Maize Variety PHRDC Breeding for Disease and Drought Resistance

The breeding process is segmented into distinct phases: initial crossing to introduce disease resistance and drought tolerance genes, followed by multiple backcrossing generations to progressively recover the uniformity of the recurrent parent. This segmentation allows trait introduction and uniformity restoration to occur in separate stages, resolving the contradiction between introducing new traits and maintaining variety uniformity.

Selection for uniformity and stability is performed preliminarily at each generation during the backcrossing process. Plants exhibiting both the desired resistance traits and uniform characteristics of the recurrent parent are selected before proceeding to the next backcrossing generation. This preliminary selection ensures that uniformity is maintained throughout the breeding process rather than being addressed only after trait introduction.

The recurrent parent variety serves multiple functions: it provides the uniform genetic background, contributes to the desired agronomic traits through backcrossing, and serves as the basis for the final hybrid combination. This multi-functionality reduces breeding complexity by using a single recurrent parent for multiple purposes rather than requiring separate lines for each function.

Performance evaluation of resistance traits and agronomic characteristics is conducted at each generation of the backcrossing process. This feedback allows breeders to select plants that simultaneously express multiple desirable traits and maintain uniformity, guiding the breeding process toward the desired outcome and reducing the need for extensive later-generation testing.