FIGURE 1.
Images of microspores at different developmental stages in Nip, WK21, and WK21/Nip F1 plants. (A) Panicles and pollen grains of Nip, WK21, and WK21/Nip F1 plants. Panicles in Nip and WK21 were fertile, while the panicle in WK21/Nip F1 was sterile. Awns developed in the interspecific F1 hybrid (white arrows) but not in the parents. Pollen grains from Nip and WK21, which were stainable with Lugol’s iodine solution, exhibited potential fertility, whereas pollen from WK21/Nip F1 was sterile, as reflected by the absence of staining. (B) Microspores at early uninucleate, late uninucleate, binucleate, and trinucleate stages. Microspores were stained with acetocarmine. The black bar in each panel corresponds to 100 μm. (C) Abnormal microspores in WK21/Nip F1 plants at the early uninucleate stage. Microspores were stained with acetocarmine. Black arrows indicate abnormally shaped microspores. The black bar in each panel corresponds to 100 μm.