**4. Conclusions about the role of biotechnology in Chilean potato breeding program**

Currently our program keeps in vitro the 11 INIA varieties, 134 advanced breeding lines from

*Pectobacterium* spp. Y1/Y2 *Pel* [18] Darrasse et al., modification of protocol

Molecular fingerprints have been done to characterize 61 varieties, 25 advanced breeding lines, and 823 native landraces. We use the CIP identity kit for molecular profiling of the most valuable material for reliable identification and traceability during breeding process and seed

We use 11 molecular markers for marker-assisted selection, and at the date, we have analyzed 461 breeding lines and 33 varieties. The most important advantage of applying these markers is to allow more precision to choose parents for crossing in order to combine or pyramiding

In **Table 4**, we can see the markers associated with resistance genes and light yellow flesh color present in the released varieties. It is possible to see that many varieties hold markers associated to golden nematode resistance, a quarantine pest in Chile but present in some

> **Late blight resistance**

**PVY resistance** **Light yellow flesh/ white flesh**

[19] Du et al., modification of protocol

INIA program, and 32 foreign varieties and breeding lines with research purposes.

N

**Table 3.** Procedures used for molecular diagnosis for *Pectobacterium* spp. and PVY in potato plants.

production and in the future to track the presence in the market.

**Test Marker Gene target Reference**

*PVY* PVYF/PVYR Capsid protein, strain:

10 Potato - From Incas to All Over the World

**PVX resistance**

Fueguina-INIA *— R3a–R3b —*

Purén-INIA *Gro VI R1*; *R3a*; *R3b —*

R87009–28 *Ryadg*

Karú-INIA *H1*; *Gro VI Allele 3 BCH 2* Patagonia-INIA *Gro VI Allele 3 BCH 2* Pukará-INIA *Gro VI*; *Gro 1–4 RX2 Allele 3 BCH 2* Puyehue-INIA *H1*; *Gro VI*; *Gro 1–4 R3a Allele 3 BCH 2* Yagana-INIA *H1*; *Gro VI RX2 Allele 3 BCH 2*

Ona-INIA *— R1 Allele 3 BCH 2* Pehuenche-INIA *Gro VI*; *Gro 1–4 R3a Allele 3 BCH 2*

**Table 4.** Molecular markers associated with resistance genes and light yellow flesh color present in the released varieties.

genes.

**Variety Golden nematode** 

**resistance**

Kuyén-INIA *— RX2* — Rayún-INIA *H1*; *Gro VI R3b* The program has implemented six biotechnological techniques; these are applied in the stages of characterization of the gene bank, selection of parents, marker-assisted selection, characterization of varieties, and propagation of material for seed production. One hundred percent of the varieties have been released involving biotechnology, especially by the use of in vitro culture techniques to produce pathogen-free material for initial stages of seed production of advanced lines. Biotechnological techniques have participated in the improvement of 2 of the 13 main characteristics associated with the program objectives. Two of the 11 varieties were characterized by molecular fingerprint at the time of their release. Biotechnological techniques such as in vitro culture, molecular fingerprint, and molecular diagnosis of diseases are used to produce primary multiplication of reproductive material for 100% of the varieties released by INIA currently present on the market.

Some important facts about the use of biotechnology in breeding and development of varieties are:


In potato breeding, the selection of desirable phenotypes from a large breeding population will remain essential.

• Automatic, low-cost, and high-throughput phenomic technologies would be a valuable tool for massive screening of phenotypes.

• Screening methods based on next-generation sequencing technologies promise to revolutionize screening for desired genotypes, but it is necessary to solve the problem of distinguish between three different heterozygous genotypes (AAAB, AABB, and ABBB) in traits where plex number affects the character under selection.

to Ma*R11*. In Ma*R8* and Ma*R9*, at least four (*R3a*, *R3b*, *R4*, and *R8*) and seven (*R1*, *Rpi-abpt1*, *R3a*, *R3b*, *R4*, *R8*, and *R9*) R genes were present, respectively [15, 25]. This set can be used to simultaneously introduce multiple R genes. However, since this set has a low agronomic value, crosses must be made with elite breeding material to obtain breeding lines suitable for propagation.

The Use and Impact of Biotechnology in Potato Breeding: Experience of the Potato Breeding…

http://dx.doi.org/10.5772/intechopen.72961

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Significantly, the resistance provided by the R genes is background dependent as genes that suppress R genes can also be segregated into F1 offspring plants [26]. Thus, more knowledge is needed about how R genes perform in different genetic backgrounds. Research has also focused on creating GM organisms carrying constructions with the described R genes [27]. However, this class of plant material is not allowed in many parts of the world for human or animal consumption including Europe and Chile. Furthermore, society is suspicious about its sustainable utilization because of the health, environmental, and social implications of GMOs. For this reason, it is necessary to investigate the applications of the natural stacking of several

**a.** To combine multiple R genes that confer resistance to late blight in new lines of the potato

**b.** To evaluate the level of resistance to *P. infestans* in genotypes carrying different R genes inherited from hybridization between Ma*R8* and Ma*R9* with elite breeding material

Controlled crosses were performed between five commercial varieties and the genotypes

Ten progenies from each cross were randomly selected for molecular analysis and phenotypic evaluations in order to assay for the presence of R genes. The performance of these genotypes

During the 2013–2014 season, 90 randomly selected progenies were evaluated for pathogen resistance. We calculated the area under disease progress curve (AUDPC) in individual plants under natural infections in the field. To promote infections, the progeny was watered by a

For the molecular analysis, DNA extractions and PCR amplification were performed using genetic markers as described in **Table 2** for *P. infestans* to track the presence or absence of R

Progeny was also phenotypically evaluated. We determined the percentage of leaves affected by late blight during plant development by visually estimating the green and non-green portions of the leaves. The estimations were integrated into the AUDPC or area under the disease progress curve. AUDPC is obtained by the repeated visual inspections and estimation of the percentage of the leaf affected in a set of plants. The value is calculated by the formula used by Jo et al. [28]. Percentages of damaged foliage are plotted through a period of time. AUDPC

spray system twice a week although the natural inoculum was high in Osorno, Chile.

was calculated for the 10 randomly selected individuals from each cross in the field.

Ma*R8* and Ma*R9* that hold four and seven genes of resistance, respectively.

was monitored under pathogenic pressure in field conditions.

genes in the Ma*R8* or Ma*R9* crossed with elite material progeny.

R genes to overcome *P. infestans.* The objectives of our work are:

**5.2. Materials and methods**

breeding program of INIA Remehue, Chile

• In order to make more precise the addressing of breeding procedures to improve specific traits (i.e., compounds with nutritional value or to eliminate undesired characters), methods as the new biotechnological techniques (NBTs) could be promising in countries where GMOs are not allowed. These new technologies as CRIPSR/Cas can be used to develop a genetic engineering with no transgenic status of the final product.
