What would the phenotypic and genotypic ratios be if a cross was made between a plant that produced red flowers (RR) and one that produced white flowers (rr)? What would the phenotypic and genotypic ratios be for a cross of the F1 generation? The phenotypic and genotypic ratios of a cross between a black lab (BB) and a yellow lab (bb). Predict the phenotypic and genotypic ratios of an F1 cross. Gardener wanted to know if her red roses were true breeding. Is the genotype of her red roses? Are they true breeding? Why or why not? Same gardener breeds red roses (RR) on long stems (LL) to white roses (rr) on short stems (ll). Red roses and long stems are dominant. What are the phenotypic and genotypic ratios of this cross? What is the phenotypic ratio of the F1 generation cross?