Induced Mutations in Connection with Biotechnology for Crop Improvement in Latin America

Objective:

To stimulate regional co-operation in the field of radiation induced mutations and related biotechnology for improving local cultivars through increased adaptability and tolerance to biotic and abiotic stresses.

Activities:

The CRP started in 1994 following the recommendation of plant breeders and geneticists involved in applications of mutation and related biotechnologies for crop improvement. Among the factors limiting crop production, the most important are: soil aluminum toxicity, salinity, drought, lack of available phosphorous in soil, and disease and pest susceptibility. Modern biotechnology, including induced mutations, offers considerable possibilities to breed desired varieties in a relatively short time. Additionally, both these techniques can be used for breeding some vegetatively propagated crops, which until now were improved by selection from natural or cultivated populations.

The final RCM was held at the National Agricultural University La Molina, Lima, Peru. More than 16 scientists from 8 countries took part in the RCM. On the basis of presented papers it is possible to state that induced mutation have become a frequently used tool to generate biodiversity in such countries of the Region as Costa Rica, Cuba, Brazil, Guatemala, Peru and Uruguay. Leading institutes from these countries have already moved to the application of mutation techniques in connection with modern biotechnology. This indicates that the main objective of this CRP was fully met. The CRP also brought significant results in development of new technologies/approaches and in the generation of the desired diversity for breeding programmes.

New methodologies/approaches:

  • Induced mutations were very effective to obtain mutants carrying different single resistance genes effective against the different lineages of the blast pathogen (Pyricularia grisea). Mutant lines exhibiting a partial resistance to other rice pathogens such as rice hoja blanca virus and/or its vector (Tagosodes oryzicolus) in Colombia and Cuba, and stem rot in Uruguay were also reported. These mutants can also be used effectively in crosses for the development of rice cultivars with resistance to these pathogens which have no known resistance genes.
  • Methodology for induced mutations in citrus trees using the cuttings irradiation method was successfully modified and applied for the development of desired new germplasm with such agronomically important characters as seedlessness, reduced plant growth or thin skin.
  • The phenomenon of high level mutant heterosis was confirmed on a large scale experiment with gamma ray induced wheat mutants in Chile. Similarly, the heterotic effect was also observed in some experiments with barley and rice in other countries.

Induced diversity for breeding:
The widely demonstrated usefulness of induced mutants in crop breeding programmes stimulated plant breeders from the Region to organize collections of valuable mutants. This activity was already initiated in a few countries but it should be expected that during the next few years more mutant collections will be established throughout the Region. Successful implementation of the ARCAL XXIa project has definitely increased the interest of breeders in conservation of mutated germplasm. Nevertheless, the number of mutants already kept in working collections is significant and could also be a valuable source of markers for genomic research:

  • Uruguay: 218 rice mutants from two varieties (characters: dwarfness, earliness, grain quality, disease resistance);
  • Cuba: more than 100 mutants from 5 rice varieties (dwarfness, earliness, grain quality, salinity tolerance, blast resistance);
  • Guatemala: 15 rice mutant lines with resistance to particular blast lineages;
  • Colombia (CIAT): 15 rice mutant lines with resistance to particular blast lineages;
  • Brazil: 25 wheat mutants (aluminum tolerance, earliness, dwarfness), 20 rice mutants (morphological characters);
  • Peru: 155 barley mutants from three varieties, 300 quinoa mutant lines.

Participants:

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Reports:

  • Report of the First RCM, Guatemala, 1994
  • Report of the Second RCM, Buenos Aires, Argentina, 1996
  • Report of the Final RCM, Lima, Peru, 5-9 October 1998. IAEA-TECDOC-1216. May 2001 publication. pp 1-71.

Project Officer:

P.J.L. Lagoda