ALLELIC VARIATION FOR YIELD AND CULM STRENGTH GENES/QTL’S IN RICE (Oryza sativa L.)
dc.contributor.advisor | ESWARI, K.B | |
dc.contributor.author | RACHANA, B | |
dc.date.accessioned | 2020-10-05T05:52:32Z | |
dc.date.available | 2020-10-05T05:52:32Z | |
dc.date.issued | 2018 | |
dc.description.abstract | The present investigation is an attempt to evaluate the traits which either directly or indirectly influence the yield and to validate the reported QTLs/genes for yield and culm strength in rice germplasm. The experiment was carried out during kharif season of 2017 at the ICAR- Indian Institute of Rice Research (IIRR), Hyderabad, Telangana. Forty six (46) genotypes were selected based on the evaluation of 652 rice genotypes in augmented block design for all the yield traits at ICAR- IIRR during kharif of 2016. Forty six rice germplasm accessions were evaluated for variability, heritability, genetic advance, correlation and path coefficient analysis in different yield and yield contributing traits. The data was recorded on five randomly selected plants for thirteen quantitative characters. ANOVA and LSD are quite useful in assessing the presence of variability and significant differences respectively among the test genotypes. The analysis of variance revealed significant differences for the characters under study, indicating the presence of genetic variability among the genotypes. For yield attributing traits viz., desirable plant height, effective tiller number and panicle length, promising genotypes could not be precisely selected as LSD analysis revealed overlaps. Promising genotypes for five major traits viz., test weight, grain number, strong culm, biomass and yield per se traits have been identified. The estimates of PCV were slightly higher than GCV for all the characters studied indicating less influence of environmental factors on the expression of traits. Moderate estimates of PCV and GCV were observed for days to 50% flowering, panicle length and harvest index and high estimates were observed for plant height, number of tillers per plant, number of panicles, panicle weight, grain number, test weight, culm strength, single plant yield, plot yield and biomass, indicating the possibility for genetic improvement through direct selection for these traits. Moderate heritability coupled with moderate genetic advance was observed for panicle length. Characters like days to 50% flowering, plant height, number of tillers per plant, number of panicles, panicle length, panicle weight, grain number, test weight, culm strength, single plant yield, plot yield, biomass and harvest index showed high heritability coupled with high genetic advance as percent of mean, suggesting that selection for the improvement of these characters may be rewarding. Single plant yield showed high positive and significant association with tillers per plant, days to 50% flowering, biomass and productive tillers per plant. Culm strength showed high significant and positive correlation with culm inner diameter and significant, negative correlation with days to 50% flowering, indicating that early duration and increased inner culm diameter would aid in the improved tolerance to lodging. Path coefficient analysis showed maximum direct contribution towards single plant yield with productive tillers per plant exerted highest positive direct effect followed by panicle length, number of grains per panicle, test weight, panicle weight, culm strength, harvest index and biomass. Correlation and path co-efficient analysis revealed that productive tillers per plant and biomass are very important traits as selection criteria for effective yield improvement. Based on Duncan’s multiple range test (DMRT) for least significant differences among the 46 genotypes, promising genotypes for yield and culm related traits were identified and validated with reported gene specific markers. Eleven markers were polymorphic and six were monomorphic. The promising genotypes which had allele different to the yield-positive control includes KJ 241 for SCM2, GS5 and GS3 alleles, KJ 182 for SCM2, GS5, Gn1a, SPL14 and Ghd7 alleles, KJ 274 for Gn1a, Ghd7 and GS3 alleles, KJ 55 for Gn1a, Ghd7, SPL14 and GS3 alleles, KJ 199 for Gn1a, Ghd7, SPL14 and GS3 alleles, KJ54 for TGW6, Ghd7 and SPL14 alleles, KJ 251 for GS3 and GS5 alleles, KJ 244 for TGW6 allele, D107 and KJ 263 for GS5 allele and KJ 204 for Ghd7 allele, which would serve as potential donors for breeding rice cultivars with improved grain yield and lodging resistance. For genetic diversity anlaysis, 38 out of 64 markers were polymorphic across all accessions with an average of 2.2 alleles per polymorphic marker. The PIC value ranged from 0.07 to 0.51 with an average of 0.31 and marker RM 340 was found to be the most appropriate marker to discriminate among the rice genotypes owing to the highest PIC value of 0.51. The cluster analysis showed these genotypes grouping in to eight clusters in which cluster IA-1 had maximum twenty five genotypes followed by cluster IB and cluster IA-2. Clusters IIA, IIB, III, V and VII have two genotypes each, whereas the clusters IV, VI and VIII have only one genotype each. The highest similarity coefficient value was observed between the cultivar KJ217 and KJ 263 (0.67) followed by KJ 29 and KJ 142 (0.66), KJ 218 and KJ 236 (0.66) and D54 and D63 (0.65), whereas lowest value was observed for Swarnadhan (0.18) and IFT 200 (0.21), showing highly diverse genotypes. ANOVA coupled with LSD analysis provides scope for selection of genotypes with distinctness while ANOVA assesses only the amount of variability. Productive tillers per plant, culm inner diameter and biomass are considered as important attributes in formulating selection criterion for achieving desired targets. Analysis of genetic diversity and allelic variation identified novel sources of genotypes possessing alleles for gene specific markers that are different from known sources, which would serve as potential donor for breeding rice cultivars with improved grain yield and lodging resistance. | en_US |
dc.identifier.citation | D10,302 | en_US |
dc.identifier.uri | https://krishikosh.egranth.ac.in/handle/1/5810152335 | |
dc.keywords | ALLELIC VARIATION FOR YIELD AND CULM STRENGTH GENES/QTL’S IN RICE (Oryza sativa L.) | en_US |
dc.language.iso | English | en_US |
dc.publisher | PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY | en_US |
dc.sub | Genetics and Plant Breeding | en_US |
dc.theme | M.Sc | en_US |
dc.these.type | M.Sc | en_US |
dc.title | ALLELIC VARIATION FOR YIELD AND CULM STRENGTH GENES/QTL’S IN RICE (Oryza sativa L.) | en_US |
dc.type | Thesis | en_US |
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