bluuebunny/crossref_metadata_2025 huggingface dataset:
Soybean Cultivars: Acute Foliar Response to Ozone1
Authors: Tingey David T. , Reinert Richard A. , Carter Hershell B.
Published: July 2010

Fourteen cultivars of soybean [Glycine max (L.) Merr.] from maturity groups 0 through VI were exposed to 30 and 70 pphm ozone for 1.5 hours to determine differences in cultivar sensitivity. Cultivar ‘Hark’ was the most susceptible, whereas ‘Hood’ was the most tolerant to ozone injury. ‘Hawkeye’ was the most sensitive cultivar at 70 pphm and among the least sensitive at 30 pphm, whereas ‘Chippewa 64’ was relatively tolerant at 70 pphm but among the most sensitive at 30 pphm. Ozone symptoms ranged from chlorotic and/or necrotic fleck and pigmented lesions to upper surface bleaching and bifacial necrosis of the leaves.
Resistance Among Some Maize Inbreds and Single Crosses to Fall Armyworm Injury1
Authors: Widstrom N. W. , Wiseman B. R. , McMillian W. W.
Published: July 2010

Analyses of fall armyworm, Spodoptera frugiperda (J. E. Smith), leaf feeding injury data for eight maize, Zea mays L., inbreds and their F1 progeny were made to determine the kind of gene action involved in conditioning resistance. General combining ability effects were highly significant. We concluded that dominance and/or specific combining ability were relatively unimportant in conditioning resistance. Heterosis contributed substantially to the mean level of resistance among F1 progenies. Successful selection among these lines and their progeny will depend on the accumulation of additive gene effects for resistance to fall armyworm damage. Recurrent selection based on selfed progeny performance is suggested for developing a resistant plant population.
Sorghum Cultivars and Progenies Rated for Resistance to Greenbugs1
Authors: Weibel D. E. , Starks K. J. , Wood E. A. , Morrison R. D.
Published: July 2010

F1 and F2 populations of sorghum plants [Sorghum bicolor (L.) Moench] from the resistant varieties ‘Shallu Grain’ (SA 7536‐1), PI 264453, and ‘IS 809’ were scored for damage from the greenbug [Schizaphis graminum (Rondani)] in short rows in flats in the greenhouse. The study was conducted to determine the inheritance of greenbug resistance, to determine the feasibility of transferring the resistance to adapted lines, and to predict the usefulness of the resistance in hybrids. F1 plants gave an intermediate score between resistant and susceptible parents but indicated that one parent in a hybrid could give considerable resistance to greenbugs. Data from F2 populations indicated that the inheritance of resistance probably was controlled by a single incompletely dominant factor, and that breeders should have little difficulty transferring resistance to adapted lines. Average number of dead plants per entry and average reduction in height due to greenbugs were highly correlated with damage scores.
Genetic Parameters for Earworm Injury in Maize Populations with Latin American Germ Plasm1
Authors: Widstrom N. W. , Wiseman B. R. , McMillian W. W.
Published: July 2010

Genetic variances for earworm [Heliothis zea (Boddie)] injury were estimated for three composite populations of corn (Zea mays L.) with Latin American germ plasm and for a cross between two of the composites. Heterosis was weak in the hybrid population. Estimates of dominance were much less significant than those for additive genetic variance in these populations, with the possible exception of the broader genetic‐based RFC population. Estimates of heritability and genetic response to selection were highest in those populations that also had the largest estimate for dominance and the highest level of earworm resistance. Prospects for successful selection within these populations are good.
Crown‐Freezing and Natural Survival Comparisons of F2–F4 Bulk Populations from 25 Winter Barley Crosses1
Authors: Warnes D. D. , Johnson V. A.
Published: July 2010

Crown‐freezing survival and natural survival were used to compare the relative winterhardiness levels of bulk progenies of F2 to F4 generations of 25 winter barley (Hordeum vulgare L.) crosses advanced under natural selection at Lincoln, Nebr. The winter of 1960–61 more effectively increased winterhardiness and coldhardiness of segregating populations than did the preceding or succeeding winters. None of the 25 crosses produced bulk generations with average natural survival that statistically exceeded the hardy parent. Crosses involving a wintertender parent and a hardy parent generally showed significant increases in survival with each succeeding generation. The crown‐freezing technique should be a valuable tool for the prediction of coldhardiness in winter barley and supplement winterhardiness data from natural field survival.
Inheritance of Pericarp Thickness in Corn Belt Maize1
Authors: Helm J. L. , Zuber M. S.
Published: July 2010

Corn (Zea mays L.) pericarp strips were excised and thickness of the strips measured with a plunger type micrometer at six positions: upper, middle, and lower areas on the germinal and abgerminal surface. The inheritance of pericarp thickness was studied in two experiments. Experiment 1 consisted of six inbred lines ranging in pericarp thickness from 84 to 160 microns, and the 15 possible single crosses and reciprocals among them making a total of 30 F1 hybrids. Experiment 2 was composed of six inbred lines ranging in pericarp thickness from 55 to 114 microns, their 30 F1 hybrids, 15 F2 progenies, 30 first and 30 second generation backcrosses. The experiments were grown at two locations in Central Missouri in 1965. Highly significant mean squares were obtained for estimates of lines, line heterosis, and specific heterosis using Gardner and Eberharts analysis II, but mean squares for lines were many fold times the mean squares for line heterosis and specific heterosis in both experiments. Reciprocal effects were of small magnitude. Heterosis was meager and inbreeding depression small. Heritability estimates in the narrow sense were very high, (80%). We conclude that breeding procedures that would take advantage of the large proportion of line effects should be successful in selection for either thin or thick pericarp
Simulation of Growth and Yield in Cotton: I. Gross Photosynthesis, Respiration, and Growth1
Authors: Baker D.N. , Hesketh J.D. , Duncan W.G.
Published: July 2010

A valid simulation of crop growth and yield requires quantitative data on the effect of the environment on photosynthesis, respiration and organ development. Seedling growth and boll growth of cotton, (Gossypium hirsutum L.) were studied in the phytotron at Duke University. We found extremely high respiration rates in the seedlings and an efficiency in the conversion of photosynthate to dry matter of 33% for the first 0.3 g accumulated and 53.5% for the next 0.5 g. Boll growth is exponential at first and then becomes linear. Growth efficiency in young bolls ranges from 67% at 18 C to 77% at 28 C. Later boll growth efficiency was essentially constant at about 61% at mean temperatures commonly found in the cotton belt, e.g., 26 – 27 C. Photosynthesis and respiration were measured in field stands during the boll‐filling stage with 2m ✕ 2m plexiglass chambers. Light respiration varied with temperature (25 to 42 C) from 8 to 15% of gross photosynthesis at a light intensity of 700 Wm−2. The ratio of total respiration to photosynthesis (R/P) varied diurnally, ranging from 0.29 under intense light [0900 local standard time (LST)] to infinity at sundown.
Oxygen Consumption Rates Predicted from Respiration, Permeability and Porosity Measurements on Excised Wheat Root Segments1
Authors: Luxmoore R. J. , Stolzy L. H.
Published: July 2010

Respiration rates were determined at 3.9, 20.8, and 79.9% oxygen concentration for consecutive excised root segments of ‘Ramona,’ ‘Inia,’ and ‘Yecora’ wheat (Triticum aestivum (L.) em Thell.). From these data, the maximum respiration rate, the O2 concentration at which respiration was half of the maximum rate, and the root permeability to O2 were derived for segments up to 9 cm from the root tip. The gas filled porosity of each segment was measured by the pycnometer method.

Maximum respiration rate and permeability decreased with distance from the root tip to a relatively constant value at 2 to 3 cm from the tip, whereas root porosity increased to a maximum value of about 10% at 3 cm from the root tip. The O2 concentration for half maximal respiration rate was about 10% for root segments of Ramona and Inia cultivars and about 7% for Yecora. The data for Yecora were more variable than for the others.

These root characteristics were used in a model of root O2 relations to obtain estimates of mean respiration rate of wheat roots under simulated field conditions at three soil temperatures. Mean root O2 consumption rate decreased with increase in root length to a relatively constant value for roots longer than 50 cm. Under well aerated conditions, O2 consumption rates were higher for roots with smaller radii, whereas with flooded conditions respiration rates increased with root radii. Predicted mean respiration rate was higher with increase in soil temperature.
Cold Tolerance in Adapted Maize Populations1
Authors: Mock J. J. , Eberhart S. A.
Published: July 2010

We evaluated two U.S. Corn Belt maize (Zea mays L.) populations (BSSS2 and BSSS13) for percentage emergence, emergence index (emergence rate), and seedling dry weight in two different “cold” environments: early field planting and growth chamber at constant 1O.OC. Genotypic variances of the traits within environments were large, but genotype ✕ environment interaction was large and significant so that parameter estimates (δ2g and h2) from data combined across environments were low. Genotypic correlations suggested that within a population the same, or very similar, genetic systems conditioned cold tolerance in both environments. These genes were independent of genes controlling stand and maturity under “normal” planting conditions. Predicted selection responses indicated field selection for cold tolerance would be more efficient.
Estimates of Genetic Effects of Heading Date, Plant Height, and Grain Yield in Durum Wheat1
Authors: Amaya A. Arnoldo , Busch R. H. , Lebsock K. L.
Published: July 2010

A weighted least squares analysis of parental, F1, bulk F2 and F3, B1C, and B2C means was used to estimate genetic effects of plant height, heading date, and grain yield in four crosses of durum wheat (Triticum durum Desf.). F3 lines from randomly harvested F2 plants from each cross were included in replicated tests in three of four environments.

The F1 hybrids exceeded their high‐yielding parents by an average of about 25% in grain yield; expression of heterosis, however, varied widely among the environments. Heterosis was of less magnitude in the expression of plant height and heading date.

Dominance genetic effects ĥ were relatively more important than additive effects (d̂) in the inheritance of grain yield. Additive genetic effects predominated in the expression of plant height and heading date. Epistatic effects were detected in some crosses when analyzed in individual environments, but these effects were not detected for grain yield and heading date when data were combined over all environments.

Some F3 lines from all crosses were not significantly different from their corresponding F1's in grain yield and more desirable than the F1's in heading date (earlier) and plant height (shorter).
Mitochondrial Complementation in Sugar Beet1
Authors: Doney D. L. , Theurer J. C. , Wyse R. E.
Published: July 2010

Physiologically active mitochondria were isolated from roots of 10‐week old sugar beet (Beta vulgaris L.) inbreds and hybrids as well as inbreds in the bolting stage of growth. Mitochondrial oxidation and phosphorylation (ADP:O and R:C ratios) using alpha‐ketoglutarate substrate were measured for each inbred, 1:1 mixtures of the inbreds, and for the hybridsi The 1:1 mixtures of inbreds had APD:0 and R:C ratios higher than either inbred parent for combinations that exhibit heterosis for root yield (complementation), and ADP‐O and R:C ratios between the two inbred parents for combinations that do not show heterosis. Heterotic hybrids had ADP:O and R:C ratios slightly higher than those of the l:l mixlures.
Crosses between Hordeum Jubatum L. and Taeniatherum Asperum (Sim.) Nevski to Determine Genomic Relationships
Authors: Schooler A.B. , Bell A.R. , Nalewaja John D.
Published: July 2010

Fl hybrids were obtained from crosses between Hordeum jubatum L. (2n=28) and Taeniatherum asperum (Sim.) Nevski (2n=14). The F1 hybrids had a chromosome complement of 2n=21 and were self‐sterile. Chromosome behavior was irregular in microsporocytes of the hybrids examined. Chromosome doubling was induced in Fl hybrids by colchicine treatment and partially selffertile amphiploid intergeneric hybrids (2n=42) were produced. Cytological observations showed many micronuclei in the microspores which resulted from chromosome fragmentation during meiosis II.

The F1 intergeneric hybrids and amphiploid resembled the Hordeum parent more closely than Taeniatherum but were smaller than either parent in most morphological characteristics. There was only slight evidence of a genome relationship between the two genera.
A Path Coefficient Analysis of Some Yield Component Interrelations in Field Beans (Phaseolus vulgaris L.)1
Authors: Duarte Rodrigo A. , Adams M. W.
Published: July 2010

A path‐coefficient analysis was performed in field beans of the direct and indirect effects of leaf number and leaf size upon number of pods per plant, number of seeds per pod, and seed weight, and of the latter components upon yield. The data on which the analysis was based were obtained from F3 and F4 families in a recurrent selection experiment grown at three locations. Selection had been practiced for each component separately, at three levels of expression (high, modal, low), in sub‐populations maintained at each of the three locations.

The chief findings were: 1) Pods/plants exerts a preponderant effect upon yield in every set of families studied.

2)In families where selection had produced divergent types with respect to seed number per pod, and seed weight, these components also assumed major roles in determining yield.

3) Leaf number was highly associated with pod number per plant and leaf size was highly associated with seed size in families selected for high, modal, and low levels of expression of the two leaf area components.

Interpretations of these findings are given, based first on a common genetic program regulating the number of main stem internodes, and secondly on another genetic program regulating leaf cell number and/or rate of expansion. The rationale connecting these fundamental characteristics with the first‐ and second‐order yield components is given.
Effects of Mass Selection and Irradiation in Corn Measured by Random S1 Lines and Their Testcrosses1
Authors: Harris R. E. , Gardner C. O. , Compton W. A.
Published: July 2010

Two populations of corn (Zea mays L.) improved by nine cycles of mass selection for yield and the unselected parent variety, ‘Hays Golden,’ were evaluated in 1969 and 1970 using random S1 lines and their testcrosses to related and unrelated single‐cross testers. One selected population received thermal neutron seed treatment prior to the first and third selection cycles.

S1 lines of the selected populations, per se and in testcrosses, demonstrated significant superiority in mean yield over lines of the parent variety in each year. Like progenies of the two selected populations produced similar yields. Selection evidently eliminated radiation‐induced deleterious mutants from the “irradiated” population while increasing frequencies of favorable yield genes common to both selected populations. This apparently produced similar germ plasm reservoirs much more suitable for the extraction of superior inbred lines than the parent variety. Indications are that selection also reduced genetic variability in yield and combining ability.

Prolificacy resulting from selection for yield was evident in S1 lines but not in the testcrosses. Since inbreeding did not reduce prolificacy in the selected populations, results are interpreted to mean that tester genes masked recessive genes which induce prolific potential when homozygous. All phenotypic correlations between S1 and testcross yields were too low to be of much predictive value; but in general, lines of the selected populations exhibited the least correlation with their testcrosses. Genetic correlations were somewhat higher, indicating sizeable environmental fluctuations in individual experiments. We postulate that non‐prolific testers by inhibiting prolificacy in turn limit the expression of genes controlling yield in these populations. Use of a prolific tester might have provided greater yield differentiation, more precise estimates of line genotypes and higher correlations between S1 and testcross progenies.
A Maize Breeding Methods Study in Kenya1
Authors: Darrah L. L. , Eberhart S. A. , Penny L. H.
Published: July 2010

Four years of reciprocal recurrent selection has produced rapid improvement in one of the parental varieties (‘Ecuador 573’), in the variety cross, and in a commercial topcross maize (Zea mays L.) hybrid. The improved strain of Ecuador 573 is now used as the male parent of the current commercial hybrids, ‘H611C’ and ‘H613C,’ and they yield approximately 25% more than the original versions.

Estimates obtained from seven years of the selection trials showed no changes in genetic variances for yield. Hence, this rate of improvement is not expected to change in the near future. Progress from modified ear‐to‐row selection was greater in the introduced Ecuador 573 variety and in KCA, (‘Kitale II’ ✕ Ecuador 573)syn‐4, than in the local Kitale II variety. No improvement was detected in KCA from mass selection. An increased number of ears per plant was associated with yield improvement by reciprocal recurrent selection and modified ear‐to‐row selection. Selection for lodging resistance and blight resistance in the breeding nurseries resulted in slight improvements in the varieties under reciprocal recurrent selection and in the variety cross. Greater attention to ear height and lodging resistance is required to reduce harvesting losses in the commercial maize crop in Kenya.
Alteration of Protein Composition of Corn (Zea mays L.) Seedlings During Moisture Stress1
Authors: Maranville Jerry W. , Paulsen Gary M.
Published: July 2010

The rapidity and magnitude of change in nitrate reduction and assimilation, protein metabolism, and associated ribonucleic acid were investigated in corn (Zea mays L.) seedlings subjected to moisture stress. The objective of the study was to determine the sequence of events that lead to protein alteration. Nitrate reductase was highly susceptible to tissue dehydration and markedly lost activity with only slight reductions in leaf relative turgidity. Reduced protein synthesis instead of increased protease activity caused leaf protein concentration to decrease during severe moisture stress conditions. Appreciable loss of protein was not detected during mild stress. Alterations in RNA synthesis appeared to be as important as increased RNase activity in determining leaf RNA concentration during mild stress. During severe stress, however, increased RNase activity was probably more important in decreasing RNA.
Effects of Herbicides Applied Postemergence on Weeds and Sunflowers1
Authors: Johnson B. J.
Published: July 2010

Herbicides were applied as postemergence treatments either as early over‐the‐top spray or late‐directed spray to sunflowers (Helianthus annuus L.) for weed control and crop tolerance determinations at Experiment, Ga. Treatments of RP 17623 (2‐tertiobutyl‐4‐(2,4‐dichloro‐5‐ isopropyloxyphenyl)‐5‐oxo‐l,3,4‐oxadiazoline) were applied to sunflowers in the cotyledon, first leaf, and second leaf growth stages. Several herbicides commonly used on other crops were applied late postemergence directed spray to sunflowers when they were 25 to 35 cm tall.

were obtained from early postemergence treatments of RP 17623 when applied as over‐the‐top spray at either the cotyledon or the first‐leaf stage of sunflower growth. Weed control results were similar to RP 17623 from several herbicides that were applied as late‐directed postemergence sprays. Early postmergence treatments with RP 17623 caused some early injury to sunflower plants and a reduction in achene oil percent when compared with achenes from untreated plants, but achene yields were not reduced. None of the herbicides applied as late‐directed postemergence sprays injured sunflowers, reduced achene yield, or achene oil percent.
Factor Analysis of Yield in Spring Wheat (Triticum aestivum L.)1
Authors: Walton P. D.
Published: July 2010

Fourteen characters were studied in a 5 by 5 diallel cross among varieties of spring wheat (Triticum aestivum L.). The characters consisted of yield components, certain morphological structures above the flag leaf nodes, and three developmental stages. Factor analysis was used to analyze the relationship between these characters. This analysis indicated that the factor concerned with flag leaf area and duration was the most important. Characters that determined the nature of the “sink” were divided among three factors. The components of yield formed part of Factors 3 and 4. Factor analysis clarified the relationship between correlated characters in the dependence structure.
Chromosome and Genetic Constancy in a Poa pratensis L. Cultivar1
Authors: Wilton A. C. , Wiseman E. , Murray J. J.
Published: July 2010

Chromosome numbers were determined on genetically identifiable plants to evaluate chromosomal and genetic constancy of the ‘Windsor’ cultivar of the facultative apomict Poa pratensis L. Seed size, seedling pigmentation, and chromosome number were interrelated in most plants but varied within the cultivar.

Large seeds produced 93% pigmented seedlings, of which 84% had 70 chromosomes. Small seeds produced 86% nonpigmented seedlings, of which 94% had 49 chromosomes. Although the cultivar consisted largely of these two relatively stable components, chromosome numbers varied among plants with inverse associations of seed size and seedling pigmentation. Throughout the experiment the following chromosome numbers were found: 35, 49, 56, 60's, 70's, 80's, and 105. A set of twin plants occurred, with one member with 49 chromosomes and the other with 74 chromosomes. The wide range of chromosome numbers was accounted for on the basis of classical explanations of agamospermy in facultative apomicts.
Chemical Composition of Mentha arvensis var. piperascens and Four Hybrids with Mentha crispa Harvested at Different Times in Indiana and Michigan1
Authors: Murray Merritt J. , Faas William , Marble Phillip
Published: July 2010

Unlike Mentha piperita, the oil from juvenile and immature herbage of Mentha arvensis and four M. arvensis ✕ Mentha crispa F1 hybrids may not have substantially higher amounts of menthone and lower amounts of menthol/menthyl acetate than oil from mature herbage. In contrast, oil from very overmature and senescent herbage usually has more menthyl acetate (ester) without marked reduction of menthol (alcohol) content. Flower oil has as much menthol as total herbage oil but less ester. Oil differences due to the time of harvest are minor compared to those due to inherited differences. In comparison to the cultivar, each illustrated hybrid has a distinctive characteristic, namely, higher isomethone, piperitone, menthyl acetate, or neomenthol with these differences present in juvenile, mature, and overmature herbage. Biogenetic reasons are given to explain the absence of major ontogenetic trends in limonene/menthone/menthol, but the colder temperatures of early spring or late fall are believed to have a direct effect on increasing the amount or efficiency of the enzyme that converts menthol to menthyl acetate. Low temperature‐induced increases in menthol and ester may occur in 3 to 6 days in juvenile plants. From an agricultural viewpoint, harvest should be at time of maximum oil yield and prior to severe leaf loss due to Puccinia rust or Verticillium wilt.
Downy Mildew Resistance in Cultivated Sunflower and Its Inheritance1
Authors: Zimmer D.E. , Kinman M.L.
Published: July 2010

Resistance in sunflower (Helianthus annuus L.) to the widely virulent Red River race of downy mildew, incited by Plasmopara halstedii (Farl.) Berl. et de Toni, was discovered in three inbred lines selected from the cross 953‐88‐3 ✕ ‘Armavirsky 2497.’ All other breeding lines, sunflower introductions, and varieties, including AD 66, CM 90RR, and S‐37‐388RR, which were reported to be resistant in tests in Romania and France, were susceptible. The failure of the breeding lines AD 66, CM 90RR, and S‐37‐388RR to respond the same to downy mildew in our trials as they did in Europe indicates the existence of pathogenic races.

Resistance to the Red River race found in HA 61, one of the three resistant lines, is due to a single dominant gene that we have designated Pl2. The Pl2 gene is inherited independently of the gene presumed to be Ra which conditions rust resistance of HA 61. The Pl2 gene is probably synonymous to one of the genes reported to condition resistance of HA 61 to downy mildew in France.
Accumulation of Simple Sugars in Developing Cotton Bolls as Influenced by Night Temperatures1
Authors: Conner J.W. , Krieg D.R. , Gipson J.R.
Published: July 2010

Cotton plants (Gossypium hirsutum L. var. Dunn 56 C) growing in the field were subjected to four different night temperature regimes (10, 15, 20, and 25 C) during the boll development phase. Total and individual sugars were determined on developing bolls ranging in age from 0 to 45 days. Total soluble sugars were found to be directly associated with temperature, with the lowest concentration occurring in the 10‐C treated bolls, and the highest concentration in the 25‐C treated bolls for the first 15 days. After 15 days this relationship was reversed. Definite time‐temperature relationships that were apparently associated with the cessation of fiber elongation and the initiation of secondary wall formation were noted. The principal sugars present were glucose, fructose, and sucrose. The concentration of each varied with boll age and temperature treatment.
Identification of Rust‐Conditioning Genes in Flax Cultivars1
Authors: Flor H. H. , Comstock V. E.
Published: July 2010

The selective pathogenicity of races of Melampsora lini (Ehrenb.) Lev. was utilized to identify rust‐conditioning genes in cultivars of flax (Linum usitatissimum L.). New rust‐resistant cultivars developed for commercial production possessed the rust‐conditioning genes expected based on knowledge of their parents. A heretofore‐unknown gene, designated L11, was identified in ‘Linore,’ a cultivar of unknown parentage. This gene conditions resistance to all North American races of rust. Tests of several hundred cultivars of foreign origin revealed that most introductions are heterogenious for rust reaction.
Estimated Gains from Selection for Protein and Yield in the F4 Generation of Six Soybean Populations1
Authors: Shannon J. G. , Wilcox J. R. , Probst A. H.
Published: July 2010

Seventy‐eight F2‐derived F4 lines from each of six soybean [Glycine max (L.) Merr.] populations were evaluated to determine which population had the best potential for improving yield, protein, and yield and protein in combination. The six populations, one high protein ✕ high protein, four high protein ✕ high yield, and one high yield ✕ high yield, were derived from diallel crosses among two adapted high‐protein (P1 and P2) and two adapted high‐yield parents (Y1 and Y2).

P1P2 contained more lines high in percent protein and in protein per hectare, contained more lines that combined high protein with high yield, showed the greatest expected advances for yield and protein per hectare, was exceeded only by P1Y2 for predicted progress in percent protein, and was the only population in which expected advance exceeded parental means for percent protein and protein per hectare. Its highest‐yielding lines, however, were below the highest lines in other populations, particularly P1Y1 and P2Y2.

Genotypic and phenotypic correlation coefficients were computed among yield, percent protein, and percent oil. Highly significant negative correlations were observed for protein and oil in all six populations. Correlations between yield and percent oil were positive, but significant in only two populations. Significant coefficients between yield and percent protein were negative in P1P2 and P2Y2 and positive in Y1Y2.
Vegetative Growth Responses of Alfalfa Pathogens to Saponin and Other Extracts from Alfalfa (Medicago sativa L.)1
Authors: Leath K. T. , Davis K. H. , Wall M. E. , Hanson C. H.
Published: July 2010

Various fractions extracted from ‘DuPuits’ and ‘Lahontan’ alfalfas (Medicago sativa L.) were assayed for biological activity on the vegetative growth of 15 alfalfa pathogens, Rhizobium meliloti Dangeard, and Trichoderma viride Pets. ex Ft. Alfalfa plant materials were defatted with hexane‐heptane, followed by extraction with alcohol. The alcohol extracts were further fractionated into chloroform, chloroform‐methanol, butanol, and water fractions. Saponin mixtures were obtained as precipitates from butanol. DuPuits contained more saponin than did Lahontan. Thin‐layer chromatographic analysis revealed the presence of highly complex saponin mixtures in each alfalfa cultivar. Growth responses of the test organisms varied with the organism, the fraction, the source cultivar, and the concentration of the fraction. All test concentrations were below those of saponins naturally occurring in alfalfa. In general, the effects of the four saponin mixtures were similar, with those from DuPuits exhibiting more activity than those from Lahontan. The test organisms varied greatly in their responses to all fractions, i.e., unaffected, stimulated, or inhibited (fungistatic and fungicidal). The nonsaponin fractions greatly affected the growth of the test organisms, but little effect of source variety was noted. The potential role of saponins in disease resistance was discussed.
Carbohydrates in Grasses: V. Incorporation of 14C into Plant Parts and Nonstructural Carbohydrates of Timothy (Phleum pratense L.) at Three Developmental Stages1
Authors: Balasko J. A. , Smith Dale
Published: July 2010

Distribution of photosynthates in forage grasses is important in terms of yield, quality, and persistence. The objectives of this study were to learn more about the distribution of 14C fed to timothy (Phleum pratense L.) at different growth stages and to follow its incorporation into nonstructural carbohydrates of stem bases. Plants at three developmental stages — initiation of stem elongation, ear emergence, and anthesis N were exposed to 14CO2. Plants were harvested at 1, 3, 8, 32, and 168 hr following exposure. Specific activity of 14C in leaf blades, leaf sheaths, inflorescences, stems, stem bases, roots, and yellow leaves was measured. Radioactivity in each plant part was calculated and expressed as a percentage of total plant radioactivity.

One week following exposure to 14CO2 at initiation of stem elongation, roots and leaves were primary recipients of 14C. At ear emergence stems and inflorescences were major sinks. One week following feeding at anthesis, stems and roots contained 73% of the total plant 14C. At initiation of stem elongation, very little 14C was incorporated into the fructosan fraction of the stem bases, whereas at ear emergence and anthesis, labelled fructosan was more abundant. Major storage of fructosan took place after most meristematic sinks were satisfied.
Incorporation of 14C‐Photosynthate into Developing Cotton Bolls, Gossypium hirsutum L.1
Authors: Benedict C. R. , Smith R. H. , Kohel R. J.
Published: July 2010

Incorporation of 14C‐photosynthate into developing cotton (Gossypium hirsutum L.) bolls of several ages was studied in the cultivar ‘Paymaster III.’ Maximum incorporation of 14C‐assimilate into developing boll walls and fiber occurred at 8 to 10 and 23 to 40 days after anthesis, respectively. 14C‐photosynthate incorporation was rapidly increasing in the developing fibers prior to the completion of fiber elongation. For Paymaster III, ‘Acala SJ‐1,’ and ‘Stoneville 213’ cultivars, the rate of increase of fiber dry weight was maximal prior to the completion of fiber elongation.
Relationship Between Decarboxylation of Glutamic Acid and Vigor in Soybean Seed1
Authors: Abdul‐Baki Aref A. , Anderson James D.
Published: July 2010

The relationship between seed vigor and decarboxylation of glutamic acid in 16 lots of soybean (Glycine max L. cv. Lee‐68) was determined (i) manometrically by incubating ground seeds in 75 mM solutions of glutamic acid at pH 5.2 and measuring CO2 production, and (ii) isotopically by incubating excised embryonic axes in 1 mM glutamic acid‐1‐14C (0.3 µCi/ml) and measuring 14CO2. Both methods agree in that decarboxylation of glutamic acid, presumably by glutamic decarboxylase, was high in both the low‐ and high‐vigor lots. The high decarboxylation of glutamic acid in dry soybean seeds and the low content of glutamic acid in either the imbibed or nonimbibed seed suggest that glutamic acid concentration limits the decarboxylation rate during imbibition. Comparison of total CO2 produced by whole seeds or seed parts (axes and cotyledons) during early germination with that estimated from glutamic acid decarboxylation suggests that CO2 production by the tissues via glutamic acid decarboxylation accounts for only a small portion of the CO2 produced by the seeds.

Vigor of the soybean lots is highly correlated with the ability of the excised embryonic axes to incorporate glutamic acid into water‐soluble protein and maintain a relatively high rate of respiration. The decreased 02 uptake and CO2 production by the low‐vigor lots, pronounced in the axes and negligible in cotyledons, suggests that a search for biochemical indices to measure seed vigor should be focused on embryonic axes rather than on whole seeds.
Cross‐Fertilization of Alfalfa as Affected by Genetic Markers, Planting Methods, Locations, and Pollinator Species1
Authors: Kehr W. R.
Published: July 2010

Studies were made to determine the extent of crossfertilization of alfalfa, Medicago sativa L., involving genetic markers, planting methods, locations, field cages and isolations, pollinator species, and their interactions. Crossing between alfalfa populations by honeybees, as measured in white‐ and yellow‐flowered populations, varied from 32 to 96%. The average crossing in noninbred populations was about 50%.

Crossing percentages were similar for alternate row and alternate plant methods of planting in Idaho and Nebraska and for a yellow‐flowered population in California. However, crossing percentages were significantly higher with the alternate plant method than with the alternate row method of planting for a white‐flowered population in both caged and uncaged areas in California and for another white‐flowered population in California cages.

Crossing percentages were similar in caged and uncaged isolations in Nebraska. Honeybee pollination in California and leafcutter bee pollination in Idaho resulted in 50.5 and 51.0% cross‐fertilization, respectively, averaged over kinds of field isolation, planting methods, and markers used at both locations.
Combining Ability and Gene Action Estimates in an Eight Parent Diallel Cross of Sugarbeet1
Authors: Smith G. A. , Hecker R. J. , Maag G. W. , Rasmuson D. M.
Published: July 2010

Twenty‐eight F1 hybrids from an eight parent diallel cross grown at two nitrogen fertility levels were analyzed for type of gene action controlling 11 sugarbeet (Beta vulgaris L.) characters. Nonadditive genetic variance was of prime importance in controlling root weight under low and high nitrogen levels, accounting for 51% and 68% of the total genetic variance, respectively. For recoverable sugar, nonadditive genetic variance accounted for 67% and 83% of the total genetic variance under low and high nitrogen. Additive genetic variance accounted for most of the genetic variance for sucrose percentage and root/shoot ratio. Both additive and nonadditive genetic variance were significant for percent thin juice purity, but only at the high nitrogen fertility level.

Additive genetic variance was predominant for six nonsucrose components of purified juice. In addition, significant amounts of nonadditive gene action were found for all six nonsucrose components at one or both nitrogen levels. Betaine was the least affected by change in nitrogen of all the characters measured.
Changes in Quantitative Traits Associated with Inbreeding in a Synthetic Variety of Maize1
Authors: Hallauer Arnel R. , Sears J. H.
Published: July 2010

Inbreeding studies were initiated in a synthetic variety of maize (Zea mays L.), ‘Iowa Stiff Stalk Synthetic’ (BSSS), in 1962 by selfing 250 unseIected S0 plants. One genotype of the zygotic array for each S0 plant was maintained by single‐seed descent for seven generations of selfing. In the S7 generation, 248 lines from the original 250 S0 plants were available, and a bulk increase was made for each line. Five experiments were conducted in 1969 and 1970 to evaluate the agronomic changes associated with inbreeding (by selfing) for 10 quantitative traits: plant and ear height, leaf width, kernel‐row number, ear length and diameter, cob diameter, kernel depth, yield, and days to silk. Multiple‐range tests of the combined means showed that most of the differences among generations S0 through S4 were significant. Except for ear diameter, kernel depth, and yield, the differences among generations S5, S6, and S7 were not significant. Linear and quadratic models were fitted for the generation means for each trait on ercentage homozygosity. The regression analyses showed that the relation between the mean performance and levels of inbreeding in BSSS can be described by a genetic model based on the cumulative effects of loci with dominance for most traits; i.e. inbreeding depression resulted from an increase in the frequency of homozygous recessive deleterious loci. In BSSS, inbreeding to homozygosity would, on the average, reduce yield by 45 q/ha, decrease plant height by 48 cm, and increase days to silking by 4.6 days.
Relationship of Stomatal Length and Frequency and Pollen‐Grain Diameter to Ploidy Level in Bromus inermis Leyss1
Authors: Tan Geok‐Yong , Dunn G. M.
Published: July 2010

Stomatal length and frequency and pollen grain diameter were examined as indirect methods for identification of 4x, 6x and 8x ploidy levels in Bromus inermis. The study was conducted in the greenhouse on seedlings and mature plants. Mean stomatal lengths were 40.4, 43.0, 53.1, and 66.6 µ for mature 4X (clonal), 4X (selfing), 6X and 8X plants, respectively. Coefficients of variation among observations within each ploidy level were relatively low. Stomatal frequency decreased with increasing ploidy while pollen‐grain diameter increased, but considerable overlapping occurred among ploidies for both characters. Greater ploidy differences and smaller standard deviations were associated with stomatal length rather than with stomatal frequency and pollen‐grain diameter. Therefore, the former is recommended as a rapid method for identification of ploidy level.
Reduction in Carbonic Anhydrase Activity in Zinc Deficient Leaves of Phaseolus vulgaris L.1
Authors: Edwards G. E. , Mohamed A. K.
Published: July 2010

The effect of zinc deficiency on plant growth and levels of carbonic anhydrase, ribulose diphosphate carboxylase, glycolic oxidase, and malic dehydrogenase was measured in two varieties of Phaseolus vulgaris L. Varieties ‘Saginaw’ and ‘Sanilac’ were grown in nutrient solution in a growth chamber at 0.005, 0.05, and 0.2 ppm zinc. Both varieties showed a similar increase in dry weight production after 4½ weeks of growth with increasing zinc concentrations. Enzyme, chlorophyll, and zinc analyses were made on the first, third, and fifth trifoliate leaf from the bottom of the plants. The level of carbonic anhydrase per unit leaf area was dramatically decreased in either variety at 0.005 and 0.05 ppm zinc when compared to 0.2 ppm zinc. The most severe reduction of carbonic anhydrase and zinc in the leaves was in the third and fifth trifoliate leaf. A decrease in growth with the lower levels of zinc was paralleled by a decrease in carbonic anhydrase activity and zinc levels in the younger trifoliate leaves. Zinc deficiency in the two varieties had little effect on the levels of ribulose 1,5‐diphosphate carboxylase, glycolic oxidase, or mallc dehydrogenase.
Patterns of Translocation, Respiratory Loss, and Redistribution of 14c in Maize Labeled after Flowering1
Authors: Palmer A. F. E. , Heichel G. H. , Musgrave R. B.
Published: July 2010

Maize (Zea mays L.) growing in the field was labeled with 14CO2 at four leaf positions 15 to 18 days after flowering. On four occasions after labeling, entire plants were harvested and 14C in several plant fractions was analyzed by liquid scintillation spectroscopy to reveal patterns of translocation within the plants, losses of 14C by respiration, and patterns of mobilization and redistribution of 14C among and within organs. The first and third leaf blades above the ear (+1 and +3, respectively), and the first blade below the ear (–1), exported 14C mainly kernels of the developing ear. Among these three leaf blades, the extent of export of 14C was more rapid from upper positions than from lower ones. Movement of 14C from the fifth leaf blade (–5) below the ear was much slower than that from the upper three blades, but kernels of the developing ear ultimately became the principle sink for 14C exported by this blade. Compared with the upper three leaf blade positions, however, appreciable label from –5 accumulated in the lower stem and roots. Labeling plants bearing partly‐fertilized ears caused a large accumulation of 14C in the stem, roots and to a lesser extent, husks, compared with completely‐fertillzed controls. About 20% of the 14C assimilated by the +1, +3, and –1 blades was lost by respiration in the 5 weeks following labeling. During the same interval, nearly 70% of the 14C assimilated by the –5 blade was lost by respiration. Approximately half of the carbon assimilated by +3, +1, and –1 blades was translocated directly to kernels within 24 hr after assimilation. A similar quantity of label assimilated by +3, +1, and –1 blades was deposited in cobs and husks within 24 hr after assimilation. Estimates of redistribution of label within the plants suggest that 60 to 80% of the 14C accumulated in kernels between days 1 and 35 following labeling was derived from 14C originating in upper leaves and deposited in the cob and husk within 24 hr.
Black Layer Maturity and Filling Period Variation Among Inbred Lines of Corn (Zea mays L.)1
Authors: Carter M. W. , Poneleit C. G.
Published: July 2010

Kernels of 20 corn (Zea mays L.) inbred lines were examined for 3 years to determine variation for black layer maturity, filling period, and associated characters. The color of the black layer and the rate at which it developed at maturity varied among the inbreds. For each inbred, the black layer was observed at a time that was coincident with the observed maximum dry weight accumulation. Moisture content at the time of black layer maturity varied among the inbreds from 15.4 to 35.0%. Differences among inbreds were significant but year means did not differ. There was a significant year ✕ inbred interaction.

The growing degree days required to reach black layer maturity varied from 1337 to 1808 and the growing degree days required for kernel filling varied from 512 to 821. Year differences were significant; however, interaction of inbreds with years was found to be minor. The variability among inbreds was always much greater than among years. The growing degree days required for the filling period had positive phenotypic and genotypic correlations with the growing degree days required from planting to pollination, but the correlations were small enough to suggest possible selection for types with long filling periods and short time to pollination. The rate of kernel dry weight accumulation during the filling period was significantly different among inbreds and years but had a significant inbred ✕ year interaction. The rate of kernel dry weight accumulation was not correlated with any character other than dry weight at black layer maturity.
Seasonal Patterns and Genotypic Differences in Phosphofructokinase Activity in Corn (Zea mays L.) Leaf Blades1
Authors: Luthe Dawn Sywassink , Schrader L. E.
Published: July 2010

Phosphofructokinase (ATP: D‐Fructose‐6‐phosphate‐lphosphotransferase, E. C. 2.7.1.11) activity was assayed in a four‐parent diallel cross of corn (Zea mays L.) to determine if there were seasonal changes and genotypic differences in enzymatic activity in leaf blade tissue. Tissue was assayed every week from 2 weeks after seedling emergence until 5 weeks after silking. Seasonal patterns of phosphofructokinase (PFK) activity were found to be similar for all genotypes. A split‐plot‐in‐time statistical analysis showed the effect of time to be highly significant. There was a rapid increase in activity during the first few weeks after seedling emergence, a drop in activity near silking, and a slight increase in activity during the period when starch accumulation in kernels was initiated. When PFK activity was compared at each weekly sampling, the genotype effect was nonsignificant. However, some significant differences were observed when seasonal means for PFK activity in each genotype were compared, even though the range in seasonal means was small.
Application of Genetic Male Sterility to Recurrent Selection Schemes in Soybeans1
Authors: Brim C. A. , Stuber C. W.
Published: July 2010

Recurrent selection schemes for soybeans [Glycine max (L.) Merr.] that use a genetic male‐sterile factor to obtain natural crosses are outlined. A basic scheme with three generations per cycle, intermating, advancing, and testing, and modifications of the scheme are discussed. Guidelines for population size and selection intensity are considered. Expected genetic progress is presented for each selection program.
Quick Test for Reed Canarygrass (Phalaris arundinacea L.) Alkaloid Concentration1
Authors: Frelich J. R. , Marten G. C.
Published: July 2010

We modified a generalized, plant‐alkaloid screening procedure to provide a quick, semiquantitative test for concenrtation of total basic alkaloids in reed canarygrass (Phalaris arundinacea L.). The test is based upon ocular assessment of discernible differences in turbidity or precipitates produced by silicotungstic acid added to plant extracts. The extracts are prepared by macerating frozen grass in ammoniacal chloroform and then by partitioning into 2 N H2SO4.

Alkaloid concentrations determined by a summation of readings over five dilutions using the quick test were highly correlated (r = 0.94, P ≤ .01) with concentrations determined by the quantitative laboratory test of Simons and Marten (1971). The quick test is about four times faster than the Simons and Marten test and should enable plant breeders to select low‐alkaloid plants or alkaloid‐free plants among large numbers of genotypes.