1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item 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) Swathy Sivan; Arya, KItem 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 Diversity interrelationships among capsicum spp. and forms and developement of papricas(Department of Olericulture, College of Horticulture, Vellanikkara, 1994) Indira, P; Peter, K VCapsicum, a new world genus, has richness in diversity that has not yet received the needed attention. The cultivated chilli varieties offer many problems in classification because of their great number, the transitory nature and creation of new ones through hybridization and selection processes. The present studies on “Diversity inter relationships among Capsicum spp. And forms and development of paprikas” were conducted at the College of Horticulture, Vellanikkara. The main objectives were grouping of chilli genotypes biometrically and biochemically and development of paprikas. For biometrical grouping chilli genotypes belonging to four cultivated species of Capsicum were evaluated during two seasons (August, 1991- January, 1992 and May, 1992- September, 1992). They were clustered into different groups based on D2 values. There were 9 clusters during first season and 6 clusters during second season. The distribution of genotypes into clusters showed no regularity. The isozyme patterns of two enzymes viz.peroidase and esterase were studied in the three cultivated species of Capsicum and also for the nine biometrical groups. Among the different plant parts studied roots showed clear bands in case of peroxidase and mature leaves were the best sampling tissue for esterase enzyme. There were species specific bands in all the three species. The nine biometrical groups showed variation for banding pattern in case of peroxidase and esterase. There were some common bands for both the enzymes. Twenty paprika genotypes were collected from different sources and their morphological descriptions were made as per IBPGR descriptor. Field evaluation was done for two seasons (October –March, 1991; May – October, 1992). There was significant difference among genotypes for the different characters studied. There was much seasonal variation also. CA 517 recorded minimum incidence of bacterial wilt during both seasons under the field conditions. CA 582 showed highest colour value but CA 604 and CA 605 recorded minimum pungency.Item 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 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; Elsy, C RThe 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.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 Genetic diversity and combining ability in cucumber (Cucumis sativus L.)(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2017) Suma, A; Elsy, C RAssessment of genetic diversity is the key tool in any crop improvement and germplasm management programme. Evaluation of genetic variation will help to provide valuable information about new sources of genes. The studies on combining ability and heterosis can support utilization of promising lines in further crop improvement programmes. Cucumber (Cucumis sativus L. 2n= 2x= 14) is an indigenous vegetable crop of India. Even though rich diversity for cucumber is available in India, studies on genetic diversity of this crop are scanty. Therefore, the present project was proposed to explore genetic diversity in cucumber using morphological and molecular markers and to study combining ability and heterosis in selected genotypes. Morphological characterization of 50 accessions of cucumber revealed presence of significant difference among accessions for majority of vegetative, floral and fruit characters. Mean days to first male and female flower opening was 36 and 43 days respectively. Majority of the accessions possessed elliptical elongated fruits with light green skin colour and white flesh colour. Sixteen accessions exhibited significantly higher fruit length than AAUC-2, the standard check, the maximum being exhibited by IC613472 (20.85 cm). Accessions with oblong ellipsoid fruits possessed higher fruit diameter. Mean fruit weight showed high variability among accessions with a range of 33 g to 343 g. Fourteen accessions exhibited significantly high yield than AAUC-2. Number of fruits per plant, yield per plant, loss of weight during storage and sex ratio showed high values for all the genetic parameters studied. IC613481 was the promising genotype identified in morphological characterization, followed by IC613480. Cluster analysis grouped accessions into seven distinct clusters based on the level of similarity in quantitative characters. Random grouping of accessions into various clusters indicated absence of parallelism between genetic diversity and geographical diversity. Cluster II and III were the largest clusters, with 14 accessions each and Cluster V and VI, the smallest ones with single accession each. Results of Principal component analysis revealed that first three principal components, with Eigen values more than unity accounted for 85.80 per cent of cumulative variance, contributed by fruit weight, fruit length, fruit diameter and days to first harvest. The diversity analysis of the accessions was done using DIVA-GIS by generating grid maps. The results of the study indicated that highly diverse accessions with respect to the selected characters were sourced from Mizoram, Tripura and West Bengal. Molecular characterization revealed high level of genetic distinctness between genotypes. SSR11742 and AF202378 were found to be highly polymorphic markers, with high polymorphism information content and number of polymorphic bands. In-depth evaluation of selected 22 genotypes revealed significant difference for all fruit characters except days to last harvest and harvest duration and further revealed the superiority of IC613480. Evaluation of 15 hybrid combinations developed through half diallel mating design and their parents indicated presence of significant difference among parents and hybrids for various characters studied. Among the parental genotypes, IC613480, exhibited significantly high GCA effects for fruit length, number of fruits per plant and yield per plant whereas IC595508A, for fruit weight and loss of weight during storage, and IC613485 for fruit diameter, thus proving to be promising parents for accumulating genes for these characters. The hybrids, IC613480 x IC595508A and IC613480 x IC613471 showed significant SCA effects for yield per plant and sex ratio. IC613480 x IC613471, IC613480 x IC595508A and IC613471 x IC595508A were exhibiting significantly high relative heterosis, heterobeltiosis and standard heterosis for number of fruits per plant and yield per plant. IC613480 and IC613485 were the most promising genotypes identified from the study whereas IC613480 x IC613471 was the most promising hybrid based on SCA effects, heterosis, per se performance on yield contributing characters and organoleptic qualities. This hybrid showed high fruit length (17.01 cm), yield per plant (2163.45 g), number of fruits per plant (11.43) and sex ratio (0.11). IC613480 x IC613476 and IC613485 x IC595508A were the other promising hybrids.