Avaliação de métodos de superação de dormência em sementes de ziziphus joazeiro mart.

Abstract

Ziziphus joazeiro Mart. is a species of high environmental and socioeconomic potential, but the slow and ununiform emergency process is a great obstacle to the production of seedlings. The objective of this work was to apply different methods of overcoming dormancy, seeking to accelerate the seedling emergence process of Ziziphus joazeiro Mart. The work was carried out in the Municipality of Sumé-PB, being sowing in trays in the nursery with 50% shading in May 2018. The treatments were: Witness - intact seeds (T1), imbibition in water at room temperature by 18, 36, 72 and 144 hours (T2, T3, T4, T5, respectively), imbibition in goat manure for 18, 36, 72 and 144 hours (T6, T7, T8, T9 respectively), imbibition in water for 2 minutes at 60, 65, 70 and 75 °C (T10, T11, T12, T13 respectively), imbibition in bovine manure for 18, 36, 72 and 144 hours (T14, T15, T16, T17 respectively), mechanical scarification with sandpaper number 80 (T18), crack in the endocarp with hammer (T19), hole in the central part of the endocarp (T20) and extraction of the seed (T21). The experimental design was completely randomized, with four replicates for each treatment. Data were submitted to analysis of variance and means were compared by the Skott-Knott test. Z. joazeiro presented low and slow emergency process during the 30 days of evaluation. Seed extraction provided the best percentage of emergence (48%) and emergence velocity index (0.7), followed by endocarp cracking, sanding scarification and control, which also provided the greatest diameter development at the soil level of the seedlings of Z. joazeiro. Seed extraction generated the highest values for root length while the aerial part was benefited without statistical divergence both by this treatment and by the crack of the endocarp, which also resulted in the best results for root and aerial dry matter.