02452naa a2200277 a 450000100080000000500110000800800410001902400490006010000230010924501160013226000090024852016400025765000240189765000090192165000100193065000350194065000170197565000250199265300170201765300230203465300170205770000180207470000220209270000210211477300390213511960162022-06-02       2003    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1023/A:10246402023532DOI1 aCORDEIRO, A. C. C.  aEffect of the number of intercrosses on grain yield in basic rice synthetic populations.h[electronic resource]  c2003  aThe effect of 0, 1, 2, 3 and 4 intercross cycles using genetic male sterility on the mean yield and genetic variability of the CNA 5 irrigated rice synthetic population was assessed studying 300 S0:2 (1998/99) and S0:3 (1999/00) families grown in two locations (Lambari, MG and Goianira, GO). Each intercross was investigated using a 8 × 8 triple lattice design experiment containing 60 families and four control cultivars. Five experiments were carried out per location and generation, totaling 20 experiments. Individual, combined over locations, combined over generations and combined over locations and generations analyses of variance were performed. Linear regression equations were fitted to data of each location and generation as well as, genetic and phenotypic parameters were estimated. An average increase of 3.91% in grain yield was obtained with the increase in the number of intercrosses. However, when genetic gains obtained from selection of the five and ten highest yielding families were considered, negative b estimates were always obtained, suggesting a tendency of gain increase reduction with the increase in the number of intercrosses. This was confirmed by the analysis of the means of the best families, since increases in the number of intercrosses did not result in selection of families with greater mean grain yield. The estimates of the genetic variances and heritabilities did not suggest an increase in genetic variability with the increase in intercross cycles. Therefore, carrying out intercrosses on the base population did not improve the results of the irrigated rice recurrent selection program.  aRecurrent selection  aRice  aArroz  aMelhoramento Genético Vegetal  aOryza Sativa  aSeleção Recorrente  aGenetic gain  aGenetic parameters  aIntercrosses1 aSOARES, A. A.1 aRAMALHO, M. A. P.1 aRANGEL, P. H. N.  tEuphyticagv. 132, p. 79-86, 2003.