Over the past 15 to 25 years the plant characteristics of small grains have changed; however, little is known in the Pacific Northwest about the production practices necessary to maximize grain yields with these short statured, early maturing, lodging resistant small grain cultivars. A 4‐year (1977 to 1980) field study at Pullman, Wash. on a Palouse silt loam (fine‐silty, mixed, mesic pachic Ultic Haploxerolls) examined grain yield and test weight responses to three seeding dates (early, normal, and late) and three seeding rates (40, 75, and 110 kg/ha). Five spring barley (Hordeum vulgare L.), three spring oats (Avena sativa L.), and five spring wheat (Triticum aestivum L.) cultivars were tested. Significant cultivar × seeding date and cultivar × seeding date × year interactions existed for grain yield. Seeding date delays past the normal date significantly reduced grain yield and test weight for the majority of the cultivars when averaged over the 4‐year period. However, several cultivars showed yield reductions with seeding date delays past the earliest date. Several cultivars showed yield reductions with the lowest or highest seeding rate. Reduced yields with the 110 kg/ha seeding rate were caused by lodging. The non‐significant seeding rate × seeding date and cultivar × seeding rate × seeding date interactions for yield indicate that increasing the seeding rate with later seeding dates was not beneficial in increasing grain yield. Test weight values for the small grains averaged over years were generally reduced with late seeding dates.

The stomatal frequency of 43 soybean [Glycine max (L.) Merr. genotypes varied significantly. The mean frequency on the adaxial surface was 130 (range: 81 to 174); on the abaxial surface, it was 316 stomata/mm2 (range: 242 to 345). The mean guard cell lengths were 21.9 and 20.4 µ for the adaxial and abaxial surfaces, respectively.Stomatal frequency and leaf area were measured on the terminal leaflet of the third trifoliolate of soybeans grown at 18, 24, and 30 C and at 19,300 and 32,300 lux. Stomatal frequency significantly decreased with temperature on the abaxial surface, but there was no effect on the adaxial surface. Stomatal frequency significantly increased with light intensity on both surfaces. Leaf area increased with temperature and decreased with light intensity. Stomatal number/leaflet did not vary significantly with light or temperature treatments.Water‐stressed, field‐grown plants had significantly greater stomatal frequency and smaller leaf area than nonwater‐stressed plants. Stomata/leaflet surface were significantly lower on water stressed plants than nonwater‐stressed plants.

Winter wheat (Triticum aestivumL.) producers in the Palouse Region of southeastern Washington generally seed one wheat cultivar over a wide range of environmental conditions formed by the rolling topography of the area. A 2‐year field study was conducted during 1977–1979 growing seasons on five slope positions across a Palouse silt loam (fine‐silty mixed, mesic pachic Ultic Haploxerolls), a Naff silt loam (fine‐silty, mixed, mesic Ultic Agrixerolls), and a Snow silt loam (fine‐silty, mixed, mesic Cumulic Haploxerolls) to examine the influence of slope position on grain yield and yield components of 12 soft white winter wheat cultivars. Slope position and cultivar significantly influenced grain yield while only cultivar significantly influenced test weight. There were significant cultivar ✕ slope position and slope position ✕ year interactions for grain yield, test weight, and culm height. Differences in mean grain yield for an individual cultivar ranged from 0.45 to 1.90 Mg/ha when compared across slope positions. Yield components were examined during the 1977–1978 growing season and were found to be significantly influenced by slope position and cultivar. Spikelets/spike and 100‐seed weight were the only yield components to show a significant cultivar ✕ slope position interaction. These findings indicate the need to more clearly define where soft white winter wheat cultivars are best adapted to meet specific environmental and topography conditions.

Soil erosion is a serious problem in the wheat (Triticum aestivum L.) producing areas of the Palouse Region of the Pacific Northwest. A field study was conducted under three environmental conditions [a Palouse silt loam (Pachic Ultic Haploxerolls, fine‐silty, mixed, mesic) during 1980 and an Athena silt loam (Pachic Haploxerolls, fine‐silty, mixed, mesic) during 1979 and 1980] to determine the effects of three tillage systems on grain yield and yield components of four soft white spring wheat cultivars, WS‐1, Urquie, Fielder, and Walladay. The tests were conducted using conventional (fall plow and spring disk), conservation (fall chisel and spring disk), and no‐tillage (standing stubble) tillage systems. Average grain yields with no‐tillage and conservation tillage were significantly greater than yields using conventional tillage. No‐tillage increased test weights while reducing tillage operations significantly reduced the number of spikelets per head, but increased the 100‐seed weight. Tillage practice had no significant influence on heads/m2, seeds per spikelet or seeds per head. Environment significantly influenced all yield components but not grain yield itself. There were significant differences in yield and yield components among the cultivars examined. Cultivar ✕ tillage interaction for yield (p ≤ 0.06) and test weight (p ≤ 0.03) were significant when examined across all environments. These findings show that no‐tillage spring wheat yields were equal to or greater than that obtained with conventional tillage. Significant cultivar ✕ tillage interactions for yield and test weight emphasize the need to evaluate individual spring wheat cultivars for specific tillage conditions.

Rains after wheat (Triticum aestivum L.) is physiologically ripe can cause preharvest sprouting which can lower the baking quality of flour due to de novo synthesis of alpha‐amylase. A fast, repeatable method is needed by plant breeders to screen wheat lines for their susceptibility to preharvest sprouting. In this study, three winter wheat cultivars varying in susceptibility to preharvest sprouting were grown in six different environments within the Pacific Northwest and were used to evaluate four germination and three enzymatic tests that measure sprouting susceptibility. Germination tests were performed with intact spikes and threshed seeds at four temperatures (15, 20, 25, and 30°C). Enzymatic tests were performed using flour milled from seeds that had been germinated at 15°C. The evaluation was based on 15 parameters of sprouting measured in the various tests. For a sprouting parameter to be considered a useful indicator of sprouting susceptibility it had to show significant (P < 0.05) differences in both cultivar and environmental effects at a given germination temperature, and its coefficient of variation had to be low. A germination test using intact spikes rolled in paper towels and one using threshed seeds in petri dishes at 20°C were the only tests that yielded parameters meeting the required criteria. Although disadvantages and advantages are associated with each of the parameters examined, germination tests were better in predicting sprouting susceptibility whereas enzymatic tests were better in quantifying actual sprout damage.