During the maintenance of haploid inducing germplasm, a certain percentage of "self-induced" offspring can be observed, showing that haploids in the genetic background of inducer are possible, and that they are able to germinate and grow into haploid plants. Thus DH technology could be applied in inducer development, provided a system for haploid detection is available. We exploited the interaction between the two transcription factors R1 and C1, that regulate the anthocyanin pathway. The C1-I allele effectively suppresses anthocyanin production in the seed, even in the presence of R1-nj.
In haploid inducer seed, the expression of R1-nj will be suppressed in the crown, due to the presence of the C1-I allele, whereas the embryo will show the typical dark coloring.
We applied DH technology in inducer development in our effort to develop a high oil haploid inducer as well as in a graduate student project with the goal to apply GWAS in inducer development.
The C1-I haploid inducer (ISURF# 05202) is a useful tool to speed up and streamline inducer development. The induction rate obtained in a B73 background fixed for R1-nj is between 12-14% - this rate might be lower in haploid inducer backgrounds. If the haploid inducer background contains the red root marker Pl1, the distinction between haploid and hybrid seed is not as clear due to additional coloring in the kernel, which is not suppressed by C1-I, but still doable with reasonable false positive rates. The C1-I haploid inducer germplasm is available for licensing upon request.