Epistasis for grain yield and plant traits in a tropical maize population

In maize, studies on the importance of epistasis in the inheritance of quantitative traits have shown contradictory results; therefore, is of great importance to determine the influence of epistatic effects involved in the inheritance of these characters in the crop. Thus, this research was conducted to (a) to verify the presence of epistasis, (b) to verify the importance of epistasis by environment interaction and (c) to estimate epistatic effects in plants F-2 for grain yield and plant traits using the triple test cross design in a tropical maize population developed from two inbred lines genetically divergent. One hundred F-2:3 progenies backcrossed to both parental lines and F-1 were evaluated in eleven environments. Epistasis was detected for all traits, except for root and stalk lodging. For grain yield, plant height and anthesis-silking interval the additive x dominance and/or dominance x dominance epistasis were more important than additive x additive epistasis; however, for ear height, ear placement, days to anthesis and days to silk emergence, both types of epistasis were important. Epistasis by environment interaction was significant for days to silk emergence and anthesis-silking interval. Significant epistatic non-unidirectional effects were identified in F-2 plants for all traits. The results suggest that, in the studied population, epistasis is an important component of genetic variance; therefore, the dominant additive model is not sufficient to describe the genetic variation of the studied traits.