Overcoming tegumentar dormancy in polymorphous clover aerial seeds

Abstract

Trifolium polymorphum (polymorphous clover) is a native forage legume that occurs in the southern half of Rio Grande do Sul and propagates by aerial and subterranean seeds (amphicarpy). However, little is known about the germination potential of aerial seeds. This work aimed to evaluate different times of mechanical scarification with sandpaper on a rotating cylinder in two lots of seeds (2016 and 2022) to verify the presence of dormancy in the aerial seeds. The seed lots were subjected to five times of mechanical scarification with sandpaper (0, 3, 6, 9 and 12 seconds) in a completely randomized experimental design, with four replications of 25 seeds each. The germination speed index (IVG), average germination time (TMG), germination speed coefficient (CVG), first germination count (PC), accumulated germination (GA), dead seeds (MO) and firm seeds (FI) were evaluated. The lots showed few variations in the characteristics evaluated. In the 2016 lots seeds scarified for six seconds had the best GA (75.30%), while in the 2022 lots the GA was less than 30% in all treatments. The treatment using mechanical scarification increased the germination of T. polymorphum aerial seeds when compared to the control, highlighting the occurrence of dormancy in the seeds.