Deciphering Higher Order Non-Allelic Interactions For Quantitative Characters Through Twelve Generation Mean Analysis In Castor (Ricinus Communis L.)

Abstract The genetic architecture of oil content, seed yield and its related biometric traits in castor was investigated through generation mean analysis of four crosses viz., JP 104 x JI 433, SKP 84 x JI 433, SKP 84 x JI 437 and SKP 84 x JI 441 in twelve generations (P1, P2, F1, F2, B1, B2, B11, B12, B21, B22, B1s and B2s). Significance of simple scaling tests and Cavali’s joint scaling test in all the crosses for one or more traits indicated the presence of digenic and trigenic gene interactions. Further, the significant 𝜒2(2) value at six degrees of freedom based on six- parameter model of Hill (1966), depicted the presence of trigenic or higher order epistasis in all the crosses for all the characters. The trigenic ten-parameter model was found to be adequate in cross JP 104 x JI 433 for effective length of primary raceme; in crosses JP 104 x JI 433 and SKP 84 x JI 437 for number of capsules on primary raceme; and in cross SKP 84 x JI 441 for number of effective branches per plant. On the other hand, 𝜒2(3) with two degrees of freedom was found significant for remaining traits in all the four crosses showing the presence of higher order epistasis and/or linkage. All the ten-parameters were significant for shelling out turn percentage in three crosses SKP 84 X JI 433, SKP 84 x JI 437 and SKP 84 x JI 441 and for days to maturity of primary raceme in cross SKP 84 x JI 433. Moreover, the duplicate epistasis was reported for the inheritance of oil content, seed yield and its component traits. This information can be utilized in developing castor lines with high seed yield and oil content.