Inheritance of the Flesh Color and Shape of the Tuberous Root of Sweet Potato (Ipomoea batatas [L.] Lam.)

The continued success of any conventional sweet potato breeding program is limited to knowledge of the inheritance of the traits studied, such as flesh color and tuberous root shape, because it is difficult to fractionate color frequencies by visual separation. The objective was to understand the mode of inheritance of these genetic traits. The crossing blocks were established at the Research Institute of Tropical Roots and Tuber Crops (INIVIT-Cuba). Eight parental genotypes of known compatibility were selected, with contrasting phenotypic characteristics to develop seg-regating populations. To express color objectively, the CIE L*a*b* color space was used (L*: lumi-nosity; a* and b*: chromatic coordinates), in addition, four morphometric variables associated with the shape and dimensions of the tuberous roots were evaluated. From 2419 reciprocal cross-es, 2045 botanical seeds and 1764 seedlings were obtained. Incomplete dominance of the white and purple flesh colors over the orange color was observed, as well as transgressive segregation for purple, orange and white flesh colours, and for the shape of the tuberous roots. The results al-lowed to propose a genetic model of biparental crosses to improve the flesh color of I. batatas, as well as a predictive formula of the progenies to be selected.