59-05-032 Proceeding

64 Proceedings of the Princess Maha Chakri Sirindhorn Congress and seed type mutations and early maturity mutations were observed at 400 Gy (2.18) and (0.87). The total frequency of viable mutations ranged from 0.96 to 4.36. The highest total frequency of viable mutations was observed at 400 Gy (4.36) followed by 300 Gy (3.78) and 500 Gy (3.72). Dose 700 Gy showed the least spectrum and lowest frequency of viable mutations. Significant changes in the spectrum and the frequency of recoverable mutations could be brought by a single gene difference [13]. Figure 1 (A) Narrow leaf mutant (B) Broad leaf mutant (C) Tall mutant (D) Early mutant (E) Twin stem mutant (F) Twin panicle mutant (G) Different types of panicles: compact (left), control (middle) and spread (right) (H) Different seed color, size and shape: a. control, b. pink, c. white, d. brown, e. bold, f. small, g. long, h. round. A C E G B D F H