Figure 7.

Genetic interaction between Sos1 and ra2. A, Photographs of the mature tassel of all genetic classes of an F₂ family segregating for Sos1 and ra2. B, Classification of the number of different types of axillary structures produced by the tassel. C, Close-up view of individual branches produced in Sos1/+; ra2/ra2 double mutant tassels. D, Close-up view of aborted spikelets produced in Sos1/Sos1; ra2/ra2 double mutant tassels. E, Photograph of mature ear of all genetic classes of an F₂ family segregating for Sos1 and ra2. F, Close-up view of axillary structures produced in ears of double mutant family. Normal and ra2 produce two kernels per row, Sos1 mutants produce one kernel per row, Sos/+; ra2/ra2 produce long branches with multiple kernels, Sos1/Sos1; ra2/ra2 produce long sterile branches with no kernels. G to J, SEM of ear inflorescence. G, Normal ear showing rows of paired SM. H, ra2 ear in which SPM produce three SM or occasional branches. I, Sos1/+; ra2/ra2 ear in which SPM form elongated branches. J, Sos1/Sos1; ra2/ra2 ear in which SPM produce barren elongated branches. Scale bar = 100 μm.