The inheritance of systemic resistance to the bacterial blight pathogen (Xanthomonas axonopodis pv. dieffenbachiae) in Anthurium andraeanum (Hort.)

The inheritance of resistance to systemic infection by bacterial blight disease (blight) caused by Xanthomonas axonopodis pv. dieffenbachiae in anthurium (Anthurium andraeanum Hort.) was investigated in 83 biparental crosses involving 39 anthurium cultivars, using a green fluorescent protein-based screening method. Genetic analysis was based on North Carolina mating design II analysis, combining ability analysis and parent-offspring regression analysis. The results showed a role for both additive and non-additive effects in the inheritance of systemic resistance to blight, although the former was predominant and between four- to five-fold larger than the latter. General combining ability (GCA) of the parents was able to fairly accurately predict the performance of progeny in 15 of the 17 M × N ('M' male cultivars crossed with 'N' female cultivars) mating designs. The highly resistant cultivars were the best general combiners, while the susceptible cultivars generally produced negative GCA values. Dominance was in the direction of susceptibility. Narrow sense heritability (h2) based on North Carolina mating design II analysis, was 42.5%, with broad sense heritability (H2) of 96.5%. The estimate of h2 based on mid-parent-offspring regression analysis was slightly higher (58-62%). In conclusion, the results indicated that resistance to systemic blight is governed by both additive and non-additive genetic effects with the former playing a larger role. Clonal breeding for systemic resistance to blight using a family selection approach is suggested.