Resumo

TORREALBA-NUNEZ, Gelis T et al. Biochemists and molecular markers associated with water stress tolerance in rice. Agronomía Trop. [online]. 2014, vol.64, n.3-4, pp.211-226. ISSN 0002-192X.

Drought in Venezuela has become a limiting factor for national rice production, as the cultivated varieties traditionally are adapted to high water supply. This study aimed to identify biochemical (isozymes) and molecular markers (microsatellites, SSR) associated with water stress tolerance in rice (Oryza sativa L.). Gene mapping study was conducted in a BC₁F₂ population product of the crossing (LO2 x Fonaiap 2000) x LO2 using the MapDisto program and the method of one marker at a time. Eighty-nine putative quantitative characters (QTLs) associated with vegetative, reproductive and yield traits were identifi ed. Using five isozymes (PRX, G6PDH, ACP, 6PGD and SDH) and 40 SSR drought susceptibility indexes (ISS) were estimated. Next, the association between isoenzymes, water stress tolerance and ISS in the families of the segregating population were identified for variables related to the vegetative, reproductive and maturation of the grain phase in rice. In the 2 linkage groups (chromosome 3 and 9) 4 QTL associated to ISS, 2 regions associated with 50% flowering, 1 for threshability (chromosome 3) and 1 for fertility (chromosome 9) were detected in RM107, RM442 and RM570. This information can be used as a criterion in molecular marker assisted selection in future rice breeding programs in order to identify families and genotypes tolerant to the water stress condition.

Palavras-chave : Oryza sativa L; drought; production; Isozymes; microsatellite.

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