A SNP in RPT5b intron 7 correlates with unequal redundancy between RPT5a and RPT5b in pollen development. A, Schematic representation of the F1 crosses used in this study. A and a represent wild-type RPT5 and rpt5a-4 mutated allele, respectively. BCrepresents the Col allele RPT5b while X stands here for a non-Col accession. B, Gamete segregations for the F1 plants obtained in A. Two hypotheses are taken into consideration: that either the non-Col RPT5b allele complements the rpt5a mutation (BX, from the X accession) or that it does not (BYfrom the Y accession). For each genotype, the percentages of expected gametes are indicated. Hence if the hypothesis is correct the percentage of dead pollen is either null or indicated by the grey column. C, Mature pollen stained with Alexander's stain in anther locules from a Aa4 BCBBu-11F1 hybrid and parents. Only the F1 plants show some dead pollen (indicated by arrows). D, Percentage of dead pollen determined by Alexander staining and subsequent counting in F1 AA BCBX(black boxes) and Aa4 BCBX(blue boxes where X stands for the accession written below the graph) plants. For each genotype, 300 grains were counted per plant. Values are shown as means on 4 independent plants (±SD).