for NRT3 gene, further functional studies are required to confirm this result. The study identified three main nutrient efficient genotypes viz., KBH18, which was the highest yielder, highest in N efficiency and third highest in K efficiency, 8S501-2, which was second highest in yield, highest in K efficiency, third highest in N efficiency and also exhibited early bulking and 15S409, which was the third highest yielder, second highest in N efficiency & K efficiency. The superior genotypes identified in the present study can be subjected to field trials for confirming their superiority and release as a variety.
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    ThesisItemOpen Access
    Characterization and identification of black pepper accessions (Piper nigrum L.) for stress tolerance and quality
    (Department of plant breeding, College of Horticulture, Vellanikkara, 2019) Prakash, K M; KAU; Jiji, Joseph
    Black pepper (Piper nigrum L.), often described as the ‘King of spices’ is the most important spice crop, grown for its berries in the world. Indian pepper is preferred across the globe due to its intrinsic qualities. Foot rot is a devastating disease of black pepper. In the changing climate, drought can be a major threat in black pepper production. Hence, the present study was taken up at College of Horticulture, Vellanikkara and ICAR-IISR, Kozhikode to characterise and to identify superior accessions of black pepper for yield, quality and tolerance to biotic and abiotic stresses. Fifty accessions of black pepper in the bearing stage maintained in the National Active Germplasm Site of ICAR-IISR, Kozhikode formed the base material for the study. The accessions were characterised for fifty qualitative and fifty quantitative characters following the descriptor developed by IPGRI (1995). Wide variability was observed among the accessions for ten qualitative characters. Quantitative characters of shoot, leaf, spike and fruit also showed wide variability. Field tolerance to foot rot disease and pollu beetle infestation was observed among the accessions. Twenty accessions were selected from the base collection based on superiority of yield (> 450g green berries/vine) , field tolerance to foot rot disease infection (biotic susceptibility score 1) and pollu beetle infestation (biotic susceptibility score 1-3). They were further evaluated for biochemical principles of quality, tolerance to foot rot disease under artificial inoculation and tolerance to drought by physiological and biochemical analyses. Piperine, essential oil and oleoresin ranged from 3.61 - 6.96 per cent, 3.00 - 5.87 per cent and 7.10 - 11.18 per cent, respectively, across the accessions. The accessions with high value of piperine, essential oil and oleoresin were identified as 7293, 7211 and 7289 respectively. The two accessions identified viz. 7293 and 7252 contained more piperine than the highest of Panniyur 2 (6.6 per cent) reported among the released varieties . Artificial inoculation of selected accessions using Phytophthora capsici culture for screening for foot rot disease resistance based on over all disease severity index of both stem and leaf lesions showed that accession 7259 was moderately resistant. The selected accessions did not exhibit significant variation for various physiological and biochemical parameters at field capacity. However higher value of photosynthesis, chlorophyll content, chlorophyll stability index, relative water content and membrane stability index and low leaf temperature were observed for accessions viz. 7215, 7240, P 5 and 7241 after five days and ten days of moisture stress induction following field capacity compared to other accessions. Higher values of proline, SOD, catalase and peroxidase were also observed for these accessions. The visual scoring showed that accessions with higher values for most of physiological and biochemical parameters of drought tolerance viz. 7215, 7240, P5, and 7241 had lesser number of fallen leaves and more number of leaves retained at permanent wilting point (PWP). The accessions 7215 and 7240 took twenty days to reach PWP compared to eleven accessions which took only 16 days to reach PWP. Foliar nutrition with sulphate of potash, IISR - Power mix and Pink Pigmented Facultative Methylotrophs (PPFM) had positive effect on drought tolerance for the accessions (7215, 7240, P5 and 7241) having natural tolerance. The identified accessions with high yield , quality and tolerance to biotic or abiotic stress can be used for further breeding programme.
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    ThesisItemOpen Access
    Heterosis breeding in sesame (Sesamum indicum L.).
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2011) Gayathri, G; KAU; Dijee, Bastian
    The study entitled ‘Heterosis breeding in sesame (Sesamum indicum L.)’ was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara. The objectives of the study were to collect and evaluate different genotypes of sesame for morphological traits and yield attributes, to identify useful parents producing heterotic crosses and developing hybrids in sesame. The study also intended to develop male sterile lines in sesame through interspecific hybridization with Sesamum malabaricum. Sesamum indicum and Sesamum malabaricum accessions were collected from Kerala and Tamil Nadu and evaluated for their morphological traits. Wide range of variation was noticed for characters like plant height, number of days to flowering and seed yield per plant which contributed maximum to genetic divergence. The genotypes studied were grouped into six clusters. High genotypic coefficient of variation (GCV) was recorded for number of capsules per plant, plant height, seed yield per plant and number of branches per plant. High heritability with high genetic advance as per cent of mean was recorded for number of days to flowering, plant height, number of branches per plant, number of capsules per plant and seed yield per plant. This indicates that the characters are governed by additive gene effects and selection for these traits will be effective. Association analysis revealed that seed yield per plant was correlated to plant height, number of capsules per plant and number of days to flowering. Path coefficient analysis indicated maximum positive direct effect by number of capsules per plant, capsule length, plant height and 1000 seed weight on seed yield per plant. In order to develop hybrids, fourteen parents were selected based on the per se performance of the genotypes. They were crossed in line X tester mating design. Forty eight hybrid combinations obtained were raised in the field along with the parents and evaluated for their heterosis and combining ability effects. Parental genotypes AVTS-06-5, AVTS-06-10, IVTS-06-12, KYM-1, Tilak and TMV-6 were identified as high combiners based on general combining ability (gca) effects. Two combinations viz. AVTS-06-5 X KYM-1 and IVTS-06-12 X TMV-3 had significant values of per se performance, specific combining ability (sca) effects and standard heterosis for seed yield per plant. They can be evaluated for their hybrid vigour over locations and seasons. The crosses AVTS-06-5 X TMV-3, AVTS-06-5 X TMV-6 and TCR 3279A X KYM-1 have been identified as potential cross combinations for isolation of promising segregants as the parents involved in these crosses had high significant gca effects for seed yield per plant but the hybrids recorded non significant sca effects. Interspecific hybridization between S.malabaricum and S.indicum was attempted to develop male sterile lines. Seed set was noticed in three interspecific hybrids which failed to germinate due to embryo abortion. Hence these embryos were rescued and raised in vitro to obtain the hybrids.
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    ThesisItemOpen Access
    Development of Cytoplasmic male sterile line in an identified rice variety of Kerala through marker assisted back crossing
    (Department of Plant Breeding & Genetics, College of Agriculture, Vellayani, 2019) Tejashree Shivaputra, Lachyan; KAU; Jayalekshmy, V G
    Production and productivity of rice, the staple food for over half of the world's population, is insufficient to meet the demand of the increasing population in the rice consuming nations. One of the readily available and economically viable technological options for meeting the projected global demand of rice is exploitation of heterosis through large-scale cultivation of rice hybrids. The role of hybrids in enhancing the productivity is widely acknowledged. The commercial rice hybrids are currently based on cytoplasmic genic male sterility (CGMS) system. The availability of stable cytoplasmic male sterility and fertility restoring system is vital for commercial exploitation of heterosis in rice. The cytoplasmic male sterile (CMS) lines introduced from China were found unsuitable to use as such in developing hybrid rice in India. Limited resources of CMS and low variation of CMS lines causes genetic vulnerability. Therefore, to diversify CMS lines, breeders can transfer this character to the existing putative maintainer lines through repeated backcrosses. So the present study entitled “Development of cytoplasmic male sterile line in an identified rice variety of Kerala through marker assisted back crossing” was undertaken as an initial step for the development of hybrid rice for Kerala with the objective of transferring the cytoplasmic male sterility from the CMS line to the Kerala rice variety, identified as maintainer for CGMS system through marker assisted back crossing. This study was conducted from December 2016 to August 2019. In the present study, four Kerala rice varieties were used, which were reported as potential maintainers of CRMS31A line in the research work conducted by Das (2017). For identification of the best maintainer among the four potential maintainers under study, these lines were crossed with CMS line CRMS31A. The pollen fertility per cent and spikelet fertility percent of hybrids was lowest in the cross CRMS 31A x Jyothi and highest in the cross CRMS 31A x Aruna. The highest pollen and spikelet fertility percent was observed in cross with Aruna with 60% seed set. Kanchana and Bharathy on crossing with CRMS31A showed 91% and 57% pollen sterility which lead to 99.11% and 74.83% of spikelet sterility respectively. Among 30 F1’s obtained from the cross CRMS31A x Jyothi, two F1 plants showed 99.99% pollen sterility and 100% spikelet sterility. Pollen and spikelet sterility of the hybrids indicated that Kanchana, Bharathy and Aruna were partial maintainers for CMS line. Rice variety Jyothi, alone was identified as maintainer for cytoplasmic male sterile line CRMS31A. The transfer of ms gene was confirmed at molecular level using mitochondrial WA-CMS-specific marker “drrcms”. Foreground selection was carried out in 30 F1 plants and it showed homozygous band similar to male sterile line. F1 plants with 99.99% pollen sterility and 100% spikelet sterility, were backcrossed with maintainer Jyothi to obtain BC1F1 seeds.. These BC1F1plants were screened with cytoplasmic male sterility specific marker and all the plants were identified with gene of interest i.e. cms gene. Selection of polymorphic markers was done for background selection in the identified plants with 100% spikelet sterility. 170 genome wide SSR primers were used for screening of the maintainer and CMS line to locate 31 SSR markers specific to the maintainer. The background selection was carried out on 17 BC1F1 plants using 31 loci polymorphic in the parents. The BC1F1 plants with highest percentage of recurrent parent genome recovery were selected based on the background markers. The maximum percentage of recovery of recurrent parent genome was found to be 68.13% in BC1F1 generation. Pollen sterility in these plants was also studied by screening for fertility restoration gene (Rf). Out of 10 Rf markers used for screening only four markers for Rf4 Rf6 and Rf7 gene were present in the maintainer line Jyothi. The identified markers were then used for screening of BC1F1 plants. It was observed that the BC1F1plants had only Rf7 gene. Pollen and spikelet sterility percent of these plants could not be recorded due to absence of flowering even on the 240th day after sowing. The plants were under vegetative phase upto 260-270 days, after which they started wilting. Due to absence of flowering, these plants were screened with marker specific to flowering time gene Hd3a. On gel documentation the band was obtained revealing the presence of Hd3a gene at 179bp. To confirm the possible reason for absence of flowering even in the presence of Hd3a gene, the expression of Hd3a gene was studied. Expression was studied at different stages of plant growth i.e. 15, 30, 45, 60, 75 and 110 days after sowing in Jyothi variety and 240 days old BC1F1 plants. It was observed that the expression of target gene in the variety Jyothi was reduced at 30 days after sowing. But in later stages, gradual increase in the expression level was observed. A drastic increase in expression was recorded at flowering stage (75DAS) of the Jyothi variety and then the expression was gradually reduced towards maturity stage. Whereas the Hd3a gene was not expressed in BC1F1 plants i.e. the gene was silenced. The reason for non expression of Hd3a gene in the background of sterile cytoplasm and ms gene requires further investigation. Advanced generation of the cross between another CMS line, UPRI95-17A and maintainer line Kanchana, which was developed earlier under a project for transferring male sterility to Kanchana variety was further studied. Sterility was studied by pollen test and spikelet test. Three of the plants showed 99.09% - 100% pollen sterility and 100% spikelet sterility. All the plants were screened with 28 SSR markers. Foreground selection was carried out using mitochondrial WA-CMS-specific marker “drrcms”. Band obtained in the advanced generation plants were similar to the band of male sterile parent. Recovery of the recurrent parent genome was analysed using 28 SSR markers. One plant of this advanced generation, recovered 92.86% of recurrent parent genome. Observations were taken on eight morphological traits viz. plant length, leaf length, leaf breadth, total number of tillers, panicle length, days for flowering, number of spikelets per panicle and pollen fertility percentage. It was observed that out of eight quantitative traits, four traits i.e. plant length, leaf length, total number of tillers and panicle length were almost similar to the maintainer line Kanchana. The number of spikelets per panicle and leaf breadth was less than Kanchana. In the present study, Kerala rice varieties, Jyothi and Kanchana showed 100% pollen and spikelet sterility when crossed with CMS line CRMS 31A and UPRI95-17A respectively. On the basis of pollen and spikelet sterilirty Jyothi and Kancjana were identified as maintainers for WA-CMS line CRMS 31A and UPRI95-17A. The reason for non expression of Hd3a gene in the background of sterile cytoplasm i.e. backcrossed plants of Jyothi variety needs to be further investigated. The identified plants from the backcross population of UPRI95-17A and Kanchana, with higher recurrent parent genome (RPG) recovery percentage can be backcrossed for another generation to get RPG of 99%. Later it can be used for commercial hybrid seed production with compatible restorers for UPRI95-17A. This will be the first CMS line in the background of Kerala rice variety.
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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.