Genetic progress over twenty-three years of irrigated rice breeding in southeastern Brazil

Abstract

The importance of rice (Oryza sativa) is indisputable this cereal is the staple food for half of the global population. Genetic progress estimation allows evaluation of the effectiveness of genetic improvement of crops and helps in the planning of breeding programs. This paper aims to estimate the genetic yield progress made by the program in the state of Minas Gerais, Brazil, which is run by the Epamig/UFV/Embrapa consortium. A total of 210 lines were evaluated by value for cultivation and use testing that was conducted in the municipalities of Janaúba, Leopoldina, and Lambari, from 1993 to 2016. Based on Vencovsky’s (1986) method, the genetic gains in Lambari, Janaúba, and Leopoldina were 1.46, 0.14, and 0.11%, respectively. The gain in Leopoldina was considered very low during the evaluated period. According to Breseghello’s (1998) method, the annual average genetic gain was 0.23 and 0.04% in Lambari and Janaúba, respectively. In Leopoldina, a yield gain of - 2.37% per year was observed for the evaluation period from 1994 to 1999, and a yield gain of 0.1% per year was observed from 2000 to 2016. These results can be explained by the focus on quality as a strategy for the breeding program in Minas Gerais State in the 1990s. Vencovsky’s (1986) and Breseghello’s (1998) methods were able to quantify yield gains and demonstrate the dynamics of the irrigated rice genetic improvement program in Minas Gerais State.

Genetic gain for technological traits in new cultivars developed by the Southern Brazilian common-bean network

“…In previous experiments conducted by the commonbean breeding program (Ribeiro et al, 2008) and by a rice breeding program (Silva Júnior et al, 2021), the generalized least squares method also provided high environmental gain estimates. The strategy of keeping a greater number of common treatments between selection cycles provides greater safety in estimating environmental variance (Cruz;Regazzi;Carneiro, 2012).…”

“…As a consequence, data from three experiments conducted to estimate the genetic gain of different traits. This method was appropriate for obtaining consistent genetic gain estimates using unbalanced data from few environments Possebom;Storck, 2003;Ribeiro et al, 2008;Follmmann et al, 2017;Silva Júnior et al, 2021;Woyann et al, 2019). Environmental gain estimates were higher than genetic gain estimates for all analyzed traits (Table 3).…”

“…Several methodologies have been used to estimate the genetic gain of important traits for selection in breeding programs. The Vencovsky's (1988) method (Cruz;Regazzi;Carneiro, 2012) has been shown to be efficient in obtaining genetic gain estimates for grain yield in wheat (Follmmann et al, 2017;Woyann et al, 2019) and rice (Silva Júnior et al, 2021) breeding programs and for different agronomic traits evaluated in common bean breeding Possebom;Storck, 2003;Ribeiro et al, 2008). For technological grain quality traits of common bean, genetic gain estimates are restricted to a few traits evaluated in a short period Possebom;Storck, 2003).…”