ISTA proficiency test 17-2 germination results of white clover seed

The presence of hard seeds as a result of water impermeable seed coat is common in species of Fabaceae family. For wild plants, this characteristic allows better survival, but for agriculture production, hard seeds are undesirable, due to delayed and uneven germination. In seed testing laboratory several pre-treatments (pre-chill, mechanical scarification) can be applied for germination testing of these species. In this paper, Proficiency test 17-2 germination results of Trifolium repens seeds conducted in 150 laboratories around the world are presented. Those tests are organized by the International Seed Testing Association (ISTA) and are mandatory for all accredited laboratories. In this way laboratory’s competence (staff, apparatus, test methods) is checked. In August 2017, samples of three Trifolium repens seed lots were distributed. In the Seed Testing Laboratory at the Maize Research Institute Zemun Polje (LIZP), germination was tested in September using mechanical scarification and pre-chilling (2 days at 5-10°C) prior to germination at 20°C. Among 90 accredited participants, only one more laboratory applied mechanical scarification, 42 laboratories did not use any pre-treatment, and 39 laboratories applied pre-chilling. Obtained germination results in LIZP (Lot1-84.50%, Lot2-84%, Lot3-88.50%) were higher than overall mean (Lot1-76.95%, Lot2-79.63%, and Lot3-83.27%). The main conclusion of this Proficiency test is that seed scarification significantly reduced the number of hard seeds in favour of normal seedlings. The reason for the rare application of scarification may be the requirement of the applicant to obtain adequate information regarding the number of hard seeds that will appear during seed sowing.