Genetic analysis of quantitative characters in cigar and pipe tobacco, Nicotiana tabacum. III. Economic indices: grade index, yield, and crop revenue

Abstract

A diallel cross of four cigar cultivars and one pipe tobacco (Nicotiana tabacum L.) cultivar was analyzed for the following parameters: grade index, yield, crop revenue or index, percentage of nicotine, percentage of total alkaloids, and susceptability to pole rot. The experiment was performed over 3 years. Analysis was done for general combining ability and specific combining ability. General combining ability was greater than specific combining ability for all variables although significant specific combining ability effects were also present for all parameters with the exception of nicotine and total alkaloids. Reciprocal effects were completely absent. The line Pennbel 69 showed a positive general combining ability effect for yield, crop index, and infestation by pole rot and a high negative general combining ability effect for grade index and percentage of nicotine and total alkaloids. Petit Havane showed a complete reverse of general combining ability effects for these parameters while the other three cultivars were intermediate. High positive specific combining ability effects for grade index, yield, and crop index and high negative specific combining ability effects for the percentage of pole rot were shown by crosses of Pennbel 69.