Lenis Alton Nelson

Genetic improvement trends in agronomic performances and end-use quality characteristics among hard red winter wheat cultivars in Nebraska

Evaluation of wheat cultivars from different eras allows breeders to determine changes in agronomic and end-use quality characteristics associated with grain yield and end-use quality improvement over time. The objective of this research was to examine the trends in agronomic and end-use quality characteristics of hard red winter wheat cultivars grown in Nebraska. Thirty historically important and popular hard red winter wheat cultivars introduced or released between 1874 and 2000 were evaluated at Lincoln, Mead and North Platte, Nebraska in 2002 and 2003. An alpha lattice design with 15 incomplete blocks of two plots and three replications was used at all locations. Agronomic (days to flowering, plant height, spike length, culm length, grain yield and yield components, and grain volume weight) and end-use quality (flour yield, SDS-sedimentation value, flour protein content, and mixograph time and tolerance) traits were measured in each environment. Highly significant differences were observed among environments, genotypes and their interactions for most agronomic and end-use quality characteristics. Unlike modern cultivars, older cultivars were low yielding, and less responsive to favorable environments for grain yield and yield components. Semidwarf cultivars were more stable for plant height than traditional medium to tall cultivars. All cultivars had high grain volume weight since it is part of the grading system and highly selected for in cultivar release. Modern cultivars were less stable than older cultivars for SDS-sedimentation and mixing tolerance. However, the stability of older cultivars was attributed to their having weak mixing tolerance and reduced SDS-sedimentation values. The reduced protein content of modern cultivars was offset by increased functionality, as measured by mixograph and SDS sedimentation. In conclusion, breeders have tailored agronomic and end-use quality traits essential for hard red winter wheat production and marketing in Nebraska.

Skip-Row Planting Patterns Stabilize Corn Grain Yields in the Central Great Plains

The highly variable climate of the central Great Plains makes dryland corn (Zea mays) production a risky enterprise. Twenty-three field trials were conducted across the central Great Plains from 2004 through 2006 to quantify the effect of various skip-row planting patterns and plant populations on grain yield in dryland corn production. A significant planting pattern by plant population interaction was observed at only one of 23 trials, suggesting that planting pattern recommendations can be made largely irrespective of plant population. In trials where skip-row planting patterns resulted in increased grain yields compared to the standard planting pattern treatment (every row planted using a 30-inch row spacing), the mean grain yield for the standard planting treatment was 44 bu/acre. In those trials where skip-row planting resulted in decreased grain yield compared to the standard planting pattern, the mean yield was 135 bu/acre. The plant two rows, skip two rows planting pattern is recommended for riskaverse growers in the central Great Plains where field history or predictions suggest likely grain yields of 75 bu/acre or less. Planting one row and skipping one row is recommended for growers with moderate risk-aversion and likely yield levels of 100 bu/acre or less.

Row spacing affects grain yield and other agronomic characters of proso millet

Proso millet (Panicum miliaceum L.), a short-season summer annual with excellent water-use efficiency, is well adapted to crop production systems in semi-arid environments. It is used as an emergency crop or as a rotation crop in a three-year rotation with winter wheat (Triticum aestivum L.). Row spacing and cultivar may impact the success of proso millet in the semi-arid Great Plains. Six row spacings; 15, 19, 23, 30, 38, and 46 cm, were compared in three environments; conventional tillage irrigated, conventional tillage dryland, and no-tillage dryland. These plots were evaluated at two different weed density levels: weedy (allowed all weeds to grow in the plots during the growing period) and weed-free (did not allow any weeds during the growing period). These trials were conducted in 1995 at the High Plains Agriculture Lab, Sidney, Nebraska (latitude 41°16′ North and longitude 103° 00′ West) at an elevation of 1250 m. Proso millet responded to changes in row spacing. Grain yield, tiller number, and straw weight decreased as row spacing increased while seed weight and plant height increased with row spacing. Seed weight increased with row spacing at all row spacings in the irrigated treatment while in the dryland sites, the increase was only at the narrower row spacing. The relatively light weed pressure in all but the no-till treatment reduced the effect of weeds in the response of grain yield to row spacing. Even in the no-till treatment, row spacing had little influence on weed weight. Narrow rows were superior for grain yield and weed control. In areas of limited moisture, however, 15 cm appears to be too narrow. Thus, 19 cm would appear to be a better choice of row spacing for areas where drought is likely. *Contribution of the Nebraska Agric. Exp. Stn. Journal no. 12892. Received Jan. 20, 2000.

Environmental Effects on Developing Wheat as Sensed by Near-Infrared Reflectance of Mature Grains

ABSTRACT For 30 years, near-infrared (NIR) spectroscopy has routinely been applied to the cereal grains for the purpose of rapidly measuring concentrations of constituents such as protein and moisture. The research described herein examined the ability of NIR reflectance spectroscopy on harvested wheat to determine weather-related, quality-determining properties that occurred during plant development. Twenty commercial cultivars or advanced breeding lines of hard red winter and hard white wheat (Triticum aestivum L.) were grown in 10 geographical locations under prevailing natural conditions of the U.S. Great Plains. Diffuse reflectance spectra (1,100–2,498 nm) of ground wheat from these samples were modeled by partial least squares one (PLS1) and multiple linear regression algorithms for the following properties: SDS sedimentation volume, amount of time during grain fill in which the temperature or relative humidity exceeded or was less than a threshold level (i.e., >30, >32, >35, 80%, <40% rh). ...