Iridescent colors in feathers are some of the brightest in nature, and are produced by coherent light scattering from periodic arrangements of melanosomes (melanin-containing organelles). Hollow melanosomes, an evolutionary innovation largely restricted to birds, contain an optically powerful combination of high and low refractive indices (from the melanin and air, respectively) that enables production of brighter and more saturated colors than solid melanosomes. However, despite their significance to avian color and potential utility as optical biomaterials, little is known about the ontogeny of either the melanosomes themselves or the nanostructures they comprise. We used light and electron microscopy to characterize nanostructural development in regenerating feathers of wild turkeys, a species with iridescent color produced by a hexagonally close-packed array of hollow melanosomes. We found that melanosomes form as solid bodies in melanocytes. Later in development, largely after placement in developing barbules, their interiors dissolve and leave hollow cores. These now hollow melanosomes are initially disorganized in the barbule, but become close-packed as they are pulled to the edge of the barbule, likely through a combination of forces including depletion-attraction. These data suggest that these structurally colored tissues are self-assembled and represent novel pathways of development.

Soybean [Glycine max (L.) Merr.] yield is a function of many factors including genetic attributes of the cultivar, environmental conditions, and management practices. Temporally variable weather patterns in North America, especially in the northern Great Plains, have resulted in the re‐examination of how spring production practices interact with the environmental conditions to influence yield. This study evaluated the impact of four plantings dates, four seeding rates, and two soybean maturity groups (MGs) using treated and untreated (control) seed on soybean growth, seed yield, and composition. The study was conducted at Volga, SD, in 2014, 2015, and 2016. The planting dates in the study ranged from early May to early July and the four seeding rates were 247,000; 333,500; 420,000; 506,500 seeds ha−1. Stand establishment decreased as seeding rate increased irrespective of planting date. The number of growing degree days (GDDs) to R1 decreased with delayed planting. Delayed planting also decreased the number of GDDs to R8, the length of the reproductive phase (R1−R8), and seed yield. Delayed planting decreased seed yield for both MGs but the rate of decrease was greater for MG 2.4 than MG 1.4. Seed treatment increased seed yield irrespective of planting date. Seed protein was variable among planting dates and between MGs while seed oil decreased with delayed planting. The research documents the impact of delayed planting on soybean yield and quality and highlights the importance of early planting in soybean irrespective of maturity group and growth habit.

Soybean growers in the northern latitudes of the United States plant the crop in a wide range of row spacings although there has been a shift toward wider rows (>50 cm) in some Upper Midwest states in the last 5 years. The objective of this study was to evaluate the impact of row spacing and seeding rate on the performance of soybean and to determine whether these management practices interact to influence soybean yield. A row spacing study was conducted at Aberdeen and Beresford, South Dakota, USA, in 2014 and 2015. The study had two row spacings (19 and 76 cm), four seeding rates (247,000, 333,500, 420,000, and 506,500 seeds ha À1 ), and two soybean varieties at each location. Soybean had greater stand establishment in 19 cm rows (6-10% higher) compared with 76 cm rows. Soybean in 19 cm rows yielded 0.8-10% more than in 76 cm rows depending on the location or year. Seed yield increased with increasing seeding rate with the highest seeding rate of 506,000 seeds ha À1 yielding greatest. The increase in seed yield due to the increase in seeding rate ranged from 3 to 7%. At each location, the longer duration soybean variety yielded higher than the shorter duration variety.