02128naa a2200277 a 450000100080000000500110000800800410001910000290006024500910008926000090018052013310018965000220152065000130154265000170155565300140157265300270158665300090161365300320162265300150165470000220166970000180169170000160170970000210172570000210174677300830176711336282018-09-24       2002    bl uuuu     u00u1 u    #d1 aFERREIRA, M. A. J. da F.  aSexual expression and mating system in watermelonbimplications for breeding programs.  c2002  aThis study had the following objectives: to investigate the sexual expression in seven watermelon populations; to evaluate some population parameters and the genetic potential of a population (PCS) obtained by crossing and segregating for sexual expression and other traits. For verifying the sexual expression, populations were evaluated with respect to type of flower controlled conditions. Maternal and selfed progenies were obtained from the PCS population for field evaluation, considering: fruit yield per plant, fruit weight, number of fruits per plant, flesh colour and sugar content. On the basis of molecular marker data (RAPD), the outcrossing rate (t m and t s, allelic frequencies (p i) and the coefficient of inbreeding (F) were estimated for the PCS population. Result indicated that populations B9 and P14 are andromonoecious in which natural selfing occurs, giving rise to normal fruits. The remaining populations are monoecious PCS practices a mixed mating system (t m = 0.765) and, having shown sufficient genetic variation and relatively low inbreeding depression, has high potential for breeding purposes. The importance of obtaining accurate estimates of the outcrossing rate is pointed out, specially because sexual expression and the mating system are genetically conditioned in watermelon populations.  aCitrullus Lanatus  aMelancia  aMelhoramento  aGenática  aMelhoramento genético  aRAPD  aSistema mixto de cruzamento  aWatermelon1 aQUEIROZ, M. A. de1 aVENCOVSKY, R.1 aBRAZ, L. T.1 aVIEIRA, M. L. C.1 aBORGES, R. M. E.  tCrop Breeding and Applied Biotechnology, Londrinagv. 2, n. 1, p. 39-48, 2002.