Steneotarsonemus spinki IN RICE VARIETIES AND ITS EFFECT ON PERFORMANCE COMPONENTS

Abstract

The objective of this study was to evaluate the presence of the mite Steneotarsonemus spinki in rice cultivars and their impact on yield components. The study was located at El Coco, Penonome, from April to August, 2004. Thirteen rice varieties and two experimental lines were evaluated. The evaluation of S. spinki was based on the methodology described by Almaguel and Botta. Crop yield was estimated in kg^.ha^-1, grain was classified and milling performance was estimated. A randomized complete block experimental design was applied with 15 treatments and 3 replicates. ANOVA, as well as Duncan’s and Tukey’s mean comparisson tests were realized. S. spinki. populations varied a lot from floral primordia to flowering, finding variation in population tendency per cultivar. This allowed grouping the cultivars in two groups. Some cultivars, which showed high populations of S. spinki, had acceptable yields, while other cultivars with less population had intermediate to low yields. This result provides the first assessment of the presence of populations of S. spinki in commercial cultivars and advanced lines from IDIAP rice breeding program.