Ten progenies involving self-, sib-, and backcross matings and an outcross were compared to determine the effects of inbreeding and selection in amphidiploid Dendrobium Jaquelyn Thomas. The progenies included two sets of reciprocal matings. The measurements of yield, size, and earliness of flowering indicated a decline due to inbreeding. Selection increased flower size and improved the purity of flower color. Detrimental effects of inbreeding on these characters were not detected. Significant differences were obtained for keeping quality, number of flowers per spray, and length of the scape of the spray. However, it was not possible to attribute these differences to either inbreeding or selection effects. Spray length differences were nonsignificant. Offspring of reciprocal crosses did not differ significantly in all characters measured
