bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Selection Methods for Autotetraploids. I. Theoretical1
Authors: Hill R. R. , Haag W. L. 
Published: July 2010

The relative effectiveness of selfed progeny test, selfed family, polycross progeny test, polycross family, full‐sib family, and individual selection was compared theoretically. Initial gene frequency, level of environmental variance, and level of dominance were variables in the comparisons. The comparisons were based on theoretical changes in gene frequencies with one cycle of selection in two‐allele autotetraploid populations that were in random‐mating equilibrium.Theoretical responses with selfed progeny test and selfed family selection were equal and always greater than the other methods. Polycross progeny test selection was the second most effective method, and polycross family selection was the least effective method. Full‐sib family and individual selection were intermediate between polycross progeny test and polycross family selection. Fullsib family selection was more effective than individual selection when environmental variance was large, but individual selection was more effective for some gene frequencies when environmental variance was small.
Comparison of Selection Methods for Autotetraploids. II. Selection for Disease Resistance in Alfalfa1
Authors: Haag W. L. , Hill R. R. 
Published: July 2010

One generation of selection based on selfed progeny test, selfed family, polycross progeny test, polycross family, and individual phenotype was conducted for resistance to Uromyces striatus Schroet. var. medicaginis (Pass.) Arth., Phoma herbarum West var. medicaginis Fckl., and Stem. phylium botryosum Wallr. in alfalfa (Medicago sativa L.). Selected individuals from each method with each pathogen were intermated separately. The resulting populations were compared experimentally to evaluate relative effectiveness of the selection methods.Each method of selection produced a significant increase in resistance to U. striatus. Selfed progeny test and selfed family selection gave similar responses and were the most effective methods. Polycross progeny test and polycross family selection also gave similar responses, but were the least effective methods for U. striatus resistance. Response with individual selection was intermediate to responses with selfed and polycross methods. Each of the progeny test and family methods produced similar and significant increases in resistance to P. herbarum. Individual selection for resistance to P. herbarum was not effective. No method of selection produced a significant increase in resistance to S. botryosum
Effect of Water Stress on Photosynthesis and Transpiration of Flag Leaves and Spikes of Barley and Wheat1
Authors: Johnson R. R. , Frey N. M. , Moss Dale N. 
Published: July 2010

‘Dickson’ barley (Hordeum vulgare L.) and ‘Era’ wheat (Triticum aestivum L.) were grown in a growth chamber in 25‐cm diameter ✕ 29‐cm deep plastic pots. Starting 7 days after the spike emerged from the flag leaf sheath, water was withheld for up to 7 days, during which time flag leaf water potentals fell as low as −33 bars. Rates of net photosynthesis and transpiration of both flag leaves and awned spikes decreased linearly with decreasing flag leaf water potential. Net photosynthesis reached zero in the flag leaves and spikes of each species when the leaf water potentials reached −31 to −33 bars. Flag leaf transpiration reached zero at −28 bars in both barley and wheat, and linear regression equations predicted that spike transpiration would reach zero at −39 and −31 bars in barley and wheat, respectively. Barley spikes possessed a greater amount of awn tissue and had higher net photosynthetic and transpiration rates than did wheat spikes.A significant linear relationship existed between ribulose 1,5‐diphosphate (RudP) carboxylase activity and flag leaf water potential for flag leaves and awns of both varieties. Photosynthetic rates decreased to zero at −33 bars while substantial RudP carboxylase activity remained in all tissues. If in vivo RudP carboxylase activities are comparable to the in vitro rates measured, this enzyme did not likely limit photosynthesis at low water potentials.The rapid and severe stress imposed in this growth chamber experment similarly affected the potosynthetic process of both awned spikes and flag leaves of wheat and barley. The time course of the development of severe stress in plants growing in the field may be quite different, however, than for potted plants. Thus, if awned spikes have an advantage in drought situations in the field, it is probably related to their recovery or survival capability and not to differences in the way water stress affects photosynthesis in awns compared to leaves.
Contribution of Cotyledons to Growth of the Sainfoin Seedling1
Authors: Cooper C. S. , Fransen S. C. 
Published: July 2010

We studied growth of the sainfoin (Onobrychis viciaefolia Scop.) seedling in three experiments designed to measure energy relationships during early seedling development and the photosynthetic contribution of the cotyledons.Growth of the sainfoin seedling depends on stored substrates during the first 7 days of growth. Stored substrate, however, was not adequate for normal first‐leaf formation and expansion, which appeared to depend on cotyledonary photosynthesis. Once stored reserves have been used, cotyledon photosynthesis is of major importance to early seedling growth. Covering the cotyledon resulted in: (1) a greater proportion of accumulated dry matter being transported to leaves and stems at the expense of root growth; (2) a significant decrease in specific leaf weight of first leaves; and (3) a reduction in seedling growth of 36% at 18 days of age. Cotyledons provided all of the photosynthate when seedlings were 7 days old. A subsequent decrease in photosynthetic contribution of cotyledons was in proportion to the decrease in cotyledon area as a percentage of total photosynthetic area and was only 18% by the time seedlings were 19 days old.
Function of Peroxidase in Resistance of Soybean to Bacterial Pustule1
Authors: Urs N. V. Ramaraje , Dunleavy J. M. 
Published: July 2010

Peroxidase activity of soybean [Glycine max (L.) Merr.] plants was determined to investigate its possible role in disease resistance. Activity of the enzyme was determined in mitochondrial and supernatant fractions obtained from roots of the near‐isogenic soybean cultivars ‘Clark’ and ‘Clark 63,’ susceptible and resistant, respectively, to bacterial pustule disease caused by Xanthomonas phaseoli var. sojensis. Peroxidase activity in both mitochondrial and supernatant fractions from roots of Clark 63 was greater than in those from Clark. Peroxidase activity was higher in the mitochondrial fraction than in the supernatant fraction from Clark 63.Peroxidase activity of the mitochondrial fraction from Clark 63 was threefold greater than that of Clark. Peroxidase was partially purified from mitochondria from roots of both cultivars. The peroxidase preparation from Clark 63 had greater bactericidal activity in the presence of hydrogen peroxide than that of Clark. There was a highly significant correlation between peroxidase activity per mg protein in the root preparations and percent survival of bacterial cells. A correlation coefficient of ∓0.7112 was obtained when ascorbic acid was present in the bactericidal assay system, and a coefficient of ∓0.6141 was obtained when ascorbic acid was omitted from the system.
Windbreak Influence on Water Relations, Growth, and Yield of Soybeans1
Authors: Frank A. B. , Harris D. G. , Willis W. O. 
Published: July 2010

Response of ‘Norman’ soybeans [Glycine max (L.) Merr.] to a shelter‐induced microclimate was studied under dryland and irrigated soil water regimes. Leaf water potential (Ψ1), xylem water potential (ΨX), stomatal diffusion resistance (rB), canopy temperature, dry matter accumulation, leaf area, leaf density, plant height, and yield components were measured to determine the effects of shelter influences on a soybean crop.Plant water status, characterized by measuring Ψ1, ΨX, rB, and canopy temperature during selected days, was strongly affected by soil water regime and sheltered conditions. The treatment combination of shelter plus irrigation resulted in the most favorable plant water status. Under dryland, where soil water was limiting, plant water status of the sheltered and exposed treatments was similar.Dry matter production, green leaf area, and plant height were generally increased under sheltered treatments if soil water was not limiting. Dryland sheltered treatments showed early vegetative stimulation when compared to exposed treatments, but the resulting depletion of soil water in the sheltered treatment restricted later growth. Both irrigated and dryland sheltered plants had a lower leaf density compared to exposed plants.Soybean yields were increased from 20.4 hl/ha for the irrigated exposed treatment to 24.0 hl/ha for the irrigated sheltered treatment. Under dryland, the yields were 11.8 and 12.8 hl/ha for exposed and sheltered treatments, respectively.
Response of Intersubspecific Peanut Hybrids to Photoperiod1
Authors: Wynne J. C. , Emery D. A. 
Published: July 2010

Three peanut (Arachis hypogaea L.) lines tracing to three geographic areas of South America and representing Valencia, Virginia, and Spanish types and their three F1 hybrids with reciprocals were evaluated for response to short‐ and long‐day treatments in the North Carolina State Phytotron Unit of the Southeastern Environment Laboratories.Lines and hybrids, when grown under a 9‐hour shortday photoperiod, were smaller but produced more fruit than when they were grown under a long‐day treatment produced by 9 hours of light plus a 3‐hour interruption of the dark period. The Valencia and Spanish lines flowered earlier and produced more flowers and fruit than the Virginia line.Most hybrids showed greater heterotic response for fruit yield under short than under long days. All hybrids exceeded the midparent value for the yield of fruit for the short‐day treatment, while only two of the six crosses exceeded the midparent value for fruit yield under long days.Reciprocal crosses involving the Spanish line showed significant differences for five of seven characters. Means were superior when the Spanish Hne was used as the female.
Performance of Original and Advanced Maize Populations and Their Diallel Crosses1
Authors: Genter C. F. , Eberhart S. A. 
Published: July 2010

Six maize (Zea mays L.) breeding populations, 7 advanced populations developed from them by recurrent selection, diallel crosses among all 13 populations, and 9 check hybrids were evaluated in 17 environments during 1970 and 1971. The objective was to evaluate, under a wide range of environmental conditions, observed progress from three methods of recurrent selection and to estimate changes in genetic parameters obtained from a diallel of the original populations versus estimates from a diallel of the advanced populations. VCBS(S)C4 and VCBS(HT)C3 were about 20% higher yielding than VCBS; this improvement was expressed in their population crosses. Selection also increased the environmental response (b1) of these populations and their crosses. Very little improvement was detected for the other populations or their crosses. Source materials and environmental conditions under which recurrent selection trials are conducted may be as important as the selection method used.Population and average heterosis effects explained most of the variation among entries. Hence, relative performance of the population crosses could be predicted reasonably well by population performance per se. Yields of the best population crosses did not differ significantly from yields of the hybrid checks. Extraction of inbred lines from VCBS(S)C4 or VCBS(HT)C3 to be used with lines extracted from BSSS(HT)C7 or PHWI(M)C9 should resuit in superior hybrids with a wide range of adaptation.
Cotton Flowering and Fruiting Responses to Application Timing of Chemical Growth Retardants1
Authors: Thomas Robert O. 
Published: July 2010

The influence of several chemical growth modifiers on suppression of undesirable late fruiting and on yield of cotton (Gossypium hirsutum, L.) was studied in 1972 and 1973. Plant responses were critically dependent on timing of application. With application at first flower, two compounds had no effect on rate of flowering, but reduced boll retention from 3rd and 4th week flowers. A third compound reduced both flowering and boll retention during weeks 4 and 5. Yield was significantly reduced in each case. A fourth compound was evaluated at three dates of application: Jul. 23, Aug. 8 (peak of flowering), and Aug 23. Yield was reduced by treatment at the early and intermediate dates. Treatment Aug. 23 did not reduce yield significantly but effectively suppressed late boll set.Comparisons of yield responses to growth retardants for both years revealed that the 1973 crop with generally higher yield, was the more sensitive to yield reduction. Application in early to mid‐August at peak of flowering reduced yield significantly in 1973, whereas application 2 weeks later did not. Boll weight was reduced somewhat in late opening bolls from plots sprayed at peak of flowering. Thus chemical growth retardants that suppress late boll set may also impair full development of the last bolls that mature. Therefore, application timing is a compromise between the desired earlier termination of fruit set and the possible loss in yield and quality of late‐opening bolls.
Correlation of Fusarium Wilt of Cotton in the Field and Greenhouse1
Authors: Kappelman A. J. 
Published: July 2010

Cultivar expression of cotton (Gossypium hirsutum L.) to Fusarium oxysporum Schlecht f. vasinfectum (Atk.) Snyd. & Hans, was studied under field conditions where nematodes were present and under greenhouse conditions where only the wilt fungus was artificially introduced into the plant.In greenhouse studies, seedlings were artificially inoculated with either mixtures or individual wilt isolates in the absence of nematodes. When a highly‐virulent isolate of fusarium was used for greenhouse inoculations, results were highly correlated with those obtained under field conditions where nematodes and wilt were both present. Isolates of fusarium obtained from resistant or susceptible varieties were not always of high or low virulence, respectively. Therefore inoculum of known high virulence must be used in greenhouse tests for symptom expression to be correlated with that obtained under field conditions.
Effect of Diseases on In Vitro Digestibility of Smooth Bromegrass1
Authors: Gross D. F. , Mankin C. J. , Ross J. G. 
Published: July 2010

Disease epidemics reduce the forage yield of smooth bromegrass (Bromus inermis Leyss.) but little is known about their effects on in vitro dry matter digestibility (IVDMD). Thirty‐one gcnotypes infected with three pathogens through natural inoculation in the field were evaluated for incident foliar diseases and IVDMD percentages. IVDMD percent was negatively correlated (—0.64, significant at the 1% level) with disease percent. A 1% increase in diseased area on the leaf, and age of leaf (as measured by one leaf lower on the culm), decreased IVDMD 0.12% and 0.19%, respectively.Greenhouse inoculation of 33 genotypes with Drechslera bromi (Died.) Shoem. produced a significant decrease in IVDMD. Inoculation with bromegrass mosaic virus did not significantly reduce in vitro digestibility. Greenhouse inoculation of the same genotypes with Rhynchosporium secalis (Oud.) Davis. resulted in significant differences between IVDMD of inoculated and uninoculated plants; linear regression showed that the effects of increasing disease lesions by 1% would decrease IVDMD by only 0.04%. Since low levels of infection did not appear to have a large effect on digestibility as measured by IVDMD, a medium degree of resistance to foliar diseases should be sufficient for a smooth bromegrass cultivar for pasture use.
Stomatal Size and Frequency in Soybeans1
Authors: Ciha A. J. , Brun W. A. 
Published: July 2010

AbstractThe stomatal frequency of 43 soybean [Glycine max (L.) Merr. genotypes varied significantly. The mean frequency on the adaxial surface was 130 (range: 81 to 174); on the abaxial surface, it was 316 stomata/mm2 (range: 242 to 345). The mean guard cell lengths were 21.9 and 20.4 µ for the adaxial and abaxial surfaces, respectively.Stomatal frequency and leaf area were measured on the terminal leaflet of the third trifoliolate of soybeans grown at 18, 24, and 30 C and at 19,300 and 32,300 lux. Stomatal frequency significantly decreased with temperature on the abaxial surface, but there was no effect on the adaxial surface. Stomatal frequency significantly increased with light intensity on both surfaces. Leaf area increased with temperature and decreased with light intensity. Stomatal number/leaflet did not vary significantly with light or temperature treatments.Water‐stressed, field‐grown plants had significantly greater stomatal frequency and smaller leaf area than nonwater‐stressed plants. Stomata/leaflet surface were significantly lower on water stressed plants than nonwater‐stressed plants.
Genotypic and Phenotypic Variances and Correlations in Peas1
Authors: Pandey Shivaji , Gritton E. T. 
Published: July 2010

AbstractEight lines of peas (Pisum sativum L.) and all possible Fl's among them were grown in five environments to study the genotypic and phenotypic variances and correlations among eight traits. Genotypes and environments had highly significant effects on all traits. Parents exhibited highly significant genotype × environment interactions but Fl's were remarkably stable.Plant height was often positively correlated with pods/plant, seeds/plant, and yield/plant, indicating superior yielding ability of taller plants. However, indeterminate growth is unacceptable in peas for canning because of the range in maturity of peas borne at the different nodes and the excessive vine growth which interferes with harvesting. Correlations of percentage seed protein with the different traits were variable, but generally positively correlated with increased yield. There was some indication of lower protein with heavier seeds. Strong positive genotypic and phenotypic correlation coefficients obtained between pods/plant and seeds/plant, seeds/pod and seeds/ plant, and between those two traits and yield/plant, indicate that selection for either or both of these traits would result in superior yield. The genotypic correlation between weight/seed and yield was high, but the phenotypic association was low.
Genetic Variability for Chemical Composition of Alfalfa. I. Mineral Elements1
Authors: Hill R. R. , Jung G. A. 
Published: July 2010

A series of four‐parent diallel crosses was constructed with patents randomly selected from ‘Saranac’ alfalfa (Medicago sativa L.). The single crosses and parents were evaluated in small field plots during each of 2 harvest years to determine genetic variability for mineral concentration. Quantitative genetic analyses were conducted for concentrations of phosphorus, potassium, calcium, magnesium, manganese, iron, copper, boron, aluminum, zinc, sodium, and Ca/P in first‐harvest forage.Significant additive genetic variance was observed for all traits, except Cu, Al, Zn, and Na concentrations. Except for digenic genetic variance for Cu concentration, nonadditive genetic variances were not significant. At the soil fertility levels of our experiment, clones from Saranac alfalfa contained less P, Cu, Zn, and Na, more K and Ca, and a higher Ca/P ratio than recommended for a moderately producing dairy cow. Deviations from the recommended levels of the remaining elements were minor and considered unimportant. Estimated potential ranges of mineral concentrations that could be achieved through plant breeding showed that i) the P‐deficiency could be corrected, ii) correction of the Zndeficiency and the excessive Ca/P ratio would be possible, but difficult, and iii) deviations from dairy cow requirements for Cu, Na, K, and Ca could not be corrected through plant breeding without alteration of soil fertility levels.Genotypic correlations were significant for the following pairs of traits: P and K, P and Fe, K and Fe, Ca and Mg, Ca and Fe, Ca and the Ca/P ratio, and Mg and Fe. All these genotypic correlations were positive.
Low Temperature‐induced Floret Sterility in Rice1
Authors: Lin Shiow Shong , Peterson Maurice L. 
Published: July 2010

Sterility of 296 rice breeding lines grown in the field at Davis, Calif., ranged from 3.6 to 96.8%. Mean sterility was 30.1% from an April 28 seeding and 35.2 for a May 7 seeding. A large part of the variability was caused by differential tolerance to cool night temperature at the young microspore stage of pollen development (10 to 15 days before heading). Higher sterility from the later seeding was probably associated with cooler temperature during this critical period. Growth chamber trials indicated that percent sterility increased in almost direct relation to cool‐temperature exposure. No difference was found between cool‐temperature treatments only during the dark and cool temperature during both dark and light so long as the total length of exposure was the same.Floret and pollen sterility were highly correlated, whereas cool‐temperature‐treated plants fertilized with pollen that was not cool treated were equal in sterility to self‐pollinated, cool‐temperature‐treated plants. Comparisons of plants exposed to various light and darkperiod temperatures showed least sterility at 28 to 24 C and most at 36 to 16 C. Proposed procedures for screening rice germplasm for tolerance to temperature extremes are discussed.
Average Gene Frequency Estimates in Two Open‐Pollinated Cultivars of Corn1
Authors: Goodrich C. L. , Stucker R. E. , Compton W. A. 
Published: July 2010

The purpose of this study was to obtain information on average gene frequency in two corn (Zea mays L.) populations. A design I mating system consisting of 100 males crossed to three females was developed in each of two open pollinated cultivars, ‘Golden Jewel’ and ‘Osterland's Yellow Dent.’ In addition, the male plants of the design I in each cultivar were selfed and crossed to females of the other cultivar. The intra‐population progenies, the inter‐population progenies, and S1 progenies from each cultivar were evaluated at two locations for yield, ear moisture, stalk lodging, and ear height. Days to flower was evaluated at one location only.Ratios of estimated genetic components of variance and covariance were compared with corresponding theoretical ratios computed for various gene frequencies and levels of dominance. From these comparisons, approximate ranges of the gene frequencies in the two cultivars and relative magnitudes of gene frequencies were obtained.The average frequency of favorable genes for yield appeared to be greater than 0.5 in both cultivars. There was some indication that the frequencies of favorable genes were lower for the other traits than those for yield. The ratios of variances among S1 progenies and covariance of S1 progenies with intra and inter‐cultivar crosses did not appear to add new information on gene frequencies, but supported the information gained from the comparison of the ratio of additive to dominance variance, the ratio of intra to inter‐cultivar variance, and the ratio of covariance of intra‐cultivar crosses with inter‐cultivar crosses. The average gene frequency for yield appeared to be higher in Osterland's Yellow Dent than in Golden Jewel.