A Phenomics Approach for Studying the Genetics of Fruit Quality Traits in Cranberry (Vaccinium macrocarpon Ait.)

摘要

The American cranberry (Vaccinium macrocarpon Ait.) is a minor fruit crop of great importance in North America. Given its recent domestication, cranberry breeding efforts are commonly hampered by the limited genetic resources and germplasm availability. Moreover, studies regarding cranberry genetics and genomics are scarce hindering the implementation of genetic marker technology for breeding programs. In this research, we generated important genetic resources of major interest for cranberry researchers, breeders, and industry. Particularly, we carried out two quantitative trait locus (QTL) mapping studies involving fruit quality traits, which are becoming determinant factors for processing within the cranberry industry. The first study revealed important QTL for anthocyanin content, Brix, titratable acidity and proanthocyanidin. In addition, a computer-vision method called GiNA was developed and implemented as a reliable alternative to predict anthocyanin content, which is a laborious wetlab task. The second study was focused in fruit shape and size. We used GiNA to obtain a massive amount of phenotypic data and multiple consistent QTL. Parallel to this, we used imagining methods and firmness analysis to study the internal structure of cranberry fruit and how it changes during the ripening process. This project allowed us to characterize different cultivars terms of pericarp size, locule cavity size, and firmness, which are of special interest for processing specific cranberry products such as sweetened dried cranberries (SDC). Finally, we studied organelle diversity in cranberry closely-related wild species' V. micrcarpum and V. oxycoccos . Our results suggested that Alaskan V. microcarpum could have been the cytoplasm donor of cultivated cranberry, and that all these species possess high genetic sequence similarity. Therefore, they could be used as important germplasm resources for the incorporation of novel traits into cultivated cranberry.