Plant population influences Niger seed yield in the northern Great Plains

Niger [Guizotia abyssinica (L. f.) Cass.] is imported into the USA for use as birdseed. An early maturing niger cultivar, 'EarlyBird' may have the potential to be grown in the northern Great Plains. This study evaluated the effect of different EarlyBird niger seeding rates on seed yield, test weight, plant height, and pest incidence. Eight to ten seeding rates, ranging from 0.56 to 16.8 kg [ha.sup.-1], or 15 to 465 pure live seeds [m.sup.-2], were evaluated in seven environments: Red Lake Falls (RLF) and Kennedy (Ken), MN, in 2000 and 2001, and Carrington (Car), Langdon (Lan), and Prosper (Pro), ND, in 2001. Mean yield across the seven environments was 355 kg [ha.sup.-1]. At RLF00 and RLF01 (Red Lake Falls, MN, 2000 and 2001) the mean yield was 535 and 580 kg [ha.sup.-1], respectively. Maximum yields across all environments corresponded to a seeding rate of 284 seeds [m.sup.-2] and a plant stand of 157 plants [m.sup.-2], or approximately 10.0 kg seed [ha.sup.-1], whereas 90% of the maximum yields corresponded to a seeding rate of 127 seeds [m.sup.-2] and a plant stand of 72 plants [m.sup.-2] or the planting of slightly under 6.7 kg seed [ha.sup.-1]. Plants at the lowest seeding rate had more heads and higher aboveground biomass per plant than the other seeding rates evaluated; however, individual head weight did not differ. For production purposes, a seeding rate of 6.7 kg [ha.sup.-1] provided high yields with early canopy closure and uniform seed maturation.