Contribuição genética na produtividade do arroz irrigado em Minas Gerais no período de 1998 a 2010

Abstract

ResumoO objetivo desse estudo foi quantificar o ganho genético para produtividade de grãos do programa de melhoramento do arroz irrigado de Minas Gerais, no período de 1998 a 2010. Foram utilizados dados dos ensaios comparativos avançados realizados em quatro localidades diferentes de Minas Gerais. Nem todos os locais foram contemplados em todos os anos agrícolas e para estimativas com maior acurácia, utilizou-se o método de modelos mistos. O ganho genético para produtividade de grãos no período considerado foi de 107,42 kg ha -1 , o que representou uma proporção de 17,88% da estimativa total do progresso. Esse ganho correspondeu ao aumento de 8,95 kg ha -1 ano -1 , ou ainda, aumento de 1,99% em produtividade de grãos por ano. Apesar de o ganho genético ter sido satisfatório, novas alternativas de melhoramento podem ser empreendidas para que o incremento produtivo seja maior nos próximos anos.Palavras-chave: Oryza sativa, progresso genético, obtenção de cultivares, REML/BLUP. Genetic contribution in yield of irrigated rice in Minas Gerais State between 1998 and 2010 AbstractThe objective of this study was to quantify the genetic gain for grain yield of the breeding program of irrigated rice in Minas Gerais State, Brazil, in the period of 1998 to 2010. For this, data from advanced comparative trials performed in four different sites of Minas Gerais were analyzed. Some sites were not included in all crop years and thus a mixed model methodology was used to obtain more accurate estimates. The genetic gain for grain yield over the period was 107.42 kg ha -1 , which represented a proportion of 17.88% of the total progress estimative. This gain corresponds to an increase of 8.95 kg ha -1 yr -1 or even a 1.99% increase in grain productivity per year. Although the genetic gain has been satisfactory, new alternatives may be applied to improve the rice yield in coming years.

Genetic progress in homogeneous regions of wheat cultivation in Rio Grande do Sul State, Brazil

“…The maintenance rate of cultivars was similar in comparison to the values found in genetic progress studies on wheat with 52% (Cargnin et al, 2008) and 58% with rice (DoVale et al, 2012).…”

“…The locations that most contributed with presence of trials during the study period (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) were: São Borja and Vacaria (12 years) Cruz Alta, Júlio de Castilhos, and Passo Fundo (11 years), Coxilha and Santo Augusto (10 years). The same balance was not observed for irrigated rice in trials conducted in Minas Gerais, being the variation of one to four trial locations per year (DoVale et al, 2012).…”

“…Genetic progress studies have been performed with wheat (Nedel, 1994;Rodrigues et al, 2007;Cargnin et al, 2008;Oury et al, 2012;Beche et al, 2014;Thomas and Graf, 2014;Wu et al, 2014;Gummadov et al, 2015) and cereals from the same wheat family, including oat (Barbosa Neto et al, 2000;Redaelli et al, 2008) and rice (Borges et al, 2009;Breseghello et al, 1999Breseghello et al, , 2011DoVale et al, 2012). It is assumed that there was genetic progress for wheat grain yield in RS influenced by homogeneous regions of cultivation.…”

Genetic progress in oat associated with fungicide use in Rio Grande do Sul, Brazil

“…Moreover, these trials were present in all evaluation years with good annual representation of the locations, which presented minimal variation of the five locations and maximum variation of the seven locations during the study period. However, the same balance was not observed in the study regarding genetic progress in irrigated rice in the State of Minas Gerais, where among the four study locations, none was present in all evaluation years and the variation of trial locations per year was one to four trial locations (DoVale et al, 2012). Therefore, it can be inferred that the database was suitable to evaluate genetic progress in oat during this period.…”

“…For the oat crop, the studies developed by Barbosa Neto et al (2000) in Brazil and by Redaelli et al (2008) in Italy can be emphasized. In addition, the studies with cereals from the same family as wheat (Nedel, 1994;Rodrigues et al, 2007;Cargnin et al, 2008;Oury et al, 2012;Beche et al, 2014;Thomas and Graf, 2014;Wu et al, 2014), rice (Borges et al, 2009;Breseghello et al, 1999Breseghello et al, , 2011DoVale et al, 2012), and popcorn (Ribeiro et al, 2012) can be highlighted.…”