Self-(in)compatibility inheritance and allele-specific marker development in yellow mustard ().

Yellow mustard () has a sporophytic self-incompatibility reproduction system. Genetically stable self-incompatible (SI) and self-compatible (SC) inbred lines have recently been developed in this crop. Understanding the haplotype of different inbred lines and the inheritance of the self-(in)compatibility (SI/SC) trait is very important for breeding purposes. In this study, we used the -locus gene-specific primers in and to clone yellow mustard -locus genes of SI lines Y514 and Y1130 and SC lines Y1499 and Y1501. The PCR amplification results and DNA sequences of the -locus genes revealed that Y514 carried the class I haplotype, while Y1130, Y1499, and Y1501 had the class II haplotype. The results of our genetic studies indicated that self-incompatibility was dominant over self-compatibility and controlled by a one-gene locus in the two crosses of Y514 × Y1499 and Y1130 × Y1501. Of the five -locus gene polymorphic primer pairs, Sal-SLGI and Sal-SRKI each generated one dominant marker for the SI phenotype of Y514; Sal-SLGII and Sal-SRKII produced dominant marker(s) for the SC phenotype of Y1501 and Y1499; Sal-SP11II generated one dominant marker for Y1130. These markers co-segregated with the SI/SC phenotype in the F populations of the two crosses. In addition, co-dominant markers were developed by mixing the two polymorphic primer pairs specific for each parent in the multiplex PCR, which allowed zygosity to be determined in the F populations. The SI/SC allele-specific markers have proven to be very useful for the selection of the desirable SC genotypes in our yellow mustard breeding program.