Figure 2.

Morphological abnormalities and conditional male sterility in CMS genotypes. (A) Two-month old plants grown in the greenhouse under 16 h of artificial light; 1, CMS I; 2, CMS II. (B and C) Cross-section of T (B) or CMS I (C) half-anther at the microspore stage, collected during winter in the greenhouse; t, tapetum; m, microspores. (D–G) Anthesis in T (D and E) and CMS II (F and G) flowers; plants were maintained for 3 weeks in controlled chambers with 16 h of light at 300 μmol of PAR photons m⁻²·s⁻¹ (D and F) or 9 h at 30 μmol of PAR photons m⁻²·s⁻¹ (E and G). (H and I) T (H) and CMS I (I) pollen collected at anthesis in summer and stained with Alexander dye; viable pollen is round and dark purple, dead pollen (d) is irregular and light green.