bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yield of Cool‐Season Soybean Lines Differing in Pubescence Color and Density
Authors: Morrison Malcolm J. , Voldeng Harvey D. , Guillemette Ron J. D. , Cober Elroy R. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] pubescence color may affect yield in cool‐season soybean growing areas. The objective of this research was to examine the interaction of tawny (T) and gray (G) pubescence color with dense (D) and normal (N) pubescence density on seed yield. Lines differing in pubescence color and density were created from crosses with eight soybean cultivars adapted to Maturity Group 00 and 0 conditions. Within each cross, quadruplets were selected that had the four pubescence types: TD, TN, GD, and GN. These lines were evaluated for yield across 4 yr at Ottawa, Canada. Lines with gray pubescence had from 7.6 to 27.7% higher yields than those with tawny pubescence in years receiving >2664 crop heat units (CHU) during the growing season. In a year receiving <2664 CHU, soybean lines with tawny pubescence had 9.3% higher seed yields than those with gray pubescence. The interaction between pubescence color and seasonal temperature was similar among lines of diverse genetic background. Tawny lines with dense pubescence had from 3.1 to 10.6% higher yields than tawny lines with normal pubescence when the seasonal precipitation was <360 mm. In gray lines, changing pubescence density did not consistently affect seed yields. Soybean pubescence color did affect seed yield and should be considered when breeding for cool‐season regions.
Defoliation Tolerance of Bluebunch and Snake River Wheatgrasses
Authors: Jones Thomas A. , Nielson Dale C. 
Published: July 2010

AbstractBluebunch wheatgrass [Pseudoroegneria spicata (Pursh) A. Löve] has long been noted for poor tolerance to grazing during culm elongation in the spring. Bluebunch wheatgrass is an autoploid series of diploids (2x) and tetraploids (4x). In the mid‐1980s, a group of populations were found to be allotetraploid and are now commonly referred to as Snake River wheatgrass. Relative grazing tolerance of 2x and 4x bluebunch wheatgrass and of Snake River wheatgrass is unknown. This study evaluated the effect of multiple defoliation on these grasses to simulate one consequence of grazing, removal of photosynthetic tissue. Fifteen entries representing the three taxa were established at North Logan, UT, on a Millville silt loam (coarse‐silty, carbonatic, mesic Typic Rendolls; 2–4% slope) during 1988. Seedlings were vegetatively propagated into two clones apiece and transplanted adjacent to one another; one clone was subjected to multiple defoliation and the other served as an undefoliated control. Multiple defoliation at 10 cm was applied from late spring to midsummer from 1990 to 1992 at 4‐wk intervals and dry matter yield was measured in late fall 1991, early spring 1992, late fall 1992, and late spring 1993. We used the defoliated‐to‐control ratio of plant response to estimate defoliation tolerance. The defoliated‐to‐control ratio for dry matter yield of Snake River wheatgrass (0.17 and 0.38 in late fall 1991 and early spring 1992, respectively) was greater than for 4x (0.06 and 0.18) or 2x (0.06 and 0.19) bluebunch wheatgrasses after the first year of multiple defoliation. The defoliated‐to‐control ratio for dry matter yield did not differ among taxa in late fall 1992, but the ratios for Snake River wheatgrass (0.20) and 4x bluebunch wheatgrass (0.21) were both greater than for 2x bluebunch wheatgrass (0.13) in late spring 1993. Less variation was seen among Snake River than bluebunch wheatgrass entries. Because Snake River wheatgrass had both higher yield and greater defoliation tolerance than bluebunch wheatgrass, Snake River wheatgrass is more likely to survive defoliation over the long term.
Kill Date of Vetch, Rye, and a Vetch–Rye Mixture: I. Cover Crop and Corn Nitrogen
Authors: Clark Andrew J. , Decker Alvin M. , Meisinger John J. , McIntosh Marla S. 
Published: July 2010

AbstractSpring kill date affects cover crop N content and N availability to subsequent no‐till corn (Zea mays L.). This 2‐yr study was conducted in 1990 and 1991 at Coastal Plain and Piedmont locations in Maryland to evaluate three cover crop kill dates, three corn planting dates, and four corn fertilizer N (FN) rates following hairy vetch (Vicia villosa Roth), cereal rye (Secale cereale L.) and a vetch‐rye mixture. No‐cover checks were included for each corn planting date. Fertilizer N rates were 0 to 202 kg ha−1 in the Piedmont and 0 to 270 kg ha−1 for the Coastal Plain. The vetch‐rye mixture contained as much or more N than vetch, and more N than rye within each kill date. Cover crop biomass and N content increased for each delay in kill. In a 50‐d period from late March until early May, vetch and the vetch‐rye mixture accumulated about 2 kg N ha−1 d−1, with total topgrowth N accumulation from 144 to 203 kg ha−1 over two locations and two years. Greatest rye N accumulation was 51 kg ha−1. Corn N content ranged from 37 to 293 kg ha−1, and was significantly affected by FN rate. Within FN rate, N content was greater following vetch or vetch‐rye than following rye or no cover, particularly at low FN rates. Corn N content was greater if cover kill and corn planting were delayed until late April or mid‐May. This was attributed to greater cover crop N production and mulching effects, and the timing of summer rainfall. Corn FN requirements were greatest following rye or no cover, intermediate following vetch‐rye, and least following vetch. This demonstrates that cover crop species and kill date can be managed to conserve N with rye, supply N for the next crop with vetch, or provide both N conservation and N supply with a vetch‐rye mixture.
Early‐Maturing Soybean Cropping System: III. Protein and Oil Contents and Oil Composition
Authors: Kane Mark V. , Steele Colleen C. , Grabau Larry J. , MacKown Charles T. , Hildebrand David F. 
Published: July 2010

AbstractExpanding production of early‐maturing soybean [Glycine max (L.) Merrill] cultivars in the southeastern USA has exposed such cultivars to a wide range of environmental conditions during seedfill. Temperatures during this growth stage influence levels of specific fatty acids, particularly of the unsaturated fatty acids. Our objective was to evaluate the grain quality responses of early‐maturing cultivars to the wide range of planting dates in the southeastern USA. Protein and oil contents, along with fatty acid profiles, were assessed for cultivars from Maturity Group (MG) 00 through IV using late April, mid‐May, early June, and late June planting dates on a well‐drained Maury silt loam (fine, mixed, mesic Typic Paleudalf) in 1990 through 1993. Across years and cultivars, delayed planting increased protein content and linolenic acid levels and reduced oil content and oleic acid levels, but had little or no influence on palmitic, stearic, or linoleic acid levels. The higher seed‐fill temperatures associated with early planting were strongly correlated with increased oil content and oleic acid levels and reduced linolenic acid levels. Increasing seed‐fill temperatures were closely associated with reduced linolenic acid levels for all six cultivars. However, the oleic acid response to seed‐fill temperatures strongly depended on cultivar maturity. Oleic acid levels of early‐maturing cultivars were much more sensitive to seed‐fill temperatures than were those of later maturing cultivars. While overall effects of environment on grain quality characteristics may be relatively small, perhaps the quality of new low linolenic acid cultivars could be amplified through culture under the warmer conditions of the southeastern USA.
Managing Yield and Water Use of Pearl Millet in the Sahel
Authors: Payne William A. 
Published: July 2010

AbstractDrought occurs often in the West African Sahel, but studies have shown that soil water availability is not usually the limiting factor to pearl millet [Pennisetum glaucum (L.) R. Br.] production, and that field water‐use efficiency (WUE)—i.e., the ratio of yield to evapotranspiration (ET)—is almost always very low. The purpose of this study was to determine management effects on yield and water use of pearl millet for a range of climate conditions in the Sahel. Grain and aboveground dry matter yield, daily vapor pressure deficit, and soil water data were taken during four years of contrasting rainfall. Within any given year, genotype, plant population, and fertilizer had relatively small to no effect on ET, but large effects on yield. When high plant population (≥20 000 hill ha−1) was combined with high fertilizer application (≥40 kg N ha−1 and ≥18 kg P ha−1) during the wettest year, total ET was increased by ≈50 mm. High fertilizer application tended to slightly increase ET and thereby deplete soil water reserves, but this was not associated with yield decline. Yield and water‐use data refute the view that, by maintaining fields at low fertility and low plant populations, farmers reduce risk of crop failure during drought by reducing crop water use. Compared with traditional practices that use plant populations as low as 5000 hill ha−1 and zero fertilizer input, moderate plant population (10 000 hill ha−1) and fertilizer application (20 kg N ha−1 and 9 kg P ha−1) substantially increased yield and approximately tripled WUE even during 1984, the driest year on record. In general, grain yield was better predicted from ET within different management categories when corrections were made for mean daily vapor pressure deficit during the growing season (VPD). The study provides evidence for the need to moderately increase pearl millet plant population and fertilizer application in the Sahel to efficiently use available water without risk of crop failure through depletion of soil water reserves. It also provides a practical, albeit empirical, basis for predicting yield under different management systems from seasonal ET and VPD data.
Growth and Water Status in Meadow Fescue is Affected by Neotyphodium and Phialophora Species Endophytes
Authors: Malinowski D. , Leuchtmann A. , Schmidt D. , Nösberger J. 
Published: July 2010

AbstractGrowth and water status in meadow fescue (Festuca elatior L.; syn. F. pratensis Huds.) is affected by Neotyphodium and Phialophora endophytes. Meadow rescue is often infected with Neotyphodium uncinatum (Gams, Petrini & Schmidt) Glenn, Bacon, Price & Hanlin or cosymbiotically with this and a Phialophora‐like endophyte. In a growth chamber experiment, we determined the influence of these endophytes on selected growth attributes and plant water status of one genotype of meadow fescue. Single plants of clone M1 free of endophytes (E‐) or infected with N. uncinatum (N), Phialophora like endophyte (P), or both endophytes (NP) were adequately irrigated (control plants) or subjected to a gradually established soil water deficit for 26 d (stressed plants). Afterwards, stressed plants were rewatered and allowed to regrow for 4 wk. Cumulative herbage dry matter (DM) yield was greater in P plants by 7.5% compared with N plants, generally. Control P plants produced more root DM thanE ‐ andN Pp lants. RootD Min N plants wass ignificantly greater during recovery from drought, compared with P and NP plants (36%). Tiller number of NP plants was the lowest among endophyte treatments in the predrought period. In response to waters tress, P plants produce more tillers than E ‐ plants (24%), but average tiller weight of P plants was lower than in E‐ plants (14%). During imposed waters tress, stomatal conductanc(ge) and leaf water potential (ΨL) decreasedin all plant‐endophyate associations to a similar extent. At severe soil water deficit, however N plants had significantly lower (g3) and ΨL than the other plant‐endophyte associations. Control plants benefited from the symbiosis with endophytes by increasing root growth( both endophytes) and shoot growth( Phialophora‐like endophyte). Plants infected with N. uncinatum were potentially able to adjust to soil water depletion earlier, suggesting a greater potential for adaptation to drough.
Variation in Eastern Gamagrass Forage Yield with Environments, Harvests, and Nitrogen Rates
Authors: Brejda John J. , Brown James R. , Lorenz Todd E. , Henry Jimmy , Lowry Stephen R. 
Published: July 2010

AbstractEnvironmental variation, and the interaction of environment with management practices, can significantly affect perennial forage yields. The objective of this research was to evaluate the importance of environmental main effects and the interaction between environments, N rates, and harvests on eastern gamagrass [Tripsacum dactyloides (L.) L.] forage yields. Established eastern gamagrass stands were fertilized with 0, 168, or 336 kg N ha−1, and harvested three times during the growing season for three consecutive years at two locations in northern Missouri. Year and the year × location interaction were significant environmental sources of variation affecting forage yields. The year main effect had the larger variance component and accounted for 9% of the total variation in forage yields. The harvest main effect and year × harvest interaction had the largest variance components, and together accounted for more than 67% of the total variation in forage yields. Most of the variation between harvests resulted from differences in first‐harvest yields, taken at the reproductive growth stage, compared with regrowth harvest yields which were at vegetative growth stages. Variation in precipitation amounts between harvests significantly influenced regrowth harvest yields, causing a significant year × harvest interaction. Forage yield responses to N rates also varied between years, causing a significant year × N rate interaction. Location was not an important source of variation in eastern gamagrass forage yield in this study, nor was there a significant interaction between N rates and harvests. Resultsuggest that supplemental irrigation and longer rest periods between harvests may help improve forage yields and distribution.
Nutritive Value of Clipped ‘Mott’ Elephantgrass Herbage
Authors: Chaparro Cesar J. , Sollenberger Lynn E. 
Published: July 2010

AbstractMany tropical grasses are low in nutritive value, but ‘Mott’ dwarf elephantgrass (Pennisetum purpureum Schumacher) has supported gains of yearling cattle (Bos taurus) approaching 1 kg d−1. To aid in identifying optimum harvest management practices for Mott, this study quantified crude protein (CP) and in vitro digestible organic matter (IVDOM) concentrations of leaf blade, leaf sheath, stem, and total herbage harvested following imposition of a wide range of clipping treatments. Treatments in 1989 and 1990 included all 16 combinations of four defoliation frequencies (3, 6, 9, and 12 wk) and four stubble heights (10, 22, 34, and 46 cm) in a randomized block design with three replicates. The soil was a hyperthermic, uncoated Aquic Quartzipsamment (Adamsville series). Data were analyzed by fitting multiple regression equations starting with a second‐order polynomial model. The range in IVDOM of total herbage harvested was from 653 to 791 g kg−1 (1989) and 680 to 739 g kg−1 (1990). Frequent defoliation to short stubble resulted in greatest IVDOM; herbage harvested infrequently to short stubble was least digestible. Total herbage CP ranged from 87 to 140 g kg−1 in 1989 and 89 to 133 g kg−1 in 1990, and was greatest with frequent harvest to a tall stubble. Mott elephantgrass CP and IVDOM were high across a wide range of defoliation frequencies and stubble heights. Because of Mott's high nutritive value even when defoliated infrequently (e.g., 9 wk), achieving yield and persistence goals can be the primary basis for selecting defoliation management practices.
Effect of Annual Medic Smother Plants on Weed Control and Yield in Corn
Authors: De Haan Robert L. , Sheaffer Craig C. , Barnes Donald K. 
Published: July 2010

AbstractUsing spring‐seeded smother plants for weed control could reduce the environmental impact of corn (Zea mays L.) production. Research was conducted to determine whether currently available medic (Medicago spp.) cultivars are adapted for use as smother plants in corn. In field experiments in 1992 at Becker and Rosemount, MN, Medicago scutellata (L.) Mill. cv. Sava and Kelson were interseeded with corn at 0, 85, 260, or 775 seeds m−2. In 1993, Sava and Kelson, along with M. polymorpha L. cv. Santiago and M. lupulina L. cv. George, were interseeded with corn at 260 seeds m−2 and N fertilizer was applied at 0, 84 (56 at Rosemount), or 168 kg−1. Land equivalent ratios for corn and medic intercrops grown in 1992 were not > 1, indicating that corn and medics competed strongly for resources. Medics seeded with corn at a rate high enough to consistently suppress weeds (260 seeds m−2) reduced weed dry weight 14 wk after corn emergence by 69% at Becker and by 41% at Rosemount compared with monoculture corn. The same seeding rate reduced corn grain yield in weed‐free plots by 21% at Becker and 15% at Rosemount compared with monoculture yields. In 1993, medic smother plants reduced weed dry weight more when grown in the 0 kg ha−1 N plots than in the 168 kg ha−1 N plots. Corn yield losses, however, were less severe in the 168 kg ha−1 N treatments than with 0 N. Annual medics managed as smother plants in corn effectively reduced weed biomass; however, additional research is needed to identify medic genotypes and smother plant management systems that reduce corn yields less than those we evaluated, and that provide more consistent weed suppression across environments..
Wheat Coleoptile and Root Growth and Seedling Survival after Dehydration and Rehydration
Authors: Guedira M. , Shroyer J. P. , Kirkham M. B. , Paulsen G. M. 
Published: July 2010

AbstractWheat (Triticum aestivum L.) seed frequently is planted deeply in dry soil that supports germination but not emergence. Our objective was to ascertain the effect of dehydration on seedling survival and development, particularly the coleoptile and root, and their ability to resume growth after rehydration. Seeds of ‘Larned’, a tall, hard red winter wheat with a long coleoptile, were germinated for 1, 2, 3, 4, or 5 d and seedlings were dehydrated for 1, 2, 3, 4, or 5 d and then rehydrated. Seedling survival was greater than 75% after 1 to 3 d germination and all dehydration treatments, but declined from about 60% to zero after germination for 4 d and dehydration for 3 d or more. Dehydration reduced coleoptile lengths by 17 to 58% compared with the control. Seminal roots also were highly sensitive to dehydration, except at early stages, but were replaced quickly at all stages when seedlings were rehydrated. Changes in seed weight suggest that reserves were important for recovery of seedlings from dehydration. Increasing depth of planting and duration of germination successively reduced emergence of seedlings from seeds that were germinated for 1 to 4 d and then dehydrated for 2 d. The results demonstrated that emergence of wheat seedlings is increasingly impaired by dehydration as germination progresses, that the seedling stage when dehydration occurs is more important than the duration of the stress, and that coleoptile and root growth and seed reserves are involved in seedling responses to dehydration.
Near‐Infrared Analysis of Cotton Leaves as a Guide for Nitrogen Fertilization
Authors: Saranga Yehoshua , Landa Ari , Shekel Yehuda , Bosak Arie , Kafkafi Uzi 
Published: July 2010

AbstractNitrate level in cotton (Gossypium hirsutum L.) leaf petioles is commonly used as a practical guide to N fertilization, especially in cases of critically low N levels. The optimization of N supply to irrigated cotton requires a reliable method for monitoring the plant's N status. The feasibility of using leaf N concentrations monitored by near‐infrared analysis (NIRA) as a guide for N fertilization in irrigated cotton was examined in this study. Three field trials were conducted in three consecutive years. The NIRA data from fresh leaf disks were calibrated against laboratory N measurements expressed as g N kg1−1 dry matter (R2 = 0.90). Validation of the calibration showed a high correlation between NIRA estimates and laboratory data from two field trials. Dawn leaf sampling was selected for routine monitoring of plant N status. Application of NIRA‐guided N fertilization was examined in the third‐year trial. The NIRA‐guided treatment, with only 60 kg N ha−1, resulted in only a 7.5% lower yield (statistically nonsignificant) relative to the commercial predetermined N treatment with 150 kg N ha−1. Yield was linearly correlated with leaf N concentration. Cotton leaf N concentration was reliably monitored by NIRA. Only 30 s are required for each N determination; using 10 samples, about 7 min are needed per plot. Once its reliability under various conditions is established, this method could be used for on‐the‐spot decision‐making regarding N‐fertilizer application in irrigated cotton.
Nondestructive Estimation of Shoot Nitrogen in Different Rice Genotypes
Authors: Ladha Jagdish K. , Tirol‐Padre Agnes , Punzalan Gloria C. , Castillo E. , Singh Upendra , Reddy C. Kesava 
Published: July 2010

AbstractPlant N uptake and grain yield are important components of N use efficiency. Grain yield is easily measured, but plant N analysis is time consuming and requires hazardous chemicals or expensive equipment. A nondestructive method involving the least equipment and skill, to determine N uptake, is needed in agronomic and plant breeding experiments. A nondestructive method to determine shoot (aboveground biomass) N of transplanted rice (Oryza sativa L.) was developed based on SPAD‐502 chlorophyll meter readings, leaf area, and tiller number. In two dry‐season and one wet‐season field experiment, shoot N of various genotypes at flowering were highly correlated (P < 0.05) with CLAT, the product of SPAD reading from a selected leaf (C), area of that leaf (LA), and number of tillers (T) (r2 = 0.46, 0.90, and 0.85 in Exp. 1, 2, and 3, respectively); and with LAT, the product of LA and T (r2 = 0.56, 0.88, and 0.76). Shoot N may be estimated using LAT for larger differences in leaf area compared with SPAD readings. Lower correlations in Exp. 1 were due to the lower range in shoot N contents. The highest correlation between shoot N and CLAT was observed in the third uppermost leaf. Regressions of shoot N on LAT and CLAT varied across growth stages and seasons. Thus, LAT or CLAT can be used to evaluate N uptake among N fertilizer treatments and different rice genotypes at a given stage within a season. Further work is needed to assess the reliability of this method under different seasons and cultural practices.