Biotechnology as an important tool for rice breeding in Venezuela: Increasing resistance to biotic stress and improving grain quality traits

摘要

Our project focuses on improving grain quality traits and biotic stress resistance in Venezuelan rice cultivars, using biotechnology. Primarily we try to identify molecular regions associated with traits for disease resistance and high grain quality that could be used by rice breeders to improve crop productivity and sustainability. Diseases and pests greatly reduce rice yield and productivity. In Venezuela, rice blast (Magnaporthe grisea syn. Pyricularia grisea) and sheath blight (Thanatephorus cu-cumeris syn. Rhizoctonia solani) display a high pathogenic capacity in a wide range of cultivars. The development of resistant cultivars has proved to be a difficult task because pathogens can rapidly overcome the resistance genes. Thus, highly efficientand rapid methods are needed to introduce and follow resistance-associated traits in breeding programmes. The use of DMA marker technology could facilitate the efficient and effective incorporation of valuable traits into improved rice cultivars. It is difficult to combine different important traits simultaneously into cultivars, but marker-assisted breeding gives geneticists a versatile set of tools that can augment, as well as verify, traditional selection techniques. This project identifies markers to tag genes for resistance to blast and sheath blight in local varieties of rice. Several microsatellite (SSR) markers located in the twelve rice chromosomes are being evaluated. Different DMA marker bands will be scored, assessed and analyzed, and theirassociation with agronomical traits determined. Polymorphic markers per primer pair between the cultivars and lines will be detected. The aim is to generate information about genetic components that can be useful in breeding programmes, specifically inthe development of crop varieties with resistance to the pathogens causing sheath blight and rice blast.