Trait Capture for Crop Improvement

The ultimate development goal is to provide new crop varieties that are selected and adopted by the target communities and farmers in resource-limited regions. Through Subprogrammes 1 and 2, this Challenge Programme will identify new germplasm with genes/traits that will be valuable if incorporated into adapted varieties. This new germplasm will be found in raw germplasm that requires considerable plant breeding effort to transfer to locally adapted types by traditional plant breeding methods.

The Challenge Programme will define protocols (e.g., with case studies) for more efficient gene transfer. This will include marker genes that are closely genetically linked to the genes for the desired trait (marker-assisted selection), rapid tests for phenotype recognition, and genetic transformation of new genes into locally adapted genetic materials, such as improved varieties and landraces. The scope for the Challenge Programme is to identify genes, develop ways for detecting them in plant breeding programmes, and to make initial gene transfers by hybridization and transformation into several locally adapted genotypes (varieties). Therefore, the Challenge Programme will not produce finished varieties. Materials developed by the Challenge Programme will be made available to breeding programmes of NARS, CGIAR Centers, ARIs, and private breeding programmes utilizing many of the networks that already exist for this purpose.

Protocols for selecting the desired traits will be produced and demonstrated to NARS breeders and others through the Challenge Programme. The new genetic materials that are produced will be distributed to breeders under material transfer agreements (MTAs) and assurance of adherence to biosafety standards. These transfers will require the recipients to guarantee that the materials will be used to develop locally adapted varieties and will be readily available to farmers. The MTAs will be modeled after those currently used by the CGIAR Centers and other institutions.

The transfer of genes by hybridization or transformation will be done in collaboration with NARS scientists who participate in the Challenge Programme capacity-building activities. Selection protocols using marker-assisted selection, or in some cases functionality, may be assayed to detect specific gene products or pathways that have been correlated with improved performance (Ribaut et al. 2002).

While the vast genetic resources available are likely to provide the majority of the optimal gene systems, in some cases the optimal or critical gene or gene system may be entirely lacking in a species. In this case, genetic engineering will be employed to introduce the required gene into the target species. For example, modifications of gene expression by manipulating promoters by gene insertion will be studied. Genetic engineering may also be used for gene discovery and validation. The ability to target a single gene and modify both its expression and resulting products confers unparalleled power for better understanding the role of a specific gene in a biological context. Transgenic materials will be developed and made available only in strict accordance with biosafety regulations and ethical principles. The capacity for biosafety handling will be enhanced in the context of Subprogramme 5.

Following gene transfer, it will be necessary to validate the expression of the desired traits, both from the standpoint of the genetic background to which they were transferred and under field conditions representative of the farms in the targeted regions. In the Challenge Programme, validation will be done by agronomists, breeders, physiologists, and social scientists. The participating institutions will provide scientists for this step, but NARS scientists have a principal role because the validation is most appropriately done under representative conditions of the targeted farmers’ environments.

Many of the CGIAR Centers and NARS have crop improvement programmes that are well established and have made significant contributions over the past decades. The products of these breeding efforts are appropriate genetic resources for introducing new genes and gene combinations to build upon or enhance already productive materials. Protocols for optimizing gene and trait expression, in particular for drought tolerance, will be provided to the breeding programmes so that they can efficiently select for the desired genes and/or traits. In most cases, molecular markers will be available so that the gene(s) can be followed most efficiently by simply assaying for the associated marker.

Subprogramme Leader
Jonathan Crouch,
j.h.crouch@cgiar.org

mo·lec·u·lar breed·ing
n. 1. The use of molecular markers in association with linkage maps and genomics to select plants with desirable traits based on a genetic assay(s), which can make plant breeding more precise, rapid and cost effective in comparison to phenotypic selection. It also offers the possibility of addressing previously unattainable goals.

Research updates

Click here to read the most recent updates about this programme

Subprogramme 3
First Year Workplans
 
Cluster 1:
Marker-Assisted Selection
Training Workshop
Cluster lead:
Rodomiro Ortiz, IITA
r.ortiz@cgiar.org
 
Cluster 2:
Marker-Assisted Selection
Across Crop Groups
Cluster lead:
Rodomiro Ortiz, IIT
r.ortiz@cgiar.org
 
Cluster 3:
Transformation Across
Crop Groups
Cluster lead:
Marc Ghislain, CIP m.ghislain@cgiar.org
 
Cluster 4:
Seed Collection
of Materials
Cluster lead:
Tom Hash, ICRISAT c.t.hash@cgiar.org