Lodging can be a limiting factor of hard red spring wheat (HRSW) production. The main objective of this study was to determine the optimum timing and rate of trinexapac‐ethyl (TE) to improve straw strength, resistance to lodging, and related agronomic responses of HRSW. Field experiments arranged in randomized complete blocks were conducted from 2004 to 2006 in Crookston, MN. Five TE rates (0, 62.5, 93.75, 125.0, and 250.0 g a.i. ha−1) and one ethephon rate (280.2 g a.i. ha−1) were applied at Zadoks growth stage (GS) 30, 32, or 37. Measurements included crop injury, plant height, lodging, straw strength, acid detergent lignin (ADL) content, plant maturity, plant density, and yield. Increasing TE rates linearly decreased plant height and increased lodging resistance, straw strength, and ADL content. Lodging resistance was negatively correlated with plant height and positively associated with straw strength and ADL content. The TE rate of 125 g a.i. ha−1 decreased plant height by approximately 6%, and increased plant erectness by 9% and straw strength by 13%, without causing crop injury, delaying maturity, or affecting yield. Applications of TE at GS 37 resulted in less crop injury, shorter stand, and more erect plants than those at GS 30 or 32. These data suggest that the optimum application rate and timing of TE may be 125.0 g a.i. ha−1 at GS 37 for HRSW.

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Seed germination and vegetative growth studies were conducted to determine relative salinity tolerance of greens‐type Poa annua L. compared with other cool‐season turfgrass species. Effects of increasing salinity stress on final germination percentage (FGP), germination rate (GR), clipping yield dry weight (CYD), verdure dry weight (VD), root dry weight (RD), and the longest root length (LRL) were evaluated for nine experimental lines of greens‐type P. annua, two cultivars of Kentucky bluegrass (P. pratensis L.), three cultivars of creeping bentgrass (Agrostis stolonifera L.), and one cultivar of perennial ryegrass (Lolium perenne L.). Generally, FGP, GR, CYD, VD, and RD declined with increasing salinity; LRL increased at lower salinity levels but decreased at higher levels. Perennial ryegrass ‘Charger II’ and creeping bentgrass ‘Mariner’ exhibited the most salinity tolerance while Kentucky bluegrass cultivars exhibited the least. Salinity tolerance of greens‐type P. annua was intermediate; however, some experimental lines exhibited nearly equal salinity tolerance to that of Mariner. Our data suggest greens‐type P. annua possesses moderate to good salinity tolerance during seed germination and vegetative growth relative to other cool‐season turfgrass species and has potential to be used on golf courses with moderate salt problems affecting turf establishment and maintenance.

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Wheat straw is a potential cellulosic feedstock for bioethanol. This study was conducted to evaluate straw yield potential and its relationship with grain yield for wheat (Triticum spp.) grown in the United States. The specific objective was to determine if differences in straw yield and harvest index (HI) exist between and within regions and/or wheat classes. Using ongoing variety performance trials in eight states, a total of 255 varietal trial entriess from five classes of wheat were surveyed for above-ground biomass. Averaged over all wheat classes and regions the HI was 0.45. Soft red winter wheat in Kentucky had, on average, the highest HI and lowest straw yield among regions and wheat classes. Soft white winter wheat under irrigation in the Pacific Northwest produced the highest straw yield. Hard red winter wheat in the southern plain states of Texas and Oklahoma had, on average, the lowest HI. Differences in the amount of precipitation and cultivars were the major contributors to the variation detected within wheat classes. The amount of wheat straw available as cellulosic feedstock in a state or wheat class can be estimated using the grain yield estimates provided by the National Agricultural Statistics Service and the class specific HI.

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