Growth experiments on autopolyploids of Gracilaria tikvahiae (Rhodophyceae)

Abstract

Unreduced gametes generated by mitotic recombination on tetrasporophytes of the red alga Gracilaria tikvahiae McLachlan were used to construct a variety of autopolyploid lines. Triploids often appeared robust, having a luxuriant growth habit and stout fronds. Tetraploids often appeared less robust than triploids, and pentaploids had an abnormal morphology. In spite of their robust appearance, the growth rates of polyploids did not significantly exceed those of diploid tetrasporophytes either as sporelings or as mature plants. A high degree of heterozygosity for the polyploids did not improve their growth performance over that of control diploid plants.