Title: The contribution of traditional potato breeding to scientific potato improvement Author
Submitted to: Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2011
Publication Date: December 15, 2012
Citation: Brown, C.R. 2012. The contribution of traditional potato breeding to scientific potato improvement. Potato Research. 54:287-300. Interpretive Summary: The potato is a tuber crop domesticated from wild porgenitors in the Andes. European invaders took the potato to the EasternHemisphere where it was developed further and became a major world crop. From relatively small numbers of introductions potato was apparently grown within a few years after introduction in gardens and gained renown as nourishing food especially for people suffering ill-health. It seemed to be a common associate of religious refugees as Protestants were pushed from one place to another. Its productivity and nutrient content made it a savior of poor and persecuted people. In the twentieth and twentieth-first century the production of new varieities through crossing was and remains to this day the dominant source of commercial introduction. Although various schemes have sought to maximize vigor through the enhancement of genetic diversity, none of these techniques have become standard practice. The levels of sugars have been lowered over years of breeding as the importance of fried porcessed products grew. Introduction of traits, particularly disease and pest resistances, from wild relatives has produced a few highly resistant varieties. In addition new varieties will be more nutritious as understanding of the variation in the Andean Center of Origin expands.
Technical Abstract: Conventional potato breeding refers to development of new cultivars from sexual crosses followed by clonal propagation and selection. Nearly all new varieties of potato still emerge from this process free from modern technologies of gene insertion. Conventional breeding remains the most important force for introduction of new phenotypes underlain by new genes. However, these come from already selected potato breeding lines or named varieties or from wild potatoes or more distant solanaceous relatives that are amenable to somatic hybridization. Potato breeders are constantly searching for new germplasm, in part because the potato as a crop still remains a highly vulnerable to biotic and abiotic stresses. In addition, the widening of the genetic base is seen as a means of increasing heterozygosity. Despite a highly conscious import of genetic variability, commercial varieties often emerge from a relatively restricted genetic pool. This is due to the long list of traits that must fall within narrow boundaries of performance. The potato must be able to navigate the conditions of modern agriculture, withstand unusual weather events, and arrive at harvest with skin and flesh appealing to the market for which it is intended. A storage period must also be endured during which appearance and suitability for processing or the consumer’s kitchen must be maintained. A lapse in any of these phases usually signals that a new variety will exit commercial use as fast as it entered. The inconvenient accompaniment pf introducing exotic genetic variation is that the breeding products are often outside of the targeted market niche. It is not surprising that many new varieties stem from crosses from older named varieties. Efforts to diversify are in conflict with conformism leading to relatively high co-ancestry coefficients between advanced breeding lines. Conventional breeding has advanced through the last hundred years the appearance, sugar status, verticillium resistance, and yield of larger sized tubers in statistically robust ways. Potato arrived from the new world and very quickly became the secret solution to famine for the poor by virtue of its productivity and nutrient content. Meanwhile, in modern times, challenges to the consumption of potato come from a sedentary and carbohydrate over- satiated society. The genetic repository of potato germplasm is so rich that a new era of potato varieties beneficial to health may be at hand. Conventional breeding will certainly be a major part of this.