Study of gene effects for seed oil yield and its component traits in bidi tobacco (Nicotiana tabacum L.)

Tobacco is one of the important non-food crops traditionally used for manufacturing of cigarettes, it is also considered as an oilseed crop as the tiny tobacco seeds contain 30 to 40 percent oil. There is little information on gene effects governing seed oil yield in tobacco available. Hence present study on genetic analysis for seed oil yield and its components were carried out in bidi tobacco using six basic generations viz., P1, P2, F1, F2, BC1 and BC2 of five different crosses namely, I) Dediapada Selection x A 145, II) Dediapada Selection x A 119, III) GABT 11 x Dediapada Selection, IV) Jayalakshami x Sanand Local and V) A 119 x L 108-15-3. Three parameters model was found adequate in cross I for branches per plant, for test weight in crosses II and III, and for seed weight per capsule in cross V. All types of gene effects i.e., additive (d), dominant (h), additive x additive (i), additive x dominant (j) and dominant x dominant (l) were significant in most traits studied in all these crosses. Additive gene effect was found prominent for test weight and seed oil content in cross I, for leaf yield per plant in cross II, for days to capsule maturity in crosses III and IV, and for branches per plant, test weight, leaf yield per plant and seed oil yield per plant in cross V. Thus, the magnitude and type of gene effects differed for different characters in the same cross and for the same character in different crosses, which requires specific handling of individual crosses in segregating generations for further improvement.