Influence of harvesting terms on the quality of switchgrass seeds
Abstract
V.V. Dryha, V.A. Doronin, V.M. Sinchenko, Yu.A. Kravchenko, H.S. Honcharuk, N.S. Zatserkovna, L.M. Karpuk* and V.P. Mykolaiko
The paper covers some specific aspects of the quality formation of switch-grass seeds depending on growing conditions and harvesting terms. Methods. Field, laboratory, and statistics. To find out how emergence vigor and seed germination change under the effect of a seed maturation method, seed samples threshed after mowing (direct combining) and seed samples after drying and maturation on the mown plants (a particular harvesting method) were taken. Results. We found that switch-grass seed germination depended on post-harvest maturation on the mown plants. On average, within three years, emergence vigor and seed germination were significantly higher at seed maturation on the mown plants – by 8% and by 7%, respectively. The quality improvement of the seeds matured on the mown plants results from the outflow of the nutrient substances from plants to seeds, which is not the case when seeds threshed after the plants were mown mature in piles. The mass of 1000 seeds did not change significantly depending on a seed maturation method; at seed maturation on the mown plants, it was 1.74 g; at seed maturation in piles, it was 1.76 g. When seeds were harvested at 50% of panicle browning, regardless of a maturation method, emergence vigor and germination were the lowest – 61-66% and 63-67%, respectively. When seeds were harvested at 100% of panicle browning, the indicators were significantly higher than at an earlier harvesting term, emergence vigor and germination increased by 6 and 9%, respectively, the mass of 1000 seeds increased by 0.08-0.25 g. When seed harvesting was at 75% of panicle browning, emergence vigor and germination were reliably higher than at 50% of panicle browning, and they were much lower when seed harvesting was done at 100% of panicle browning. Conclusions. Germination of switch-grass seeds depended on both harvesting terms and post-harvest maturation on the mown plants. Hence, one way to improve seed quality is to apply a particular harvesting method: mowing plants in swathes, seed drying and maturation on the mown plants, and threshing.