2018 ASHS Annual Conference

With a number of genomics approaches now being able to be applied to perennial tree fruits relatively easily and inexpensively, the availability of segregating hybrid populations is often a constraint. We have two hybrid populations, each derived from crosses of a large-fruited genotype (’20 Ounce’ and ‘Edward VII’) and a very small-fruited crabapple genotype (‘Prairie Fire’). These populations have a much wider genetic basis than commonly found in apple breeding populations since the parents represent different Malus species. Each population is comprised of approximately 100 fruiting seedlings. While our primary purpose is to use these populations to investigate fruit size regulation, the populations are segregating for many other traits of potential interest. Some of these include tree characteristics such as branch angle, leaf color, flower color, and flower number per tree and per cluster. Wide variation in fruit characteristics is also evident including fruit size, fruit skin and flesh color, soluble solids concentration, fruit acidity, maturity time, fruit abscission, and fruit surface characteristics. There is also likely segregation for pest and disease susceptibility. We are in the process of genotyping all the seedlings in both populations, however phenotyping has been limited to focusing on fruit size. We are inviting collaborators to phenotype these populations for traits of interest and we are willing to share genotype information.