Genetic base of paddy rice cultivars of Southern Brazil

摘要

The genetic knowledge of the germplasm is crucial to the plant breeding in order todevelop new varieties. This study was carried out to evaluate the genetic similarity of 40 rice cultivarsdeveloped in Southern Brazil with the use of two tolls: genealogy and AFLP markers. The genealogy approach showed that 90% of the cultivars were developed from only six parents, revealing a narrow genetic basis among these cultivars.A little genetic diversity among them was confirmed by AFLP markers, since 111polymorphic markers identified 87% similarity among them. The geneticsimilarity among the cultivars released by Epagri in Santa Catarina state waslower, compared to that among the cultivars released by others public institutions, Embrapa and Irga. This study has demonstrated that rice cultivars developed in Southern Brazil have narrow genetic base, which suggests high genetic vulnerability risk.