Overcoming dormancy in Rubus sellowii Cham. & Schlitdl. seeds, an endemic species to Brazil

ABSTRACT:

The seeds are used for conservation, genetic improvement and production of seedlings of native and cultivated species. However, seed dormancy has been a challenge, a process that prevents or delays germination, delaying or hindering their use in these applications. Thus, this study aimed to evaluate, understand and overcome, the seed dormancy in Rubus sellowii, a raspberry species native to Brazil. In our observations it was confirmed the existence of a rigid layer in seeds of R. sellowii that impedes water absorption. Seed scarification using sulfuric acid for 10 to 20 minutes increased the germination (up to 42.5% and 51.3%, respectively), and germination speed index (1.01 and 1.58), compared to no seed germination without scarification. Therefore, scarification was necessary and sufficient to overcome dormancy and allow the germination of R. selowii seeds. As well as in vitro experiments, the germination in substrate was favored by incubation under germination chamber conditions with day/night temperature alternation, improving R. sellowii seed germination. The alternation of temperature proved to be an important factor in controlling the germination of R. sellowii seeds.

Index terms:
chemical scarification; raspberry; seed germination; temperature