Resistance to Coffee Berry Disease in Arabica Coffee Variety ‘Ruiru 11’

摘要

AbstractGeneral and specific combining ability effects for resistance to coffee berry disease (Colletotrichum coffeanumNoack sensu Hindorf) inCoffea arabicavariety ‘Ruiru 11’ and its parents were estimated according to the North Carolina Design II. A set of nine male parents and eleven females were crossed in all possible combinations to generate ninety‐nine single cross hybrids constituting the ‘Ruiru 11’ variety. The parents and their hybrid progenies were screened and the mean score data analyzed for possible genetic variation. The contributions of the parents to the total genetic variance were low hence the low narrow sense heritability (h2= 0.04). The male and female parents accounted for 9.36 and 0.96 , respectively, while their interaction effect accounted for 89.68 . In the analysis of combining ability for resistance, ExB3.96 and Cat.90 exhibited significant negative general combining ability (GCA). Specific combining abilities (SCA) were negative and significant for Cat.86 × ExB3.99, Cat.127 × ExB3.116 and Cat.119 × ExB3.879 crosses. The implications of these results in selection for highly resistant ‘Ruiru 11’ progeni