Selección de clones y progenitores para el mejoramiento de la resistencia al fitoplasma del amarillamiento de la ca？a de azúcar (SCYP)

the incidence of the disease ？sugar cane leaf yellows phytoplasma (scyp)？, was evaluated in 733 clones of 26 biparental families of the breeding program of sugarcane of the year 2006 in cuba. the objective was to determine in the stage of clonal lot 1, the incidence of the scyp through natural infection in order to select resistant clones to this disease and also to identify the parents that give origin to progenies with low incidence of this disease. the natural infection by scyp in the initial stages of the selection scheme increased with the age of the plant, as well as the severity of the disease. it was recorded the presence of symptoms in the 26,6 and 80,42 % respectively of the evaluated clones at 6 and 18 months of age, resulting that the natural infection could be used to select resistant clones to the scyp. from all the studied combinations, c86-12 x b45181, c86-503 x b6368 and c86-456 x b45181, resulted the progenies with the lowest incidence of scyp. the parents used as feminine c86-12 and c86-503 and those used as masculine b6368 and b45181, showed the lowest frequencies in incidence of scyp in their descendants. the natural infection of the scyp was grown in the parents of the biparental families evaluated, in most of them with high incidence.