RESPONSE OF SEED IRRADIATION WITH GAMMA RAY, N- FERTILIZATION AND BIkO FERTILIZATION OF BARLEY (Hordeum vulgare L.) GROWN ON A SAND SOIL

Seed irradiation during pre-sowing processes is one of the most effective methods to increase plant growth, yield components and its chemical composition. a three factor split-split plot, factorial experiment was conducted on barley to study seed irradiation, biofertilization with n2 fixing bacteria (nfb), p-dissolving bacteria (pdb) and n fertilization in the agricultural research station of el-zagazig university at el- khattara region, el-sharkia governorate, egypt during 2009/2010 season. main plots were assigned to gamma irradiation: non-radiated, 20 and 40 gy gamma radiations. sub-plots were assigned to n: 0, 119, 238 and 298 kg n ha-1. sub-sub plots were assigned to biofertilization: none, (azospirillum lipoferum + bacillus polymxa nfb1), (azospirillium braselence + azotobacter chroccocum nfb2+bacillus megatherium pdb) and nfb1 + nfb2 + pdb. the nfb1 was given in a commercial product of cerealin while (nfb2 + pdb) was in a product of microbin. barley yield and yield components as well as n, p and k content and uptake increased by gamma irradiation, n rates and biofertilization singly or combined. number of spike per m , grain weight per spike, yields of: grains + straw, grains and straw increased also, highest response occurred by n238 + (cerealin + microbin) with 40gy gamma ray. the highest straw yield was observed due to n179 + (cerealin + microbin) with 40gy gamma ray. treatment of n179 + cerealin with 40gy gamma ray gave highest n- uptake in straw, as well as p-uptake in grains and straw. protein content and protein yield increased by treatments especially with increasing n rate up to n298 + microbin + 20gy and gave highest protein content. nitrogen use efficiency (nhi) was increased with increasing n rates up to n238 followed by decrease at n298.