81 The effect of panicle blast on the physical properties and milling quality of rice cultivar M202.

B. L. CANDOLE (1), T. J. Siebenmorgen (2), R. D. Cartwright (3), and F. N. Lee (4). (1) Bio. and Agric. Eng. Dept., University of Arkansas, Fayetteville, AR 72701; (2) Food Science Dept., University of Arkansas, Fayetteville, AR 72704; (3) University of Arkansas Cooperative Extension Service, Little Rock, AR 72203; (4) Rice Research and Extension Center, Stuttgart, AR 72160.

Preliminary observations in 1997 indicated a significant reduction in bulk density and head rice yield of cultivar LaGrue due to blast. A study to determine the effect of panicle blast on the physical properties and milling quality of rice was continued in 1998. Since environmental conditions during the 1998 growing season were not conducive for blast development, only one cultivar (M202) from one location (Pocahontas, AR) was available for sampling. Rough rice from blast-infected panicles had moisture contents lower than the average moisture content of rough rice from blast-free panicles. Sixty-five percent of rough and head rices from the diseased samples had thicknesses less than the average kernel thickness of the kernels from blast-free samples. For rough rice, the incidences of unfilled, chalky and fissured kernels in diseased samples were higher by 30, 21, and 7 percentage points, respectively, than in blast-free samples. The incidence of fissured kernels in head rice from blast-infected samples was also higher. Blast reduced kernel bulk density and head rice yield by 140 and 12 percentage points, respectively. The 1998 results concur with those found in 1997 indicating a negative impact of blast on the physical properties and milling quality of rice.