Assessing the potential of genetic resource introduction into elite germplasm: a collaborative multiparental population for Flint maize

Abstract

Abstract Genetic diversity is crucial for maintaining genetic gains and ensuring breeding program’s long-term success. In a closed breeding program, selection inevitably leads to a loss of genetic diversity. While managing diversity can delay this loss, introducing external sources of diversity is necessary to bring back favorable genetic variation. Genetic resources exhibit greater diversity than elite materials, but their lower performance levels hinder their use. Establishing a bridging population that involves crosses between elite materials and diversity donors is a way to create improved genotypes that facilitate the incorporation in elite germplasm of original favorable variations coming from the donors.. Promising crosses in bridging populations can be identified thanks to their usefulness criterion (UC), which estimates progeny performance after selection, based on the average performance and the genetic variance of the cross. This paper documents experimentally these parameters in the framework of a collaborative multi-parental BC1-S2 population that includes materials from multiple breeding companies crossed to different donors. This program aims at enhancing the flint maize elite germplasm, which has only utilized so far a limited portion of the diversity available in genetic resources. Our findings show contrasted variances and UCs among crosses, resulting in an expected mean performance gain of 5% over the initial elite material. They make it possible to identify the most promising donor for each partner. They also suggest that one more generation, i.e. 3 in total, of crossing to the elite is required to fully exploit the potential of a donor.