Fig. 5
Schematic representation of rapid, multiple detection of male transmission ratio distortion (TRD) using anther culture (AC)-induced calli derived from interspecific F1 hybrids compared with the conventional method. The sativa–glaberrima (s–g) interspecific F1 population should possess four HS loci: Sa, Sb, Sc, and Sd. Blue boxes indicate parental plants displaying genotypes of each HS locus, and green boxes indicate progeny population of plants or calli displaying ratio of each genotypes resulted from TRD or either homozygous allele. Blue and red arrows indicate the flows to the conventional backcrossing method and the method using AC, respectively. With the conventional method, TRD for HS loci can appear at the earliest in the BC1F1 generation after backcrossing as the seed parent. F2 generation is unable to proceed owing to male gamete lethality. In AC-induced calli, which retain completely homozygous genotypes after meiosis of F1 plants, TRD at HS loci can be directly detected without backcrossing