Germination behaviour of Macedonian weedy rice

Abstract

The main aim of this study was to evaluate the germination behaviour of weedy rice, a problematic and persistent weed in Macedonian rice production. Seeds from six morphotypes and the cultivars San Andrea and Onice from which weedy rice was isolated were collected and stored in typical conditions (room temperature). The germination energy, total germination and germination speed were examined at 2 weeks, as well at 4, 8, 12 and 16 months of storage. The seedling vigor index I, seedling length (root, shoot and total length) and vigor index II were examined after the release from dormancy in weedy rice. Weedy rice exhibited varied degree of dormancy at the beginning of the study (total germination from 4% to 63%), while cultivated rice showed no dormancy. Weedy rice had a significantly higher vigor index I (from 2092.78 to 2366.77 across morphotypes), seedling length (21.46 cm to 24.96 cm) and root length (11.61 cm to 13.69 cm) compared to cultivated rice (seedling length: 19.64 cm in San Andrea and 20.18 cm in Onice; root length: 9.02 cm in San Andrea and 10.42 cm in Onice). Weedy rice exhibited significantly lower to non- significant vigor index II (from 1939.19 to 2110.04) compared to cultivated rice (2788.03 in San Andrea and 2112.26 in Onice). The vigor index II and dry seedling weight were in significant positive correlation with the 100 grains weight of paddy. The germination energy, total germination and germination speed in weedy rice had increased values at 8 months of storage, that is the period when paddy fields are prepared for new sawing in the next vegetative season. This information is useful for the application of good agricultural practices for the control of weedy rice.