تجزيه ژنتيكي القا و رشد كالوس در كلزا

Genetic Analysis of Callus Induction and Growth in Rapeseed

Five inbred lines of rapeseed (Brassica napus L.), Orakel, ACSN1, PF504588, PF704591 and Boanty, which were previously selected for variation in callus characteristics, were crossed to produce diallel progenies. The parents and their F 1 hybrids were evaluated in a completely randomized design with four replications. In each experimental unit, 10 seeds were grown on MS(Murashig and Skoog) medium in Petri dishes.Data were collected after five weeks on percent of callus induction, callus diameter, callus fresh weight and callus dry weight. The resulting data were analysed according to Griffingʹs(1956) method 2 mixed model B. Analysis of variance revealed significant difference among genotypes for the above characters. General combining ability (GCA) was only significant for the percent of callus induction, while significant specific combining ability (SCA) were observed for all callus characteristics. Broad sense heritabilities were high; indicating that callus induction and growth in culture media is under genetic control. However, the narrow sense heritabilities were low; suggesting that dominance gene action was more important in the genetic control of the traits under study. Orakel was also characterized by higher estimate of GCA effects for all the characters studied. This genotype, therefore, seems to be a suitable genetic material for callus growth and induction. Among hybrids, Orakel* ACSN1 and ACSN1*PF504588 showed higher means and SCA effects for callus fresh weight, dry weight and diameter. However, for percent of callus induction, higher means and SCA effects were observed for the crosses ACSN1 x PF704591 and ACSN1 * Bounty. This indicates that the genes encoding callus induction were different than those of callus growth. HI and H2 were higher than D, indicating that, the dominant component was larger than additive component. Epistasis was almost absent in all traits. Dominant alleles caused high and recessive alleles caused low expression of callus induction and growth.