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Inheritance of Resistance to Foliar Infection by Xanthomonas axonopodis pv. dieffenbachiae in Anthurium

The inheritance of resistance to the foliar phase of bacterial blight disease, caused by Xanthomonas axonopodis pv. dieffenbachiae, in Anthurium andraeanum was studied using parent-offspring regression analysis. In all, 14 parental cultivars, each represented by 3 plants per replicate, and 12 biparental progenies derived from the parents, each represented by 20 plants per replicate, were evaluated for foliar resistance using a leaf-disc, vacuum infiltration method in a randomized complete block design with three replications over two seasons. Three to five leaf discs (5.6 cm²; stage-2 leaves) obtained from each plant were vacuum infiltrated (15 psi; 10 s) with 10⁸ CFU/ml of inoculum and incubated (30°C) in trays. The time taken for the lesion to cover the entire disc was recorded for each disc. The progeny distributions were normally distributed with considerable transgressive segregation. Midparent/offspring regression analysis showed a high narrow sense heritability of 0.89 ± 0.13. These results indicate that inheritance of foliar resistance to blight is quantitative, with a major role for additive genetic effects. A breeding strategy to combine resistance to bacterial blight at both the foliar and systemic levels is discussed.