GENETIC ANALYSIS IN CASTOR (Ricinus communis L.)
Loading...
Date
2011-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
jau,junagadh
Abstract
In the present investigation entitled “Genetic analysis in castor (Ricinus communis L.)” was undertaken with a view to generate genetic information on gene effects, heterosis, inbreeding depression, and genetic correlation for seed yield and its components. The experimental material consisted of six generations, namely P1, P2, F1, F2, BC1 and BC2 of five crosses of castor viz., JP 96 x JI 368 (cross 1), JP 96 x JI 372 (cross 2), JP 101 x SKI 215 (cross 3), JP 101 x SKI 291 (cross 4) and JP 102 x JI 372 (cross 5) grown at Main oilseeds Research Station, Junagadh Agricultural University, Junagadh. Experiment was laid-out in Compact Family Block Design with three replications. The observations were recorded on five randomly selected plants from P1, P2 and F1, forty plants from F2 and twenty plants from BC1 and BC2 generations in each replication for twelve characters.
The analysis of variance between families (crosses) revealed that the mean squares due to crosses were significant for all the characters except plant height up to main raceme and number of effective branches per plant. The analysis of variance among progenies within each family indicated significant differences among six generation means for all the characters studied in all the crosses except number of nodes up to main raceme in cross 1, and number of effective branches per plant in cross 1, cross 2 and cross 5.
On the basis of individual scaling test A, B and C and joint scaling test, the additive-dominance model was found adequate for description of variation in generation means for days to flowering of main raceme in cross 1; days to maturity of main raceme, shelling out turn and oil content in cross 4. For remaining crosses either all the three or any one or two individual scaling test A, B or C were found significant. This was also confirmed by joint scaling test showing significant chi-square values for these cases, indicating involvement of digenic interaction parameters in the inheritance of the characters.
On the basis of perfect fit solution of six parameter model, all the six parameters viz., m, (d), (h), (i), (j) and (l) were significant for plant height up to main raceme, shilling out turn and oil content in cross 5; for number of node up to main raceme in cross 4; for length of main raceme and effective length of main raceme in cross 1 and for 100-seed weight in cross 2 and cross 4, indicated the involvement of additive, dominance as well as epistasis gene interaction for controlling these traits.
For the characters where evidence of digenic epistatic interaction was obtained, both additive and non-additive effects were significant for days to maturity of main raceme, plant height up to main raceme, shelling out turn, 100-seed weight in cross 1; days to maturity of main raceme, plant height up to main raceme, shelling out turn and seed yield per plant in cross 2; days to flowering of main raceme, days to maturity of main raceme, length of main raceme, effective length of main raceme, number of capsule on main raceme and shelling out turn in cross 3; plant height up to main raceme in cross 4 and days to maturity of main raceme, number of nodes up to main raceme, length of main raceme, effective length of main raceme and 100-seed weight in cross 5. Only additive (d) component was found significant for number of capsule on main raceme cross 1, oil content in cross 1 and cross 2; plant height up to main raceme, number of nodes up to main raceme, 100-seed weight, oil content and seed yield per plant in cross 3; length of main raceme, effective length of main raceme and number of capsule on main raceme in cross 4 and seed yield per plant in cross 5. While only dominance (h) component was found significant for seed yield per plant in cross 1; length of main raceme, effective length of main raceme, number of capsule on main raceme in cross 2; number of effective branches per plant in cross 3; days to flowering of main raceme in cross 4 and number of capsule on main raceme in cross 5.Looking to the interaction components, all the three or any one or any two interaction parameters were found significant for most of the traits in most of the crosses indicating interaction parameters also played important role in the inheritance of majority of the character in almost all the crosses.
The classification of gene action showed importance of duplicate type of gene action for most of the characters in most of the crosses. Breeding procedures involving multiple crosses, biparental crosses may be restored to get transgressive segregants. This is especially important to develop inbred lines having superiority in different characters. Such lines can give better hybrids. While in case of complementary type of epistasis, material can be utilized directly in breeding programme.
The magnitude of heterotic effects was high for plant height up to main raceme, number of nodes up to main raceme, 100-seed weight and seed yield per plant; moderate for days to flowering of main raceme, days to maturity of main raceme, shelling out turn and oil content and low for length of main raceme, effective length of main raceme and number of effective branches per plant. The cross JP 96 x JI 368 exhibited highest standard heterosis for seed yield per plant along with high to moderate heterotic effect for majority of trait in desirable direction.
Either low or moderate amount of inbreeding depression in desired direction was found for most of the traits. It is desirable to have high, significant and positive heterosis with low inbreeding depression for characters like seed yield and its components. As observed in cross JP 96 x JI 372 for seed yield per plant, cross JP 101 x SKI 291for shelling out turn and cross JP 96 x JI 368 in oil content.
Significant and positive correlation coefficient of seed yield per plant was exhibited in hybrid JP 96 x JI 368 and JP 96 x JI 372 with number of effective branches per plant; in JP 101 x SKI 215 with number of effective branches per plant and shelling out turn, in JP 101 x JI 291 with shelling out turn, 100-seed weight and oil content and in JP 102 x JI 372 with length of main raceme and effective length of main raceme.
Description
Keywords
botany