59-05-032 Proceeding

99 Proceedings of the Princess Maha Chakri Sirindhorn Congress observed (0.96) in 800 Gy. Konzak, et al., have reported that even as a single gene difference could bring significant changes not only in the spectrum but also frequency of mutations [11]. The highest frequency of mutations in leaf type (1.84), plant type (1.38), seed type (1.38) and early mutant (1.38) were observed at 400 Gy. In leaf type, the doses at 100 Gy and 500 Gy had the same frequency. In plant type, the doses 200 Gy and 500 Gy showed the same frequency (0.48) and the doses at 600 Gy and 700 Gy had also the same frequency (0.47). In high brix mutants, the dose 300 Gy induced a high frequency of brix% value (1.29). B. Quantitative traits of selected mutants The quantitative traits among nine selected mutants of Sorghum in M2 generation viz, plant height, stem width, stalk weight, juice volume, brix%, number of seeds per plant, 100 seed weight, yield per plant and days to maturity, were described in (Table 2). Nine mutants of quantitative traits selected in M2 were compared for mean values of control. In this generation, both positive and negative mutation occurred as compared to the parent cultivar. The plant height ranged from 125.2 cm to 248.9 cm in M2 generation as compared to 215.3 cm in the control. The highest plant height was observed in high brix mutant. The biggest stem width was observed in big seed mutant and compact leaf mutant. The smallest stem width was found in early mutant (9.2). High brix mutant (812.4 g) and big seedmutant (758.6 g) showed a significant increase in stalk weight over the control (404 g). The maximum juice extraction compared to the control was observed in high brix mutant (142 ml) followed by big seed mutant (116 ml). High brix mutant produced juice more than two fold increases over the control. Early mutant and small seed mutant had the same juice extraction. Among all mutants, high brixmutant showed nearly two fold increases in brix% (23.4) compared to the control (12.6). This type of mutant was induced by 300 Gy of gamma radiation. The highest number of seeds per plant was observed in small seed mutant (1648) followed by compact leaf mutant (1083) as compared to the control (863). White spotted seed mutant had the lowest number of seeds per plant. Big seed mutant and white spotted seed mutant had higher 100 seed weight than the control. Conversely, small seeded mutant showed nearly two fold decrease as compared to control. Big seed mutant showed a significant increase in yield per plant (26.45 g) followed by high brix mutant (25.82) whereas the lowest yield was found in white spotted seed mutant (8.5). Days to maturity ranged from 116 to 130 days. In all mutants, early mutant matured (10 days) significantly earlier than the control. Narrow leaf mutant and compact leaf mutant had the same matured days.