Weed Control Efficacy and Arbuscular Mycorrhizal (AM) Colonization of Upland Rice Varieties as Affected by Population Densities

Abstract

Field  experiments were  conducted in 2011 and 2012 at the Teaching and Research Farm of the Federal University of Agriculture, Abeokuta (Latitude 7 20`N and Longitude 3 23`E) in the Forest/ Savanna Transition Agro- ecological zone of South Western Nigeria  to determine the weed control efficacy and AM colonization  of upland rice varieties   at different population densities. The experiment was a 3x3 factorial arranged in a Randomized Complete Block Design (RCBD) and replicated three times. The three plant population used included 333, 333; 250, 000 and 166, 666 plants per hectare obtained by planting at 20cm x 15cm, 20cm x 20cm and 20cm x 30 cm respectively, while the three rice varieties used were ITA 150, NERICA 2 and OFADA. The results obtained from the study showed that plant population at 333, 333 plants per hectare significantly (p < 0.05) reduced weed population, number of tillers per hill and yield of rice varieties. Moreover, the local rice variety, OFADA was observed to be significantly (p < 0.05) taller than the other varieties, reduced weed biomass and consequently gave better yield advantage over the other tested varieties (ITA 150 and NERICA 2).   Panicle length and days to 50% flowering were significantly (p<0.05) longer in OFADA and NERICA 2.  Planting density did not affect AM root colonization but significant differences were observed among the rice varieties with respect to spore abundance.

Keywords: rice, arbuscular mycorrhizal, plant population, varieties