A Combining Ability Analysis of Cassava Manihot esculenta Crantz Genotypes to Anthracnose Disease

Abstract

Cassava Anthracnose Disease (CAD) caused by Colletotrichum gloeosporioides f sp. manihotis has been recognized as one of the major economic disease of cassava in all the cassava growing regions of Africa. Little information is available on the resistance of cassava to C. gloeosporioides f sp. manihotis. This study was conducted to determine the relative importance of general (GCA) and specific (SCA) combining ability, maternal and non-maternal reciprocal effects on resistance to C. gloeosporioides f sp. manihotis in selected cassava genotypes. A complete diallel mating scheme including reciprocals of nine resistant and susceptible genotypes of cassava were evaluated in the field over a period of two planting seasons. The combining ability analysis revealed that both the additive and nonadditive gene effects were present. Crosses between the resistant lines and susceptible genotypes showed intermediate disease reaction to CAD suggesting a polygenic system of resistance to the disease. The significant maternal and specific reciprocal differences among the parents and crosses indicated that maternal and/or cytoplasmic inheritance is involved in the reaction of cassava genotypes to Colletotrichum gloeosporioides f sp manihotis. The significant genotype X environment interaction suggested lack of stability in the development of lesions/cankers on cassava stems. Therefore, recurrent selection would be appropriate for accumulating genes for resistance to CAD in cassava and progeny performance may not be based on their parents performance sec −1 .

Heritability, combining ability and inheritance of storage root dry matter in yam beans

“…This observation is supported by the argument that the ratio of additive to non-additive variance in a population gives an indication of relative importance of GCA and SCA estimates in predicting progeny performance (Owolade et al, 2009).…”

Genetic analysis in a six parent diallel cross of cassava (Manihot esculenta Crantz)

“…Therefore, Maunjili can be a desirable parent for hybrids as well as for inclusion in breeding program aimed at developing varieties resistant to CGM due to its significant negative value (Table 3). The foregoing suggestion is in tandem with the report by Owolade et al (2008) andDa Silva (2008). The study has found that the best rated general combiners based on GCA effects were Mulola for average root number, fresh root weight and above ground weight and Maunjili for fresh root weight, harvest index and cassava green mite which means that these could be good parents to use when breeding for genotypes for the said traits.…”

“…For CGM, significant positive combining ability effects were considered as low, non-significant as average and significant negative as high (Saleem, 2008). GCA and SCA values with negative effects show contribution towards resistance, and positive values show contribution towards susceptibility for CGM (Owolade et al, 2008). Baker's prediction ratio (PR) (Baker, 1978) was used in determining progeny performance, that is, .…”

Farmers’ knowledge and perception of postharvest physiological deterioration in cassava storage roots in Ghana

“…It is the third most important source of carbohydrates in Africa [2] and the second most important staple crop in Ghana [3]. Cassava serves as food for over 800 million people worldwide [4], providing about 500 calories daily for more than 70 million people [5].…”