Controle genético da incidência de fumonisinas em milho tropical

Abstract

Due to the development of pathogenic fungi in the ear, the occurrence of grain rot in maize not only brings direct losses in yield and grain quality, but also brings indirect losses with the incidence of mycotoxins, which are toxic to humans and animals. Among the different mycotoxins occurring in maize, the fumonisins need special attention, due to their high toxicity and wide dissemination throughout Brazil. Fumonisins are produced mainly by the fungus Fusarium verticilioides and, despite their importance, there are no reports about the genetic control for the incidence of these mycotoxins in tropical maize. Thus, this study aimed to investigate the genetic control of the incidence of fumonisins in tropical maize, through a complete diallel design with no reciprocal crosses. The single-cross hybrids were evaluated in three experiments, two in Sete Lagoas and one in Goiânia, in a randomized complete block design with two replications. The incidence of fumonisins in maize kernels were evaluated in laboratory, according to the protocol proposed by VICAM (VICAM SCIENCE AND TECHNOLOGY, 1998). Based on the mixed model approach, individual, for each experiment, and joint diallel analyzes were performed. In the joint diallel analysis, different models for the genetic ( G ) and residual ( R ) variancecovariance matrices were compared, including the additive genomic relationship matrix for lines. Experimental accuracies, measured by the index of selective accuracy, were considered adequate in all analyzes. Based on the results of this study, it was possible to infer that there is a predominance of non-additive effects in the genetic control of the incidence of fumonisins in tropical maize.