Avaliação de indutores na obtenção de duplo-haploides em germoplasma tropical de milho

Abstract

The technology of double-haploid is an important tool for corn breeding, allowing the swift achievement of inbred lines. However, the efficiency of the haploidy inducers in three tropical regions is still low. The objective of this work was to evaluate the haploidy induction rate of three inducers in different corn populations derived from the Syngenta Brasil company. This work was conducted during the year of 2015 at the Syngenta Experimental Station in Uberlandia, Minas Gerais, Brail. In March of 2015, three haploidy inducers (A, B and C) were sown in order to be used as male genitors, and six populations (1, 2, 3, 4, 5 and 6), sown in order to be used as female genitors. The harvested seeds were visually classified as haploids using the R-Navajo morphological marker. The plants originated by the seeds considered haploid were treated with colchicines for chromosome duplication. Subsequently, the plants were transplanted to the field in October of 2015, and, those presenting reduced vigor were confirmed as double-haploid. With the number of seeds obtained in each cross, and the number of plants considered double-haploid in the field, we calculated the double-haploid (DH) occurrence rates, verifying rates between 0.18 and 5.6%. We observed that both inducers and populations influenced the DH occurrence rate. In addition, these factors interact between each other. Inducer C provided the highest DH occurrence rate for most of the evaluated populations. In general, populations 2, 4 and 6 presented the highest DH occurrence rates.