Fertility study of mating types of Gibberella xylarioides Heim & Saccas on coffee robusta in natural conditions of infection in Democratic Republic of Congo

Marcel Muengula-Manyi, Mafuta Wayisi, Augustin Ngombo-Nzokwani, Adrien Kalonji-Mbuyi, Patrick Tshilenge-Djim
2016 International Journal of Research in Plant Science   unpublished
A study was conducted on the fertility of mating types of Gibberella xylarioides, the causal agent of Coffee Wilt Disease (CWD). The trial was performed using a randomized complete block design with three replications. Coffee seedlings were inoculated in different positions using MUCL 44532 and MUCL 44536 strains of G. xylarioides. Results obtained showed that browning of leaves appeared 67 days after inoculation (dai), and drying of leaves and mortality appeared respectively 93 and 103 dai.
more » ... 93 and 103 dai. The rate of browning of leaves was equal to 46%, 18% for drying of leaves and 17% for mortality of seedlings. Seedlings inoculated with Mat1/Mat2 and Mat2/Mat1 produced more than 10 perithecia, and those inoculated with Mat2 and Mat1-Mat2 produced more than 3 to 10 perithecia. Fertile perithecia was observed on seedlings inoculated with Mat1-Mat2 and Mat1/Mat2 with respectively 13 and 17%. Defoliation was attributed to a physiological cause. Except on seedlings inoculated with Mat2/Mat1, and on control, the presence of G. xylarioides was confirmed in dead woods of other seedlings. There is a heterothallism in G. xylarioides, which would be the cause of variability within this pathogen and could be among the causes of the resurgence of CWD in Democratic Republic of Congo.