PG Thesis
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/2
Browse
10 results
Search Results
Item Genetic diversity analysis of horse gram [Macrotyloma uniflorum (Lam.) Verdc.] for moisture stress tolerance in south central laterites of Kerala(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2022) Visakh, R L; Bindu, M RThe study entitled “Genetic diversity analysis of horse gram [Macrotyloma uniflorum (Lam.) Verdc.] for moisture stress tolerance in south central laterites of Kerala” was carried out at Farming Systems Research station, Sadanandapuram during October, 2020 – March, 2021 with the objective to identify superior genotypes of horse gram with moisture stress tolerance having high yield and quality, suitable for south central laterites of Kerala. The 30 horse gram genotypes collected from RARS Pattambi under KAU and other SAUs were evaluated for moisture stress tolerance at seedling stage in laboratory using two different concentrations of PEG 6000 (10% and 20%), in factorial completely randomized design replicated thrice. These 30 genotypes were further evaluated for water stress tolerance in field by withholding irrigation for 15 days at reproductive stage, in randomized block design replicated thrice. The seeds were sown on raised beds of 2.25 m2 size at a spacing of 30 cm х 30 cm and cultural operations were adopted as per the “Package of Practices Recommendations Crops 2016” of Kerala Agricultural University. The soil moisture was also measured during water stress-imposed period at weekly interval by following gravimetric method. In laboratory experiment, genotypes were evaluated for six different morphophysiological characters and in field experiment, genotypes were evaluated for 31 characters which included biometric, physiological, biochemical and seed quality characters. The genotypes showed significant differences for all the characters studied. Genetic parameter analysis was performed for nineteen characters and for all the characters PCV values were higher than GCV values indicating the influence of environment. High heritability coupled with high GAM was observed in days to 50% flowering, number of primary branches per plant, plant height, number of pods per plant, haulm yield per plant, harvest index, days to maturity, leaf area index, total phenol content of the seed, root dry weight, proline content, total chlorophyll content and seed yield per plant. 124 The correlation studies revealed significant positive correlation of the characters RWC, number of pods per plant, number of seeds per pod, total chlorophyll content, harvest index, proline content, root dry weight, root length, LAI and hundred seed weight with seed yield. However, days to 50% flowering, days to maturity, plant height and number of primary branches showed a significant negative correlation with yield. Path analysis of the thirteen characters showing significant correlation with seed yield revealed high positive direct effect of the number of pods per plant on seed yield. High indirect effect on yield was observed for number of seeds per pod through number of pods per plant. Genetic divergence analysis using Mahanalobis D2 statistic following Tocher’s method grouped the 30 genotypes into four clusters. Cluster II with 14 genotypes was the largest followed by cluster I (9 genotypes), cluster III (6 genotypes) and clusters IV was solitary cluster. Highest intra cluster distance was recorded among the genotypes of cluster II and lowest in cluster IV whereas highest inter cluster distance was observed between the genotypes of the clusters I and III, while lowest inter cluster distance was between the genotypes of the clusters III and IV. The present study revealed that the genotypes IC71841, IC139464 and IC22785 as water stress tolerant ones in laboratory experiment and in field experiment, genotypes IC22785, IC221105, IC22759 and IC139464 were identified as high yielding and moisture stress tolerant ones. The superior genotypes identified in the study can be recommended for cultivation and future breeding programs.Item Performance evaluation of ecotypes of banana (Musa AAB plantain subgroup)(Department of Pomology and Floriculture, College of Agriculture, Vellayani, 2017) Annjoe Joseph, V; Simi, SItem Genetic diversity analysis of indigenous rice varieties in Kerala using molecular markers(Department of Plant Pathology, College of Agriculture, Vellayani, 2019) Ajith, M K; Jayalekshmy, V GThe present study entitled “Genetic diversity analysis of indigenous rice varieties in Kerala using molecular markers “was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, Thiruvananthapuram during 2017-2018. The study was conducted with the objective to analyze the genetic diversity of traditional rice varieties in four agro climatic zones of Kerala using RAPD and SSR markers. Five varieties were collected from the each agro climatic zones viz., hill areas of Wayanad, rice growing tract of Palakkad, saline soils of Pokkali and Kuttanad soils. The DNA was isolated and RAPD analysis with 10 Operon primers and SSR analysis was done with ten RM primers. In the RAPD analysis the ten operon primers produced 88 amplicons with an average polymorphism 82%. Resolving power OPC-07 (15.4) had the highest value but its Polymorphism Information Content and Effective Multiplication Ratio (EMR) were considerably low. Considering all the three parameters together primer OPF-06 is found to be the best RAPD primer with considerably high polymorphism information content, resolving power and effective multiplication ratio. The dendrogram constructed based on the RAPD scoring showed that varieties Pokkali and VTL-2 had maximum similarity. These two were from Pokkali rice tract. PTB 12 from Pattambi was found to be unique and it clustered with others only at 30% similarity.The clustering of the genotypes did not show any correlation with the geographic origin. ABL 12 and VTL- 2 showed 70 % similarity but those two were from Wayanad Hills and Pokkali tract respectively. Vellakuttadan from Moncombu clustered with PTB 2 from pattambi at 72% a similarity. Kochuvith and Vellakuttadan from Moncombu clustered at 67 %. All the SSR markers produced two alleles except RM 210 and RM 204 which produced four alleles and one allele respectively. All the alleles of all the markers were polymorphic except that of primer RM204. The polymorphism information content of the SSR primers used in the study ranged from 0 to 0.88. In this study the highest PIC value of 0.88 was reported by RM 210 followed by RM 567 (0.85). The resolving power and EMR was also highest for RM 210. The dendrogram constructed based on the SSR markers could give a clustering of genotypes more correlated with the geographic origin. Genotypes Kochuvithu and Vellakuttadan showed 100 % similarity both where from Kuttanad. But Karavalakochuvith, T.virippu, and PTB 2 also showed 100% similarity but these three were from Moncompu, Pokkali and Palakkad respectively. At around 90 % similarity AMB 14, AMB 22 from Wayanad, Pokkali andVTL-2 from Pokkali, PTB 13 and PTB 8 from Palakkad clustered showing more correlation to the Geographic origin. SSR markers being sequence specific and flanking the repeat sequence which has more role in evolution, are more reliable in predicting the Genetic diversity based on origin. Since both of them could not give a clear-cut clustering based on geographic origin an analysis using both the markers together was done. This gave a better picture of the clustering as it involved more number of variables. But here also the varieties from Wayanad A1 to A5 were scattered in different clusters. Only A 14 and A15 (AMB 14 and AMB 5) clustered at 60 percentage similarity. The accessions from moncompu (A6-A10) clustered at around 50 % similarity. In the accession from Pokkali tract (A11-A15) only T.virippu to VTL-2 clustered at 78 % similarity. Accession from central zone Pattambi (A16-A20) was scattered into different clusters. PTB 12 was unique from other accessions. This molecular diversity analysis of the traditional rice genotypes from four different agro climatic zones could find that the maximum similarity was 78% and that too only between two accessions. The diversity among the genotypes was 64% as all the genotypes clustered at 36% similarity. The clustering of the genotypes did not show any correlation with the geographic origin. Exchange of varieties between the farmers and some amount of natural crossing would have led to the mixture of populations of rice genotypes in different agro climatic zones.Item IC divergence in coconut(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1982) Balakrishnan, P C; Narayanan Namboodiri, K MA study was conducted at the Regional Agricultural Research Station, Pilicode and in the College of Horticulture, Vellanikkara during 1981-82 with the objectives of assessing the extent of variability present in the 24 cultivars of coconut maintained in the germplasm collection at Pilicode and to assess their genetic divergence using Mahalanobis D2 statistic. All the 24 cultivars were planted during 1924-25, and hence were of the same age group and were receiving the same management practices. Observations on 17 economic characters were recorded from 120 palms at the rate of 5 palms per cultivar. Four observations at quarterly intervals were recorded during the 12 month period of study. The data were subjected to relevant statistical analyses and the results were interpreted.Item Generation mean analysis in yard long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt) for yield and quality(Department of Vegetable Science, College of Agriculture, Vellayani, 2018) Merin Elza George; Sarada, SItem Molecular characterization of rice genotypes having Variability in heat tolerance(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2017) Neethu V Mohan; Beena, RThe study entitled “Molecular characterization of rice genotypes having variability in heat tolerance” was conducted at the Department of Plant Physiology, College of Agriculture, Vellayani, Thiruvananthapuram. Rice (O. sativa) is very sensitive to high temperature especially at the reproductive and grain filling stage which leads to higher spikelet sterility and ultimately yield losses. The present investigation was, therefore, carried out with the objective to study the variation in rice genotypes for heat tolerance using microsatellite markers. In the present study, a set of 50 SSR primers were employed to assess the genetic diversity among the 10 genotypes. Out of 50 markers, 11 markers showed polymorphism, the marker RM6100 was found as a functional marker associated with heat tolerance in rice, and is functional for further crop breeding programmes. A dendrogram was generated with the aim of analyzing the relationships between the 10 genotypes tested. The genetic similarity index ranged from 0.1 to 0.833. The lowest value 0.1was obtained between PTB7 and CR Dhan202 while highest similarity value (0.833) calculated was between the PTB7 and CR Dhan204 genotypes. However, the genetic diversity analysis with SSR markers will contribute to maximize the selection of diverse parents in the future rice breeding program or development of heat tolerant cultivars.Item DNA fingerprinting of released varieties and selected superior somaclones of ginger (Zingiber officinale Rosc)(Centre for plant biotechnology and molecular biology, College of horticulture, Vellanikkara, 2013) Pujaita Ghosh; Shylaja, M RGinger (Zingiber officinale Rosc.), one of the widely cultivated and consumed spices worldwide, is well known for its medicinal properties also. As the natural variability stands limited in the crop, induction of variability through tissue culture techniques was attempted at College of Horticulture, Vellanikkara from 1996 onwards. After indepth investigations on the somaclones regenerated, two varieties viz., “Athira” and “Karthika” were released during 2010 and four clones viz. B3, 292R, 88R and 478R were selected as superior somaclones. For the newly released ginger varieties and selected superior somaclones in pipeline for release, no fingerprint data are available for genotype identification and protecting the plant varieties / clones. The investigations on “DNA fingerprinting of released varieties and selected superior somaclones of ginger (Zingiber officinale Rosc.)” were carried out at the Centre for Plant Biotechnology and Molecular Biology (CPBMB), College of Horticulture, Kerala Agricultural University, Thrissur during the period from January 2012 to March 2013. The objectives of the study were to characterize two released varieties and four selected superior somaclones using molecular markers and to develop a DNA fingerprint specific to each variety / somaclone. Morphological characters like growth habit and size and shape of the rhizomes were found to vary in the varieties / somaclones studied. The somaclone 292R could be distinguished based on its dwarf plant stature and dark green leaves. The variety Athira has bold and flat rhizomes while the variety Karthika has medium bold and round rhizomes. Quantitative clustering for vegetative and rhizome characters attempted as per Mahalanobis D2 analysis could group the varieties and somaclones into three separate clusters. Of the seven vegetative characters analysed, plant height and number of tillers showed more divergence. The number of fingers, girth of primary and secondary fingers, thickness of flesh and inner core were the characters which exhibited more divergence for the rhizome characters. For molecular characterization, good quality genomic DNA extracted from ginger varieties / somaclones using CTAB (Rogers and Bendich, 1994) method was used. Thirty five RAPD and thirty ISSR primers were screened for amplification of genomic DNA and ten RAPD and eleven ISSR primers were selected based on the amplification pattern. DNA fingerprints of the varieties / somaclones were developed utilizing the clear, distinct bands generated in RAPD and ISSR profiles and size of the bands. Different colour codes were assigned for sharing of bands between varieties / clones to generate specific fingerprints. The RAPD marker system could bring out unique bands in the variety Karthika and somaclones B3, 292R and 478R. The RAPD primer, OPA 12 produced unique band in Karthika and B3, the primer OPA 04 in 292R and the primer OPA 28 in 478R. ISSR marker system could also bring out unique band in the variety Athira with primer ISSR 06. The RAPD, ISSR and combined fingerprints developed for each variety / somaclone were unique. Variability in the somaclones and the extent of variability from source parent cultivars were analysed using cluster analysis. The dendrogram seperated Maran and Rio-de-Janeiro somaclones in two separate clusters. Somaclones derived from cultivar Maran exhibited more variability than somaclones from Rio-de- Janeiro. The variety Athira was more diverse from the source parent cultivar Maran. Similarly, the somaclone 292R was more diverse from the source parent cultivar Rio-de-Janeiro. The Resolving Power (Rp) of RAPD and ISSR primers ranged from 6.00 to 16.25, indicating the ability of the selected primers to distinguish the varieties / clones most efficiently. The Polymorphic Information Content (PIC) ranged from 0.67 to 0.88, indicating the suitability of the selected primers for DNA fingerprinting. RAPD, ISSR and combined fingerprints developed specific for the ginger varieties / somaclones could be utilized for registration, documentation of varieties and for settling IPR issues.Item Microsatallite marker based characterization of indigenous pigs of Kerala(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2006) Ariprasath, K; Usha, A PThe study was undertaken to assess the genetic diversity among four indigenous pig population of Kerala using microsatellite markers. The animals were selected from various part of Kerala, population I included the conserved Angamali pigs from university farm, Mannuthy, population II consisted of animals from Koothattukualm, population III were the animals from Ollur and animals from border districts of Kerala formed the population IV. Genetic analysis was carried out using five polymorphic microsatellite markers. Blood samples were collected from 100 unrelated indigenous pigs from all four populations and DNA was isolated. The phenol-chloroform method of extraction yielded 224.35±9.86µg/5ml of blood. PCR conditions were standardized for all five selected markers namely, S0005, S0101, SW1026, SW2517 and S0008. The forward primer of each marker was endlabelled with γ32 P-ATP as source of radio signal. The M13 single strand DNA was sequenced and used as a size standard. Autoradiography was employed to visualize the results. A total of eight alleles were detected in S0005 and S0101, five alleles in each of SW1026 and S0008, and six in SW2517. The heterozygosity varied from 0.7747 in SW2517 to as large as 0.8475 for S0005. The heterozygosity values for S0101, SW1026 and S0008 were 0.7774, 0.7672, and 0.7424 respectively. The PIC values ranges from 0.6974 for S0008 to 0.8291 for S0005. The PIC values for S0101, SW1026 and SW2517 were 0.7483, 0.7284 and 0.7381 respectively. The allele frequencies were used to estimate the Nei’s standard genetic distance among the populations. The distance measure ranged from 0.5704 to 0.7161, with the highest value noticed between population II and IV and the lowest between population I and III. A dendrogram was constructed using the POPGENE version 3.2 program which grouped the population I and IV in one cluster and II and III populations in another cluster.Item Detection and characterization of macluravirus infecting greater yam (Dioscorea alata L)(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2014) Manasa, V G; Jeeva, M LItem Mining of resistance genes associated with anthracnose infection in greater yam (Dioscorea alata Linn.)(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2016) Saranya, G; Jeeva, M LAnthracnose caused by Colletotrichum gloeosporioides is the major fungal disease of greater yam (Dioscorea alata), which is one of the important tropical tuber crops with high production and nutritive potential. For identifying the Resistance Gene Analogues (RGAs) in greater yam, degenerate primers based on the conserved motifs were used to isolate nucleotide-binding site (NBS) type sequences. Cloning and sequencing of identified NBS-type sequences called resistance gene analogues (RGAs) showed similarity to other cloned RGA sequences available in the database and the presence of conserved domains, viz. P-loop, RNBS-B, RNBS-C, Kinase-2 and GLPL, categorising them with the NBS–leucine-rich repeat class gene family. Amino acid sequence alignment of the Dioscorea RGAs with RGAs of other plant species grouped them with the non-Toll interleukin receptor (TIR) subclasses of the NBS sequences. The expression profiles of RGAs determined using semi quantitative Reverse Transcriptase polymerase chain-reaction in Sree Keerthi (tolerant) and Orissa Elite (susceptible) genotypes in response to anthracnose infection demonstrated that, Dioscorea alata RGAs were up-regulated three days after disease inoculation in the tolerant genotype, whereas in the susceptible genotype it was observed on the 5th day. In contrast, RGAs were found to be expressed in both tolerant and susceptible control plants, but the level was found to be increased in the test plants following pathogen inoculation. The reverse transcription PCR product was normalized and the efficiency was evaluated using Actin primers, which serves as reference gene. The result suggests a role of Resistance Genes Analogues in the early pathogen recognition of Sree Keerthi against C. gloeosporioides, which may be one of the reasons for its tolerance to anthracnose disease. These genes could be a good start point for further studies such as candidate gene mapping or understand the bases for resistance in greater yam. The isolation and expression analysis of D. alata RGAs have been reported for the first time in this study.