A Promising Breeding Strategy for Improving Tuber Quality in Chipping Potatoes

Tuber internal quality is a major limiting factor for the U.S. potato industry.  Breeding efforts have produced varieties with improved processing traits such as ‘Atlantic’ but this variety lacks of desirable internal quality. In-season fertilization with calcium is known to result in an increase in tuber calcium, improved internal quality, and lower incidence of tuber internal defects, bruise susceptibility, and reduced storage rot. Significant genetic variation was found for tuber calcium content among the major U.S. potato cultivars, and ‘Superior’ has been the highest calcium accumulator among the chipping varieties.  Our studies aimed to investigate the genetic potential for improving internal quality of ‘Atlantic’ type by increasing tuber calcium content. Therefore, reciprocal populations were generated by crossing ‘Atlantic’ and ‘Superior’ in order to study the genetics of tuber quality traits and select varieties with chipping quality similar to ‘Atlantic’ and improved internal quality similar to ‘Superior’. From the evaluation of over 300 clones, significant genetic variation for tuber calcium, chip quality and internal quality was found for both reciprocal populations. One of the reciprocal populations, ‘Atlantic’ x ‘Superior’, was SNP-genotyped by the SolCAP project. Combining the phenotypic and genotypic data, a tetraploid linkage map was developed and quantitative trait loci (QTL) for tuber calcium, yield, specific gravity, internal defects such as hollow heart, and pitted scab were identified. We also found a relationship between improved tuber quality and tuber calcium concentration. In addition, we have identified promising cultivars with good chipping quality, enhanced tuber internal quality, and tolerance to scab.