Inheritance of resistance to coffee wilt disease (Fusarium xylarioides Steyaert) in Robusta coffee (Coffea canephora Pierre) and breeding perspectives

Abstract

Knowledge on heritability is essential for select- ing varieties resistant against coffee wilt disease caused by Fusarium xylarioides, which is currently devastating coffee in East and Central Africa. Variability of the resistance against coffee wilt disease in Coffea canephora and its inheritance were investigated in three experiments corresponding to a clonal trial involving 20 clones, a 10- parent partial diallel progeny, and a half-sib progeny test. There were significant quantitative genetic variations among the clones and progenies, suggesting polygenic control of the resistance. Around 50–65 % tree mortality was the optimal disease level for calculating heritability and genetic gains. General and specific combining abilities calculated within the optimal disease range for partial diallel analysis were significant. Broad-sense heritability for the same anal- ysis and same disease range was moderate (0.329), and Communicated by A. Dandekar C. Cilas (*) CIRAD, UR 106, TA A-106/02 Avenue Agropolis, 34398 Montpellier Cedex 5, France e-mail: christian.cilas@cirad.fr: A. Charrier SUPAGRO, 2 Pl. P. Viala, 34060 Montpellier Cedex 1, France D. Bieysse CIRAD, UMR BGPI, TA A-54/K Campus Baillarguet, 34398 Montpellier Cedex 5, France corresponding narrow-sense heritability was low (0.112). Broad-sense heritability from clones in the field at the same disease range was also moderate (0.333). Narrow-sense heritability from regression of half-sib progeny means onto parent means in the field and screen house was 0.183 and 0.369, respectively. Selecting tolerant clones for improve- ment against the disease is possible, and genetic gains are possible by using tolerant parents in breeding programs.