VARIETAL RESISTANCE: FIFLD EVALUATION AND SCREENING OF CERTAIN RICE MATERIALS AGAINST THE RICE LEAF MINER, HYDRELL1A PROSTERNALIS DEEM. AND ROLE OF SOME FACTORS IN PLANT RELATIVE RESISTANCE

This investigation was carried out on forty one commercial rice varieties and promising lines to evaluate their relative resistance and se­lect some against rice leaf miner; Hydrellia prostemalis Deem., and role of some factors in this resistance . It proved that : - Entries ; Giza 172, LR 25571-31-1, GZ 3766-38-1-2, GZ 4127- 2-1-3„G2 4255-6-1 and GZ 4294-10-2 were relatively the most resist­ant (least preferred) entries to rice leaf miner infestation showing 0.13,0.14,0.15,0.16 and 0.19 % , respectively, as damaged leaf area (DLA%) which is the most accurate parameter for the miner damage. On the other hand, Giza 180, Giza 181, GZ 4255-6-3, Giza 171, Giza 175, GZ 4386-34-3 and Yabani 15 were relatively the most susceptible (Most preferred) entries showing 0.41, 0.47, 0.51, 0.52, 0.56, 0.58 and 0.62%, respectively. As based on the percentage of the infested leaves (IL %), as the most common and easiest parameter, GZ 4127-2-1-3, GZ4294-9-4 AND GZ 4255-9-1 entries were relatively the most resist­ant (least preferred) showing 18, 18.6 and 19.1%, respectively, as com­pared to Giza 171 of 33.6%. As based on the number of mines/leaf, GZ 3766-38-1-1 and GZ 4249-4-9 entries were the most resistant showing 0.29 and 0.33, while Giza 171 of 1.09 was the most susceptible one. Using the damaged area/leaf as a parameter, GZ 4294-10-2 was the most resistant entry showing 2.63 mm compared to Yabani 15 of 9.63 mm/leaf When overall resistance or susceptibility indices (ORSI); as a col­lective measure for all used parameters was calculated, GZ 4127-2-13, Todorpkiwase, GZ 4255.6-1, GZ 3766-38-1-1 and GZ 4294-9-4 were highly resistant entries as compared with Giza 176 the most common variety in Egypt.