bluuebunny/crossref_metadata_2025_split huggingface dataset:
Release of Soluble Protein and Nitrogen in Alfalfa. II. Infleunce of Potassium and Nitrogen Fertilizer on Three Cultivars1
Authors: Walgenbach R. P. , Marten G. C. 
Published: July 2010

Reduced incidence of ruminant bloat was reported on legume pastures fertilized with high levels of potassium (K) or K plus nitrogen (N). Amount of soluble protein released from alfalfa (Medicago sativa L.) into sodium maleate buffer (pH 6.9) was proposed as possible estimate of ruminant bloat potential in comparative studies. Our objective was to determine whether K and N fertilization would influence concentration of several N fractions released from alfalfa.‘Ramsey,’ ‘Saranac,’ and ‘520’ alfalfa cultivars were fertillzed in the fall with 0 (control), 350, and 700 kg as K2SO4/ha and in the following spring with these same levels of N as NH4NO(34 3 × 3 factorial). The upper 10 to 15 cm of told‐bud stage alfalfa in first and second crops was analyzed for several N fractions.As N applied increased, mean concentrations of total N (TN), total soluble N (TSN), soluble nonprotein (SNPN), and soluble protein N (SPN) increasedm first‐harvest herbage. Mean concentrations of SPN increased 10.8% at 300 kg N/ha and 13.3% at 700 kg over that in alfalfa not fertilized with N. As the K level increased, mean concentrations of TN, TSN, and SNPN decreased in first‐harvest herbage. Fertilization with K did not affect concentration of SPN. Mean concentrations of TN, TSN, and SNPN in Saranac and TN, TSN, and SPN in 520 first‐harvest herbage were slightly but significantly greater than those in Ramsey. Cultivars did not affect concentrations of N fractions in secondharvest herbage.We found no evidence that fertilization of alfalfa with K or N reduced its apparent bloat potential, as estimated by SPN release. Instead, we showed that alfalfa fertilized with high levels of N had a slightly increased apparent bloat potential.
Phenotypic Recurrent Selection for Increased Leaf Weight and Decreased Alkaloid Content of Burley Tobacco1
Authors: Gupton C. L. 
Published: July 2010

Nine populations were derived in the selection phase of experiments designed to evaluate a recurrent selection scheme in hurley tobacco (Nicotiana tabacum L.). We produced an unselected population of heterozygotes (Co), three populations by recurrent selection for increased weight of green leaves, and five populations by recurrent selection for decreased percent total alkaloids (% TA) of green leaves. Evaluations of the experimental material were made at three locations. The objectives wre to determine the effects of phenotypic recurrent selection on green tobacco and to ascertain the correlated effects of such selection on the yield and alkaloid content of cured tobacco.In response to selection, green leaf weight increased somewhat consistently from C0 to C3 and % TA declined linearly from Co, to C3 The correlated response of cured leaf weight to selection on a green weight basis was a linear increase, averaging 8.1 g per plant per cycle. Percent total alkaloids of cured leaf also declined linearly with successive cycles of selection on a green leaf basis. Five cycles of selection resulted in nearly 23% reduction in percent TA.The genetic correlation coefficient between green leaf weight and percent TA was −0.50 and −0.62 at two locations. This negative relationship may be a limiting factor in practical usage of phenotypic recurrent selection to increase yields without the aid of a selection index.
Water Absorption of Soybean Seeds ans Associated Causal Factors1
Authors: Calero Eduardo , West S. H. , Hinson Keull 
Published: July 2010

Soybean [Glycine max (L.) Merr.] seed quality in humid environments is related to the amount of water the mature seeds imbibe before harvest and during storage. The mechanism which restricts water uptake by the soybean seed has not been fully determined. The permeability of the seed coat to the passage of water vapor is presumed to be one such mechanism. The purpose of this study was to find genotypes which absorb water slowly and to identify factors associated with low water absorption.Twelve cultlvars, introductions and breeding lines, and seven progenies from different crosses were used to study the rate of water absorption at 100% relative humidity and 24 C for 8 days and under standard germinating conditions for 8 and 24 hours. Seed coats of selected samples of seed from the water absorption studies were observed using the scanning electron microscope.A negative correlation between seed size and the percentage of water uptake was found in some materials, but this relationship did not hold for all. A range of water uptake rates was observed. Furthermore, the shape and size of pores present in the seed coat were different for the various materials. Small seeds had a higher percentage by weight of seed coat and large, rounded pores, whereas large and medium seeds had a lower percentage of seed coat with smaller, elongated pores. Waxy material was embedded in different densities into the epidermis. Ecuador 2, Bragg, Ss‐Da‐010 and the progenies from Bragg ✕ (Cobb ✕ PI86490) F4 appear to imbibe water slowly. Small elongated pores and a high density of waxy material embedded in the epidermis were associated with low absorption.
Rhizobium — Host Specificities in Phaseolus coccineus L. and Phaseolus vulgaris L.1
Authors: Hohenberg J. S. , Munns D. N. , Tucker C. L. 
Published: July 2010

The introduction of desirable agronomic characteristics into Phaseolus vulgaris L. is being attempted by interspecific hybridization with P. coccineus, but the effects on root nodulation are unknown. Accordingly, cross‐inoculation relationships between P. vulgaris ‘Red Kidney’ and P. coccineus ‘Scarlet Runner’ were tested in the greenhouse with a group of 16 Rhizobium strains effective on Red Kidney and a group of 12 strains effective on Scarlet Runner. Both groups had diverse origins, including commercial sources and isolations from bean fields and other sites in California.Only six strains, all isolates from Scarlet Runner, were effective on both hosts. Fifty percent of Scarlet Runner isolates were as effective on Red Kidney as the more effective of Red Kidney's homologous strains. Thirty percent of the California isolates tested on Red Kidney were more effective than two commercial inocula.Strain rejection in Red Kidney was expressed in 75% of all cases as failure to form nodules. In contrast, strain rejection by Scarlet Runner was expressed in 64 to 68% of all cases as ineffective nodulation (nodule malfunction). If Scarlet Runner is representative of P. coccineus in this respect, interspecific hybridization is likely to increase rather than reduce the tendency of P. vulgaris to nodulate with ineffective rhizobia.
Photosynthetic Recovery of Peanuts to Defoliation at Various Growth Stages1
Authors: Jones J. W. , Barfield C. S. , Boote K. J. , Smerage G. H. , Mangold J. 
Published: July 2010

This experiment was designed to study the response of peanut (Arachis hypogaea L.) canopy carbon dioxide exchange rate (CER) to degrees of foliage loss at different dates throughout the season. Peanut plots were manually defoliated 25, 50, and 75 % on different dates during the season for comparison with control plots (0% defoliation). Weekly, CER was measured on control plots and on plots which had been defoliated at different dates. Canopy CER was initially reduced 45 to 70% after 75 % defoliation reduced leaf area index (LAI) to about 1.0, but subsequent measurements revealed considerable CER recovery. Recovery of CER was related to two mechanisms, leaf area production and re‐adaptation of previouslyshaded leaves to full sun.The re‐adaptation of leaves to full sun was most apparent from the inability of recently‐defoliated canopies to use all the light they intercepted for CER, but after 1 to 2 weeks, efficiency of utilizing photosynthetically active radiation utilization improved without an increase in LAI. The re‐adaptation process appeared to be related to increasing specific leaf weight. Recovery mechanisms, especially leaf production, diminished as the peanut plants matured and progressed into pod set and pod fill. Leaf area index increased after early defoliations; however, the rate of LAI increase paralleled that of control plots. For defoliations late in the season, leaf growth had ceased and was not stimulated as a result of defoliation.
A New Greenbug Biotype1
Authors: Porter K. B. , Peterson G. L. , Vise O. 
Published: July 2010

‘Amigo’, a wheat (Triticum aestivum L. em Thell.) germplasm line resistant to the greenbug [Schizaphis graminum (Rondani)], and selections from crosses and backcrosses of wheat to Amigo were evaluated for resistance to greenbug collections made each year from 1977 to 1980. Amigo, its derivatives, and ‘Insave’ rye (Secale cereale L.) were resistant to these field collections of biotype C greenbugs until January 1980 when Amigo and Amigo derivatives failed to survive a greenbug infestation of progeny of a November 1979 field collection at Bushland, Tex. A series of 11 laboratory tests of biotype C‐resistant and C‐susceptible small grain and sorghum [Sorghum bicolor (L.) Moench] lines infested with either biotype C or the Bushland collections clearly showed the Bushland greenbug to be other than the A, B, or C biotype. The Bushlandarea greenbug was designated biotype E. Insave rye, ‘Will’ barley (Hordeum vulgare L.), and biotype C‐resistant oats (Avena sativa L.) were resistant to biotype E. ‘Largo,’ an amphiploid of T. turgidum/ T. tauschii, appeared to have useable resistance for breeding biotype E‐resistant wheats.Sorghum lines possessing biotype C resistance from tunis grass [Sorghum virgatum (Hack.) Stapf] PI 38108 were susceptible, but sorghums PI 220248 and ‘Capbam’ were resistant to biotype E and should be useful sources of resistance.Biotype E was the predominanbt iotype in all greenbugc ollections made at Bushland, Tex., between November 1979 and August 1980. Biotype E was found 75 miles north of Bushland in May 1980.
The Inheritance of N2 Fixation Efficiency in Crimson Clover1
Authors: Smith G. R. , Knight W. E. , Peterson H. L 
Published: July 2010

Host plant genetics of N2 fixation efficiency in the crimson clover‐Rhizobium trifolii symbiosis was investigated using a diallel mating design and mass selection. Dinitrogen fixation was evaluated using the acetylene reduction assay. Plants were grown for 60 days prior to the assay in plastic pouches containing N free nutrient solution. Live plants were assayed using the plastic pouch to contain the gas mixture.Crosses differed significantly in acetylene reduction rate. In a combining ability analysis, both general and specific combining abillty were significant sources of variation. Only one of the six parental lines showed a significant, positive general combining ability effect. This line uniformly transmitted its high acetylene reducing ability to all but one of its progeny. In terms of variance components, specific combining ability was more important in determining the acetylene reduction rate than general combining ability for all lines tested. After one cyle of mass selection, acetylene reduction rate was increased 8%. The realized heritability of this trait was 63.1%.
Aposporous Apomixis in Schizachyrium (Poaceae: Andropogoneae)1
Authors: Carman J. G. , Hatch S. L. 
Published: July 2010

Megasporogenesis and embryo sac development of Schizachyrium sanguineum (Retz.) Alst. var. brevipedicellatum (Beal) Hatch (2n=40) and l00), S. sanguineum (Retz.) Alst. var. sanguineum (2n=80), S. cirratum (Hack.) Woot. and Standl. (2n=20), and S. scoparium (Michx.) Nash var. neomexicanum (Nash) Gould (2n=40) were investigated. Results suggest that S. sanguineum var. brevipedicellatum (2n=40 and 100) are facultative and obligate aposporous apomicts, respectively. All other taxa appeared to be sexual.It may be possible to manipulate apomixis in the potentially important forage and eonservation species, S. sanguineum var. brevipedicellatum and transfer apomixis from this variety (2n=40) into little bluestem (S. scoparium (Michx.) Nash var. frequens F. T. Hubb.), also 2n=40, through wide hybridization.
Reproductive Stage Water Stress and Sterility. I. Effect of Stress during Meiosis1
Authors: Namuco Ofelia S. , O'Toole John C. 
Published: July 2010

Increased spikelets sterility is the primary component of yield reduction in rice (Oryzas ativa L.) and other small grains subjected to water stress during reproductive growth stages. The causes of water stress induced spikelet sterility are not clear although the meiotic stage of pollen mother cells is often reported to exhibit yield‐decreasing sensitivity. We exposed rice plants, in which pollen mother cells were actively undergoing meiosis, to the following series of water stress levels as measured by flag leaf water potential: −1.6, −1.9, −2.2, −2.5, −2.8, and −3.5 MPa for 18 to 24 h. Panicles were fixed in Farmer's solution and later examined microscopically for abnormal chromosomal behavior. The occurrence of chromosomal abnormalities such as univalents, lagging of chromosomes, noncongression in metaphase and micronuclei was evaluated in 3822 pollen mother cells in response to increasing water stress levels. Spikelet fertility of comparable panicles grown to maturity decreased linearly from 80% at −1.1 MPa (control) to 50% at −3.5 MPa flag leaf water potential. Chromosomal abnormalities appeared at relatively moderate stress levels (−1.1 to −1.9 MPa) and in general peaked at the −2.2 MPa stress treatment.In general, water stress increased chromosomal abnormalities, except at severe stress levels (−3.5 MPa) where the meiotic process was partially arrested. Each meiotic stage had particular irregularities associated with water stress. Prophase I and II, univalents; Metaphase I, noncongression of bivalents and lagging chromosomes; Anaphase I and II, lagging chromosomes; Telophase II, micronuclei formation. Blasted or immature, small, colorless spikelets also were observed and their occurrence increased with stress level. Blasted spikelets, not included in the calculation of percent sterility, accounted for 10 to 20% of the total spikelets per panicle at moderate stress levels. The cause of this malady is unknown.
Effect of Pod Number on Dry Matter and Nitrogen Accumulation and Distribution in Soybean1
Authors: Schonbeck Mark W. , Hsu Francis C. , Carlsen Tina M. 
Published: July 2010

Greenhouse and field studies were undertaken to document the effects of a decreased pod number on dry matter and N accumulation and distribution during grain filling in soybean [Glycine max (L.) Merr.]. Removal of about 40% of the pods significantly shifted dry matter partitioning in favor of vegetative tissues. Total dry matter and N accumulation were not affected, indicating that partial depodding did not cause feedback inhibition of photosynthesis. The crop compensated for the lower pod number with an increased 100‐ seed weight, so that final grain yield was depressed only 7 to 14% below controls.Vegetative tissue N of control field‐grown plants decreased rapidly during grain filling, and the majority of this loss was attributed to redistribution of N to the growing seed. Partial depodding greatly decreased vegetative N loss, and stem N concentrations actually increased toward the end of grain filling. Apparently, current N2 fixation roughly equalled N demand by the seed in these plants so that little net redistribution occurred. The decreased pod load may also have made more photosynthate available to support greater late‐season N assimilation than occurred in the controls.
Visible and Near‐Infrared Reflectance Assessment of Salinity Effects on Barley
Authors: Peñuelas Josep , Isla Ramón , Filella Iolanda , Araus José Luis 
Published: July 2010

SynopsisWe studied the effects of a soil salinity gradient (0.8−1.9 dS m−1 ECa) on spectral reflectance of 10 genotypes of barley (Hordeum vulgare L.) to determine the efficacy of reflectance as a tool for assessing the responses of barley to salinity. NDVI [normalized difference vegetation index, (R900 nm − R680 nm)/(R900 nm + R680 nm)] and WI (water index, R970 nm/R900 nm) were the reflectance indices used. In response to increasing salinity, near infrared reflectance decreased and visible reflectance increased, thereby lowering NDVI from 0.85 to 0.4, in parallel with decreases in biomass (from 2500–500 g m−2) and yield (from 900–50 g m−2). NDVI was, thus, a good indicator of biomass and yield. WI increased from 0.73 to 0.96, δT (canopy temperature minus air temperature) increased from −2 to 7°C, and 13C discrimination (Δ13C) in mature kernels decreased from 19 to 14.5 with increasing salinity levels. WI was, thus, related to crop water status response to salinity. NDVI and WI were, therefore, useful for measuring agronomic responses of barley to salinity.
Yield Potential: Its Definition, Measurement, and Significance
Authors: Evans L. T. , Fischer R. A. 
Published: July 2010

ABSTRACTYield potential is defined as the yield of a cultivar when grown in environments to which it is adapted, with nutrients and water non‐limiting and with pests, diseases, weeds, lodging, and other stresses effectively controlled. As such, it is distinguished from potential yield, which we define here as the maximum yield which could be reached by a crop in given environments, as determined, for example, by simulation models with plausible physiological and agronomic assumptions. Several implications of the definitions given above are considered, particularly those arising from cultivar interactions with agronomic practices and with the biotic and abiotic environments. We then discuss both direct and indirect methods of measuring progress in yield potential. Continuing progress in yield potential through conventional breeding is apparent in many crops, and is significant for yield progress at the farm level under a wide range of conditions. Among the small grain cereals, greater yield potential has derived mainly from the rise in harvest index associated with dwarfing, whereas in maize (Zea mays L.), it has come from increased tolerance to closer planting. The duration of photosynthetic activity has been extended in several crops but there is little evidence of increases in photosynthetic capacity or maximum crop growth rate. The rise in genetic yield potential in wheat and maize cultivars has been associated with progressive widening of their genetic background, and there is little sign of this slowing down.
Soybean Maturity Genes Associated with Seed Coat Pigmentation and Cracking in Response to Low Temperatures
Authors: Takahashi Ryoji , Abe Jun 
Published: July 2010

ABSTRACTExposure of soybean [Glycine max (L.) Merr.] to chilling temperatures (≈15°C) at flowering induces browning around the hilum region and cracking of the seed coats. Both pigmentation and cracking degrade the external appearance of soybean seeds and reduce their commercial value. An earlier study showed that one of the genes responsible for pigmentation is closely associated with a maturity gene. The objective of this study was to evaluate the effect of five soybean maturity genes (E1–E5) on the intensity of seed coat pigmentation and cracking. Soybean cv. Harosoy (e1e2E3E4e5) and its near‐isogenic lines (NIL) for E1 to E5 loci were exposed to 15°C for 2 wk beginning 8 d after anthesis. Control plants were grown in a greenhouse throughout their life cycle, whereas treated plants were transferred from the greenhouse to a phytotron for the chilling treatment. Intensity of pigmentation was not affected by e3, slightly reduced by E2 and e4, and profoundly reduced by E1 and E5 Degree of cracking was slightly increased by e3 and drastically reduced by e4, E1, and E5 The results suggest that some of the soybean maturity genes have inhibitory effects on the intensity of seed coat pigmentation and cracking in response to low temperatures. Dominant alleles E1 and E5 are most effective in suppressing both pigmentation and cracking. Therefore, these two genes may be useful to ensure tolerance to chilling stress in cultivars with e3 and e4, which jointly condition the insensitivity to long daylength, an adaptive trait in high latitude regions.
Isolation and Characterization of Two Promoters from Linseed for Genetic Engineering
Authors: Jain Ravinder K. , Thompson R. Gail , Taylor David C. , MacKenzie Samuel L. , McHughen Alan , Rowland Gordon G. , Tenaschuk Don , Coffey Maxine 
Published: July 2010

ABSTRACTLinseed (Linum usitatissimum L.) is an important oilseed crop worldwide and is cultivated for the high level of linolenic acid (18:3) in its seed oil. Currently, there is a concerted effort to improve linseed by genetic engineering. This will require appropriate transgenes and tissue‐specific or constitutive promoters. We report the isolation and characterization of two linseed promoters from a two‐member gene family encoding the enzyme stearoyl‐acyl carrier protein desaturase (SAD). The SAD1 and SAD2 gene promoter were each fused transcriptionally with the reporter gene for β‐glucuronidase (uidA; GUS) and were transferred to linseed to study their expression pattern. In transgenic linseed, GUS activity mediated by the SAD2 promoter appeared to be constitutive and was detected in leaves, apices, stem, roots, flower buds, flowers, and seeds. In contrast, GUS activity mediated by the SAD1 promoter appeared to be root‐ and seed‐specific. In developing seeds, both the promoters exhibited a temporal expression pattern concomitant with protein and lipid biosyntheses. The GUS activity could be detected as early as 4 days after pollination (dap) and in mature seeds (∼50 dap) with the highest activities around mid‐development. The first pair of linseed promoters will be useful for manipulating the expression of indigenous as well as transgenes in linseed to create value‐added cultivars.
Heat Stress during Grain Filling in Maize: Effects on Kernel Growth and Metabolism
Authors: Wilhelm E. P. , Mullen R. E. , Keeling P. L. , Singletary G. W. 
Published: July 2010

ABSTRACTThe average temperature in the U.S. Corn Belt during the grain‐filling period of maize (Zea mays L.) is above optimum for maximum grain yield. The objectives of this study were to determine the effects of an extended period of high temperature during grain filling on kernel growth, composition, and starch metabolism of seven maize inbreds. Plants were exposed to heat stress (33.5/25°C) or control (25/20°C) day/night temperature treatments in a greenhouse from 15 d after pollination (DAP) until maturity, and the experiment was conducted in triplicate over time. Root zone temperature was maintained at 25/20°C in both treatments. No significant interaction occurred between genotype and temperature treatments for nine grain traits. Heat stress lengthened the duration of grain filling on a heat unit (HU) basis, but an overcompensatory reduction in kernel growth rate per HU resulted in an average mature kernel dry weight loss of 7% (P = 0.06). Proportionally similar reductions occurred for starch, protein, and oil contents of the kernel. Heat stress also reduced kernel density. A survey of 11 enzymes of sugar and starch metabolism extracted from developing endosperm revealed that ADPglucose pyrophosphorylase, glucokinase, sucrose synthase, and soluble starch synthase were most sensitive to the high temperature treatment. However, upon adjusting enzyme activities with measured temperature coefficients (i.e., Q10), only ADPglucose pyrophosphorylase exhibited reduced activity. Results indicate that chronic heat stress during grain filling moderately restrains seed storage processes and select enzymes of starch metabolism to similar degrees across multiple maize inbreds.