True Potato Seed: Changing Potato Propagation from Vegetative to Sexual

Abstract

“This thing called TPS [true potato seed] is a part of the future; how close that future is to us depends on whether people like us have what it takes.” R. Sawyer, 1984 The potato has traditionally been propagated vegetatively, but this may change someday. Today, many of the tubers produced from true potato seed (TPS), i.e., sexual seed, of selected potato progenies at the International Potato Center [Centro Internacional de la Papa (CIP)] could be sold in the markets of developing countries (Mendoza, 1984). Over the past decade of research at CIP, TPS technology has advanced significantly. More than 40 National Potato Programs are currently investigating the use of TPS. In eight countries, potatoes are being produced commercially from the first generation of tubers grown from TPS (Malagamba, 1988). CIP’s more widely tested TPS progenies are crosses between two tetraploid clones selected for progeny uniformity of tuber characteristics. Further improvements in TPS progeny uniformity could be obtained by using pollen selection techniques (Pallais et al., 1985a) and sorting for specific seed size characteristics. High levels of hybrid vigor and uniformity of tuber yields may be transmitted to the TPS progeny when produced with 2n pollen (first division restitution) of selected diploid clones crossed onto flowers of tetraploid mother plants (Peloquin, 1982; Peloquin et al., 1984). Ovules with unreduced gametes can also be formed in some potato diploids (Mendiburu and Peloquin, 1977). TPS may possibly be produced by crossing two diploid parents, which form 2n gametes, which would maximize heritability, heterozygosity, and, presumably, yield and uniformity. At present, the TPS technology has the possibility of being adopted in many tropical regions because high-quality seed tubers are difficult to produce in warm climates (Malagamba, 1988) because of the high inoculum pressure of the many tuber-borne pathogens