Vitis labrusca L. germination: influence of treatments to break dormancy, storage and ripening point of fruits

Abstract

Grapevine seeds have morphophysiological dormancy, which complicates their germination, an important step in obtaining new plants after crossing during breeding. The objective of this work was to establish the ideal conditions for Vitis labrusca L. ‘Isabella’ seed storage conditions, the method for breaking seed dormancy, ripening of fruits at harvest, need for fungicide application before seed sowing and their germination. The seeds were submitted to three tests with (1 and 2) different treatments to break seed dormancy and storage in two conditions for two different times (Isabella), and (3) seeds from unripe and ripe fruits treated or untreated with fungicide. Germination was monitored two times per week. The percentage of germination (%G), germination mean time (GMT), and germination speed index (GSI) were calculated. Data were submitted to analysis of variance (ANOVA) and means were compared using the LSD-Fisher test (p < 0.05). The 12-month storage at a controlled temperature (25±2°C) provided the best germination results (up to 19.5% of G%). Stratification for 90 or 120 days on wet paper or sand at 5±2°C of seeds from mature fruits is the most suitable for the germination of Isabella seeds (65% to 72% of G%, and 1.73 and 1.95 of GSI for the treatments of stratification on wet sand for 120 days). It is also not necessary to apply fungicide on seeds before sowing, as long as disinfestation with 70% alcohol and sodium hypochlorite 1%, and triple washing with water is done (no statistical difference for seeds from ripe fruits treated or not with fungicide, 58% and 64.7% of %G, and 1.37 and 1.22 of GSI, respectively).