Resistance Response of Chilli ( Capsicum annuum L.) F 1 to Fusarium oxysporum Involves Expression of the CaChi 2 Gene.

Cross-breeding is a method of producing progeny with better resistance to pathogens. Resistance to pathogens usually involves pathogenesis-related (PR) proteins. Class II chitinase is an example of a defensive PR protein in plants. The class II chitinase in chilli is coded by the CaChi 2 gene. In this study, we crossed susceptible with resistant chilli cultivars, analysed the F1 resistance response against pathogenic F. oxysporum , and analysed the level of CaChi 2 gene expression in the F1 . Data were collected using disease severity index (DSI) determination and gene expression analysis by qRT-PCR (quantitative Reverse Transcriptase Polymerase Chain Reaction). Results showed that the DSI of F1 was not significantly different from the resistant ancestor. The relative CaChi 2 expression level of F1 was higher than the susceptible ancestor but not significantly different from the resistant ancestor. We concluded that the F1 can be categorised as resistant to F. oxysporum , and the CaChi 2 gene is involved in the molecular defense response.