Desempenho de híbridos de linhagens parcialmente endogâmicas de milho em regiões dos estados de Roraima e Minas Gerais

Abstract

Among the types of maize hybrids those from S2 families have the advantage of higher synthesis speed. S2 families can be obtained from any kind of population, but a good option are those derived from commercial single cross hybrids that associate productivity and many segregant loci. So, the objective of the research way to evaluate hybrids derived from S2 families descendant of three single cross hybrids. The selection of hybrids was atrained from 30 S2 families derived of three segregant populations descendent of the commercial hybrids AG- 9012, C-333B and Z-8392. Three crossings were carried out using a circular partial diallel scheme, when each family from one population was crossed with three other families from other population. For the crossings the families had been sown, in line of 10 m long. When the first ear emerged, it was protected and during the pollination time a mixture of pollen of each family was used to pollinate at least ten plants of a family of an other population. The hybrids were evaluated in Boa Vista, Roraima state and Minas Gerais state, Brazil, using the simple lattice design 12x12, including 135 hybrids and nine checks. The checks were the F1 generation of the single cross hybrids AG 9012, C333 and Z 8392, a double cross hybrid (435) and five other intervariety hybrids. Each plot had one line of 3 m long, with five plants per linear meter, and spaced of 90 cm. The fertilization and others cultural care were the usually employed in the maize culture. The evaluation was based on: weight of dehushed ear (WDE), plant height (PH) and ear height (EH). 81% of the hybrids were superior to the cheeks based on WDE, 17% outyielded the single cross hybrid C333B (10.76 t/ha), and 46% were superior to C 435 (9,56 t/ha) which is a double cross hybrid widely used in both states. The results considering PH and EH were similar to WDE, however, the interaction hybrids x cheeks was not significant. Considering the results the S2 hybrids were similar to the commercial hybrids point out the potential of those hybrids for using in Brazil for replacing with advantage same commercial hybrids.