Resumo

RODRIGUEZ, Nohelia et al. Uso de patrones isoenzimáticos para caracterizar la calidad genética de la semilla certificada de arroz en Venezuela. Agronomía Trop. [online]. 2005, vol.55, n.3, pp.381-396. ISSN 0002-192X.

Seed certification is a system based upon a multiplication of a limited number of generations to assure the genetic identity of improved cultivars. The 1996 survey on the Venezuelan rice industry, reported crop limitations associated with the genetic purity and overall quality of certified rice seed utilized at the market place. The objective of this research was to determine and quality contamination of the genetic purity of the four classes of rice seed: Breeder (BS), Foundation (FS), Registered (RS) and Certified (CS), all belonging to the seed certification system of rice, as weel as “non certified seed” (NCS) coming from the illegal rice market. Also a new method was designed and validated to quantify the genetic contamination levels of seeds. This method, applied to all samples of varieties and seed classes, showed 28 and 8% of contamination for RS of Araure 4 and NCS of FONAIAP 1, when compared to their original BS profile. These results demonstrated that the previously reported levels of contamination were associated with red rice weed, due to mismanagement of seed production fields or mechanical mixtures during seed processing, rather than a truly genetic erosion of commercial varieties. Electrophoresis by itself or in combination with morphometric evaluations proved to be a consistent method to validate identity and genetic purity of rice varieties and their classes of certified seed.

Palavras-chave : Oryza sativa L; rice; seed quality; seed certification; electrophoresis; isoenzymes.