Table 2.

Classification of male steriles (modified from Imanishi et al. 1970)

Class	Characteristics of anther
	Color	Dehiscence	Pollen production
W	White or brown	−	−
G	Light green	−	−
S	Yellow, sometimes orange	−, rarely +	−
P	Yellow, sometimes orange	Both + and − are seen	±
N	Yellow	+	+