STUDIES ON GAMMA IRRADIATION EFFECTS ON GERMINATION, GROWTH, FODDER YIELD, PROXIMATE ANALYSIS AND GENETIC DIVERSITY OF SUDAN GRASS (SORGHUM VULGARE VAR. SUDANESE)

Abstract

Present studies were carried out at Rangeland Research Institute, NARC, Islamabad and Quaid-i-Azam university, Islamabad during 2001-2011. Dry seeds of Sudan grass (Sorghum vulgare var, Sudanese) were subjected to ten acute irradiation treatments ranging from 0 to 45 kR with 5 kR intervals at Nuclear Institute for Food and Agriculture (NIFA), Peshawar. Overall germination percentage decreased with increase in the doses of gamma irradiation. Seedling height decreased significantly (p≤0.05) on 4 th and 11 th day of sowing with increasing treatments of gamma irradiation. Similarly root length and root shoot ratio on 4 th day of sowing under lab conditions also depicted significantly (p≤0.01) decreasing effect with an increase in dose rate of treatments. Data regarding plant height and leaf area showed significantly (p≤0.05) increasing effect with an increase in dose rate of treatments under field condition in M-1 generation. Average tiller plant -1 increased significantly (p≤0.01) with the increase of doses in M-1 generation under field condition. Tillers showed a significantly (p≤0.05) increasing effect with increasing treatments in M- 2 generation. Data regarding green matter weight -1 and dry matter weight -1 showed significantly (p≤0.01) increasing effect with highest dose rate of gamma irradiation in M- 3 generation. Data regarding immature flowering percentage also showed increasing effect significantly (p≤0.05) which is a positive sign to prolong its life span till start of winter season which is a lean period for livestock grazing feed under natural conditions. Overall growth rates improved by gamma irradiation treatments in M-4 generation and M-5 generations. On the basis of these results high yielding mutants in Sudan grass may be developed. Data reading proximate analysis showed insignificant differences in all traits studied in M-1 generation of Sudan grass under field condition. Data regarding effect of irradiation on HCN concentration showed significant (p≤0.01) decreasing effect in red and blue color intensity. While insignificant decreasing effect in green color xiintensity which is a positive sign to reduce HCN concentration in Sudan grass and other sorghum species used as a fodder crop. There is much hope to develop HCN free mutants in these crops through irradiation in future. Data regarding SDS-PAGE analysis and RAPD technique showed great variability in genetic diversity as a result of gamma irradiation on Sudan grass under study in M-1 and M-2 generations. Further research is needed to improve the crop and develop such mutants by gamma irradiation in future.