New Frontiers in Potato Breeding: Tinkering with Reproductive Genes and Apomixis

Abstract

Potato is the most important non-cereal crop worldwide, and, yet, genetic gains in potatohave been traditionally delayed by the crop’s biology, mostly the genetic heterozygosity of autotetraploidcultivars and the intricacies of the reproductive system. Novel site-directed geneticmodification techniques provide opportunities for designing climate-smart cultivars, but they alsopose new possibilities (and challenges) for breeding potato. As potato species show a remarkablereproductive diversity, and their ovules have a propensity to develop apomixis-like phenotypes,tinkering with reproductive genes in potato is opening new frontiers in potato breeding. Developingdiploid varieties instead of tetraploid ones has been proposed as an alternative way to fill the gap ingenetic gain, that is being achieved by using gene-edited self-compatible genotypes and inbred linesto exploit hybrid seed technology. In a similar way, modulating the formation of unreduced gametesand synthesizing apomixis in diploid or tetraploid potatoes may help to reinforce the transition toa diploid hybrid crop or enhance introgression schemes and fix highly heterozygous genotypes intetraploid varieties. In any case, the induction of apomixis-like phenotypes will shorten the timeand costs of developing new varieties by allowing the multi-generational propagation through trueseeds. In this review, we summarize the current knowledge on potato reproductive phenotypes andunderlying genes, discuss the advantages and disadvantages of using potato’s natural variability tomodulate reproductive steps during seed formation, and consider strategies to synthesize apomixis.However, before we can fully modulate the reproductive phenotypes, we need to understand thegenetic basis of such diversity. Finally, we visualize an active, central role for genebanks in thisendeavor by phenotyping properly genotyped genebank accessions and new introductions to providescientists and breeders with reliable data and resources for developing innovations to exploitmarket opportunities.