Oryza glumaepatula Steud.

Abstract

Oryza glumaepatula is the only native wild rice from the Americas that has a diploid genome (2n = 24). Thus, this species constitutes a source of genetic variability for the improvement of Oryza sativa cultivated in the New World. Wild rice species are important sources of commercially important characters, such as tolerance to acid soils and drought, yield potential, cytoplasmic male-sterility, heat tolerance, and elongation ability. The transference of alleles associated to target characters from O. glumaepatula into O. sativa could be done via introgression or through the use of genetic engineering. Oryza glumaepatula occurs in Central and South America and Caribe, growing in flooded areas, swamps, rivers, and humid areas with clay soils and that present invasive or colonizing behavior. It presents populations with perennial, annual, or biannual cycle, depending of geographical localization, with bushy growth, fragile stems near the base of plants, which can detach and fluctuate, forming new populations. Flowering occurs between October and November, presenting self- and outcrossing. Recently, O. glumaepatula had its genome sequenced, enabling comparative studies among different Oryza species. These studies suggest the expansion and contraction of gene families, diversity, and variation in the number of noncoding genes and divergence in the sequences among the species are associated with the adaptation of each species to different environmental conditions. These results demonstrate the importance of species from the Oryza genus in the development of new O. sativa cultivars.