Genetic analysis of resistance to bacterial spot in sweet pepper genotypes
Roberto Alexandre Costa and Rosana Rodrigues
Bacterial spot (BS) is considered one of the most important diseases in sweet pepper cultivation and can cause great yield losses. Combining abilities for leaf and fruit resistance to BS of five sweet pepper genotypes were assessed. Analysis was performed using the diallel cross design following Method II, Model I proposed by Griffing (1956). Leaves were inoculated using the infiltration method while fruits were inoculated by perforation with a hypodermic needle. Leaf reaction to BS was assessed three weeks after inoculation by a score scale ranging from 1 (resistant) to 6 (susceptible). Fruit reaction was assessed seven days after inoculation according to a score scale ranging from 1 (resistance) to 5 (susceptible). Significant General Combining Ability (GCA) effects were detected for both leaves and fruits. Specific Combining Ability (SCA) for resistance to BS was not significant for either leaves or fruits. According to the analysis of Griffing (1956), the parents BGH 1772 and BGH 3071 contributed to the increase in leaf resistance, and BGH 1772 and UENF 1421 to fruit
resistance.