SEED GERMINATION AND SEEDLING PERFORMANCE OF THREE RICE VARIETIES AS AFFECTED BY BACTERIAL ISOLATES ANTAGONISTIC WITH Xanthomonas oryzae pv. Oryzicola

Xanthomonas oryzae p.v oryzicola, the casual organism of the bacterial leaf streak disease in rice, is a well-known seed-borne and water-borne plant pathogen with deleterious effect in rice farming due to its capacity for long distance dispersal. Modern sustainable control of XOOc, has generally been through the use of culturable and indigenous antagonistic mircooragnism, although depending upon the nature of these antagonists, their effect upon rice and its varieties may vary during crucial growth stages. In retrospect therefore, this study was conducted in two phases to determine the effect of select antagonistic bacterial isolates on the seed germination and seedling performance of three test rice varietie, (NSIC Rc 25, Black, and Brown Varieties) through comparison of germination and agronomic parameters among different treatments (Controls, ALE25, MDE06, KB04, KAT12, KBE25). Phase 1 (laboratory trial), following a 3x6 factorial experiment in completely randomized design showed that among treatments, KB04 (treament 4) and ALE25 (treatment 2) induced varying effects among homogenous subsets of test varieties in terms of germination rate, with the fewest germination being observed with the brown rice variety at 53.33%. On the other hand, KB04 also induced varying effects for homogenous subsets of test varieties for hypocotyl length, with the black rice variety showing the tallest hypocotyl. On the other hand, main effect of bacterial isolates for the non-interactive parameters (length of radicle, number of radicles, vigour index) show no significant differences in comparison to control. Meanwhile, Phase II (net-house trial), following a 3 x 6 fatorial experiment in RCB design, showed that no interaction effect was observable among the treatment combinations on either 15 DAP and 30 DAP, nor was there any significant differences amongs treaments in terms of the main effect of bacterial isolates. Among varieties however, there were highly significant differences among parameters, with brown rice having the tallest height. most number of leaves (comparable with NSIC Rc25 at 15 DAP and comparable with black rice at 30 DAP), and most number of tillers at 15 DAP and 30 DAP. NSIC rc25 on the other hand, displayed the least in all parameters except for number of leaves at 15 DAP. Overall, all bacterial antagonists are recommended for in-planta suppression of XOOc with accompanying attention in terms of varying effects on different varieties of rice especially in terms of seed germination