Partial Inhibition of Pollen Degradation by Gibberellic Acid Mutants Derived from cv. First (Lycopersion esculentum Mill.)

The young flower buds in three male sterile mutants derived from cv.First were treated with gibberellins to determine whether pollen degradation could be inhibited.Microscopic observations of acetocarmine preparations revealed that the application of gibberellins inhibitde pollen degragation for all tested mutants of Fms-1,Fms2 and Fms-3 in which their breakdown in microsporogenesis occurs at microspore stage,during meiosis and at tetrad formation ,respectively.The optimum concentration and treatment time were 10mg/1 and 6-12days before flowering,GA7 proved to be preferable to GA3 for pollen fertility restoration.With the elingation of stameans by gibberellin application,viable pollens appeared frequeitly in Fms-2 mutant,being over 200grains on a 0.5mm equatorial section of anthers in the best case,as compared to the other mutants.Bioassay using dwafrice seedilings showe that the Fms-2 plants had lower levels of gibberellin in their anthers compared with normal ones.