title: Combining ability of tropical maize lines for seed  quality and agronomic traits.
abstract: Studies of genetic effects of early selection of maize  based on seed quality traits are rare, especially those that use materials from  different heterotic groups. These studies are also useful in tropical  environments and for the advancement of sustainable agriculture with cropping  during seasons not commonly used for cultivation. We estimated, through diallel  crosses, the predominant genetic effects on the expression of agronomic traits  and seed quality and on the general combining ability of nine maize lines from commercial  hybrids and the specific combining ability of hybrid combinations among them.  In the evaluation of seed quality, seven tests were used: first count and final  count of seed germination, seedling vigor classification, cold tolerance,  seedling emergence rate in a sand seedbed, speed of emergence in a sand  seedbed, and speed of emergence index. Plant height, first ear height and grain  yield were the estimated agronomic traits. In the diallel analysis, method 3  (model I) proposed by Griffing was used. There was a greater significance of  non-additive genetic effects in the genetic control of seed quality of the  various lines. The Flash, Dekalb 350 and P 30F80 lines combined high seed  quality and high grain yield. For growth during the normal planting season, the  combinations CD 3121-1 x P 30F80, Speed x CD 3121-2, Dow 8330 x AG 8080 and  Dekalb 350 x CD 3121-2 were the most promising for both seed quality and  agronomic traits.
authors.affiliation: Universidade Estadual de Maringá, Maringá, PR, Brasil.
authors.forename: L M
authors.initials: LM
authors.lastname: Moterle
authors.forename: A L
authors.initials: AL
authors.lastname: Braccini
authors.forename: C A
authors.initials: CA
authors.lastname: Scapim
authors.forename: R J B
authors.initials: RJ
authors.lastname: Pinto
authors.forename: L S A
authors.initials: LS
authors.lastname: Gonçalves
authors.forename: A T
authors.initials: AT
authors.lastname: do Amaral Júnior
authors.forename: T R C
authors.initials: TR
authors.lastname: Silva
mesh_terms: D000383:Agriculture; D001947:Breeding; D002678:Chimera; D003433:Crosses, Genetic; D002523:Edible Grain / Q000235:genetics; D005838:Genotype; D006823:Hybrid Vigor; D010641:Phenotype; D012639:Seeds / Q000235:genetics*; D003313:Zea mays / Q000235:genetics* / Q000502:physiology*