Efficiency Of Soybean Research Articles

Stomatal control and water use efficiency of soybean ( Glycine max L. Merr.) during progressive soil drying

The objectives of this study were to investigate the involvement of root and shoot factors in controlling leaf gas exchange of soybean ( Glycine max L. Merr.) during progressive soil drying, and its implication in improving water use efficiency (WUE) at mild soil water deficits. Soybeans were grown in pots in a climate-controlled glasshouse. Shoot dry mass (DM), transpiration ( E), stomatal conductance ( g s), light-saturated photosynthetic rate ( A max), leaf water potential ( Ψ l), leaf osmotic potential ( Ψ π), leaf turgor pressure ( Ψ pl), root water potential ( Ψ r), and xylem sap ABA concentration ([ABA] xylem) were followed in well-watered and drought-stressed plants. As soil dried, g s, E, A max, Ψ l, Ψ π, Ψ pl, Ψ r, [ABA] xylem, and DM of the drought-stressed plants started to diverge from the well-watered controls from 8, 8, 9, 9, 9, 11, 7, 7, and 14 days after imposition of stress (DAIS), respectively. During soil drying, [ABA] xylem increased linearly with decreasing Ψ r. To minimize day-to-day variation, g s, Ψ pl, [ABA] xylem, and WUE of the drought-stressed plants were expressed relative to the well-watered controls. It was found that the relative g s decreased linearly from 1.0 to about 0.40 with increasing relative [ABA] xylem; thereafter it decreased further to 0.10 and was linearly correlated with decreasing relative Ψ pl, indicating that at mild soil water deficits g s was seemingly controlled by root-originated ABA; and Ψ pl significantly affected g s only at severe soil water deficits. Relative WUE at single leaf level (WUE leaf) was around 1.0 for fraction of transpirable soil water (FTSW) > 0.60–0.65, thereafter it increased exponentially and reached a peak at FTSW = 0.25–0.30. As FTSW approached zero then relative WUE leaf declined linearly to less than 1.0. Similarly, relative WUE at whole plant level (WUE plant) increased exponentially as FTSW < 0.60 and reached a peak at FTSW ≈ 0.20, and then declined dramatically as the soil was further dried. The results indicate that WUE, at both single leaf and whole plant levels, was improved at mild soil water deficits.

Modeling the water use efficiency of soybean and maize plants under environmental stresses: application of a synthetic model of photosynthesis-transpiration based on stomatal behavior

Understanding the variability of plant WUE and its control mechanism can promote the comprehension to the coupling relationship of water and carbon cycle in terrestrial ecosystem, which is the foundation for developing water-carbon coupling cycle model. In this paper, we made clear the differences of net assimilation rate, transpiration rate, and WUE between the two species by comparing the experiment data of soybean (Glycine max Merr.) and maize (Zea mays L.) plants under water and soil nutrient stresses. WUE of maize was about two and a half times more than that of soybean in the same weather conditions. Enhancement of water stresses led to the marked decrease of Am and Em of two species, but water stresses of some degree could improve WUE, and this effect was more obvious for soybean. WUE of the two species changed with psiL in a second-order curve relation, and the WUE at high fertilization was higher than that at low fertilization, this effect was especially obvious for maize. Moreover, according to the synthetic model of photosynthesis-transpiration based on stomatal behavior (SMPTSB) presented by Yu et al. (2001), the WUE model and its applicability were discussed with the data measured in this experiment. The WUE estimated by means of the model accorded well with the measured values. However, this model underestimated the WUE for maize slightly, thus further improvement on the original model was made in this study. Finally, by discussing some physiological factors controlling Am and WUE, we made clear the physiological explanation for differences of the relative contributions of stomata- and mesophyll processes to control of Am and WUE, and the applicability of WUE model between the two species. Because the requirement to stomatal conductance by unit change of net assimilation rate is different, the responses of opening-closing activity of stomata to environmental stresses are different between the two species. To obtain the same level of net assimilation rate, soybean has to open its stomata more widely to keep small stomatal resistance, as compared with maize.

Carbon Dioxide and Temperature Effects on Evapotranspiration and Water Use Efficiency of Soybean

Rising CO2 and potential global warming will cause changes in evapotranspiration (ET). Our research objective was to determine the impact of CO2 and air temperature on canopy ET, water use efficiency (WUE), foliage temperature, and canopy resistance (Rc) of soybean [Glycine max (L.) Merr.]. Plants were grown in sunlit, controlled‐environment chambers at cyclic maximum/minimum air temperatures from 28/18°C to 44/34°C and CO2 of 350 or 700 μmol mol−1 Maximum ET rate in the early afternoon at 35 d after planting ranged from 7.5 mol m−2 s−1 at 28/18°C to 19.0 mol m−2 s−1 at 44/34°C. Daily ET during the middle of the season ranged from 260 mol H2O m−2 d−1 (4.7 mm d−1) at 28/18°C to 660 mol H2O m−2 d−1 (11.9 mm d−1) at 44/34°C. Mean daily ET was linearly related to mean air temperature (Tair) as: [Mean daily ET = 21.4 × Tair − 306, r2 = 0.99 (mol H2O m−2 d−1), or mean daily ET = 0.385 × Tair − 5.5 (mm d−1)]. Doubled CO2 caused a 9% decrease in ET at 28/18°C, but CO2 had little effect at 40/30°C or 44/34°C. Whole‐day WUE declined linearly with air temperature, with a slope of −0.150 [(μmol CO2 mmol−1 H2O) °C−1]. Changes in ET and WUE were governed by changes in foliage temperature and Rc. In conclusion, increases in temperature anticipated by climate change could more than offset decreases of ET that would be caused by increases in CO2

Efficient soybean transformation using hygromycin B selection in the cotyledonary-node method.

The efficiency of soybean [Glycine max (L.) Merrill] transformation was significantly increased from an average of 0.7% to 16.4% by combining strategies to enhance Agrobacterium tumefaciens-mediated T-DNA delivery into cotyledonary-node cells with the development of a rapid, efficient selection protocol based on hygromycin B. Wounded cotyledonary-node explants were inoculated with A. tumefaciens carrying either a standard-binary or super-binary plasmid and co-cultivated in the presence of mixtures of the thiol compounds, L-cysteine, dithiothreitol, and sodium thiosulfate. Transformed shoots began elongating only 8 weeks after co-cultivation. Southern analysis confirmed integration of the T-DNA into genomic DNA and revealed no correlation between the complexity of the integration pattern and thiol treatment applied at co-cultivation. All T(0) plants were fertile and the majority of the lines transmitted the beta-glucuronidase (GUS) phenotype in 3:1 or 15:1 ratios to their progenies.

Light energy efficiency in soybean (Glycime max (L) Merr.)

Light energy efficiency in soybean (Glycime max (L) Merr.)

Phosphorus Use Efficiency of Soybean as Affected by Phosphorus Application and Inoculation

Phosphorus Use Efficiency of Soybean as Affected by Phosphorus Application and Inoculation

Reproductive partitioning and seed set efficiency in soybean, sunflower and maize

Seed number per plant (SNP) can be modelled as a function of plant growth rate during the critical period for seed set (PGR C), the proportion of plant growth partitioned to reproductive organs ( P R) and the minimum assimilate requirement per seed ( λ). In comparison to PGR C, less attention has been given to P R and λ. In this paper, we analysed reproductive partitioning and λ in three species of contrasting reproductive strategies, soybean ( Glycine max L. Merrill), sunflower ( Helianthus annuus L.) and maize ( Zea mays L.). To study plant-to-plant variation and to characterise stability of the variables analysed, we focused on individual plants grown under a wide range of plant densities. In soybean and sunflower, reproductive partitioning comprised about 50% of shoot growth, was fairly stable in a wide range of plant growth, and only decreased in a few, very small plants. In comparison, reproductive partitioning in non-prolific maize showed an optimum, was generally below 50% and exhibited a strong variation and instability at plant growth rates ≅2 g/day. Among species, stability of reproductive partitioning correlated inversely with a PGR C threshold for reproductive growth and positively with reproductive plasticity at high PGR C. Consideration of reproductive partitioning improved estimation of seed number, particularly in maize, a species prone to barrenness. Seed number as a function of reproductive growth was adequately described through linear (soybean) and hyperbolic models with x-intercepts (sunflower and maize). Seed set efficiency in terms of seed number per unit of reproductive growth (Ef) was constant only in soybean. In sunflower and maize, Ef increased with decreasing reproductive growth and became highly variable and unstable when reproductive growth was close to the threshold for seed set. In maize, such threshold was higher than in soybean and sunflower possibly as a consequence of a higher minimum combined demand for assimilate, resulting from a higher λ and number of simultaneously developing sinks. Inclusion of parameters assessing (i) stability in reproductive partitioning at low plant growth rates, and (ii) the minimum assimilate requirement per seed might improve seed number estimation.

Salinity reduces radiation absorption and use efficiency in soybean

The potential rate of plant development and biomass accumulation under conditions free of environmental stress depends on the amount of radiation absorption and the efficiency of utilizing the absorbed solar energy to drive photosynthetic processes that produce biomass materials. Salinity, as a form of soil and water stress, generally has a detrimental effect on plant growth, and crops such as soybean are usually sensitive to salinity. Field and greenhouse experiments were conducted to determine soybean growth characteristics and the relative impact of salinity on radiation absorption and radiation-use efficiency (RUE) at a whole plant level. Cumulative absorption of photosynthetically active radiation (∑APAR) was estimated using hourly inputs of predicted canopy extinction coefficients and measured leaf area indices (LAI) and global solar radiation. On 110 days after planting, soybean plants grown under non-saline conditions in the field accumulated 583 MJ ∑APAR m −2. A 20% reduction in ∑APAR resulted from growing the plants in soil with a solution electrical conductivity (EC) of about 10 dS m −1. Soybeans grown under non-saline conditions in the field achieved a RUE of 1.89 g MJ −1 ∑APAR for above-ground biomass dry materials. The RUE reached only 1.08 g MJ −1 ∑APAR in the saline soil, about a 40% reduction from the non-saline control. Salinity also significantly reduced ∑APAR and RUE for soybeans in the greenhouse. The observed smaller plant and leaf sizes and darker green leaves under salinity stress were attributed to reductions in LAI and increases in unit leaf chlorophyll, respectively. Reductions in LAI exceeded small gains in leaf chlorophyll, which resulted in less total canopy chlorophyll per unit ground area. Analyzing salinity effect on plant growth and biomass production using the relative importance of ∑APAR and RUE is potentially useful because APAR and total canopy chlorophyll can be estimated with remote sensing techniques.

Effect of irrigation and management practices for water use efficiency of soybean

Field experiments were conducted on soybean (var. Col) during summer and Kharif seasons of 1996 with two irrigation schedules viz., 0.40 and 0.60 IW/CPE ratio and three methods of irrigation viz., all furrow, alternate furrow and double row furrow irrigation coupled with three management practices which included application of coirpith at 12.5 t ha-1 as soil mulch; KCI at 0.5 per cent foliar spray and control. Higher grain yield was recorded during kharif than summer. Scheduling irrigation at 0.60 IW/CPE ratio through all furrow method along with coirpith application at 12.5 t/ha recorded higher grain yield during both the seasons.

An Additional QTL for Water Use Efficiency in Soybean

Water use efficiency (WUE) is one of the physiological traits that has been associated with drought tolerance in soybean [Glycine max (L.) Merr]. In a previous publication, we reported the identification of four quantitative trait loci (QTL) that conditioned WUE in a F4-derived soybean population obtained from a cross of ‘Young’ × PI416937. The purposes of this study were to identify WUE QTL in a F2-derived soybean population from a cross of ‘S100’ × ‘Tokyo’ and to determine the consistency of WUE QTL across the two soybean populations. A restriction fragment length polymorphism (RFLP) linkage map was created from 142 markers and 116 F2-derived lines of the population. The map covered about 1100 cM of the soybean genome with 120 markers linked on 25 linkage groups. Twenty-two of the markers remained genetically unlinked. The WUE of the parents and the F2-derived lines was evaluated in a greenhouse at Athens, GA, in 1996. S100 produced 9% more dry matter per unit of water used than did Tokyo. Progeny lines with greater WUE than S100 were identified in this population. Two independent markers were associated with WUE in this soybean population. There was no interaction between the two markers. One (A063E) of the two independent markers was also associated with WUE in the Young × P1416937 population. Marker A489H, on Linkage Group (LG) L, was unique to the S100 × Tokyo population and explained 14% of the variation in WUE in this soybean population. Interval mapping with MAPMAKER/ QTL indicated that the most probable location of the QTL on LG L was at marker locus A489H. The likelihood of odds (LOD) score for the presence of a QTL at this location was 3.4. Thus, we have identified a previously unreported QTL for WUE on LG L.

Precipitation Use Efficiency of Soybean and Grain Sorghum in Monoculture and Rotation

AbstractRainfed cropping systems are highly dependent on water use efficiency of crops in the rotation, especially in subhumid and semiarid areas. Precipitation use efficiency (PUE), an alternative to water use efficiency, is equally effective for water use evaluation in long‐term rainfed studies. We hypothesized that crop rotation and N fertilizer rates altered PUE of soybean [Glycine max (L.) Merr.] and grain sorghum [Sorghum bicolor (L.) Moench]. To test this, soybean (five cropping systems) and grain sorghum (four cropping systems) were grown under rainfed conditions at Mead, NE, on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic Argiudoll), each at three N fertilizer rates. Precipitation use efficiency values for the 1984 through 1991 cropping seasons varied from 15.5 to 59.9 and 21.6 to 159 kg ha−1 cm−1 for soybean and grain sorghum, respectively. Soybean PUE values averaged 30 kg ha−1 cm−1 and varied from 25 to 33 kg ha−1 cm−1 for the 8 yr. Grain sorghum PUE values averaged 89 kg ha−1 cm−1 and with sufficient N fertilization varied from only 94 to 99 kg ha−1 cm−1 for the 8 yr. Similar PUE values for soybean and grain sorghum (with adequate N fertilizer) within a given year and similar PUE values during the study among cropping systems for each crop indicated that both of these crops would be excellent options for rotations in areas with similar precipitation patterns.

Crop Net Carbon Dioxide Exchange Rate and Radiation Use Efficiency in Soybean

AbstractPlant growth is directly related to the fraction of the C fixed by photosynthesis that is converted into phytomass. We report here the results of a study aiming at the estimation of the net CO2 exchange rates (CNCER) of a soybean crop over the growing season. Hourly values of CNCER were estimated based on eddy correlation measurements of CO2 fluxes above the canopy, on chamber measurements of CO2 fluxes at the soil surface, and on the assumption that root respiration can be computed as a fraction of plant daily photosynthesis. Mean daytime CNCER varied between 0.70 and 0.83 mg m−2s−1 for a leaf area index (LAI) greater than 1, with a maximum hourly value of 1.48 mg m−2s−1. Absolute mean nighttime CNCER values were usually &lt;20% of daytime values. Hourly CNCER varied nonlinearly with intercepted photosynthetically active radiation (IPAR). The accuracy of the CNCER estimates was evaluated by comparing the radiation use efficiency of the soybean crop calculated using CNCER estimates with radiation use efficiency calculated using phytomass accumulation. Agreement between the two approaches was within 10% for LAI&gt;2, but calculated CNCER overestimated radiation use efficiency based on phytomass accumulation for smaller values of LAI.

Diurnal rhythmicity of root iron reduction in soybean as affected by various light regimes

Abstract Root iron (Fe) reduction is correlated with genotypic Fe efficiency in soybean (Glycine max L. Merr.) and is reportedly a reliable method for identifying chlorosis‐resistant genotypes. If used on a large‐scale, it would be advantageous to measure Fe reduction at various times of the day. Experiments were conducted to determine whether such a practice is possible without affecting the accuracy of the results. Despite extensive understanding of Fe‐reducing activity in dicots, it is not known if root Fe reduction shows diurnal rhythmicity similar to phytosiderophore release, the Fe‐deficiency stress response of grasses.. Five soybean cultivars showed a diumally rhythmic pattern of root Fe reduction when grown in a normal 16‐h light, 8‐h dark cycle. Continuous illumination (no dark) slowed Fe reduction and eliminated the rhythmic pattern as well as any correlation between root Fe reduction and Fe efficiency. Preceding a continuous light period with two 16‐h light, 8‐h dark cycles did not improve the results. Satisfactory genotypic screening for Fe‐efficiency in soybean cannot be accomplished in continuous light, but rather should be performed in normal light/dark cycles while limiting measurement to a 6‐ to 8‐h period during illumination.

Possible identification of quantitative trait loci affecting iron efficiency in soybean

Abstract Iron (Fe)‐deficiency in soybean [Glycine max (L.) Merr.] may cause yield reductions when certain genotypes are planted on 4 calcareous soil. This research was conducted to map quantitative trait loci (QTL) for Fe‐efficiency in a set of lines (set 1), and to test these associations in another set of lines of the same population (tester set). The population was formed by crossing a Glycine max experimental line (Fe‐inefficient) and a C. soja plant introduction (Fe‐efficient). Set 1 was used to construct a restriction fragment length polymorphism (RFLP) linkage map using 272 markers for the analysis. The tester set was developed to check the results obtained from set 1. Iron‐efficiency was measured using 13 F2‐derived lines of both sets in field plantings on calcareous soils. Set 1 and and the tester set were evaluated over two and one years, respectively. The lines were grown each year at two locations per year, with three replications per location in Iowa. Three markers were significantly (P<0.01)...

Root iron‐reduction capacity for genotypic evaluation of iron efficiency in soybean

Abstract Genetic resistance to Fe‐deficiency chlorosis is the most viable and economical means to overcome this problem in soybean [Glycine max (L.) Merr.], but current field evaluation is slowed and constrained by soil heterogeneity and environmental fluctuation. Highly resistant (Fe‐efficient) cultivars have been shown to reduce Fe3+ to Fe2+ more actively by the roots under Fe‐deficiency stress than highly susceptible genotypes. The objective of this study was to determine if Fe3+ reduction could be used to predict the degree of resistance or susceptibility to Fe‐deficiency chlorosis. Thirteen genotypes (both commercial and experimental) with known field susceptibility ratings were grown in a growth chamber in modified Hoagland solution. The more Fe‐efficient genotypes reduced Fe3+ earlier and to a greater extent than the less Fe‐efficient types. The sum of the seven daily Fe3+ reduction measurements was negatively correlated with field chlorosis ratings, as high as ‐0.864 (p > 0.01), and was a good pre...

Iron-deficiency chlorosis evaluation of soybean with tissue culture

The objectives of this study were: (i) to develop a tissue culture technique for the evaluation of Fe efficiency in soybean, and (ii) to compare the laboratory technique with field Fe chlorosis scores. Nineteen genotypes that had low and high levels of Fe efficiency were evaluated in the laboratory and at five field locations. Friable callus was induced from epicotyl sections, weighed, and placed on two different modified Murashige and Skoog media; one low in α-naphthaleneacetic acid and the other low in Fe. Callus growth was rated as lack of growth compared to respective controls. As an example, Fe-inefficient cultivars ('Asgrow A3205' and 'Pride B216') had significantly reduced growth compared to Fe-efficient germ plasm lines ('All' and 'A14'). Correlation between the laboratory and field chlorosis rating was highest for the low auxin medium (r (2) = 0.78), although correlation for the low Fe medium was also significant (r (2) = 0.72). These results show that in vitro evaluation for Fe efficiency can be a useful tool for plant breeders.

Indirect Effects of Recurrent Selection for Fe Efficiency in Soybean

Genetic improvement for Fe efficiency was achieved in the soybean [Glycine max (L.) Merr.] population AP9 by recurrent selection. The purpose of this study was to evaluate possible indirect effects of recurrent selection for Fe efficiency on plant and seed traits. Parents of the Cycle 0 (C0) through Cycle 7 (C7) populations were evaluated in replicated tests over 2 yr on noncalcareous soil. There was a significant linear increase in yield of 1.4 g m−2 cycle−1, height of 2.6 cm cycle−1, and lodging of 0.I score cycle−1. There were significant linear decreases in seed wt. of 1.9 mg seed−1 cycle−1 and seed oil of −0.6 g kg−1 cycle−1. Seed‐filling period decreased linearly an average of −0.2 d cycle−1. There were no significant linear changes in time of maturity, seed protein percentage, length of flowering period, leaflet area, leaflet wt., or specific leaflet wt. There was a significant linear change in three of the five fatty acids in the seed oil. Palmitic and linolenic acids increased 1 g kg−1 cycle−1, and oleic acid decreased 2 g kg−1 cycle−1. There were no significant linear changes in stearic or linoleic acids. A micronutrient analysis of the seed from C1 and C7 indicated that the average content of Fe was significantly greater in C7 and that the content of P was significantly greater in C1. There were no significant differences between C1 and C7 in the micronutrients B, Na, Mn, K, Ca, Mg, Zn, or Cu. The data obtained in this study indicate that, with the possible exception of an increase in lodging, the AP9 population has not been deleteriously affected by selection for Fe efficiency.

Alternative breeding strategies for the improvement of iron efficiency in soybean

Abstract The potential production loss attributable to Fe‐deficiency chlorosis in soybean [Glycine max (L.) Merr.] grown on calcareous soil is sufficient to justify the development of high‐yielding, Fe‐efficient soybean cultivars in several states. Alternative breeding methods and screening techniques for the development of high‐yielding, Fe‐efficient cultivars and parental germplasm were studied. In the breeding methodology studies, populations derived from crosses of lower yielding, Fe‐efficient X high‐yielding, Fe‐inefficient parents had lower mean yields but greater average Fe‐efficiency than populations derived by backcrossing to the high‐yielding parent. Phenotypic correlations between the yield of breeding lines on noncalcareous soil and their Fe‐efficiency on calcareous soil were positive or not significant, indicating that selection of high‐yielding, Fe‐efficient cultivars should be possible. In a recurrent selection program to improve the Fe‐efficiency of a population, a nutrient solution system...

Effects of low concentrations of O3, leaf age and water stress on leaf diffusive conductance and water use efficiency in soybean

Ozone, leaf age and water stress each affected leaf conductance in soybean [Glycine max (L.) Merr. Hodgson], but there were no interactions among these factors. Exposure to increased concentrations of O3 (0.01, 0.05, 0.09. and 0.13 μl l−1) resulted in linear declines in abaxial and adaxial conductances in leaves of all ages. There were no differences in relative response to O3 between the two leaf surfaces. For well‐watered plants, water use efficiency also decreased with exposure to increased O3 concentrations (water‐stressed plants were not tested). Abaxial conductance increased as leaves aged from 4 to 10 days and then declined with further aging. Adaxial conductance decreased with all increases in leaf age beyond 4 days, and the ratio of abaxial/adaxial conductance increased continuously throughout the leaf lifespan. During water‐stress cycles (water withheld for 2–3 days) leaves of water‐stressed plants had lower conductances than those from well‐watered plants, and there was no difference in relative response between abaxial and adaxial stomata.

Response of four grain legumes to water stress in south-eastern Queensland. III. Dry matter production, yield and water use efficiency

Dry matter production, yield and water use efficiency of soybean (Glycine max), black gram (Vigna mungo), green gram (V. radiata) and cowpea (V. unguiculata) under irrigated, rain-fed fallowed and rain-fed double-cropped culture were evaluated at Dalby in south-east Queensland. Differential species responses to cultural treatments were related to strategies of growth and water use in response to water stress. The major effect of differences between strategies related to differences in the short term rate of soil water use, which together with the seasonal pattern of water availability influenced both the total, and seasonal pattern of water use. Regardless of strategy adopted, dry matter production was primarily a function of water use. However, seed yield and water use efficiency for seed yield depended on the seasonal pattern of water use. The relative agronomic success of the various strategies therefore depended on the seasonal profiles of water availability. Some implications of the differences in stress response strategy for adaptation of these species to agricultural environments are discussed.