GENETIC VARIABILITY IN WEEDY RICE BIOTYPES FOUND IN DIRECT-SEEDED RICE AREAS IN THE PHILIPPINES

Weedy rice can severely impact production through yield reduction because of its competitive ability to reduce growth resources for cultivated rice. The characteristic weedy traits have made very challenging manage as they the same agro-morphological characteristics with study examined relationships between selected (Oryza sativa L.) cultivars, biotypes, and wild collected from different locations in Philippines, using simple sequence repeat markers. Cluster analysis, UPGMA, enabled genetic differentiation examination test materials. Subgroups 13 at least two biotypes formed 100% similarity based on post-harvest data, cultivars forming one subgroup. With polymorphic SSR markers, five major clusters range three (group I) 62 III). There was observed 15 subgroups ranging 10 biotypes. species-specific groupings. came province; likewise, both Iloilo Batangas; still another cultivar biotype Pangasinan. possible relatives (>65% similarity) include related Oryza minuta, O. meyeriana, 22 rufipogon. Concerning high (>80%) closely PSB Rc 82, NSIC 222, six 160, each 215, 152, 64, 18, 10, IR64 14.