Fig. 2. bif2 mutants make fewer branches and spikelets in a background-dependent manner. (A) Normal tassel after anthesis (B73 genetic background). The main spike and long lateral branches produce pairs of spikelets. (B) bif2 mutant tassel in the B73 genetic background. In severe cases, bif2 mutants produce no branches and almost no spikelets, resulting in a barren rachis (inflorescence stem). (C) bif2 mutant tassel in the A188 genetic background. The tassel has a sparse appearance with few branches and few spikelets on the branches and main spike. (D) bif2 mutant tassel in the A619 genetic background. Single spikelets form on the rachis. The tip of the rachis is split. (E) Normal ear (the female inflorescence). The outer protective husk leaves are removed to reveal rows of female florets with elongated silks covering the rachis. (F) bif2 mutant ear. Inside the husk leaves is a bare rachis with no spikelets or florets. The tip of the rachis is split. Scale bar, 2.7 cm.
