Fig. 4

4.1 Double mutant F₂-segregants from crosses (middle) flanked by their int mutant parents. Most combinations of int mutants in the crosses result in double mutants with a typical six-rowed spike. A. From left to right: int-c.15, double mutant, int-a.32. B. From left to right: int-c.16, double mutant, Int-d.28. C. Deformed double mutant F₂-segregant from poor combining partners. From left to right: int-e.20, double mutant, int-a.46. 4.2 Spikes of triple mutant combination from the six-rowed double mutant int-c.5 int-a.34 combined with the six-rowed mutant hex-v.3. From the left to right: int-c.5 int-a.34 double mutant, “King-size” spike of triple mutant int-c.5 int-a.34 hex-v.3, six-rowed mutant hex-v.3