Performance of a breeding program for irrigated rice in Southeast Brazil
Estimating the performance of a rice breeding program is possible by means of indexes such as the replacement rate, which quantifies the dynamism of the breeding program and provides the rate of included, excluded, maintained and renewed genotypes year after year. We evaluated the performance of the irrigated rice breeding program in the state of Minas Gerais, conducted by the EPAMIG/UFV/EMBRAPA consortium. A total of 210 lines were evaluated in the municipalities of Janaúba, Leopoldina and Lambari from 1993 to 2016. The average number of genotypes included, maintained and excluded in each year were calculated, along with the replacement rate percentage. The average genotype replacement rate was 44% for Lambari and Janaúba, and 43% for Leopoldina. The average maintenance in Lambari was 39%, and in Janaúba and Leopoldina it was 40%. In all localities, the mean rate of inclusion of genotypes was higher than the average exclusion rate, indicating good efficiency in the irrigated rice breeding program. However, new strategies should be used in the irrigated rice breeding program to increase the genetic basis of lines and increase the replacement rate.