Components of resistance to assess Black Sigatoka response in artificially inoculated Musa genotypes

Components of resistance were evaluated in seven Musa genotypes artificially inoculated with mycelia fragment suspensions of Mycosphaerella fijiensis Morelet (strain CCIBP-Pf80). Incubation period, number and area of necrotic lesions, infection index, area under the disease progress curve, asexual latent period, and number of spermogonia were evaluated in the genotype leaves to dissect the infective cycle of the fungus under greenhouse conditions. Incubation period in the inoculated leaves began at 14-21 days post infection, and significant differences were detected in the response of the different genotypes. Necrotic lesions were only observed in Grande naine, Pisang Awak, and significantly less in Pisang lilin. Grande naine reached the highest percentage of leaflet area with necrotic tissue, followed by Pisang Awak and Pisang lilin. Grande naine and Pisang Awak reached the greatest areas under the disease progress curves, while the lowest values were calculated in FHIA-18 and FHIA-25. The asexual latent period in Grande naine and Pisang Awak was significantly shorter (approximately 14 days) than in Pisang lilin. Greater numbers of spermogonia were observed in Grande naine and Pisang Awak, followed by Pisang lilin. Conidia were only detected in Grande naine, Pisang Awak and, in a significantly less number, in Pisang lilin. The different response observed of Musa spp. genotypes to the causal agent of Black Sigatoka indicated that the components of resistance used allowed the quantitative assessment of their reaction to this fungus. These results could improve or facilitate the efficiency and precision of the early evaluation process in banana and plantain breeding programs.