Phenotypic characterization of VF cdka;1 cdkd;3 and VF cdka;1 cdkd;1 mutant combinations. (A) Siliques of WT versus VF cdka;1/−, VF cdka;1/− cdkd;3/+, and VF cdka;1/− cdkd;3/−. Red asterisks indicate aborted seeds. Scale bar, 1 mm. (B and C) Number of aborted seeds in at least five siliques (B) and pollen viability using at least eight flower buds (C) for the genotypes shown in A. Level of significance (*, P < 0.05; **, P < 0.01; ***, P < 0.001) determined by one-way ANOVA followed by Tukey’s test. (D) Pollen sizes (in pixels) after Peterson staining of diploid and tetraploid WT pollen versus pollen from VF cdka;1/−, VF cdka;1/− cdkd;3/+, and VF cdka;1/− cdkd;3/− from ≥500 pollen grains for each genotype. (E) Peterson staining revealing the difference in pollen size for the genotypes quantified in D. Scale bar, 20 µm. (F) Repartition of meiotic stages within one flower bud undergoing meiosis from metaphase I to telophase II/tetrad in VF cdka;1/− cdkd;1/+ (n = 272) and VF cdka;1/− cdkd;1/− (n = 285). (G) Chromosome spread analysis of male meiocytes of VF cdka;1/− cdkd;1/+ and VF cdka;1/− cdkd;1/−. Orange arrows highlight the premature exit after meiosis I in 75% of the meiocytes analyzed. Scale bar, 10 µm.