title: Use of molecular markers in  reciprocal recurrent selection of maize increases heterosis effects.
abstract: We  examined the effect of incorporation of molecular markers on variability  between and within populations in order to maximize heterotic effects and  longevity of a maize reciprocal recurrent selection program. Molecular  variability was quantified by inter-simple sequence repeat (ISSR) markers  between and within the maize populations Cimmyt and Piranão in the 10th cycle  of a reciprocal recurrent selection program. Forty-two S(1) progenies of each  population were analyzed, these being families of full-sibs selected according  to their agronomic traits. Thirteen primers were selected, which produced 140  bands; 114 of them were polymorphic and 26 monomorphic. Based on UPGMA grouping  analysis and by genetic distances, it was possible to identify "contaminant"  progenies. These progenies belong to the Piranão or Cimmyt groups, but cluster  in the opposite heterotic group. Identification of "contaminant" progenies is  relevant for selection, because, besides identifying genotypes that should be  eliminated at the recombination stage, it allows increased heterosis expression  in crosses between more genetically distinct individuals. After the elimination  of the "contaminant" progenies and those that were allocated between the  heterotic groups, a new statistical analysis was carried out, which  demonstrated increased genetic distances between the populations. It was  concluded that the application of molecular markers in reciprocal recurrent  selection programs allows the optimization of the monitoring of genetic  variability within and between populations, favoring recombination between more  distant progenies, besides ensuring increased longevity of the reciprocal  recurrent selection program.
authors: Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brasil.
authors: A P C G
authors: AP
authors: Berilli
authors: M G
authors: MG
authors: Pereira
authors: L S A
authors: LS
authors: Gonçalves
authors: K S
authors: KS
authors: da Cunha
authors: H C C
authors: HC
authors: Ramos
authors: G A
authors: GA
authors: Souza Filho
authors: A T
authors: AT
authors: do Amaral Júnior
mesh_terms: D001947:Breeding; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics*; D005819:Genetic Markers; D014644:Genetic Variation; D006823:Hybrid Vigor; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development
chemical_list: D017931:DNA Primers; D018744:DNA, Plant; D005819:Genetic Markers