bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Eleven Thermal Unit Methods for Predicting Soybean Development1
Authors: Major D. J. , Johnson D. R. , Luedders V. D.
Published: July 2010

Dates of emergence, flowering, beginning pod fill, termination of flowering, and physiological maturity were recorded for two soybean [Glycine max (L.) Merr.] cultivars from each of the maturity groups I to V. The cultivars were planted on five dates at three Missouri locations in 1971, 1972, and 1973, and at weekly intervals at Columbia, Mo., in 1972 and 1973. Daily maximum and minimum temperatures were used to calculate five thermal unit methods with no base temperature subtracted, four methods with a base temperature subtracted, and two methods using quadratic formulas.

Thermal units with a base temperature subtracted, including the “growing degree day method” used by the corn industry, and thermal units using quadratic formulas were the best for predicting flowering. The number of thermal units was not better than calendar days for predicting post‐flowering development. Prediction of flowering was more accurate for early cultivars than for late cultivars, suggesting that another factor (probably day‐length) also influenced flowering and had its greatest effect on the later maturing cultivars.
Effect of Plant Spacing on Phenological Development of Early and Midseason Corn Hybrids in a Semiarid Region1
Authors: Alessi J. , Power J. F.
Published: July 2010

Within recent years, early maturing hybrids (Zea mays L.) (less than 70 days from seeding to silking) have become commercially available. This study at Mandan, N. Dak. was conducted to evaluate phenological differences between early and midseason maturing hybrids under semiarid conditions. Hybrids with 68 and 85‐day relative maturity were grown at plant populations of 20, 30, 40, 60, and 74 thousand plants/ha in 50 and 100‐cm spaced rows for 3 years. The 20, 40, and 74 thousand‐plant populations were sampled at intervals of 2 weeks in 1968 and 1969 and 3 weeks in 1970 to measure phenological development of leaf area and weights of stalks, leaves, and ears.

Leaf area index during midseason was generally highest for the highest population and for the later maturing hybrids. Likewise dry weights of leaves and stalks, but not necessarily of ears, were usually highest for the 85‐day hybrid and for the higher populations. Particularly in drier years the 68‐day hybrid silked I to 2 weeks earlier than the 85‐day hybrid, providing more time before late summer drought or frost for grain filling. Treatments that resulted in less than about a 7‐week growing period after silking generally produced immature grain. Correlations between leaf area duration and total plant and grain yields were positive when water stress was not severe, but negative when water stress was severe. Higher populations fixed the greatest percentage of solar energy, as indicated by dry matter production. Row spacing generally had little or no effect upon the development and yield of the plant parts measured for either hybrid.

Results indicate that early maturing hybrids are generally adapted to semiarid agriculture.
Inheritance of a Chlorotic Seedling Trait that Affects Zygote Survival in Diploid Alfalfa1
Authors: Buss G. R. , Barnes D. K.
Published: July 2010

Two independent genes were shown to control inheritance of yellow and white seedlings in diploid alfalfa (Medicago sativa L.). The dominant allele of the Gc‐gc locus was epistatic to either allele of the Yc‐yc locus and produced normal green seedlings. The gcgc Yc genotypes produced yellow seedlings; the double homozygous recessive (gcgc ycyc) genotype produced white seedlings. All sells and crosses of Gcgc heterozygotes produced families with fewer than expected numbers of chlorotic seedlings. Because normal frequencies of Gcgc heterozygotes were observed among green F1 plants, we concluded that mortality of the chlorotic genotypes caused the deficiencies. Significant differences in frequency of chlorotic seedlings occurred between several Gcgc YcYc ✕ Gcgc Ycyc crosses. We postulated that the differences were caused by epistatic interaction with partially lethal genes at other loci. This supports the prediction by Busbice that such genes do occur and that they may be responsible for the rapid decline in seed yield observed on inbreeding alfalfa.
Anatomical Responses of ‘Merion’ Kentucky Bluegrass and ‘Pennlawn’ Red Fescue at Reduced Light Intensities1
Authors: Wilkinson J. F. , Beard J. B.
Published: July 2010

The objectives were to characterize the anatomical responses of Kentucky bluegrass and red fescue to reduced light intensities. Kentucky bluegrass (Poa pratensis L. ‘Merion’) and red fescue (Festuca rubra L. ‘Pennlawn’) were grown in separate growth chambers at light intensities of 2.7, 10.8. and 43 klux. Light quality, soil moisture, and soil temperature were standardized among chambers. Anatomical studies were conducted on the youngest, fully expanded leaf blade.

Merion displayed a decrease in cuticle thickness and vascular and support tissues under reduced light intensities, whereas Pennlawn did not. Stomata density of both species decreased under reduced light. Stomata pore length of both species did not vary with light intensity.

The number of chloroplasts/cross sectional unit area decreased with reduced light intensity for both species. Merion had increased thylakoid and grana stack development within individual chloroplasts at reduced light intensities, whereas Pennlawn chloroplast ultrastructure remained unchanged.

Shade adaptation of Pennlawn may be related to more developed cuticle, vascular, and support tissue and to chloroplast ultrastructure. Stomata and chloroplast density responses of the two species to reduced light intensity were similar and could not be associated with the ability of Pennlawn to provide a more desirable turf in the shade than Merion.
Performance of Genetically Comparable Diploid and Tetraploid Alfalfa: Agronomic and Physiological Parameters1
Authors: Dunbier M. W. , Eskew D. L. , Bingham E. T. , Schrader L. E.
Published: July 2010

Diploid and tetraploid alfalfa (Medicago sativa L. sensu lato) populations were produced sexually utilizing numerically unreduced gametes and parthenogenetically developed haploids of 4x‐2x crosses. The advantage of the procedure over colchicine doubling is that genetically comparable populations, rather than individuals, at different ploidy levels can be studied. Additionally, both ploidy levels were in the same cytoplasm. Populations were grown in field plots to determine dry matter (DM) production and in a space‐planted nursery for analysis of the following characters; percentage total nonstructural carbohydrates (TNC), percentage total nitrogen (N), fresh weight/trifoliolate leaf, glucose‐6‐phosphate dehydrogenase activity (G6PDA), deoxyribonucleic acid (DNA) and water soluble protein concentration (WSP).

As expected, concentrations of DNA, WSP, and N were basically the same in diploids (D) and tetraploids (T). T/D ratio was 2.10 for DM yield, 2.05 for fresh wt/trifoliolate, 2.09 for DNA/trifoliolate, and 1.78 for G6PDA/trifoliolate, indicating these characters were strongly influenced by ploidy. G6PDA/trifoliolate was higher in tetraploids but significantly higher in only one D‐T comparison, indicating that activity of this enzyme was influenced by factors in addition to ploidy. Phenotypic differences are thus demonstrated to be the result of a complex interaction between increasing gene dosage (polyploidy) and genetic regulation.
A Test of the Duncan Model of Photosynthesis in Plant Communities1
Authors: Keener M. E. , McCree K. J.
Published: July 2010

The Duncan model was tested on a rice (Oryza sativa L.) crop growing in an environmental chamber, where all the required input data could be collected. The data included; incident light environment, leaf optical properties and photosynthetic rates, and canopy architecture. Canopy extinction coefficients and canopy photosynthetic rates calculated with the model agreed with the measured values, within the estimated accuracy of the tests (± 20%).
Cytology of Some Apomictic Paspalum Species1
Authors: Burson Byron L.
Published: July 2010

Paspalum almum Chase had a chromosome number of 2n=4x=24. The number for P. brunneum Trin., P. coryphaeum Trin., P. haumanii Parodi, and P. rufum Nees. was 2n−4x−40; P. proliferum Arech. was 2n=6x−60. This is the first report of the chromosome number and cytological behavior for P. brunneum. The chromosome numbers found in P. coryphaeum, P. haumanii, P. rufum, and P. proliferum were different from any previously reported for these species. During metaphase I, the chromosomes in P. almum, P. brunneum, P. coryphaeum, P. haumanii, and P. rufum paired primarily as bivalents with occasional quadrivalents and a limited number of univalents were observed. P. almum, previously considered a diploid, had as many as five quadrivalents, which indicates it is an autotetraploid. Meiosis in P. proliferum was irregular with pairing primarily as 50 univalents and 5 bivalents at metaphase I and numerous laggards and micronuclei were observed.

Megasporogenesis and embryo sac development of all six species showed aposporous apomixis followed by pseudogamy. This limits their use in an interspecific hybridization program. The possible origin of the new chromosome races, their relationships to other reported chromosome races of the same species, the role of apomixis in their evolution, and changes in the basic chromosome number of the genus were discussed.
Leaf Vein Frequency in Barley1
Authors: Hanson James C. , Rasmusson D. C.
Published: July 2010

A survey of leaf vein frequency (LVF) in 210 varieties of barley (Hordeum vulgare L.) revealed approximately two‐fold differences (2.4 to 4.5 veins/nun) among varieties. Highly significant varietal differences were observed in four different environments, but the environment ✕ variety interactions were significant. Varieties differed significantly in number of major veins, number of minor veins, and in ratio of minor to major veins. In each variety, number of minor veins was more than double the number of major veins.

The mean realized heritability for LVF in five populations in the F2 generation was 0.20 ± 0.04. In the F3 generations, mean realized heritability was 0.45 ± 0.07 for four populations. In both the F2 and F3 generations, the selection response was asymmetrical with more gain for selection for high than for low LVF. There was little evidence of association between LVF and specific leaf weight, but LVF was negatively associated with leaf length, leaf area, and leaf dry weight.
Glandless Cotton: Susceptibility to Lygus hesperus Knight1
Authors: Tingey Ward M. , Leigh Thomas F. , Hyer Angus H.
Published: July 2010

Field and laboratory methods were used to study population growth and feeding damage of Lygus hesperus Knight (a major cotton pest) on isogenic lines of glandless and glanded cotton, Gossypium spp. In no‐choice field cages, a glandless genotype had 2.5 times more L. hesperus and 57% fewer bolls compared to its glanded equivalent. The larger lygus bug population on glandless cotton was attributed to a two‐fold increase in growth rate and survival of nymphs. Thus glandless cotton may require more intensive control of L. hesperus than normal glanded cotton, to minimize losses in yield and quality.
Heritability of Groat‐Protein Percentage of Hexaploid Oats1
Authors: Frey K. J.
Published: July 2010

Standard‐unit and realized heritabilities were computed for groat‐protein percentage using data collected from F2 or F6 oat (Avena spp.) plants from intra and interspecific hexaploid oat crosses and their progenies grown in nonreplicated hills (25 to 30 plants/hill). Nitrogen percentages were determined on groat samples by the Kjeldahl procedure. The pooled standard‐unit heritability percentage for inter and intraspecific crosses was 43.0%. In one experiment, the realized and expected gains from selection were 1.0 and 1.2% groat‐protein, respectively.
Heading Dates in Six Avena sativa L. × A. sterilis L. Crosses1
Authors: Lyrene P. M. , Shands H. L.
Published: July 2010

Heading dates were studied in six Avena sativa L. ×A. sterilis L. crosses. The A. sterilis parents (CI 8077 and PI 295932) were later than the five A. sativa parents by 2 to 30 days. F1 plants and many F3 lines were earlier than the A. sativa parents. The earliness of interspecific progenies appeared to result from earliness factors inherited from A. sterilis parents; factors which were not expressed in A. sterilis due to a vernalization requirement. The vernalization requirement was absent in F1 progenies, apparently because of genes from A. sativa.

Successful selection for early maturity in A. sativa × A. sterilis requires elimination of progeny with a vernal. ization requirement. Progeny tests of F3 lines indicated that earliness was easy to stabilize by selection.
Variability of In Vitro Dry Matter Digestion in Diallel and Polycross Progenies of Intermediate Wheatgrass1
Authors: Thaden Ronald T. , Ross James G. , Akyurek Ahmet
Published: July 2010

Variation in height, seed set, and in vitro dry matter digestion (IVDMD) within a diallel and a polycross nursery of intermediate wheatgrass, Agropyron intermedium (Host) Beauv., were studied. Significant differences in IVDMD of whole tillers occurred among diallel crosses, but did not occur among polycrosses, indicating greater precision of measurement in the diallel. Differences among diallel crosses for plant fraction (flag leaf, peduncle, and spike) IVDMD were also significant. Digestibility of the peduncle contributed the greatest effect to whole tiller digestibility. It was concluded, however, that digestibility of the upper part of the plant could not be used as an indicator of whole tiller digestibility. Correlations of height, seed weight for 10 heads, and seed set with IVDMD were low. Significant general combining ability, specific combining ability, and reciprocal effects were found for each character. General combining ability estimates were highest in one parent for almost all characters investigated. Since additive genetic effects were predominant, the variability within the diallel cross population should allow success in selection of a superior cultivar for the characters studied
Groat Protein Percentage in Avena sativa × A. sterilis Crosses in Early Generation1
Authors: Lyrene P. M. , Shands H. L.
Published: July 2010

A total of 600 F3 lines from six Arena sativa L. × A. sterilis L. crosses were screened for groat protein percentage in a test having two replications. Twelve lines having exceptionally high groat protein percentage, and nine with very low protein, were later compared with their A. sativa and A. sterilis parents in extensive progeny tests.

Three of the high‐protein lines equaled their A. sterilis parents in groat protein percentage. One low‐protein line was significantly below its A. sativa parent in groat protein percentage; two others were not significantly different from the A. sativa parent. Of four A. sativa cultivars crossed with A. sterilis CI 8077, the one having highest groat protein percentage gave the highest‐protein progenies, while the one with lowest gave the lowestprotein progenies.

It appears easy to recapture the high groat protein percentage of A. sterilis in A. sativa × A. sterills progenies. However, the most promising lines from these crosses were not those that were highest in protein, since the highest‐protein lines tended to have undesirable wildoat traits. The most promising lines were intermediate in groat protein percentage between their A. sativa and A. sterilis parents, and had the high grain yields and favorable agronomic qualities of A. sativa.
Diallel Analysis of Duration and Rate of Grain Filling of Seven Inbred Lines of Corn1
Authors: Cross H. Z.
Published: July 2010

A diallel cross of seven inbred lines of corn (Zea mays L.) was examined for duration of the grain‐filling period, rate of fill, and associated agronomi characters to determine the practicability of selection for these traits. The length of the grain‐filling period and the rate of grain filling differed among hybrids and between years, but interactions between years and hybrids were not detected. Hybrids did not differ for duration of the lag phase of the grain‐filling period.

The general combining ability effects for duration and rate of grain filling were larger than specific combining ability effects which snggested that simple selection techniques should be effective in changing these characters within the material studied. A phenotypic correlation of 0.81 was found between duration of the grain‐filling period and grain yield, while the correlation between rate of fill and grain yield was nonsignificant.

Although the association between duration of the filling period and ear moisture content at harvest was high (r = 0.82), there was some evidence that it might be possible to shorten the vegetative period without sacrificing yield.
Gardener's Grid System and Plant Selection Efficiency in Cotton1
Authors: Verhalen Laval M. , Baker Jerry L. , McNew Ronald W.
Published: July 2010

Gardner's grid system was investigated relative to plant selection efficiency within an upland cotton (Gossypium hirsutum L.) cultivar known to be genetically variable for fiber length. A relatively small area, planted to ‘Westburn,’ was arbitrarily subdivided into three equalsized grids prior to harvest. One hundred individual plant selections were made in each grid on the basis of boll type and apparent yield. Then, based on fiber length, the upper and lower 10% of the plants were selected within each grid and over the area as a whole. Progeny row performances of the selected plants were obtained for fiber length in two environments. Phenotypic variances, selection differentials, selection responses, and heritabilities under the two procedures (grids vs. no grids) were then compared at the 5 and 10% levels of selection intensity.

In this experiment, the grid method reduced phenotypic variation by 22%; lowered selection differentials by 11 to 14%; produced 20 to 35% greater selection responses; and estimated “realized” (i.e., narrow‐sense) heritabilities 41 to 52% higher than did the identical selection procedure without grids.

Based on the results of this and other experiments and on the logic underlying the method, use of grids should increase the effectiveness of plant selection regardless of crop, quantitative trait, or breeding method employed, provided there is genetic and environmental variability in the material. The method appears particularly useful when the breeder attempts to discriminate among small, inconsistent differences (i.e., when heritability is low). Use of the technique was considered for areas larger or smaller than those utilized herein, as well as for selection among progeny rows.
Effect of Soil pH and Plant Genotype on Element Concentration and Uptake by Alfalfa1
Authors: Buss G. R. , Lutz J. A. , Hawkins G. W.
Published: July 2010

Information on genetic variability for nutrient uptake by alfalfa (Medicago sativa L.) is needed to determine the feasibility of selecting for improved mineral composition of the forage, resistance to soil mineral deficiencies or toxicities, or more efficient fertilizer utilization. Plant tissues of three selected clones grown at three soll pH levels in Tatum soil were analyzed for concentration of P, K, Ca, Mg, Mn, Fe, B, Cu, Zn, A1, Sr, and Na. Significant differences in element concentration in the plants were shown for these clones for 11 elements, for soil pH effects for seven elements, and for clone ✕ p.H effects for seven elements. Differences among clones mdicated that genetic variation exists, but success in selection for increased or decreased concentration of those elements in the forage depends on the heritability of uptake for each element. The significant clone ✕ pH interaction indicates that caution must be exercised to be sure that selection is carried out under conditions similar to those in which the crop is to be grown.
Effects of Night Breaks on Floral Initiation and Development in Saccharum1
Authors: Julien M. H. R. , Soopramanien G. C.
Published: July 2010

The effects of night breaks with light of different spectral compostion applied at various stages of floral development, starting before induction up to inflorescence emergence, were studied in Saccharum spontaneum L. and S. robustum L. clones. Night interruption treatments with incandescent light decreased % inflorescence emergence and delayed flowering when applied at all stages of development in S. spontaneum L. In both S. robustum L. and S. spontaneum L. clones, the degree of inhibition of flowering depended on the stages of development at which the night interruptions were applied; the early stages of differentiation of the inflorescence (initiation of inflorescence axis and branch primorda) were found to be the most sensitive. The spectral composition of the light used was also important; red, orange, and green light were generally the most inhibitory to inflorescence development, while blue, far‐red, and ultraviolet were not effective and similar to darkness. Attempts to reverse the inhibitory effect of red light by far‐red failed. Night breaks also had their maximum inhibitory effects when applied towards the end of the dark period and had minimum effects when applied at the middle of the dark period.
Percentage of Tissue Types in Tropical and Temperate Grass Leaf Blades and Degradation of Tissues by Rumen Microorganisms1
Authors: Akin Danny E. , Burdick Donald
Published: July 2010

Tropical and temperate grasses were investigated for the amounts and the relative ease of degradation of tis. sue types in leaf blades to relate microanatomy to digestibility. Leaf blades of five tropical and six temperate grasses, grown in different locations but harvested at four weeks of summer regrowth, were examined by light microscopy for cross sectional percentages of total vascular tissue, lignified vascular tissue, phloem, epidermis, sclerenchyma, and mesophyll. Leaf blades of four of the tropical grasses and the six temperate species were evaluated for in vitro degradation of tissue types by tureen microorganisms using scanning electron microscopy.

Bermudagrasses, Cynodon dactylon (L.) Pers. possessed about 36% total vascular tissue with 27% of the leaf blade section composed of parenchymal bundle sheaths; totals of vascular tissue for the other grasses were lower, ranging from 11.0% to 22.1%. The parenchymal bundle sheaths, which occupied > 50% of the area for total vascular tissue in tropical grasses but < 50% in all temperate species, were more rigid and usually digested at a slower rate in the tropical grasses. In all grasses, mesophyll and phloem were degraded before the other tissues but were degraded more rapidly in the temperate species. Leaf blades of tropical grasses had an average of 22 percentage units less of the easily digested tissue (mesophyll and phloem) and 25 percentage units more of the slowly digested tissues (epidermis and parenchymal bundle sheath) than temperate species. Except for the bermudagrasses, the percentages of lignified tissue were higher in temperate species. Differences in the ease of degradation were apparent between similar tissues of different grass types, species, and cultivars. Results indicated that leaf blade microanatomy and inherent characteristics of cell walls affect digestibility by rumen microorganisms.
Plant Composition and In Vitro Digestibility in Bromegrass Genotypes1
Authors: Bhat A. N. , Christie B. R.
Published: July 2010

Nineteen genotypes of bromegrass (Bromus inermis Leyss), 10 of high in vitro digestibility (IVD) and nine of low, were harvested at three stages of maturity in the field and two stages in the growth room. “Stems” (including leaf sheaths and heads) were divided into top and bottom portions, dried, ground, and analyzed for acid detergent fiber (ADF), lignin, cellulose, silica, total cell wall constitutents (CWC), and IVD. The IVD declined at the rate of one percentage unit/day from head emergence to headed stage and 0.5 percentage unit/day from headed stage to anthesis under field conditions. The top portion was approximately 4 to 8 units more digestible than the bottom. All cell wall components increased from head emergence until headed. From the headed stage to anthesis, lignin and silica increased, whereas, ADF, cellulose, and CWC declined. All cell wall components except silica were higher in the bottom portion than in the top. All cell wall components showed significant negative correlations with IVD, but lignin had the highest phenotypic and genotypic correlation coefficients followed by ADF. Lignin and ADF were positively correlated. Lignin content of the plant could be used as a criterion for selection for IVD.
Inheritance of Brittle Stems in Safflower1
Authors: Temple S. R. , Knowles P. F.
Published: July 2010

A brittle‐stemmed strain of safflower (Carthamus tinetorius L.) was crossed to 10 genetic types with normal stems. Data showed that the inheritance of brittle stems is determined by a single recessive allele, assigned the symbol br. Brittle stems were not closely linked with the single‐locus recessive characters: closed floret‐A, closed floret‐C, pigmentless, thin hulls, appressed branching, decumbent branches, crinkled foliage, light‐green foliage, and black foliage.
Influence of Potassium Stress on Growth, Stomatal Behavior, and CO2 Assimilation in Corn1
Authors: Koch D. W. , Estes G. O.
Published: July 2010

Crop potassium stress could be more easily diagnosed if the sequential plant responses to K deficiency were known. A greenhouse study was conducted to determine plant responses to K stress at several stages of development of corn (Zea mays L.). Potassium was supplied at 0.50 mM (Kl) and 3.0 mM (K2) of nutrient solution. Leaf stomatal resistance (rs) and CO2 uptake of the youngest fully expanded intact leaves were measured 30, 47, and 62 days after emergence. Potassium concentration of individual leaves of K‐adequate (K2) plants declined progressively with maturity; however, leaves of K‐stressed (Kl) plants declined to a much greater extent. High t, was associated with low K concentration of leaves at all three measurement dates. Stomatal frequency did not vary significantly with K treatment. The increase in rs did not result in reduced CO2 assimilation rates or plant dry matter weights at 30 or 47 days. At 62 days, r6 for leaves of K‐stressed plants was nearly 30% higher than for K‐adequate plants. Leaf area/plant was not significantly different; however, CO2 uptake was nearly 70% lower for K‐stressed plants at 62 days.

There was a corresponding 30% reduction in dry matter accumulation for K‐stressed plants. High leaf K levels were associated with high specific leaf weights (SLW). Both high rs and low SLW in low‐K plants occurred before visible K deficiency was evident and at a concentration above the reported critical concentration. Potassium deficiency symptoms were not evident at any time during the experiment on recently expanded leaves of Kstressed plants. Increased rs and decreased SLW were early indicators of developing K stress and may be useful in diagnosis of K deficiency
Variation in Susceptibility to Manganese Toxicity in 30 Soybean Genotypes1
Authors: Carter O. G. , Rose I. A. , Reading P. F.
Published: July 2010

Thirty soybean (Glycine max (L.) Merr.) genotypes showed a wide range in tolerance to Mn toxicity when grown in nutrient solutions containing from 0.1 to 20 ppm Mn. The varieties ‘Hill’, ‘Dare’, ‘Davis’, ‘Delmar’, and ‘Bragg’ were very sensitive and ‘Hawkeye’, ‘Custer’, ‘Lee’ and ‘Amredo’ very tolerant to Mn toxicity. Field observations showed similar symptoms and varietal differences when soybeans were grown on an acid soil high in available Mn.
Influence of Osmotic Potential on the Growth and Development of Soybean Tissue Cultures1
Authors: Kimball S. L. , Beversdorf W. D. , Bingham E. T.
Published: July 2010

The influence of reduced osmotic potentials on soybean (Glycine max L.) tissue cultures was evaluated. Reduced osmotic potentials were generated by addition of mannitol, sorbitol, glucose, or sucrose to a standard medium. Cells in control callus were comparatively large and about half were elongated or irregularly shaped. As osmotic potential decreased, all cells became smaller and spherical, regardless of which osmoticum was used. The addition of metabolically active or inert osmotica resulted in increased callus production. Maximum callus growth (fresh weight) occurred when the osmotic potential of the culture medium was lowered 8 to 12 bars. Decreasing osmotic potentials by 2 to 20 bars did not increase the frequency of adventitious bud differentiation above the low frequency observed on the standard medium.
Automated Hydrolysis of Nonreducing Sugars and Fructosans from Plant Tissue1
Authors: Wolf D. D. , Ellmore T. L.
Published: July 2010

Analytical procedures for chemical analysis of carbohydrates by measuring reducing power before and after hydrolysis, have been automated once the carbohydrates have been removed from the plant tissue. Sugars and fructosans were removed from forage tissue by hot water treatment. Reducing sugars in an aliquot were assayed by automated procedures without acid hydrolysis. Total water‐soluble carbohydrates were measured with automated acid hydrolysis of the same aliquot. Nonreducing carbohydrates were calculated as the difference between total water‐soluble carbohydrates and reducing sugars. Sucrose and fructosan were completely hydrolyzed during the 2 min. exposure to 0.2 N acid at 95 C that were the conditions in automated hydrolysis. However, starch, if present in the water solution, was not broken down by the automated hydrolysis procedure due to low acid concentration and short duration of exposure to heat.

Automated procedures increased lab efficiency, reduced routine errors, and eliminated filtration, pipetting, and manual dilution often required by most procedures.
Heterosis and Combining Ability Estimates for Air Pollution Damage, Primarily Ozone, in Maryland Tobacco1
Authors: Huang Tsun‐shih R. , Aycock M. K. , Mulchi C. L.
Published: July 2010

Estimates of heterosis and general and specific combining ability for air pollution damage, primarily ozone, on Maryland tobacco (Nicotiana tabacum L.) were obtained under greenhouse and field conditions. A diallel set of crosses (excluding reciprocals) among seven Maryland tobacco cultivars was used for the greenhouse fumigation‐chamber study. Tobacco plants, aged 10 to 12 weeks, were exposed to ozone at 50 pphm for 4 hours in a fumigation chamber. Significant differences in ozone susceptibility were observed among the seven parents and their 21 F1 hybrids. The heterotic response of the hybrids was toward greater ozone susceptibility. Diallel analysis of variance of the F1 hybrid generation indicated a large amount of variance due to general combining ability and a small amount due to specific combining ability.

An additional cultivar was added to the diallel set of crosses for the field study and was grown at three locations. Air pollution data (commonly referred to as weather fleck under field conditions) for the eight parents and 28 F1 hybrids were similar to the data obtained in the greenhouse. However, heterosis for weather fleck was small and not significant in the combined analysis over locations. Variability for general combining ability was significant for the three locations and in the combined analysis over locations, and specific combining ability was significant at one location only. These estimates suggest a predominance of additive genetic variance in the population for weather fleck.
Polyembryony in Kentucky Bluegrass as a Source of Variation in Disease Reaction1
Authors: Ostazeski S. A. , Poole T. E. , Wilton A. C. , Murray J. J.
Published: July 2010

Twin‐sets and a few triplet‐sets from ‘Belturf,’ ‘Fylking,’ and ‘Cougar’ Kentucky bluegrass (Poa pratensis L.) were inoculated with Drechslera triseptata (Drechs.) Subram. Jain, Erysiphe graminis DC. ex Merat, or both. Plants were identified that differed from their parent cultivar in reaction to each pathogen. When inoculated with D. triseptata, 10 plants from 32 Belturf sets were more resistant than the cultivar. In 27 Fylking sets, 2 plants were more resistant and 12 more susceptible than the cultivar. When inoculated with E. graminis, 8 plants in 34 Belturf sets were more resistant than the cultivar. In 30 Fylking sets, 1 plant was more resistant and 4 more susceptible than the cultivar. In 26 Cougar sets, 4 plants were more susceptible than the cultivar. Populations of polyembryonic seedlings appear to be valuable sources of disease resistance in Kentucky bluegrass.
Protein Composition in Developing Groats of an Avena sativa. L. Cultivar and an A. sativa ✕ Avena sterilis L. Selection1
Authors: Ohm H. W. , Peterson David M.
Published: July 2010

‘Noble’, CI9194, an Avena sativa L. cultivar with a medium percentage of groat protein, and Purdue 65256C4‐38, a selection from a cross of A. sativa ✕ Avena sterilis L. with a high percentage of groat protein, were grown in the field in 1972 and 1973 at Lafayette, Ind. Primary groats in the top half of panicles were harvested at 2 or 3‐day intervals from anthesis until several days after maturity. Groat dry weight, percentage of protein, and protein solubility fractions were measured.

Increase in dry weight ceased at about 22 days after flowering, whereas percentage of protein increased slightly until about 28 days after flowering. The high‐protein cultivar maintained a higher level of protein throughout groat development. Globulins and glutelins comprised the major portion of protein in both cultivars, but levels of these two fractions were higher in the highprotein cultivar. Albumins and prolamins increased during maturation of the groats, but at maturity, each comprised less than 20% of the total protein.
An Unusual Miniature Soybean1
Authors: Kilen T. C.
Published: July 2010

A miniature soybean, Glycine max (L.) Merr., was found in the F2 generation of a three‐way cross that had a wild soybean (Glycine soja Sieb. & Zucc.) as one parent. Miniature plants had small unifoliolate leaves, very short internodes, minute curved rugose trifoliolate leaves, cleistogamous flowers, and an occasional pod with seed. Cotyledons remained green until maturity and were larger than any other leaf on the plant. Mature plants were 2 to 3 cm tall when grown in the field or in the greenhouse during the winter. Segregation in the F2 generation was for normal plants, plants with curved leaves, and miniature plants in a ratio of about 1:2:l. Normal and miniature segregates bred true. Plants with curved leaves segregated for all three types in a 1:2:l ratio. These plants may be used to maintain the miniature character.
Changes in Leaf Area and Specific Leaf Weight of Sugarbeet Leaves during the Growing Season1
Authors: Cole D. F.
Published: July 2010

The purpose of this investigation was to observe the rate of leaf accretion and changes in specific leaf weight (SLW) of sugarbeet leaves initiated during the latter portion of the growing season. Leaves increased in area at a rapid rate during the first 14 days after leaf emergence. Specific leaf weight changed as the leaves expanded in area. Diurnal changes in SLW may be related to changes in temperature incoming radiation, or translocation rates. Leaves initiated late in the growing season were smaller and had a higher SLW than leaves initiated earlier in the growing season.
Absorption, Distribution, and Form of Ca in Relation to Ca Deficiency (Tip Burn) of Sugarbeets1
Authors: Mostafa M. A. E. , Ulrich A.
Published: July 2010

Sugarbeet plants (Beta vulgaris L.) were grown in the greenhouse in nutrient solutions containing 0.33 and 5.0 meq Ca/liter. Carrier‐free 45Ca was added at transplanting to nutrient solutions of a set of sugarbeet pots and the rest were left untreated. Two weeks later, the 45Catreated pots were harvested and another set was treated with 45Ca. This process was repeated for three more harvests with addition of 45Ca at 2, 4, and 6 weeks and harvesting, respectively, at 4, 6, and 8 weeks after transplanting. All in all, there were four 45Ca additions and four harvests. At each harvest, the various parts of the plant were assayed for 45Ca that was associated with Ca soluble hi 80% alcohol, as chloride and nitrate, in water as salts of organic acids, in 1 N NaCI as pectate, in 2% CH3COOH as di‐ and triphosphate, in 0.6 N HCI as oxalate and insoluble residue.

Symptoms of Ca deficiency were associated with an incomplete uptake of Ca from the nutrient solution, a high rate of Ca consumption by the storage roots, and a failure to translocate sufficient Ca to the tops to support rapid young leaf growth, but were not associated with the formation of an insoluble Ca compound(s). Since 45Ca was detected in various forms in all parts of Cadeficient sugarbeets, the pathway for Ca remained functional even as the symptoms increased in severity.

Calcium phosphate, rather than Ca oxalate, was at a high concentration hi all parts of the Ca‐deficient and Ca‐sufficient plant, except Ca oxalate exceeded Ca phosphate in the mature and old blades of the Ca‐sufficient plant. If Ca immobility inhibits the transport of Ca from older to younger parts, then the formation of Ca phosphate could be a limiting factor under deficiency and not under sufficiency conditions.
Nutritional Stress and Ethylene Evolution by Young Cotton Bolls1
Authors: Guinn Gene
Published: July 2010

Previous results have shown that a nutritional stress increases the rate of young boll abscission from cotton (Gossypium hirsutum L.) plants. Tests were conducted to determine whether a nutritional stress affects the rate of ethylene evolution by 4‐day‐old bolls. Fruiting cotton plants were subjected to conditions that should decrease photosynthesis (dim light, short days), increase respiration (long warm nights), or change the demand for products of photosynthesis (partial boll removal, changing boll load during a growing season).

As little as one day of dim light caused a measurable increase in ethylene. Partial boll removal slightly decreased the effects of subsequent exposure to dim light. Bolls from plants exposed to three consecutive long warm nights produced more ethylene than bolls from control plants. Rate of ethylene evolution by bolls of field‐grown plants increased almost eightfold from June 25, when the boll load was light, to July 30, when the boll load was heavy.

Sugar analyses indicated significant negative correlations between sugar content of bolls and their rate of ethylene evolution.

The results indicate that a nutritional stress increased rates of ethylene evolution by young cotton bolls. This additional ethylene is probably a causal factor in the increased rates of boll abscission that occur when cotton plants are subjected to conditions that promote a nutrltional stress.
Performance of Cytoplasmic Male‐Sterile Cotton Under Natural Crossing in New Mexico1
Authors: Rosales Franklin E. , Davis D. D.
Published: July 2010

Cytoplasmic male‐sterile (Gossypium harknessii Brandg. ✕ Gossypium hirsutum6 L.) lines versus similar malefertile lines of cotton were evaluated for yield and lint percentage under conditions of natural pollination for 2 years at Las Cruces, N.M. Two locations distinguished by their relative distance from a honeybee (Apis mellifera L.) apiary were used each year.

Bee populations appeared to be a major factor in these experiments. Fewer bees were apparently necessary for good pollination of the male‐sterile lines than was previously reported. Eight of the twelve comparisons for yield between steriles and fertiles were statistically significant. The male‐sterile lines produced less seed cotton and lint each year in the field more distant from the bee hives. Near the apiary, the steriles produced significantly more seed cotton and seed than the fertiles. No significant differences were detected for the interactions of sterility ✕ pollinators or of sterility ✕ nectaries for any of the agronomic traits studied, although there were some indications that there was a partial honey bee preference for nectaried plants.

Breeding programs which include improved Cytoplasmic male‐sterile strains and adequate populations of honey bees may provide the means for commercial production of hybrids.
Maternal Effects and Type of Gene Action Conditioning Resistance to Fusarium moniliforme Seedling Blight in Maize1
Authors: Lunsford James N. , Futrell M. C. , Scott Gene E.
Published: July 2010

An F1 diallel cross of eight inbred maize (Zea mays L.) lines (four resistant and four susceptible) and parents were inoculated with Fusarium moniliforme Sheldon to determine maternal influence and gene action conditioning resistance. Reaction to this fungus was influenced by the maternal parent in hybrid combinations. Additive gene action and maternal effects were more important than dominant gene action in the inheritance of resistance to seedling blight caused by F. moniliforme. Female influence could be caused by either maternal tissue in the seed or cytoplasmic factors in the embyro.
More on Modified Ear‐to‐Row Selection in Corn1
Authors: Compton W. A. , Comstock R. E.
Published: July 2010

The prediction equation for modified ear‐to‐row selection has so far only been published for one‐season selection. The objective of this paper is to show the appropriate equation when the cycle includes two growing seasons. The equation was derived by standard processes as shown by Empig et al (1972), and is
Genetic Analysis of Resistance to the Corn Virus Disease Complex1
Authors: Naidu B. , Josephson L. M.
Published: July 2010

Five highly resistant (R) and five highly susceptible (S) inbred lines of corn (Zea mays L.) were evaluated in a diallel set of 45 single crosses to study the inheritance of resistance to the corn virus disease complex. The entries were evaluated under conditions of mechanical inoculation at Knoxville and natural infection at Waverly, Tenn. Evaluations were made prior to flowering and again on fully grown plants.

Highly significant differences for mean severity ratings among genotypes were obtained in all experiments. Correlations between ratings in the two locations and for both times of rating were highly significant for both the inbreds and the hybrids. R ✕ R crosses were highly resistant in all evaluations while S ✕ S crosses were highly susceptible. Mean ratings for R ✕ S crosses were significantly lower than the mean of R ✕ R and S ✕ S crosses and the mean of all crosses indicating partial dominance of resistance. General combining ability (gca) and specific combining ability (sea) mean squares were highly significant in all evaluations but gca mean squares were substantially larger than the sea mean squares. Inbred T232 had the largest negative gca effect with both times of rating, followed in order by Tx601, Ky226, Ga209, and Mo18W. By contrast, inbred CI872 had the largest positive gca effect on susceptibility while inbred T105 had the least at both times of rating.

Vr, Wr graphs and components of variance analyses of the data provided similar results to those with combining ability analysis. Among the resistant inbreds, T232 indicated the most dominant genes for resistance when tested in both locations and with both times of rating while Mo18W indicated the least number. Inbreds Tx601, Ga209, and Ky226 varied in the two locations and time of rating. As many as four major genes for resistance were indicated to be present in the parental inbreds. Hybrids having high resistance are obtainable from crosses involving these resistant inbreds. Since some degree of dominance was indicated, a backcrossing procedure to transfer the resistance factors into elite lines is suggested. Some form of recurrent selection in populations having a degree of resistance also is suggested.

Host reaction and the nature of the genetic variation governing resistance showed that the inbreds used in this study reacted in a similar manner to the virus complex under all conditions of testing. The data also indicate that evaluations for virus resistance can be made prior to flowering and that breeders can make pollinations concurrent with evaluation.
Growth of Vernalized and Nonvernalized Creeping Foxtail1
Authors: Rumburg C. B. , Siemer E. G.
Published: July 2010

Herbage dry matter (HDM) accumulation from artificially vernalized (V) plants of ‘Garrison’ creeping foxtail (Alopecurus arundinacea Poir.) was greater than nonvernalized (NV) plants during 46 days in a growth chamber at 27/4 C (day/night). Ratio of reproductive to total shoots was 0.075 with V and 0.004 with NV. Stems and sheaths contributed about 50 and 28% of final HDM of V and NV, respectively. Shoot number was similar between V and NV at the start, but new shoots of NV developed at nearly three times the rate of V. This difference, though, was offset by a slightly increased leaf weight and nearly doubled sheath and stem weight of V over NV. Leaves/shoot were 2.0 and 1.5 on day 6 for V and NV, respectively. The V treatment retained about 0.5 leaf per shoot advantage until day 46 when the values for both were about 3.4 leaves/shoot. Mean relative growth rates (RGR) derived from quadratic functions of HDM over time for V and NV were not significantly different. However RGR of V was slightly higher than NV during the period from 6 to 13 days while RGR values from 13 to 46 days were similar for both treatments.
Variation in RuDPCase Activity in Barley1
Authors: Frey Nicholas M. , Moss Dale N.
Published: July 2010

Seasonal patterns of ribulose 1,5‐diphosphate carboxylase (RuDPCase), EC4.1.1.39, activity from leaves and awns, specific leaf weight, and total above‐ground dry matter accumulation rate were determined for two barley (Hordeum vulgare L.) genotypes. In general, RuDPCase activity was greatest in young, fully expanded leaves and was lower in each subsequent leaf down the culm. for a given leaf, RuDPCase activity also decreased sharply with increasing age. Specific leaf weight (SLW) did not change with leaf age but upper leaves on a culm had greater specific leaf weights than did lower leaves. The RuDPCase activity in the total plant canopy and in the youngest expanded leaf for both varieties was significantly and positively correlated with the rate of aboveground canopy dry matter accumulation.

Twelve barley cultivars chosen to sample a relatively broad genetic background were grown in two controlled environments and a greenhouse. Genotypes differed significantly in RuDPCase activity (dm2 leaf) −1 and (g dry wt) −1 and in SLW. Only RuDPCase activity (dm2 leaf) −1 and SLW were significantly affected by environment. There were no significant genotype by environment interactions for RuDPCase activity (dm2 leaf) −1, for activity (g dry wt) −1, or for SLW. Heritability estimates using the components of variance method were 0.67, 0.56, and 0.74 for RuDPCase activity (dm2 leaf) −1, for activity (g dry wt)−1, and for SLW, respectively. The correlation coefficients for SLW vs. RuDPCase activity (dm2 leaf) −1 and vs. activity (g dry wt)−1 were 0.83, and 0.06, respectively. It was concluded that RuDPCase activity of barley leaves might be increased in two ways: 1. by selecting for high RuDPCase activity (g dry wt) −1 and 2. by selecting for high SLW.