Abstract

ITZEL QUIROS-MCINTIRE, Evelyn  and  CAMARGO BUITRAGO, I. RESPONSE OF RICE VARIETIES (Oryza sativa L.) TO POPULATIONS OF Steneotarsonemus spinki SMILEY (ACARI: TARSONEMIDAE) IN PANAMÁ, 2007. Rev. Protección Veg. [online]. 2011, vol.26, n.1, pp.30-39. ISSN 1010-2752.

For the introduction of new varieties into the production system, it is recommendable to characterize their behavior in the presence of the common key pests of this crop; therefore the objective of this experiment was to know the response of eight IDIAP varieties and the cultivar Vioal to the presence of populations of the mite Steneotarsonemus spinki. Mite populations were counted every eight days from the 27^th day after germination. Five stems per treatment were randomly selected for each of three replications. The weights of whole, vain and chalky grains and the yields were determined. The response to diseases and the agronomic characteristics were evaluated. S. spinki density was compared by simple variance analysis, the influence of the climatic factors was evidenced by main component analysis; a cluster analysis permitted the grouping of varieties according to their full grain weights, and the polynomial regressions evidenced the population tendencies. All the varieties were resistant or moderately resistant to common diseases of the crop. The minima relative humidity changed by the action of rainfall and influenced in the mite dynamic markedly. The highest yields were spowntobe by the varieties with the highest weights of whole grains. The varietal response may be in function of the occurrence of high populations of the mite in stages near flowering, which may directly influence on the decrease or increase of whole grain weights and agricultural yields.

Keywords : varieties; Steneotarsonemus spinki; filled grains; plant age.

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