2019 ASHS Annual Conference

The Texas A&M Potato Breeding Program focuses on the development of early maturing varieties for different market classes such as processing chippers, fresh market russets, specialties, and reds adapted to Texas growing regions. Proper identity preservation (genotypic and phenotypic) and maintenance of released varieties and advanced clones/selections in tissue culture is fundamental to having sources of disease-free stocks to be used as parents and for seed multiplication. Genetic contamination or admixing between clones can occur in any program handling large amounts of plant material for extended periods of time. Initial phenotypic observations of greenhouse-propagated clones suggested that some misidentifications in the in vitro germplasm collection have likely occurred in the past 30–40 years of in vitro maintenance and regeneration. Further, little is known regarding the genetic diversity of this working potato breeding collection. Ninety-six clones from the program were genotyped using the Infinium 22K V3 Potato Array to develop DNA fingerprints. Tetraploid and diploid potatoes representing different market classes were included in the present study. Hierarchical clustering, based on 13,907 polymorphic SNP loci, was performed using the R package ‘ape.’ Accessions generally clustered together based on market class and ploidy level, with some deviations. The highest percent heterozygosity was observed in Atlantic (60%), followed by TX12484-2W (52%). The heterozygosity of diploids was much lower than tetraploids. Overall, the Infinium 22K V3 Potato Array was successfully used to genotype clones and determine unique fingerprints for clones included in the Texas A&M potato breeding collection.