Research Areas

Genetic Resources 2005-2008

Researcher: Luciano L. Nass

Genetic Resources

The conservation and use of genetic resources in Brazil face significant challenges in the areas of germplasm collection and exchange, conservation, characterization and use. The challenges include: (a) new initiatives on germplasm collection and exchange, aimed at enriching of the collections; (b) improving research on genetic resources conservation, particularly by integrating advances in biotechnology and genetics into the routines of short, medium and long-term conservation; (c) development of innovative methodologies and technologies for germplasm characterization, with special emphasis on the advancement of genomics and high throughput analytical procedures; (d) integration of tools for informatics and statistical sciences into current system used to manage biological information to make all the available biological data accessible to genetic resource users; and (e) new initiatives to circumvent the limitations on financial and human resources, necessary to support research and other activities with genetic resources. Continuous and integrated plan is necessary to overcome these challenges in the next few years in order to minimize the risk of losing valuable genetic resources.
Recent advances in genomic sciences are already changing the way one characterizes and looks for biological attributes in germplasm collections. Innovative methodologies aiming at high throughput characterization (sequencing of whole genomes, DNA microarrays etc.) should be an important objective of the research, since it will enable one to have detailed knowledge of the actual potential of the germplasm collections. Such innovations will stimulate our capacity to characterize genetic resources, impacting on the conservation procedures (eliminating duplications, developing core collections etc), and promoting new ways of conserving diversity (cell, tissue and DNA banks). The future trend will be to generate strategically structured collections for use in by the breeding programs. This will certainly promote a greater utilization of the genetic diversity available in gene banks.
Research is the cornerstone to efficient conservation of genetic resources. Efforts to integrate biotechnologies and advanced genetic knowledge in the routines of germplasm conservation are urgent. The human resources required for the genetic resources activities need to have expertise in areas as diverse as population genetics, tissue and organ culture, cryopreservation, micropropagation, molecular biology, stress physiology, etc.


NCGRP presents many opportunities for research interaction with Embrapa’s Units through the LABEX-USA Program. The NCGRP has been interacting with Embrapa Genetic Resources and Biotechnology for a long time, mainly through the exchange of plant germplasm. It should be emphasized that the US is still open for germplasm exchange and as of today, it is Brazil’s major source of foreign germplasm.
The main objectives of my participation in genetic resources conservations as part of the Labex-USA Program are:

Broad germplasm exchange activities between the USA and Brazil

There is no country in the world that is self–sufficient in genetic resources. Therefore, the exchange of germplasm between countries is important for the enrichment of the genetic diversity of the species conserved. This objective will establish a plan of action to promote the enrichment of the germplasm collections in Embrapa and ARS through a bilateral agreement.

Establish partnerships on innovative and strategic research goals

Special attention should be given to some areas of research that are strategic and innovative, including: theoretical and applied studies on germplasm sampling and the integrity of germplasm collections; new methods for germplasm conservation, including cell and DNA banking; advances in long-term conservation research, such as cryopreservation; and others.

Stimulate interactions between Embrapa and ARS scientists

The interaction between ARS and Embrapa in plant genetic resource conservation is limited, especially in the exchange of information and development of collaborative projects. Promoting a greater institutional interaction in strategic areas and establishing partnerships for grant submission to international financing agencies are actions that should be stimulated by both institutions.

Analyze methods of data documentation and information management and establish interactions for data exchange

A critical analysis of the documentation system and informatics network used by the ARS (GRIN) and by Embrapa (SIBRARGEN) is necessary to promote an intensive and efficient view of the information in germplasm banks (reports, surveys, diagnostics of genetic diversity gaps, data management etc). Defining the parameters needed for a better interface between the two information networks will be a focus for this objective.
Analyze genetic resources and curatorship systems adopted by ARS and Embrapa
The curator of a collection is essential for proper conservation, characterization and use of germplasm collections that represent the genetic diversity found in natural populations. An analysis of the advances and limitations of the curatorship systems adopted by the ARS and Embrapa will be important for the modernization of curator activities and training in the next few years.

Exchange Germplasm (Dr. David Ellis)

The main objective will be to set up a basis for a broad agreement for germplasm exchange between ARS and Embrapa. The strategy will involve the Curatorship System of both countries in this discussion to establish some target species to be used as models for this agreement. Obviously, legislation and other rules governing germplasm exchange in both countries will need to be respected. Nonetheless, it will be necessary to initiate a pro-active effort to promote advances in the Brazilian biodiversity and genetic resources legislation, since it is presently restrictive to germplasm exchange in many aspects.

Characterization of Lipid Components Before and After Cryogenic Storage of Maize Grains

To measure thermal behavior of triacylglycerols (lipids) in maize embryos as a function of storage temperature, time and viability. This assay will reveal the molecular mobility of lipids within maize at cryogenic temperatures and potentially provide a non-invasive measure of seed deterioration or longevity.


Maize grains deteriorated faster in cryogenic storage (liquid nitrogen temperatures) compared to conventional storage (-18oC) according to three independent long-term studies conducted at NCGRP. These studies, initiated between 1977 and 1987, show progressive loss of viability of hybrid and inbred lines of maize as well as in wild accessions of Zea mexicana during nearly 20 years of storage at -135 (vapor phase of liquid nitrogen) or -196oC (liquid nitrogen).
The mechanism by which seeds lose viability under cryogenic storage is poorly understood. Current research at NCGRP links the physical behavior of lipids with storage behavior. We wish to pursue these studies using maize to determine whether properties of lipids within maize embryos predisposes them to more rapid deterioration under cryogenic storage and whether changes in lipid behavior can be detected as grains lose viability.


Our experiments include 4 temperatures (25°C, 5°C, -18°C, and -160°C) and 3 replications. We already have the data using DSC analyses for all temperatures. The next step will be to evaluate all data (total of 336) for crystallization rate using specific software (Pyrus – DSC Analysis) (Figure20). During 2007 we will be also developing the papers about this study.

Expected Outcomes

By measuring the rate at which lipid molecules reorganize to effect a phase change, we will be able to infer the molecular mobility of the lipid phase within seeds. This measurement will directly address the extent to which liquid nitrogen temperatures stop molecular mobility. Changes in lipid phase behavior during storage will imply that lipids are involved in deterioration reactions. Differences among maize lines in the rate of crystallization during cooling may indicate differences in seed quality. If this is the case, then our techniques will provide a non-invasive test to reveal seed longevity and deterioration.