Pollen viability in a cultivated sunflower line, in the wild sunflower (Helianthus annuus L. ssp. texanus Heiser) and in its hybrid offspring Nhiều tác giả: Mendoza Villarreal, Rosalinda, Reyes-Valdés, M. Humberto, Espinosa Zapata, Carlos, Villarreal Quintanilla, José Ángel