**2. Breeding schemes of potato at INIA Chile**

and the annual Chilean production is 1 million tons including 50,000 ha with 60,000 farmers. Therefore, potato has a strong economic and social importance. For this reason, Instituto de Investigaciones Agropecuarias or the Agricultural Research Institute (INIA) established a potato breeding program. In Chile, official statistics indicate that among the eight potato varieties mostly sold in wholesale markets, three correspond to varieties developed by INIA [2].

Potato varieties must fulfill the requirements of the market and consumer preferences, as well as to show good agronomic performance in several environments and wide adaptation to productive systems. Traits as high yield, tuber conformation, early maturity, and resistance to

The breeding of potatoes needs to deal with some complicated issues that make potato breed-

• Tetraploidy, together with severe inbreeding depression upon repeated selfing, renders the generation of pure lines, recombinant inbred lines (RILs), or near-isogenic lines (NILs)

• Tetraploid potato genotypes are therefore highly heterozygous. The heterozygous geno-

• Current breeding of marketable varieties comprises the generation of genetic variation by

• Evaluation and selection of approximately 13 main characters of plant and tuber in the recombinant F1 generation via multiyear and location trials. The selection cycle from cross-

• As potato is clonally propagated, diseases are accumulated and transmitted to descendant tubers; therefore, a system for cleaning and maintaining virus-free stocks of seed is

These issues make potato breeding to concentrate a large effort in developing a system of controlled crosses that generate seeds from several families producing a large F1 population that will be the source of new breeding lines with potential to become varieties. Additionally, during the process, a big expense of resources is destined to rouging and maintaining of clean

Under optimized agricultural practices, potato production can yield more than 40 tons per hectare within 4 months from planting to harvest. To achieve this yield, it is essential to have high-quality seeds and improved cultivars as well as good agronomic practices and pest and disease control. With low technology, average yields are much lower ranging from 5 to 20

It is expected that through applications of biotechnology such as tissue and cell culture, genetic engineering, marker-assisted technologies, genome-assisted technologies, or a combination of

crossing elite tetraploid parents, usually varieties and advanced breeding clones.

biotic and abiotic stresses are the most important goals for potato breeding in Chile.

• Most of the cultivated potatoes are tetraploid and show tetrasomic inheritance.

types are fixed and maintained by vegetative propagation via tubers.

ing to variety release requires approximately 10–12 years.

ing a special case in genetic improvement of crops:

impractical.

4 Potato - From Incas to All Over the World

essential.

seed stocks of seeds.

tons per hectare.

The mission of the potato breeding program in Chile is to develop potato varieties for different uses and productive systems to meet the Chilean market demand, with international projection.

The INIA uses a breeding scheme that is similar to classical potato breeding programs [3–5] with modifications according to local requirements. The potato breeding program begins with the selection of a large number of genotypes to be used as crossing parents. In the early steps of selection, around 100 crosses are made and 30,000 genotypes are evaluated. Selection of F1 progeny at early breeding stages (i.e., the primary individual selection of seedlings and the secondary individual clonal selection) is based on characteristics with high heritability and little annual variation, such as skin color, flesh color, and tuber shape, according to Chilean consumer preferences. The elimination of progeny with severe defects that can devastate potato production (e.g., hollow heart, growth cracks, and brown spots) also occurs at these stages. Progeny that is extremely susceptible to diseases as PVY, PVX, common scab, and late blight is discarded based on visual inspections of the field, although molecular markers are also available for genotype analysis. In later stages (i.e., line selection and the performance yield test), selection is carried out based on quantitative characteristics, such as yield, maturity, cooking qualities, and aptitude for chips or French fries. Molecular markers are applied in all the advanced breeding lines in order to confirm combinations of several resistance genes for diseases. A fixation process is unnecessary as they are clonally propagated.

The main objectives of the program are:

	- Late blight resistance
	- Golden nematode resistance
	- PVY resistance

To achieve these objectives, the activities of the program involve controlled crosses every year (around 100), with 30,000 novel genotypes that are evaluated in multiyear and locations in field conditions.
