Gene effects from Bipolaris maydis incidence and severity on popcorn

Abstract

Popcorn suffers severe economic losses resulting from harmful effects caused by several diseases such as southern corn leaf blight (SCLB), which is one of the main leaf diseases able to cause considerable damages to corn crops. The realization conducting genetic studies in order to identify genotypes presenting genetic resistance to this disease it is essential. Accordingly, the aim of the current study is to estimate gene effects and combining abilities in popcorn, with emphasis on the resistance to Bipolaris maydis. Full diallel crosses were performed, including reciprocal crosses between eight lines (L76, L88, L70, L77, L55, L61, P1 and P8), in order to produce 56 hybrids (F1’s and reciprocal hybrids). The experiment followed a randomized block design, with four replicates; in two different cultivation periods (first and second periods), in Campos dos Goytacazes, RJ. Southern corn leaf blight incidence and severity, caused by B. maydis, were assessed in each cultivation period. No reciprocal effect was observed for the evaluated characteristics, since the diallel analysis did not find significant effect from this variation source. With respect to SCLB incidence and severity in the two cultivation periods, the mean square of the effects showed that the dominance components were superior to the additivity ones. Hybrids that stood out in the two cultivation periods to the assessed features were: L88 x L61, L88 x L70, L88 x L76, L61 x L77, L61 x P1, L70 x P1, P1 x L76, L77 x L76, and P8 x L77.