Mu. Patwary et Jp. Vandermeer, APPLICATION OF RAPD MARKERS IN AN EXAMINATION OF HETEROSIS IN GELIDIUM-VAGUM (RHODOPHYTA), Journal of phycology, 30(1), 1994, pp. 91-97
Four morphologically indistinguishable isolates Of monoecious Gelidium
vagum Okamura were crossed reciprocally to obtain hybrids for a study
on heterosis in this alga. Approximately 50% outcrossing was achieved
by adding a small fragment of the designated female parent to a much
larger quantity of designated male thallus in the crossing dish. Hybri
ds in the mixed population of isomorphic hybrid and inbred sporelings
were identified by the presence of male-specific random amplified poly
morphic DNA markers. Growth performance of hybrid tetrasporophytes was
compared to that of their gametophytic parents and with inbred tetras
porophytes at near-optimum and sub-optimum temperature and density. In
general, the hybrids showed growth superiority over inbred lines, par
ticularly under sub-optimum conditions. In these experiments, the hybr
id plants from cross 129 x 130 exhibited a 9.5-130% higher growth rate
as compared to the mid-value of the related inbred tetrasporophytes,
strongly suggesting the presence of heterosis.