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 Tres de Maio/ Brazil. In the first experiment, the pyrenes were warm-stratified at 40 degrees 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 degrees C for five weeks produced the highest speed of emergence index, with about 28 seedlings emerged from 100 sown pyrenes.