Dormancy release in diaspores of Butia yatay (Arecaceae) using scarification and warm stratification

Butia yatay (Arecaceae) is a threatened palm that occurs naturally in native grasslands of southern Brazil. Its fruits are an alternative source of income for the local populations with potential for agro-industry. This generates a demand for seedlings that is limited by the difficult propagation due to the dormancy of the seeds. Thus, this work aimed to develop a method capable of accelerating germination by overcoming dormancy. Pyrenes from four inflorescences were harvested from different trees in the municipality of Três de Maio/Brazil. In the first experiment, the pyrenes were warm-stratified at 40°C for 0 (control), 1, 2, 3 or 4 weeks. In experiment 2, pyrenes scarified manually (removal of the endocarp germ pore) or using H2SO4 for 5 or 10 minutes were subsequently warm-stratified for four weeks. In experiment 3, pyrenes subjected to physical scarification were warm-stratified for 4, 5, 6 or 8 weeks. Analyses showed that there was a significant effect of the preheating and scarification treatments on the emergence of B. yatay seedlings. Pyrenes mechanically scarified (opening of the germ pore) and subsequently subjected to preheating at 40°C for five weeks produced the highest speed of emergence index, with about 28 seedlings emerged from 100 sown pyrenes.