Stratification of yerba mate seeds in a commercial nursery and the emergence monitoring

Ilex paraguariensis A.St.-Hil. is a native species in Brazil, Argentina, Bolivia, Paraguay, and Uruguay. Propagation is carried out by seeds that have a low germination rate and morphophysiological dormancy. In order to increase the germination percentage, stratification treatments and emergence monitoring were tested. For this, yerba mate seeds were subjected to stratification treatments: Treatment 1 - seeds between two sand layers; Treatment 2 - seeds between two sand layers and commercial substrate covered with corn straw; Treatment 3 - seeds between two sand layers with the addition of 4.0 g "L" ^"-1"  of slow-release fertilizer (16-8-12 - 6 months); Treatment 4 - seeds between two sand layers covered with corn straw; and a control treatment - seeds without stratification. The stratification period for all treatments was 180 days, and at 120, 150, and 180 days, 100 seeds were removed per repetition from each treatment for emergence tests, with weekly observation for 180-days in a completely randomized design. After that period, the tetrazolium test was performed with the seeds that did not emerge. At 120-days of stratification there was no emergence and at 150-days it was 0.83%. At 180-days, treatment 3 showed the highest percentage - 13.19%. Seeds without stratification do not germinate and after 180-days of emergence the amount of non-viable seeds increased in all treatments. Stratification in sand with slow-release fertilizer favors the emergence of yerba mate seedlings.The propagation of Ilex paraguariensis A.St.-Hil. is carried out by seeds that have a low germination rate and morphophysiological dormancy. In order to increase the germination percentage, stratification treatments and emergence monitoring were tested. For this, yerba mate seeds were subjected to stratification treatments: Treatment 1 - seeds between two sand layers; Treatment 2 - seeds between two sand layers and commercial substrate covered with corn straw; Treatment 3 - seeds between two sand layers with the addition of 4.0 g  of controlled-release fertilizer; Treatment 4 - seeds between two sand layers covered with corn straw; and a control treatment - seeds without stratification. The stratification period for all treatments was 180 days, and at 120, 150, and 180 days, 100 seeds were removed per repetition from each treatment for emergence tests, with weekly observation for 180-days in a completely randomized design. After that period, the tetrazolium test was performed with the seeds that did not emerge. At 120-days of stratification there was no emergence and at 150-days it was 0.83%. At 180-days, treatment 3 showed the highest percentage - 13.19%. Seeds without stratification do not germinate and after 180-days of emergence the amount of non-viable seeds increased in all treatments. Stratification in sand, combined with controlled-release fertilizer favors yerba mate seedlings emergence. After 180-days of emergence in germinator plants at 25°C, there is an increase in non-viable seeds amount. Seeds that did not undergo the stratification process do not germinate and present a higher dormant seeds percentage after 180-days of emergence

Estratificação de sementes de erva-mate em viveiro comercial e acompanhamento da emergência

The propagation of Ilex paraguariensis A.St.-Hil. is carried out by seeds that have a low germination rate and morphophysiological dormancy. In order to increase the germination percentage, stratification treatments and emergence monitoring were tested. For this, yerba mate seeds were subjected to stratification treatments: Treatment 1 - seeds between two sand layers; Treatment 2 - seeds between two sand layers and commercial substrate covered with corn straw; Treatment 3 - seeds between two sand layers with the addition of 4.0 g L-1 of controlled-release fertilizer; Treatment 4 - seeds between two sand layers covered with corn straw; and a control treatment - seeds without stratification. The stratification period for all treatments was 180 days, and at 120, 150, and 180 days, 100 seeds were removed per repetition from each treatment for emergence tests, with weekly observation for 180-days in a completely randomized design. After that period, the tetrazolium test was performed with the seeds that did not emerge. At 120-days of stratification there was no emergence and at 150-days it was 0.83%. At 180-days, treatment 3 showed the highest percentage - 13.19%. Seeds without stratification do not germinate and after 180-days of emergence the amount of non-viable seeds increased in all treatments. Stratification in sand, combined with controlled-release fertilizer favors yerba mate seedlings emergence. After 180-days of emergence in germinator plants at 25°C, there is an increase in non-viable seeds amount. Seeds that did not undergo the stratification process do not germinate and present a higher dormant seeds percentage after 180-days of emergence.A propagação da Ilex paraguariensis A.St.-Hil. é realizada por sementes que apresentam baixa taxa de germinação e dormência morfofisiológica. Com o intuito de aumentar a porcentagem de germinação foram testados tratamentos de estratificação e acompanhamento da emergência. Para isso, sementes de erva-mate foram submetidas a tratamentos de estratificação: Tratamento 1 - sementes entre duas camadas de areia; Tratamento 2 - sementes entre duas camadas de areia e substrato comercial coberto por de palha de milho; Tratamento 3 - sementes entre duas camadas de areia com adição de 4,0 g L-1 de adubo de liberação controlada; Tratamento 4 - sementes entre duas camadas de areia coberta com palha de milho; e um tratamento controle - sementes sem estratificação. O período de estratificação de todos os tratamentos foi de 180 dias, e aos 120, 150 e 180 dias foram retiradas 100 sementes por repetição de cada tratamento para os testes de emergência, com acompanhamento semanal durante 180 dias em delineamento inteiramente casualizado. Após esse período, com as sementes não emergidas foi realizado o teste de tetrazólio. Aos 120 dias de estratificação não houve emergência e aos 150 dias foi de 0,83%. Aos 180 dias, o tratamento 3 apresentou a maior porcentagem - 13,19%. Sementes sem estratificação não germinam e após 180 dias de emergência aumentou a quantidade de sementes não viáveis em todos os tratamentos. A estratificação em areia, aliada ao adubo de liberação controlada favorece a emergência das plântulas de erva-mate. Após 180 dias de emergência em germinador a 25°C ocorre aumento na quantidade de sementes não viáveis. Sementes que não passaram pelo processo de estratificação não germinam e apresentam maior porcentagem de sementes dormentes após 180 dias de emergência