Quantitative Genetics in Sweetpotato: Where Are We within the Context of Genomic Tools for Sweetpotato Improvement Project?

The whole idea of crop improvement, be it through conventional breeding methods or through genomics-assisted breeding methods, is to increase genetic gain over time. Genomics-assisted breeding is hoped to help reduce the length of the conventional breeding cycle by allowing selection, at least in some generations, during early developmental stages thereby increasing genetic gains. For this to be realized, molecular markers have to be identified that are linked with the heritable part of the observed phenotypic variation relative to environmental variations or high density genetic markers should be available to be used in genome-wide selection. Clonally propagated crops such as sweetpotato have unique characteristics regarding quantitative genetic parameters that put them at a disadvantage in applying some of the genomic quantitative-genetic methods normally developed for seed propagated crops. These quantitative genetic parameters and the considerations to be made regarding the parameters in clonally propagated crops will be highlighted with special reference to sweetpotato. Quantitative genetic activities being carried out at the International Potato Center within the context of the Genomic Tools for Sweetpotato Improvement Project will be discussed.