Full-sib  reciprocal recurrent selection in the maize populations Cimmyt and Piranão.
We  estimated the genetic gains of the 12th cycle of reciprocal recurrent selection  for maize traits of agronomic interest. We used 23 ISSR molecular markers in an  attempt to maximize genetic variability among and within populations based on  selection of S(1) progenies. To this end, 138  full-sib families were evaluated in a randomized block design in two  environments (the municipalities of Campos dos Goytacazes and Itaocara, in the  State of Rio de Janeiro, Brazil), with replications within sets. Direct  selection for grain yield was used for the selection of the families. To assess  genetic diversity among and within populations, we examined plants produced  from part of the S(1s) seeds from the parents that  originated the 42 full-sib families that were selected from the agronomic  traits. Direct selection for grain yield provided good gains for the traits  evaluated, with estimated improvement of -0.87 days for days to flowering, 0.35  plants, 1.79 ears per plot, 0.58 g per 100-grain weight, 308.21 g ear weight  per plot, and 261.83 kg/ha grain yield. Application of molecular markers at the  stage of superior progeny selection led to increased genetic distance among  populations, which is a very important factor for utilization of heterosis and  providing greater longevity to the reciprocal recurrent selection program.
Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brasil.
K S
KS
da Cunha
M G
MG
Pereira
L S A
LS
Gonçalves
A P C G
AP
Berilli
E C
EC
de Oliveira
H C C
HC
Ramos
A T
AT
do Amaral Júnior
D003433:Crosses, Genetic; D035264:Flowers / Q000235:genetics / Q000502:physiology; D005819:Genetic Markers; D005828:Genetics, Population; D005838:Genotype; D018895:Microsatellite Repeats / Q000235:genetics; D010802:Phylogeny; D011110:Polymorphism, Genetic; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D012641:Selection, Genetic; D003313:Zea mays / Q000235:genetics*
D005819:Genetic Markers