Materials
The silflower seeds (2.37 kg) provided by The Land Institute, Salina, KS
were harvested from their research plots just south of the city limits
of Salina in 2018 and 2019. The seeds were part of the bulk that
included improved plots and new, wild introductions, and intermediate
improved x wild populations. The crude harvest from the combine was
cleaned using Clipper cleaners of various models (A.T. Ferrell Co. Inc.,
Bluffton, IN) and various screens to separate seed from chaff and then
through an indent cylinder with 16 mm indents (Seed Processing Holland,
Enkhuizen, The Netherlands) to remove longer stems and sticks. The seeds
were stored in resealable polyethylene bags and stored under ambient
conditions until processed.
Measurements of selected
physical properties
The bulk seed density was determined by weighing the seeds contained in
a 1-liter cup (203 Liter Cup, Seedburo Equipment Co., Chicago, IL). For
loose bulk density, the cup was filled with seeds flowing freely from a
hopper and then leveled using a straight-edged spatula. The tapped bulk
density was measured by shaking and tapping the cup while being filled
with seeds and then leveling as described. Seed weight was obtained by
weighing 1,000 seeds randomly picked from the bulk sample. The hull and
kernel were manually separated from 1,000 seeds. The weights of hulls
and kernels were then obtained, and their percentages to the seed weight
were calculated. The length, width, and thickness of 20 seeds and
kernels were measured using a digital caliper. The true densities of
seed, kernel, and hull were obtained by weighing the samples in a 10
cm3 cup, and the true volumes were determined using an
AccuPyc II 1340 gas pycnometer, Micromeritics, Norcross, GA. All
determinations were performed in triplicate.