GENETIC ARCHITECTURE OF SEED YIELD AND ITS COMPONENTS IN CASTOR (Ricinus communis L.) UNDER DIVERSE ENVIRONMENTS

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dc.contributor.advisorPithia M.S.
dc.contributor.authorMONPARA BABULAL ARJANBHAI
dc.date.accessioned2016-09-21T10:31:51Z
dc.date.available2016-09-21T10:31:51Z
dc.date.issued2010-05
dc.description.abstractSix generations, namely P1, P2, F1, F2, BC1 and BC2 of six crosses of castor viz., Geeta x JI 263 ( cross 1) , JP 84 x JI 263 (cross 2), JP 86 x JI 273 (cross 3), JP 90 x JI 258 (cross 4), SKP 42 x SKI 215 (cross 5) and SKP 106 x PCS 124 (cross 6) were grown under diverse environmental conditions (pre-rabi and rabi seasons) at Instructional Farm, College of Agriculture, Junagadh Agricultural University, Junagadh to study the gene effects, heterosis, inbreeding depression, heritability, genetic advance and genetic correlation for seed yield and its components. Experiment was layed-out in Compact Family Block Design with three replications. The observations were recorded on five plants from P1, P2 and F1, forty plants from F2 and thirty plants from BC1 and BC2 generations in each replication for twelve characters viz., days to flowering of main raceme, days to maturity of main raceme, plant height up to main raceme, number of nodes up to main raceme, total length of main raceme, effective length of main raceme, number of effective branches per plant, number of capsules on main raceme, shelling out turn, 100-seeds weight, oil content and seed yield per plant. ii The analysis of variance between families revealed that the mean squares due to crosses were significant for all the characters under both the environments. The analysis of variance among progenies within each family indicated significant differences among six generation means for all the characters studied under both the seasons in all the crosses except oil content in case of JP 84 x JI 263 cross in pre-rabi season. This indicates the sufficient genetic variability in the material under study. All the three or any of the individual scaling tests A, B or C were significant for all the character in all the six crosses under both seasons indicating the presence of epistasis. The application of joint scaling test expressed significant chi-square values for all the traits in all the six crosses under both the environments confirming involvement of digenic interaction parameters in the inheritance of all the characters. On the basis of perfect fit solution of six parameter model, main effects m, (d), (h) and all the three digenic interactions (i), (j) and (l) were significant for majority of the characters in most of the crosses under both the seasons indicating involvement of additive, dominance as well as epistatic gene effects. In case of pre-rabi sowing condition, only additive (d) effect was significant for days to flowering of main raceme in cross 3, days to maturity of main raceme in cross 1, total length of main raceme in cross 6, number of effective branches per plant in cross 2 and 100-seeds weight in cross 1 and 6. While only dominance (h) component was significant for days to flowering of main raceme in cross 1 and 4, plant height up to main raceme in cross 4, number of nodes up to main raceme in cross 6, number of effective branches per plant in cross 1, number of capsules on main raceme in cross 3, shelling out turn in cross 1 and 2, oil content in cross 4 and seed yield per plant in cross 3. Both additive (d) and dominance (h) effects were significant in all the remaining crosses iii for all the remaining traits. Significance of only additive (d) parameter under rabi sowing was observed for days to maturity of main raceme in cross 5, number of effective branches per plant in cross 3 and oil content in cross 6 while, only dominance (h) component was significant for days to flowering of main raceme in cross 1, number of nodes up to main raceme in cross 6, number of effective branches per plant in cross 4, shelling out turn in cross 3 and 5 and oil content in cross 4. Both main effects were found significant for remaining traits in rest of the crosses. Such situation indicated role of both additive as well as dominance gene effects for controlling the characters. Looking to the interaction components, all the three or any one or any two interaction parameters were found significant for all the traits in all the six crosses under both the environments indicating interaction parameters also played important role in the inheritance of all the character in all the six crosses. The classification of gene action showed importance of duplicate type of gene action for most of the characters in most of the crosses under both the environments. Under a situation of this type, it would be difficult for the breeder to get promising segregants better than parents involved through conventional breeding methods. While in case of complementary type of epistasis, material can be utilized directly in breeding programme. Magnitude of heterotic effects was high for number of effective branches per plant, seed yield per plant, number of capsules on main raceme, plant height up to main raceme, number of nodes up to main raceme and days to flowering of main raceme, moderate for 100-seeds weight, shelling out turn, days to maturity of main raceme and low for oil content under both the environments. The cross Geeta x JI 263 exhibited the highest standard heterosis followed by JP 90 x JI 258 and JP 86 x JI 273 for seed yield per plant under pre-rabi season. While in case of iv rabi season, the maximum standard heterosis was displayed by hybrid SKP 42 x SKI 215 followed by Geeta x JI 263 and JP 90 x JI 258. It was observed that crosses Geeta x JI 263 and JP 90 x JI 258 were heterotic for seed yield per plant and majority of traits in desirable direction under both the environments. Either low or moderate amount of inbreeding depression in desired direction was found for most of the traits. The Highest significant and positive inbreeding depression for seed yield per plant under pre-rabi sowing was found in cross SKP 106 x PCS 124 followed by JP 84 x JI 263 and Geeta x JI 263. While in case of rabi season, cross Geeta x JI 263 showed maximum and significant inbreeding depression which was followed by SKP 42 x SKI 215 and SKP 106 x PCS 124. The days to flowering of main raceme and seed yield per plant displayed the higher estimates of narrow sense heritability and genetic advance in all the crosses under pre-rabi season, while, plant height up to main raceme, total length of main raceme, effective length of main raceme and number of effective branches per plant had higher values of genetic advance for most of the crosses. While, in case of rabi sowing condition, the number of nodes up to main raceme and plant height up to main raceme showed the high values of heritability as well as genetic advance. Therefore, these characters are of great importance for the improvement of seed yield. Under pre-rabi season, significant and positive relationship was displayed between seed yield per plant with total length of main raceme, effective length of main raceme and shelling out turn in cross Geeta x JI 263; total and effective length of main raceme in crosses JP 84 x JI 263 and SKP 42 x SKI 215; number of capsules on main raceme, shelling out turn, 100-seeds weight and oil content in JP 86 x JI 273; shelling out turn and 100-seeds weight in JP 90 x JI 258 and number of effective branches v per plant, shelling out turn, 100-seeds weight and oil content in SKP 106 x PCS 124. In case of rabi season, yield components like effective length of main raceme in cross JP 86 x JI 273, number of effective branches per plant in JP 84 x JI 263, number of capsules on main raceme in JP 86 x JI 273 and shelling out turn in cross Geeta x JI 263 were positively associated with seed yield per plant. Above said yield contributing characters are useful for the indirect selection for the improvement of seed yield per plant under respective environment in castor.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/77930
dc.language.isoenen_US
dc.subPlant Breeding and Genetics
dc.subjectGENETIC ARCHITECTURE OF SEED YIELD AND ITS COMPONENTS IN CASTORen_US
dc.these.typePh.D
dc.titleGENETIC ARCHITECTURE OF SEED YIELD AND ITS COMPONENTS IN CASTOR (Ricinus communis L.) UNDER DIVERSE ENVIRONMENTSen_US
dc.typeThesisen_US
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