Chartacterization of landraces of ashgourd (Benincasa hispida (Tunb.) Cogn.)
| dc.contributor.advisor | Sreelathakumary, I | |
| dc.contributor.author | Reshmi, J | |
| dc.contributor.author | KAU | |
| dc.date.accessioned | 2019-06-06T05:30:11Z | |
| dc.date.available | 2019-06-06T05:30:11Z | |
| dc.date.issued | 2004 | |
| dc.description | PG | en_US |
| dc.description.abstract | The research project "Characterization of landraces of ashgourd [Bcnincasa h ispida (Thunb.) Co gn.]" was carried out at the Department of Olericulture and the Department of Plant Biotechnology, College of Agriculture, Vellayani during 2003-2004. The objective of the study was to catalogue the landraces based on the IBPGR descriptor for cucurbits, to estimate the genetic parameters for different traits in the germplasm for identifying superior lines based on yield, quality, pest and disease resistance and to characterize the landraces using molecular techniques (RAPD analysis). Twenty five landraces of Benincasa hispida collected from various sources upon cataloguing pointed out wide variation for several morphological characters. Analysis of variance revealed significant differences among the landraces for all the characters studied namely. vine length, internodal length, number of primary branches, number of secondary branches, root shoot length ratio, days to first male flower, node to first male flower, days to first female flower, node to first female flower, sex ratio, days to first fruit harvest, fruit length, fruit girth, fruits per plant, average fruit weight, yield per plant. seeds per fruit, 1000-seed weight and mosaic incidence. Among the landraces, BH 15 (Neyattinkara, Thiruvananthapuram) recorded the maximum yield (21.20 kg), average fruit weight (9.50 kg), fruit girth (78.05 cm) and 1000-seed weight (96.95 g). Among the landraces, maximum fruit length was observed for BH 25 (56.00 cm). BH 22 was the longest in vine length (875.00 cm) and had the highest number of primary and secondary branches (4.00 and 23.00 respectively). BH 24 (7.20 cm) was shortest in internodal length, which was also characterized by maximum fruits per plant (9.12). BH 8 was the earliest to flower (46.25 days) and harvest (88.00 days). BH 10 had the least vulnerability index for mosaic (27.50). High phenotypic and genotypic coefficients of variation were observed for seeds per fruit, average fruit weight, yield per plant and fruits per plant. High heritability coupled with high genetic advance was observed for average fruit weight, yield per plant, fruits per plant, fruit girth and fruit length. Correlation studies and path coefficient analysis revealed that fruit length and average fruit weight are the primary yield components as evidenced from its high positive correlation as well as direct and indirect effects on yield. In the discriminant function analysis, the landrace BH 15 (Neyattinkara. Thiruvananthapuram) ranked first, followed by BH 23 (KAU local, KAU) and BH 5 (CO-I, TNAU). They were found to be promising based on their superiority in yield, fruit quality, earliness in male and female flowering, narrow sex ratio and mosaic resistance and hence they may be utilized for further crop improvement. Based on the analysis for genetic divergence, the 25 landraces of B. hispida were grouped into seven clusters, with the highest intercluster distance observed between clusters V and VII. DNA isolated from the 25 landraces of B. hispida were subjected to RAPD analysis. Out of the 40 decamer primers, twenty nine yielded amplification products. A total of 83 RAPDs (average 2.08 bands per primer) were generated by the 29 primers, of which 92.77 per cent were polymorphic (77 bands) and six were monomorphic. Out of five primers showing high level of polymorphism, three prormsing primers viz .. OPA-O 1, OPA-07 and OPA-I3 were selected. The primer OPA-07 was unique as it could distinguish maximum polymorphism among the landraces tested while OPA-I3 produced maximum number of scorable bands. The selected three primers yielded 20 scorable bands (average of 6.66 bands per primer) of which 2 were monomorphic and rest, 18 were polymorphic (90.0 %). The overall Jaccard's similarity coefficients ranged from 0.14 to 1.00. Cluster analysis revealed that at about 0.35 similarity coefficient, the twenty five landraces of B. hispida grouped into two clusters. Landraces with morphologically distinct smooth and waxy textured fruits grouped into two major clusters. Considering the waxy textured group, it formed a more divergent cluster than smooth textured group. With in the group of waxy textured fruits, limited variation was detected among landraces with small and medium sized fruits. Further, morphologically similar landraces with large fruits form distinct clusters with in the major clusters. By characterizing all the twenty five landraces of Benincasa hispida using morphological (selection index and D2 analysis) and molecular (RAPD marker analysis) methods revealed that morphologically distinct and superior lines were genetically differentiable. Also the RAPD analysis gave a perfect differentiation of waxy textured group from smooth textured group, which is in line with morphological characterization. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810106911 | |
| dc.keywords | Olericulture, Genetic cataloguing, Heritability and genetic advance, Path Coefficient analysis, Genetic divergence, Random amplified polymorphic DNA (RAPD), Microsatellite, | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | Department of Olericulture, College of Agriculture, Vellayani | en_US |
| dc.sub | Agriculture | en_US |
| dc.subject | null | en_US |
| dc.theme | Llandraces of ashgourd | en_US |
| dc.these.type | M.Sc | en_US |
| dc.title | Chartacterization of landraces of ashgourd (Benincasa hispida (Tunb.) Cogn.) | en_US |
| dc.type | Thesis | en_US |