bluuebunny/crossref_metadata_2025 huggingface dataset:
Invertase Activity and Abscisic Acid in Relation to Carbohydrate Status in Developing Soybean Reproductive Structures1
Authors: Ackerson R. C.
Published: July 2010

The relationships among soluble acid invertase, carbohydrate concentrations, and abscisic acid (ABA) were examined in developing soybean [Glycine max L.(Merr.)] reproductive structures. Ontogenetic changes in enzyme activity and sucrose/glucose concentrations in flowers, pod walls, and immature seeds were followed from 2 to 30 days following flowering in growth chamber‐grown plants. The effect of exogenous ABA treatments on pod wall acid invertase and soluble carbohydrates was investigated in relation to the fluctuations in endogenous ABA in pod walls and seeds. The objective of the study was to determine potential mechanisms that may regulate early embryogenesis in soybeans. Flowers exhibited the highest acid invertase activity and activity in pod walls and seeds declined progressively from 2 to 30 days after flowering. Concentrations of sucrose and glucose in the respective tissues reflected invertase activity. Exogenous ABA stimulated invertase activity in 20‐to 25‐day old pod walls incubated in the presence of sucrose. Glucose concentrations recovered in the pod‐wall incubation medium also increased in the presence of ABA (1 to 100 μM), in accordance with the increase in invertase activity. The importance of glucose for development of immature seeds was demonstrated in experiments which showed that glucose was more effective than sucrose in enhancing the growth of seeds cultured in vitro. The data indicate that conversion of sucrose to glucose and possible regulation of acid invertase by ABA may play an important role in the growth of young soybean reproductive structures.
Monosaccharides in Detergent Residues of Tropical Forage Plants1
Authors: Pitman W. D. , Moore J. E.
Published: July 2010

Detergent extractions have been widely used to evaluate forage quality. Quantities of the major structural polysaccharides, cellulose and hemicellulose, have been calculated from these empirical fractionations and lignin content. The presence of noncellulose carbohydrate in acid detergent (AD) residue (which theoretically is composed of cellulose and lignin) of temperate forages has been reported by several investigators. Leaf anatomy and cell wall contents of temperate and tropical forage plants differ distinctly. Leaf samples from field‐grown plants of the tropical grasses ‘Ona’ stargrass (Cynodon nlemfuensis Vanderyst) and ‘Pensacola’ bahiagrass (Paspalum notatum Fluegge) and the tropical legumes ‘Siratro’ [Macroptilium atropurpureum (DC.) Urb.] and Vigna adenantha (G.F. Meyer) Marechal, Mascherpa, and Stainier were used to evaluate the neutral monosaccharide compositions of detergent residues of tropical forage plants. Leaf samples were extracted with neutral detergent (ND), AD, sequential ND and AD, and sequential ND and AD with AD reflux time increased to 2 h. Resulting residues were deliguifled with sodium‐chlorite and acid‐hydrolyzed before neutral monosaccharide compositions were determined by gas chromatography of alditoloacetate derivatives. Glucose comprised 875 and 927 g kg−1 of the neutral monosaccharides of AD residues of stargrass and bahiagrass, respectively, with similar results from the sequential extractions. Neutral monosaccharides from AD residues of Siratro and Vigna contained 815 and 807 g of glucose kg−1 of residue, respectively. The only extraction yielding a greater residue glucose concentration than AD alone was the ND, followed by 2‐h AD extraction of Vigna, which increased glucose concentration from 807 to 914 g kg−1. Although AD residues of tropical grasses were similar in neutral monosaccharide composition to published data for temperate grasses, AD residues of tropical legumes contained more neutral monosaccharides derived from polysaccharides other than cellulose. Therefore, detergent extractions of tropical forage plants, especially tropical legumes, do not provide an adequate base for calculation of cellulose and hemicellulose contents.
Genetic Analysis of Fiber Color Variants in Cotton1
Authors: Kohel R. J.
Published: July 2010

Although white is the most common color of fiber in Upland cotton (Gossypium hirsutum L.), some lines display brown lint fibers, and others have green lint. Some cottons have white lint and green fuzz. Eleven lines with brown lint, one with green lint and fuzz, and two with white lint and green fuzz were tested for allelism against known genes for lint color, and for chromosomai location of lint color loci. All lines displaying green lint and/or fuzz proved to be alleles at the Lg locus. The green fuzz allele was designated Lg1. Four of the brown‐linted lines proved to carry alleles at the Lc2 locus, and four alleles at the Lc2 locus. A dark brown phenotype was imparted by an allele at a new locus, Lc5. The Lc5 locus proved to be linked with another locus, Lc5, which harbors alleles for light brown lint color. Alleles at Lc4 and Lc6 also impart light brown lint color.
Bruchid Resistance in Cowpea1
Authors: Singh B. B. , Singh S. R. , Adjadi O.
Published: July 2010

The most damaging storage pest in cowpea [Vigna unguiculata (L.) Walp] is Callosobruchus maculatus (F.), commonly known bruchid. Therefore, concerted efforts are being made at the International Institute of Tropical Agriculture (IITA) to develop bruchid‐resistant cowpea varieties. By systematic screening of over 8000 germplasm lines, three sources of resistance m cowpea bruchid have been identified: TVu 2027, TVu 11952, and TVu 11953. Screening for bruchid resistance was done by placing 10 seeds of each variety in separate plastic boxes of 5 ✕ 5 ✕ 2 cm dimensions and infesting with two pairs of bruchids to lay eggs for 15 h. The boxes were then incubated at 27 to 28 °C and 70% relative humidity. The total number of eggs laid in each box was determined and a daily count of emerging adults was made until 50 days after infestation. Percent adult emergence was computed based on number of eggs and total adults emerged. Bulk‐sample bioassay was done by infesting 200‐g samples of each line with two pairs of bruchids in a 500‐mL jars with perforated caps. A 100‐seed sample was taken at various intervals up to 180 days and data on percent damaged seeds, number of exit holes and dry weight loss were recorded. Bioassay of these lines revealed delayed, staggered, and significantly less adult emergence as compared to the susceptible cv. Ife Brown. The average adult emergence in TVu 2027, TVu 11952, and TVu 11953 was 26.6, 32.8, and 22.1%, respectively, as compared to 86.4% for Ife Brown. Similarly, the percent damaged seeds ranged from 25 t.o 26% in the resistant lines at 103 days after infestation as compared to 95% for Ife Brown. The differences among resistant lines were not significant indicating that the level of resistance in these lines is similar. The data further indicate that the level of resistance in these lines is good enough to provide reasonable protection against bruchids during storage.
Genetic, Morphological, and Agronomic Characteristics of Lolium‐Festuca Amphiploids1
Authors: Buckner R. C. , Burrus P. B. , Eizenga G. C.
Published: July 2010

Lolium‐Festuca hybridization provides a wide range of genetic variability when breeding for improved forage quality of tall fescue (Festuca arundinacea Schreb.). Crosses were made among Italian ryegrass (a) (Lolium multifiorum Lam.) and tall fescue (t) amphiploids (2n = 56 chromosomes) and giant fescue (g) [F. gigantea (L). Vill.] and (t) hybrids (tg) with amphiploids (2n = 56) of Italian ryegrass and tall fescue (AT) with the objectives of determining the effect of cytoplasm on restoration of meiotic stability and fertility and of comparing the nutritive and agronomic performance and amphiploids with ryegrass and tall fescue cultivars. Parents and polycross progenies (pcp) of (tg)AT ✕ (at)AT[F1(tg), tall fescue ✕ giant fescue, 2n=42 ✕ AT, Italian ryegrass ✕ tall fescue amphiploid, 2n = 56] ✕ [F1, (at), Italian ryegrass ✕ tall fescue, 2n = 28 ✕ AT, Italian ryegrass ✕ tall fescue amphiploid, 2n=56] and their reciprocal (at)AT X (tg)AT amphiploids; and of (tg) AT ✕ (tg) AT parents and pep were evaluated in spaced plant rows in separate tests but in close proximity. Plants containing (t) and (a) cytoplasms had 92.3 and 61.9% 2n=56 chromosomes, respectively. Thus, the approach to meiotic stability was more rapid in (t) cytoplasm; however, cytoplasm appeared to have little effect on percent fertile florets and seed yield. All amphiploids had 79% less seed than the (t) check. Narrow sense heritability estimates for fertile florets were higher for (tg)AT ✕ (tg)AT (0.82) than for the (tg)AT ✕ (at)AT (0.38) materials. A correlation coefficient of 0.58 (P<0.05) was obtained for association of parents and pep for seed/panicle. Thus, the data suggest that further improvement for meiotic stability and fertility may be realized through selection within both groups of amphiploids. The amphiploid synthetic when compared in solid stands to (t) cultivars and ‘Grimalda’ perennial ryegrass (L. Perenne L) had significantly lower seed yields than all cultivars except ‘Missouri 96’ (t) and Grimalda, were intermediate in forage quality, and had dry matter yields significantly lower than (t) cultivars but equal to Grimalda. Nutritive value index (NVI) of 68 or above was obtained consistently for the amphiploids during the August environmental stress period. Thus, NVI values of 70 or above possibly could be obtained through selection within these hybrids.
The Weibull Function as a Dose‐Response Model to Describe Ozone Effects on Crop Yields1
Authors: Rawlings J. O. , Cure W. W.
Published: July 2010

Field experiments have demonstrated that ozone (O3) pollution can reduce yields of important crop species. The assessment of the impact of O3 is facilitated by the use of a family of dose response models that covers the range of responses observed in field O3 dose response studies. The Weibull dose response model is a flexible, biologically realistic, model that has been found useful for this purpose. The purposes of this study are i) to discuss analyses of dose response data using the Weibull model and its extensions, ii) to identify some of the problems inherent in the use of a nonlinear dose response model, and iii) to show application of the model to two sets of experimental data. The basic Weibuil model is a modification of the Weibull probability distribution function. Extensions of the basic model allow for class variables and other continuous variables in the experimental design. A bivariate form of the Weibull allows for independent effects of two pollutants. The use of the Weibull model with class variables (cultivars) is demonstrated using a 1977 winter wheat (Triticum aestivum L.) experiment grown at Raleigh, NC involving four cultivars exposed to four levels of O3 pollution. Tests of homogeneity over cultivars of the proportional yield responses show differential cultivar response to O3. The bivariate Weibull model is demonstrated using a 1981 soybean [Glycine max (L.) Merr.] experiment involving one cultivar exposed to the factorial set of treatments consisting of six levels of O3 and four levels of SO2 pollution. The test of lack of fit of the bivariate Weibuil model was nonsignificant, supporting the hypothesis that O3 and SO2 were acting independently. The percent predicted relative yield losses and their standard errors are given for two of the wheat cultivars and for the soybean cultivar.
Grain Filling and Field Drying of a Set of Maize Hybrids Released From 1930 to 19821
Authors: Cavalieri A. J. , Smith O. S.
Published: July 2010

Study of historically important cultivars may provide information on physiological traits that have been changed during selection for yield. Traits related to grain filling and drying were studied in commercially important maize (Zea mays L.) hybrids sold over the past 50 years. Hybrid studied were of approximately the same relative maturity and adapted to central Iowa. The duration of the grain filling period increased with year of release while grain filling rate was unchanged. The increase in grain filling duration was the result of later physiological maturity (black layer formation) rather than a change in flowering date. Late season plant health was improved in newer hybrids, which may have provided more viable leaf area to support prolonged grain filling. Grain drying rates were calculated by regression of water content·kernel−1 on heat units. Slopes of water loss were the same in the 2 years despite very different environmental conditions in the two seasons. Heat unit intercepts were different in the 2 years, with grain drying earlier in the hot, dry year of 1983. Grain water content at physiological maturity was correlated with year of release in 1983, but not in 1982. Several traits previously proposed to be associated with drying rate (husk number, date of husk death, ear angle, and number of kernel rows) were correlated with year of hybrid release. Correlation with drying rates over the season was significant for date of husk death in 1983.
Inheritance of Resistance to Race 1 and Race 2 Anthracnose in Arc and Saranac AR Alfalfa1
Authors: Elgin J. H. , Ostazeski S. A.
Published: July 2010

Previous inheritance studies of resistance to anthracnose in alfalfa (Medicago sativa L.) caused by Colletotrichum trifolii Bain included only race 1. The objectives of this study were to simultaneously study the inheritance of race 1 and race 2 and to determine the association between resistances. Twenty plants were randomly selected from each of ‘Arc’ and ‘Saranac AR’ alfalfa, cloned, and ramets needle inoculated with race 1 and race 2 of C. trifolii. Seven of the Arc clones were susceptible to both races, 12 clones were resistant to race 1, and one clone was resistant to race 1 and race 2. Five of the Saranac AR clones were susceptible to both races, three clones were resistant to race 1, and 12 clones were resistant to race 1 and race 2. Each of the 40 clones were selfed and testcrossed to a race 1 and race 2 susceptible, male‐sterile clone. The progeny were evaluated for anthracnose resistance, and the segregations tested for fit to tetrasomic segregation ratios. Three reaction types were observed in the progeny: a.) susceptible to both races (SS); b.) resistant to race1—susceptible to race 2 (RS); and c.) resistant to both races (RR). No plants susceptible to race — resistant to race 2 (SR) were observed. Segregation ratios supported the hypothesis that two independent dominant genes with tetrasomic inheritance control anthracnose resistance in Arc and Saranac AR alfalfa. The An1 gene in Arc codes for resistance only to race 1. The An2 gene in Saranac AR codes for resistance to both race 1 and race 2. A gene similar to the An1 gene in Arc that codes for resistance only to race 1 also occurs at low frequency in Saranac AR and is frequently masked by the An2 gene.
Histochemical Reactions, Autofluorescence, and Rumen Microbial Degradation of Tissues in Untreated and Delignified Bermudagrass Stems1
Authors: Akin Danny E. , Willemse M.T.M. , Barton F.E.
Published: July 2010

Low digestibility of stems is due to large proportions of lignified cell walls, but lignified tissues vary in resistance to microbial degradation. The objective of the research was to characterize lignified tissues histologically and by autofluorescence, and to examine the influence of delignification with potassium permanganate (PM) on the histology, autofluorescence, and tissue degradation by rumen microorganisms in mature internodes of ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.]. Cell walls of epidermis, sclerenchyma ring, and vascular xylem gave a positive lignin test with acid phloroglucinol (AP+), while those the parenchyma gave a positive reaction to the chlorine‐sulfite test (CS+). The maximum of the emission spectrum (Emax) of the autofluorescence after excitation at 365 nm was 452 to 455 nm for the sclerenchyma ring and about 460 nm for parenchyma. The intensity of the autofluorescence for the three internodes averaged 1.97 mV for the sclerenchyma ring, 1.50 mV for the middle parenchyma, and 1.27 mV for parenchyma cell walls nearer the stem center. Delignification resulted in lack of a histochemical reaction in parenchyma, but an AP+ reaction still occurred in epidermis, sclerenchyma ring, and xylem. Delignification reduced the Emax tO 450nm and the intensity to 1.28 mV for AP+ tissues and resulted in a total loss of autofluorescence in parenchyma. Treatment with PM resulted in almost total microbial degradation of the parenchyma, but AP + tissues were not degraded in untreated or PM‐treated stem sections. Results indicate that variations exist in the retention of phenolic compounds in cell walls upon oxidation with PM, and these variations relate to quality differences in forage fiber.
Factor Analysis of Components of Yield in Guar1
Authors: Seiler G. J. , Stafford R. E.
Published: July 2010

To determine the potential of genetically different lines and cultivars of guar [Cyamposis tetragonoloba (L.) Taub.], breeders must observe many different characteristics in their breeding and selection programs. Factor analysis is a type of multivariate analysis that can be used to reduce a large number of correlated variables to a smaller number of main factors, thus helping to elucidate the number and nature of causative influences and aiding in the selection of better genotypes. The objective of this study was to use factor analysis to determine the dependence relationship between 10 components of yield and morphological characteristics of 12 field‐grown guar genotypes from three locations. Principal factor analysis was used for factor extraction and varimax rotation was used to uniquely define factors. Four factors adequately accounted for most of the intercorrelations. Grams of seed/plant, number of pods/plant, number of seeds/plant, and number of racemes/plant constituted the productivity per plant factor (Factor 1). Factor 2 was considered a branchingproductivity factor consisting of number of primary branches and number of pods/raceme. Factor 3, a growth factor, consisted of plant height and number of nodes/plant. Factor 4 was considered a yield per unit area factor, and consisted of variables concerned with number of seeds/pod and wt/100 seeds. Factor analysis reduced a large number of correlated variables to a small number of main factors and also clarified the relationship between correlated characters in the dependence structure. This study indicated that selection of variables concerned with productivity per plant (Factor 1), and yield per unit of area (Factor 4) should enable breeders to better realize the desired gains in seed yield of guar.
Inheritance of Root Characters and their Relations to Drought Resistance in Rice1
Authors: Ekanayake I. J. , O'Toole J. C. , Garrity D. P. , Masajo T. M.
Published: July 2010

The ability of rice plants to tolerate drought stresses is associated with root system characters. However, the genetics of root traits are not well understood. Hence, the inheritance of six root characters of rice (Oryza sativa L.) was studied using the parents, F1, F2, and F3 populations of the cross IR20✕MGL‐2. Plants were grown in a hydroponic culture solution in a phytotron glasshouse and in an upland drought screening nursery. A polygenic system of inheritance was indicated for the root characters. The F1 plants had root systems characterized by thick, deep roots with a higher lateral and vertical distribution than the low parent (IR20), and the heterosis was significant and positive. The additive and dominant genetic effects contributed equally to the expression of all root traits. Both progeny parent regression of F3 and F2, and the narrow sense heritability estimates in F3 were high for root thickness (0.61 and 0.80), root dry weight (0.56 and 0.92) and root length density (0.44 0.77). Selection of root types, based on individual plant performance, should be successful in early segregating generations if selection is practiced on these characters. Associations between root characters and plant height, tiller number, and shoot weight were positive and significant. Five root characters were significantly correlated with the visual field drought resistance scores and with leaf water potential, confirming the role of root characters in maintaining high leaf water potential under water stress.
Sampling Variation and Resource Allocation in Soybean Canopy Photosynthesis Experiments1
Authors: Boerma H. R. , Ashley D. A. , Harrison S. A.
Published: July 2010

Canopy apparent photosynthesis (CAP) during the seed‐fill period has been shown to be related to seed yield in soybean [Glycine max (L.) Merr.]. The current techniques for measuring CAP are labor intensive and time consuming. However, estimates of error variances, coefficients of variation, and genotype ✕ environment (G ✕ E) interaction variances have not been reported. This report describes these statistics from three field experiments conducted over 5 years. These statistics were used to calculate the number of CAP measurements (replications ✕ measurement dates) per genotype per environment and the number of environments required to detect various levels of differences between two genotypes. There were no differences in the error variances or CVs in F3− and F6−derived lines. The average error variance was 7.14 (μmol CO2 m−2 s−1) and the average CV was 0.179 for our 16 measurement dates. Assuming no G ✕ E interaction and β = 0.5 (probability of Type II error), it would require 2, 4, 7, and 28 replications with one measurement date to detect 40, 30, 20, and 10% differences, respectively, between genotypes. In two of our three experiments there were significant (α < 0.05) G ✕ E interactions. The G ✕ E variance components were 0.1 and 0.2 of the error variance based on a single measurement date in these two experiments. Even with the largest amount of G ✕ E interaction present in our experiments, a 20% difference between two genotypes can be detected with four environments and a 30% difference with two environments if four CAP measurements (two measurements ✕ two replications) per genotype per environment are made. These results are discussed in regard to efficient design of experiments to determine CAP.
Growth and Yield Response of Sweet Potato to Atmospheric CO2 Enrichment1
Authors: Bhattacharya N. C. , Biswas P. K. , Battacharya Sheila , Sionit Nasser , Strain B. R.
Published: July 2010

Tuber growth of sweet potato (Ipomoea batatas) is a sink that may be limited by source capacity under present ambient CO2 levels. Hence, sweet potato may demonstrate more response to predicted increases in atmospheric CO2 than many other annual plants. The present investigation was undertaken to determine the long‐term effects of CO2 enrichment on some physiological parameters, growth, and yield, as well as on the source‐sink relationship in sweet potato at different stages of growth. Plants of the cultivar Georgia Jet were grown from stem cuttings in a mixture of gravel and vermiculite in controlled environment chambers at 350, 675, and 1000 μL L−1 CO2 and were irrigated with one‐half strength Hoagland's solution. The temperature was 28°C during 14‐h days and 20°C during 10‐h nights. The photosynthetic photon flux density was 550 μmol m−2 s−1. The length of main stem, total branch length, number of branches, and leaf area were increased for plants grown at 675 or 1000 μL L−1 COs. The production of total dry matter of plants increased at each harvest interval in response to CO2 enrichment but it was greatest in 1000 μL L−1 CO2. Specific leaf weight also increased with increased CO2 concentration. The number and diameter of tubers increased at high CO2 concentration. At the final harvest, the dry weight of roots and tubers increased 1.8 and 2.6 times in plants grown at 675 and 1000 μL L−1 CO2, respectively, compared to those grown at 350 μL L−1 CO2. Carbon dioxide enrichment resulted in the modulation of sink capacity to enhance the production of tubers in sweet potato.
Fruiting of Cotton. III. Nutritional Stress and Cutout1
Authors: Guinn Gene
Published: July 2010

Decreases in growth, flowering, and fruit (boll) retention of cotton (Gossypium hirsutum L.) occur during the season in many modern cultivars even though it is an indeterminate plant. if they are pronounced, these decreases are commonly referred to as cutout. If cutout occurs too early it may decrease yield. Conversely, complete and permanent cutout at the end of the season would facilitate the control of insect pests. Cutout is strongly affected by boll load and may occur because of competition for photosynthate, a change in hormonal status, or both. Previous results indicated that changes in free abscisic acid (ABA) did not correlate with the decreases in growth, flowering, and boll retention that occurred as boll load increased during the season. Therefore, experiments were conducted in the field to test the hypothesis that cutout occurs when the demand for photosynthate exceeds the supply. The supply of photosynthate per plant was manipulated by thinning the plant population at different times to permit better light penetration (irradiance) into the canopy and thus increase total photosynthesis per plant. The demand for photosynthate was manipulated by partial defruiting. All flowers were removed during the first 3 weeks of flowering. Thinning at the start of the season caused individual plants to produce more flowers and bolls, but did not alter the timing of changes in flower production and boll retention rates during the season. Carrying capacity per plant varied inversely with plant population. Thinning later in the season caused an immediate increase in boll retention and a subsequent increase in flowering rate. Decreasing the demand by removing flowers early in the season caused subsequent and rather prolonged increases in flowering and boll retention rates. Early defruiting also moderated the decline in growth rate late in the season. Decreases and subsequent increases in flowering rate lagged behind the changes in growth and boll retention because flowering rate was determined by prior events (production and retention of flower buds). The results are consistent with the hypothesis that growth, flowering, and boll retention decrease when the demand for photosynthate increases and exceeds the supply. Therefore, an increase in photosynthesis should permit more bolls to be set before cutout.
Soybean Leaflet Movements as an Indicator of Crop Water Stress1
Authors: Oosterhuis Derrick M. , Walker Sue , Eastham Judy
Published: July 2010

Vertical orientation of soybean [Glycine max (L.) Merr] leaflets during the onset of water stress, and the usefulness of this phenomenon as an indicator of crop water stress, were investigated in relation to leaf water potential (Ψ), stomatal diffusive resistance (ra) and soil water status in a field study. Observations were made during the reproductive stage on plants in a field with a Rhodic Paleustalf soil. Terminal leaflet movements were influenced by plant water stress and were not influenced by their azimuth direction. Increases in the angle of the terminal trifoliolate leaflet to the soil coincided with the earliest notable changes in Ψ and ra and thus provided a clear indication of the onset of crop water stress. Leaflet inversion began when Ψ was approximately ‐1.4 MPand was associated with a greater than 60% depletion of plant available water. The possible mechanism of leaflet inversion is related to changes in osmotic and pressure potentials and potassium concentration across the pulvinus.
Plant Regeneration through Somatic Embryogenesis in Common Bermudagrass Tissue Culture1
Authors: Ahn B. J. , Huang F. H. , King J. W.
Published: July 2010

Tissue culture techniques could be useful for improving common bermudagrass (Cynodon dactylon (L.) Pers.). Calli originating from immature inflorescences grew larger on a modified N6 than on MS medium. Both media contained 1 mg L−1 (2,4‐dicho lorophenoxy) acetic acid (2,4‐D) and either 20 or 60 g L−1 sucrose. Embryogenic calli were produced from 16 of 19 immature inflorescences, less than 0.5 cm long, on Ne medium with 1 mg L−1 2,4‐D and 60 g L−1 sucrose, while only non‐embryogenic calli were induced from those over 1.5 cm length. Embryogenic calli forming somatic embryos spontaneously have been maintained without loss of competence for 80 weeks by subculturing at 4‐week intervals. Numerous plantlets were regenerated from each callus upon transfer to hormone‐free Ne medium and were grown to maturity in soil. Scanning electron microscopy confirmed the bermudagrass regeneration through embryogenesis.
Accuracy of NIRS Instruments to Analyze Forage and Grain1
Authors: Shenk John S. , Westerhaus Mark O.
Published: July 2010

A study was made of the relative accuracy of three near infrared reflectance (NIR) instruments: a monochromator and two lower cost scanning filter instruments. All instruments used in this test were manufactured by Pacific Scientific, Silver Spring, MD. The monochromator was the 6100 with a scanning range of 1100 to 2498 nm. The 51A had a scanning range from 1596 to 1756 nm and 1988 to 2356 nm. The 102 scanned from 1902 to 2320 nm. Computer programs developed for the National NIR Forage Project were used to conduct the instrument comparisons tests. Agricultural products used in the experiment were hay, haylage, corn (Zea mays L.) silage and corn grain. Analyses included crude protein (CP), acid detergent fiber (ADF), Ca, P, K, M, and dry matter (DM). The 6100 generally had lower standard errors of validation than the scanning filter instruments. Although the six‐filter 51A had more spectral information than the three‐filter 102, it did not consistently out‐perform the 102. There was no trend for one math treatment or series of wavelengths to be selected across instruments, products, or analyses. Regardless of the instrument spectral capabilities, the fraction of explained variance (R2) values for CP, ADF, and DM were higher than the R2s for the minerals. Even though the accuracy of the filter instruments was often below that of the scanning monochromator, the differences were small and would be of little significance for many agricultural applications.
Performance of Related Determinate and Indeterminate Soybean Lines1
Authors: Foley T. C. , Orf J. H. , Lambert J. W.
Published: July 2010

Previous research has produced mixed conclusions on the value of the dt1 gene for improving yield and lodging resistance in northern U.S. soybean [Glycine max (L.) Merr.] cultivars. The objective of our experiment was to compare the agronomic and developmental characteristics of determinate and indeterminate stem termination types. Twenty‐one determinate and 21 indeterminate soybean lines, randomly selected from each of three crosses, were evaluated at three Minnesota locations in 1982. Stem termination type significantly affected maturity, with the determinate lines averaging more than 3 days earlier than the indeterminate lines. The stem termination types did not differ significantly for yield. Plant height was 25.7 cm less in the determinate lines than the indeterminates. Lodging was less for the determinate lines at two of the locations, while no appreciable lodging occurred at the third location. Most location effects and location interactions with crosses and stem termination types were highly significant. The determinate and indeterminate lines had similar genetic variances in all crosses for yield, lodging, and maturity. Our observations indicate that the determinate stem termination type is potentially useful for improving yield and lodging resistance in soybeans for the northern USA. However, the production practices developed for indeterminate cultivars may need to be modified to complement the determinate stem termination type.
Testcross Evaluation of Mexican Maize Populations1
Authors: Gutierrez‐Gaitan M. A. , Cortez‐Mendoza H. , Wathika E. N. , Gardner C. O. , Oyervides‐Garcia M. , Hallauer A. R. , Darrah L. L.
Published: July 2010

Maize(Zeo mays L.) breeders in the USA have emphasized selection in less than 5% of the total available maize germplasm. Although genetic gains have been made within races of maize adapted to the USA, there is interest in expanding the germplasm base available to applied breeding programs. Our objective was to evaluate the relative potential of improved Mexican germplasm in testcrosses with two U.S. Corn Belt populations. Field trials were conducted in eight environments in Mexico and four environments in the western U.S. Corn Belt in 1982 and included 24 Mexican populations crossed with U.S. Corn Belt adapted testers, BS13(S)C3 and Lancaster Composite. Few individual crosses yielded significantly better than the testers in the U.S. Corn Belt. Grain moisture at harvest, ear height, and days‐to‐flower were greater in crosses compared with testers perse. The BS13(S)C3 testcrosses had significantly greater yields than Lancaster testcrosses, but grain moisture at harvest, ear height, and lodging were not significantly different between the two sets of testcrosses. Both sets of testcrosses yielded significantly more than the checks in Mexico, suggesting that elite selections could be obtained for use in Mexico breeding programs. Crosses with BS13(S)C3 seemed to be more promising than crosses with Lancaster Composite in Mexico. Across 7729 and Poza Rica 7822 were the only Mexican populations that had significant estimates of general combining ability in both countries.
Response of Mycorrhizal and P‐Fertilized Soybeans to Nodulation by Bradyrhizobium or Ammonium Nitrate1
Authors: Pacovsky R. S. , Paul E. A. , Bethlenfalvay G. J.
Published: July 2010

Management of N2‐fixing bacteria or P‐scavenging endomycorrhizae may lead to decreased fertilizer use on extensively cropped lands. To measure the effectiveness of these microsymbionts, soybean [Glycine max (L.) Merr. cv. Amsoy 71] plants were grown in a growth chamber in a soil [Josephine silty clay loam (mesic Typic Haploxerult)] low in plant‐available N and P. Plants were inoculated with different Bradyrhizobium strains or received nutrient solutions of different N concentrations (0.0, 1.0, 2.0, 4.0 mM N) and P adequate for maximum plant growth under these conditions. Other plants were infected with a vesicular‐arbuscular mycorrhizal (VAM) fungus and a Bradyrhizobium strain and received no N or P in the nutrient solution. The purpose of this study was to determine the growth response of soybean to N fertilization or nodulation by B. japonicum under conditions of high P availability or V AM‐assisted P uptake. Nodulated non‐VAM soybean plants had dry weights and development similar to that of the 4.0 mM N fertilizer treatment. Total N and Mn, leaf area, and leaf P of nodulated plants were higher than in the comparable N‐fertilized plants in the absence of P stress. Soybeans infected with both the VAM fungus and Bradyrhizobium were similar in total dry weight, leaf area, and development to plants that received 1.0 or 2.0 mM N. They, however, contained more leaf N, more root Cu and Zn, and less Mn and P than the 2.0 mM N treatment. It is concluded that a number of host characteristics of nodulated plants are due to the altered functional aspects of the symbiosis and not N input alone. The presence of the VAM fungus can decrease nutrient stress in environments limited in P, Zn and Cu, elements essential in N2 fixation.
Temperature and Water Strees Effects on Germination of Ruby Valley Pointvetch (Oxytropis riparia Litv.)1
Authors: Delaney R. H. , Abernethy R. H. , Johnson D. W.
Published: July 2010

The frequent saline and high moisture environments associated with high elevation hay meadows prohibit the use of most forage legume species. Ruby Valley pointvetch (Oxytropis riparia Litv.) has been observed in saline and wet meadows in Southwestern Montana. Our objectives were to evaluate the sensitivity of pointvetch germination to temperature and osmotic stress levels. Seven constant germination temperatures ranged from 5 to 35°C. The NaCl and PEG‐imposed stress levels ranged from 0.0 to −3.0 MPa with intervals of −0.5 MPa. Hard seed content ranged from 87 to 96%, depending on seed lot. Germination of pointvetch was maximal between 10 and 30°C compared to 5 to 30°C for alfalfa (Medicago sativa L.). Pointvetch has the capability for over 90% germination in −2.0 MPa NaCl solutions, while alfalfa germination was reduced 70% below the control values by −1.0 MPa NaCl media. Pointvetch germination in PEG 8000 solutions was unaffected by solution potentials down to −1.5 MPa. Alfalfa germination responded similarly to NaCl and PEG‐imposed osmotic stress, while pointvetch germination was less affected by NaCl than by PEG‐imposed stress. The germination tolerance of pointvetch to osmotic and salt stress is unique and warrants further study.
Pregermination of Italian Ryegrass and Tall Fescue Seed1
Authors: Dudeck A. E. , Peacock C. H.
Published: July 2010

Repair and improvement of sports turfs are difficult because of continuous use and damage to the turf ground cover. Sowing pregerminated rather the dormant seed is a possible means fo reducing establisment time. A series of experiments with seed of cool‐season turfgrasses were conducted under diferent temperature regimes to identify pregermination treatments that effect fast rates of germination. Italian ryegrass (Lolium multiflorum Lam.), which has a relatively fast germination rate, was compared to ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.), which has a relatively slow germination rate. Seed was either treated by soaking for 24 or 48 h in aerated water, unaerated, in gibberellic acid (GA3) at 50 or 100 mg L−1, or by not soaking. Germination rates were compared 14 days after seed sown on blotters in petri dishes were incubated in controlled environments at optimum temperatures of 25 to 15°C or at suboptimum temperatures of 20 to 10°C and 15 to 5°C with an 8‐h photoperiod during the daily high temperature cycle. Fifty percent viable seed (Germ50)of Italian ryegrass germinated in 7 to 17 h depending on temperature, if pretreated with GA, at 100 mg L−1 and kept moist for 48 h at 25°C. Untreated, dry seed had Germ50 values of 4.2 to 7.1 days, respectively, depending on temperature. Germ50 values for viable seed of Kentucky 31 tall fescue were 1.8 to 5.9 days depending on temperature, if seed was pretreated with GA3 at 50 mg L−1 and kept moist for 48 h at 25°C. Untreated, dry seed had Germ50 values of 5.9 to 10.8 days, respectively, depending on temperature.
A Detached Culm Technique for Seed Production of Tall Fescue in Isolation from Foreign Pollen Sources1
Authors: Wofford D. S. , Frakes R. V. , Chilcote D. O.
Published: July 2010

The objectives of this study were to investigate the feasibility of using a detached culm technique for seed production of tall fescue (Festuca arundinacea Schreb.), and to evaluate the effects of genotype, culm length, stage of floral development, and growth medium on total seed production, 100‐seed weight, and percent germination. Genotype, stage of floral development, culm length, genotype ✕ stage of floral development, and genotype ✕ culm length interactions were significant sources of variation for total seed yield. The long culm length, and fully‐emerged panicle treatments gave higher seed yields than the short culm length and partially‐emerged panicle treatments, respectively. The highest 100‐seed weight was observed for the fully‐emerged panicle, long culm length, and nutrient growth medium combination. There were no major influences on percent germination attributable to culm length, stage of floral development, or growth medium. All genotypes produced adequate seed yields (range of 0.03 to 0.05 g/two panicle sample) with percent germination means ranging from 89 to 98%. The detached culm technique using long culm lengths and fully‐emerged panicles should be useful in tall fescue breeding programs.
Recurrent Selection Within a Population from an Interspecific Peanut Cross1
Authors: Guok H. P. , Wynne J. C. , Stalker H. T.
Published: July 2010

A transfer of genes from closely related species can be useful to improve commercial crop cultivars. The objectives of this study were to evaluate three cycles of selection for yield and to determine the potential of future progress of selection in a peanut (Arachis hypogaea L.) (2n = 40) ✕ A. cardenasii Krap. et Greg. nom. nud. (In = 20) population. Resistance to late leafspot [Cercosporidium personatum (Berk, and Curt.) Deighton] was measured for selected families. Ten families selected for high fruit yield and large fruit size from the segregates of the original cross were randomly intermated to form the initial population. After two cycles of recurrent selection using S1 testing, response to selection was evaluated by comparing the individual parents of the three cycles (C1, C2, and C3) in four environments during 1982 and 1983. Two cycles of selection resulted in an increase in fruit yield of 210 ± 70 kg ha−1 per cycle. Seed weight, meat content (proportion of total seed weight to total fruit weight in %), and extra large kernels (% seeds that are retained on a 0.85‐ ✕ 2.54‐cm screen) increased significantly, while fruit length and other kernels (% seeds that pass through a 0.60‐ ✕ 2.54‐cm slotted screen) decreased significantly over the two cycles of selection. Little variability was found among the lines after the second cycle. Genetic variability for resistance to late leafspot existed among the parents of the three cycles. The results indicate that the diploid species of Arachis contain genes that can be utilized to improve yield as well as other traits such as disease resistance of the cultivated peanut.
Genetic Variation and Selection Response for Oil Composition in Corn1
Authors: Pamin K. , Compton W. A. , Walker C. E. , Alexander D. E.
Published: July 2010

Our objectives were to study genetic variation and realized response to selection for oil quantity and quality. Information on genetic variation in broad based corn (Zeam mays L.) population is needed for decisions about breeding methods to be used for oil enhancement in such populations. Quality measures are important for determining correlated responses to selection for high oil. Previous estimates have generally been based on generation means of narrow based populations. Genetic parameters of oil quantity and composition were estimated by analysis of 89 interpopulation full‐sib families and their S1 line parents from ‘Nebraska B’ and ‘Nebraska Krugp’ populations. Percent oil was determined using Nuclear Magnetic Resonance spectroscopy. Fatty acid proportions were determined using gas‐liquid chromatographic analysis. Results revealed that significant genetic variation exists for both fatty acid composition and percent oil. Negative genetic correlation(r = −0.96) was found between oleic and linoleic acids, as expected. Percent oil was positively correlated with oleic (r = 0.51) but negatively correlated with linoleic (r = −0.48), suggesting a potential correlated response from selection of lowered quality with increased quantity of oil. A cycle of selection was completed and response to selection measured for three separate selection criteria (linoleic acid, total unsaturated fatty acids, and percent oil). Response to selection indicated that significant increases were obtained for each criterion. Both S1 line per se and reciprocal full‐sib selection were effective, however linoleic acid was increased significantly more by the S1 per se method. Our data indicate that oil quantity and quality can be changed by recurrent selection. It also appears that by careful monitoring of fatty acid proportions, oil quantity can be increased without lowering oil quality, at least for a few cycles.
Rates of Sucrose Release from Opened Seed Coats of Soybean as Affected by Genotypes: Relation with Rate of Seed Development1
Authors: Hanson W. D.
Published: July 2010

Six soybean [Glycine max (L.) Merr.] genotypes with small and six genotypes with large petiole diameters were selected from a broadbase population and used in a greenhouse study to establish sucrose release rates (SRR) from opened seed coats, adjusted for phloem exudate, and to relate SRR found among genotypes with their embryo dry matter accumulation rates (DMAR). Aspects of control for seedsink development were investigated. Sucrose exudate from cut pod walls was about 0.09 mg h−1. The SRR into EDTA were maintained for 4 h and decreased about 60% when plants were moved from light to dark. The SRR were similar with sorbitol concentrations of 0.2 to 0.8 M in the collection media and decreased 39% with 1.2 M sorbitol. The SRR per seed‐coat cup into 20 mM EDTA media were independent of cup area, while with 0.2 M sorbitol and 2.5 mM EDTA the rates were proportional to cup area. The 0.2 M sorbitol media was selected to measure SRR. With appropriate adjustments, SRR gave realistic DMAR. Significant differences for SRR were found among genotypes. The SRR per m2 was not associated with cup area or with total seed‐coat area, but was associated with petiole diameter (presumed transport capacity). Highly significant differences for DMAR were found among genotypes, but DMAR was not associated with SRR or with petiole diameter. A seed‐coat component measured as SRR, though differing among genotypes, did not reflect a measure of control for seed‐sink development. The DMAR differences among genotypes depended upon the integrated (source‐sink) system.
Effect of Benomyl Fungicide and Irrigation on Soybean Seed Yield and Yield Components1
Authors: Heatherly L. G. , Sciumbato G. L.
Published: July 2010

Soybean [Glycine max (L.) Merr.] producers are often faced with the dilemna of using expensive inputs with little or no assurance of an economic return. In order for these inputs to be feasible, a resonable expectation of success as measured in either increased quality or quantity of seed yield is required. One such production input that has gained increased attention is the use of foliar‐applied fungicides. An experiments using ‘Centenniala’ and ‘Tracy‐M’ soybeans was planted in the field on 15 May 1981 and 9 May 1983 on Sharkey clay (Vectic Haplaquept, very‐fine, montmorillonitic,thermic) Stoneville, MS, to determine the effect of benomyl [methyl 1‐(butylcarbamoyl‐2‐benzimidazolecarbamate] fungicide on seed yield of irrigated and nonirrigated soybeans. Irrigation treatments were nonirrigated (NI), and irrigation started at beginning of bloom(R1) and continued whenever soil water potential (SWP) at the 30 cm (T30) and 60 cm depths (T60) dropped to between −50 and −100 kPa. Irrigation was continued through the full‐seed stage (R6) in both T30 and T60. Two irrigation methods, furrow and overhead, were used. The fungicide was sprayed onto the foliage in equal amounts (0.28 kg a.i. ha−1) at Stages R3 and RS. Significant yield increases of 194 kg ha−1 in 1981 (P < 0.10) and 145 kg ha−1 in 1983 (P < 0.05) resulted from applying the fungicide to the most frequently watered treatment (T30). Use of the fungicide did not significantly affect yield in the less‐watered treatment (T60) or the nonirrigated treatment. Type of irrigation had no significant effect on yield response to fungicide. Yield increases resulting from optimum (T30) irrigation were large (> 1500k g ha−1) and significant in both years, and most of the increase was attributable to increased number of seed. The yield increase that was obtained from the benomyl‐treated T30 treatment was the result of about equal percentage increases in both seed weight and number of seed. These results indicate that benomyl foliar fungicide should be used only on those soybeans that will receive adequate water throughout reproductive development.