ABSTRACT

The main objective of cotton breeding is todevelop new cultivars, which represent improvement when compared with released cultivars. In order to evaluate the performance of genotypes developed by EMBRAPA Cotton Breeding Program in Mato Grosso state, the genetic gain of cotton yield was estimated from 12 years of data, based on analysis of 174 final experiments. The experiments were carried out in Mato Grosso state between 1987 and 2001, in locations differing in soil type, and climate. Data collected were analyzed based on regression of adjusted means. The estimate of genetic gain was positive and significant; representing an average of 3.63% in yield gain per year. It was concluded that EMBRAPA cotton breeding program in Mato Grosso State achieved positive and significant results in 12 years of research, which were reflected in a high average genetic gain estimate. However, the newly released cultivars did not always have both characteristics such as disease resistance, good fiber properties etc., combined with high yield, that would encourage the farmers to change the cultivars in use.