Ramulosis of cotton (Gossypium hirsutum) caused by Colletotrichum gossypii var. cephalosporioides is responsible for appreciable yield losses of cotton. The pathogen attacks all above ground plant parts basically provokes two kinds of symptoms: leaf and stem spots, and excessive sprouting. Severely infected plants are normally stunted. The process of breeding for resistance against this disease is hampered due to a lack of information about the mechanism of resistance. The objective of the present investigation was to understand the inheritance of resistance in two resistant cotton cultivars (BRS ANTARES and IAC 23) when crossed with one susceptible cultivar (STO 478). Evaluation of the segregating F2 and the backcross populations in cv. BRS ANTARES demonstrated that resistance to ramulosis is governed by one dominant gene, whereas in cv. IAC 23 the resistance is governed by two dominant independent genes with duplicated effect.
Gossypium hirsutum; genetics of resistance; ramulose
