Abstract

Mohammed O. Khomeinia, leila Ali Rouhania, Ali K. Soomekhb and Bahar O. Jobrani

Information about the genetics of callus formation is needed for efficient in vitro selection. Hybrid breeding has been proposed for genetic improvement of rapeseed but there isn't enough information on heterosis and gene action of callus growth characters in this crop. In the present study, genetic analysis and heterosis of three in vitro characters (percentage of callus induction, callus diameter and callus fresh weight) for five inbred lines of rapeseed, Orakel, ACSN1, P504588, P704591 and Boanty was investigated by a 5 × 5 diallel system using calli derived from mature embryo cultures in MS medium supplemented with 1 mg L-1 BAP and 0.5 mg L-1 2,4-D.. Variance components due to specific combining ability (dominance variance) were larger than those of general combining ability (additive variance) for the traits under study. Positive heterosis was also noticed for all of the characters. High broad-sense (70.12 to 89.43) and low narrow-sense (3.49 to 23.01) heritability values suggested that dominance gene action was more important in the genetic control of the characters studied and therefore, exploiting this type of gene action for improving callus characters seems necessary. Among the five cultivars under study, Orakel was the best general combiner for callus induction and growth and may be used in the breeding programs for improving the callus characters in rapeseed.