bluuebunny/crossref_metadata_2025 huggingface dataset:
Psychrometric Analysis of Turgor Pressure Response: A Possible Technique for Evaluating Plant Water Strees Resistance1
Authors: Johnson Douglas A. , Brown Ray W.
Published: July 2010

Turgor pressure responses were determined over a range of water stress for Zea mays L., Bromus inermis Leyss., and the following colchicine‐induced Agropyron amphiploid hybrids: A. dasystachyum (Hook.) Scribn. ✕ Acaninum (L.) Beauv., A. spicatum (Pursh) Scribn. & Smith ✕ A. dasystachyum, and A. fibrosum (Schrenk) Nevski ✕ A. trachycaulum (Link) Malte ex H. F. Lewis. These plants were grown in a greenhouse and then allowed to acclimate to a growth chamber for 10 days before turgor pressure was determined. Water potential components of detached leaf samples were measured by a psychrometric technique involving freezing and thawing of the leaf tissue. Water was withheld from the potted plants to determine turgor pressure over a range of water stress levels. Linear regressions of turgor pressure on leaf water potential were statistically significant for all comparisons of regression intercepts. Slope comparisons of Bromus inermis and Zea mays with A. dasystachyum ✕ A. caninum and A. spicatum ✕ A. dasystachyum were also statistically different. Predictions of resistance to water stress based on species ability to maintain positive turgor agreed closely with field observations. The ability of this technique to distinguish differences in turgor response between Agropyron hybrids with a common parent suggests that this technique may be useful for screening plant materials for superior resistance to water stress.
Development and Evaluation in an Opaque‐2 Maize Composite at Three Plant Population Densities1
Authors: Singh B. N. , Singh Joginder
Published: July 2010

Biparental progenies (NC Design‐l) were developed an opaque‐2 composite of maize (Zea mays L.) at 25,000, 50,000 and 100,000 plants ha‐1. They were evaluated at each of these three densities to determine the most appropriate density for development and testing to maximize grain yield. Maximum grain yield, moisture content, plant height, and ear height were observed with hybridization and testing at 100,000 plants ha1‐ Hybridization at the lowest density with progeny testing at the highest density gave the lowest yield. Irrespective of the level of evaluation, the progenies developed at 100,000 plants ha1‐were superior to those developed at the lower population density.
Ethiopia as a Source of Resistance to the Barley Yellow Dwarf Virus in Tetraploid Wheat1
Authors: Qualset C. O. , McGuire P. E. , Vogt H. E. , Topcu M. A.
Published: July 2010

Because Ethiopia provided the only source of resistance to the barley yellow dwarf virus (BYDV) disease in barley (Hordeum vulgare L.), a test for parallel variation was made with Ethiopia tetraploid wheats (Triticum turgidum L.). High levels of BYDV resistance have not been found in wheat (T. aestivum L. em Thell. or T. turgidum L.). Ethiopian materials from the USDA world collection were no exception, but 40 entries out of the 584 tested showed tolerance in 4 or 5 years of field tests. Three entries (CI 17610, CI 17621, and CI 17647) had symptom expression comparable to ‘Anza,’ a tolerant common wheat cuitivar, but none was as resistant as certain Ethiopian barleys. Ethiopia is apparently not a center for BYDV resistance in wheat, but further collections are needed.
Root and Top Growth of Irrigated and Nonirrigated Grain Sorghum1
Authors: Kaigama B. K. , Teare I. D. , Stone L. R. , Powers W. L.
Published: July 2010

Limited field research has related grain sorghum [Sorghum bicolor (L.) Moench] root to top development at more than one stage of growth. This work investigated the relationship between depth and distribution of grain sorghum roots in the field and above‐ground morphological development (plant height, leaf area index, and dry matter) during the growing season under irrigated and nonirrigated conditions. Soil cores were taken by machine throughout the season, and roots were washed free from soil using a 35‐mesh screen to collect roots. Soil water content was estimated in the 15 to 150 cm soil profile by neutron moderation and in the 0 to 15 cm layer by gravimetric sampling throughout the season. Rapid root penetration was characteristic of root development early in the growing season. Traces of roots were observed at depths of 140 to 150 cm 6 weeks after emergence. Root dry matter per 1.08 dm2 of soil surface reached a maximum of 17.1 and 12.3 g at 9 and 10 weeks after emergence in the irrigated and nonirrigated sorghum, respectively. Maximum l/3‐row root dry matter accumulation occurred about 8 weeks after emergence. A difference between irrigated and nonirrigated treatments was the increased quantity of irrigated roots in the top 15 cm of soil. A greater proportion of total root dry matter accumulated at the deeper depths in the nonirrigated than in the irrigated sorghum. Leaf dry matter increased minimally after the 7th week, but stem dry matter increased and peaked 8 weeks after emergence in both treatments. Stem dry matter declined in both treatments during panicle development. Maximum rate of dry matter accumulation of both roots and tops was higher in the irrigated treatment.
Production and Utilization of Anther‐Derived Haploids in Crop Plants1
Authors: Collins G. B.
Published: July 2010

The production of large numbers of haploid plants from the culture of immature anthers on chemically defined agar media is now possible with a number of plant species. Data are presented which illustrate that media formulation, environment under which plants produce anthers, anther culture environment, cytological stage of the microspores, and genotype of the cultured species influence the successful production of haploid plants by anther culture and should be considered in attempting to obtain haploid plants by anther culture in other species. Several methods are now being successfully used to double the chromosome number of haploid plants. Haploid plants and homozygous diploid derivatives from these haploid plants are being used in both practical and fundamental studies. Superior breeding lines in Nicotiana, characterized by changes in chemical and agronomic traits, have been developed by the haploid procedure. Haploid plant material is particularly useful in induced mutagenesis studies. Anther culture has also been instrumental in the development of nullihaploid, nullisomic, trisomic, and tetrasomic aneuploid stocks in Nicotiana tabacum.
Maximum Percentage of Mature Fruits and Associated Characters at Two Intra‐Row Spacings in Peanuts1
Authors: Gilman D. F. , Smith O. D.
Published: July 2010

Peanuts (Arachis hypogaea L.) harvested at any time include immature fruits due to the indeterminate growth characteristic of the species. Immature peanuts represent a loss in plant metabolites and have been associated with both organoleptic and storage problems. This study was conducted to assess the feasibility of genetically reducing the percentage of immature fruits at harvest. Ten genotypes differing in botanical type and geographical source were evaluated for differences in maximum percentage of mature fruits (MPMF) at both conventional (5 to cm) and wide (46 cm) intra‐row spacings. Associations of several seedling, flowering, and fruiting characters also were studied.

Genotype differences in MPMF were highly significant, with mean values ranging from 92.5 to 78.0. Years and the year ✕ genotype interaction were not significant. The results indicate that peanut genotypes differ in MPMF and that selection of superior genotypes should not be seriously complicated by genotype ✕ environmental interactions. Higher MPMF values were obtained at the close than at the wide intra‐row spacing. Interactions between genotype and intra‐row spacing were not significant indicating that selection of superior genotypes could be made effectively at either plant spacing. Correlations with MPMF generally were higher for flowering characters than for seedling or fruiting characters and higher at the wide than at the conventional intra‐row spacing. Correlations of MPMF with days from planting to opening of 25, 50, and 100 flowers and exertion of 25 pegs were all negative and highly significant for the wide intra‐row spacing.
Effect of Irrigation with Sewage Wastewater, Cutting Management, and Genotype on Tawny Blotch of Reed Canarygrass1
Authors: Zeiders K. E. , Sherwood R. T.
Published: July 2010

This study was undertaken to determine the effect of irrigation, cutting management, and genotype on severity of tawny blotch caused by Stagonospora foliicola (Bres.) Bubak in reed canarygrass (Phalaris arundinacea L.) used as a covercrop for land disposal of municipal sewage wastewater. Twelve clones were established in nonirrigated blocks and in blocks sprinkler‐irrigated with 5 cm of wastewater weekly from late May to early September. In the year after establishment (1975), plots were harvested at an 8‐cm height on 4 June and 3 October (twocut management); half of the plots were also harvested 31 July (three‐cut management). Clones were rated for naturally‐occurring disease prior to cutting on 31 July and 30 September.

Irrigated plots had significantly more tawny blotch (P <0.01) than nonirrigated plots on both rating dates. About 67% of the treatment effects on tawny blotch severity were attributed to irrigation with sewage wastewater. The lesser effects of date of rating, cutting management, and interactions of irrigation ✕ date of rating, and cutting management )✕ date of rating were significant at P <0.01. The three‐factor interaction of irrigation ✕ cutting management )✕ date of rating was significant at P <0.05. The irrigation )✕ cutting management interaction was not significant. Clones varied from resistant to highly susceptible. Reactions of most clones were consistent between rating dates or cutting treatments.

This study showed that when reed canarygrass is grown on sites used for land disposal of sewage wastewater, a three‐cut harvest system significantly reduced tawny blotch in most genotypes tested. The greenhouse ratings of clones were significantly correlated (r = 0.58 to 0.65) with field ratings except for two‐cut irrigated plots on 30 September.
Genetic Analyses of Four Diethyl Sulfate‐Induced Culm Height Mutants of Sorghum1
Authors: Singh Shree P. , Drolsom P. N.
Published: July 2010

Four diethyl sulfate‐induced culm height mutants of Sorghum bicolor (L.) Moench were crossed among themselves and to the parental cultivars and four tester lines to obtain information on inheritance of the mutant characters. The mutants varied phenotypically among themselves and were different from the parental cultivars and from the tester lines for culm height, internode length, and node number.

One mutant (ES‐1) showed a digenic difference for culm height, but two others (ES‐2 and RO‐1) exhibited monogenic differences in crosses with their parental cultivars. Monogenic inheritance was shown for internode length and number of nodes for progenies from mutant ✕ parent crosses ES‐2 and RO‐I. Data from crosses among mutants suggested that E‐2 and R‐I were nonallelic to each other for culm height, but ES‐I showed high dominance with ES‐2 and RO‐I for this character. Mutant ES‐3 was much different from the three others and did not allow flowering in 1972. Its behavior suggested that possibly a major mutation had occurred at a locus other than the four known height loci.

Non‐additive effects played a more important role than additive effects in the expression of culm height and internode length. The ratio of h/d suggested high overdominance in most crosses for these two characters. The converse was true for number of nodes.
Genetic Vulnerability and Germplasm Resources of the True Clovers1
Authors: Taylor N. L. , Gibson P. B. , Knight W. E.
Published: July 2010

The cultivated clovers (Trifolium spp.) are susceptible to a wide diversity of pests, and potential vulnerability exists in part because of a lack of programs that monitor crop‐pest relationships. The trend in number and diversity of cultivars of the cultivated species is downward, perhaps because of emphasis on other crops and narrowing of gene bases by breeding. However, because the cultivated clovers are mostly cross pollinated, heterozygous, and heterogeneous we do not believe they are particularly vulnerable at present.

Germplasm resources are believed to be in a more hazardous position. Although many accessions of the cultivated species have been assembled at USDA Regional Plant Introduction stations and by scientists of other agencies, the accessions have not been examined and cataloged extensively for genetic characters including pest resistance. Only a few germplasm pools are now being maintained in the cultivated species. A complete collection of the wild Trifolium species has not been assembled, and many of those once available have been lost. It is recommended that collection of species and ecotypes of Trifolium be started immediately so that variability in the genus can be preserved and analyzed. Phylogenetic studies, including interspecific hybridization in the genus, should be expanded. Methods of evaluation and use of accessions should be established by a committee of experts for the Trifolium genus so that recommendations for action can be made to a national coordinating committee concerned with germplasm resources.
Differential Responses of Corn Inbreds And Hybrids to Alachlor1
Authors: Narsaiah D. Bala , Harvey R. G.
Published: July 2010

The relative susceptibility of eight corn (Zea mays L.) inbreds and eight of their 28 possible single‐cross hybrids to alachlor (2‐chloro‐2′,6′‐N‐(methoxymethyl) acetanilide) was studied in a Piano silt loam soil under greenhouse conditions. Alachlor was applied preemergence at broadcast rates of 0, 2.5, 5.0, and 10.0 kg/ha. Fifteen to 17 days after emergence the seedlings were harvested and shoot height and dry weight of shoots/plant used to measure herbicidal tolerance. The results obtained demonstrated the existence of differential alachlor tolerances among both inbreds and hybrids. Alachlor severely injured inbreds W117, W182E, and A635, but inbreds WI53R and W59M were not affected even at 10.0 kg/ha. At the normal 2.5 kg/ha rate of alachlor, both shoot height and dry weights were substantially reduced in the hybrids W64A ✕ W117, W64A ✕ OH43, and W64A A632 and shoot heights were reduced in W59M )✕ W117 and OH43 ✕ A635. At both 5.0 and 10.0 kg/ha of alachlor, W64A ✕ W59M, exhibited greater tolerance than other hybrids.
Delinting Small Samples of Cotton Seed with Dilute Sulfuric Acid1
Authors: McCarty J. C. , Lambert Lavone , Jenkins J. N. , Parrott W. L.
Published: July 2010

The current procedure of using concentrated sulfuric acid to prepare numerous small samples of cotton seed for planting is tedious and is hazardous to both the seed and the technician. A dilute sulfuric acid process was adapted to delint small samples of cotton (Gossypium hirsutum L.) seed. Three to four hundred samples per day, each ca. 80 g of fuzzy seed, can be delinted using this process. More than 6,000 small samples were delinted and planted in 1976; germination was not affected.
Stomatal Indexes in Three Ploidy Levels of Bromus Inermis Leyss1
Authors: Lea H. Z. , Dunn G. M. , Koch D. W.
Published: July 2010

Stomatal index was investigated as a potential morphological characteristic which may be useful in selecting for improved gas exchange or water relations in smooth bromegrass. The lower stomatal frequency per unit leaf area in the normal 8X plants than in 4X and 6X plants was due to the larger epidermal cell size. Epidermal cell size was the main factor determining stomatal frequency. A highly significant correlation (r = 0.96) was obtained between stomatal and epidermal cell frequency. Stomatal index on the adaxial leaf surface was about 15%, regardless of ploidy levels.
Effect of the Waxy Gene on Hydrolysis of Sorghum Starch1
Authors: Tovar Douglas , Liang G. H. , Cunningham Bryce A.
Published: July 2010

Dosage effect on the rate of starch granule hydrolysis by α‐amylase was investigated with starch isolated from three sorghum (Sorghum bicalor L. Moench) cultivars. Because the cultivars are not isogenic for all genes other than at the waxy locus, their F1 hybrids, and reciprocals were also compared by both chemical and microscopic observations. Starch from ‘Texioca‐63’, a cultivar with waxy endosperm, had the most hydrolysis, as indicated by reducing groups liberated when incubated with α‐amylase. In hybrids, starch from endosperm genotypes with two doses of the recessive waxy allele were more readily hydrolyzed than starch from those with one dose. The cultivars with nonwaxy endosperm, ‘Combine Kafir 60’ and ‘PL‐I’, differed, and starch from crosses having PL‐1 as female parent had the lowest hydrolysis rate, suggesting that factors other than waxy gene also affect digestion of starch by α‐amylase. The amount of starch hydrolysis by chemical analysis corresponded with starch granule degradation observed by scanning electron microscope.
Interaction of Genetic Factors for Fertility Restoration in Hybrid Wheat1
Authors: Johnson Jerry W. , Patterson F. L.
Published: July 2010

Four different sources of genes for fertility restoration in wheat, Triticum aestivum L. em Thell., were intermated to study the interaction of these genes in the heterozygous condition compared to their homozygous parents. Parents and hybrids were evaluated for pollen production and dispersal in the laboratory on excised spikes from plants grown under field and greenhouse environments. Seed set was also evaluated in diverse controlled environments.

Parental restorer sources showed variation for pollen production and dispersal as well as for seed set. Hybrids heterozygous for restorer genes from single sources were inferior to their homozygous parents and to the restorer ✕ restorer hybrids. Most combinations of the different sources of fertility restoration in the hybrid were equal or superior to their homozygous parents for pollen production and dispersal and for seed production. The best combinations of restorers were of Triticum timopheevi/ *3‘Marquis’ parents with parents TBR 26 or TBR 76.

Both general combining ability and specific combining ability were highly significant for pollen production characters and for seed set. General combining ability for all characters except total pollen production made up the major portion of the total genetic variability.
Inheritance of Phytosterol Content in Tobacco1
Authors: Tojib Asep , Davis D. L. , Legg P. D.
Published: July 2010

The pattern of sterol concentration and estimates of combining ability effects were studied in seven selected tobacco (Nicotiana tabacum L.) genotypes. Data for total sterols and individual sterols in air‐cured laminae were obtained from the parental genotypes and all possible crosses among the genotypes.

Total sterol contents of the genotypes ranged from 1.46 to 2.34 mg/g dry weight. Stigmasterol had the highest concentration of the four sterols in four of seven lines, while in the other three lines, sitosterol was predominant. The cumulative total of stigmasterol and sitosterol accounted for about 70% of the total sterol. Cholesterol was present in the least amount, followed by campesterol.

With the exception of cholesterol, average heterosis was less than 2% and nonsignificant. The analysis of combining ability revealed that the variances of GCA effects for five variables (total sterol, cholesterol, campesterol, stigmasterol, and sitosterol) were significant (0.05 level). Variances of SCA effects were signiicant (0.05 level) for stigmasterol, sitosterol, and total sterols. The relative magnitudes of the GCA and SCA effects suggest that the variables were governed more by additive gene action than by dominance. The relatively low amounts of nonadditive types of gene action was substantiated by the (Wr, Vr) graphs. Breeding procedures designed to accumulate favorable alleles at all loci should be an effective means for altering sterol content.
Testa Comparisons of Four Peanut Cultivars1
Authors: Glueck James A. , Clark L. E. , Smith O. D.
Published: July 2010

Testa integrity and seed quality of four cultivars dried at two temperatures were compared on the basis of percentage sound split kernels. Multiple harvests compensated for differences in maturation rates. ‘New Mexico Valencia A’ had fewer sound split kernels than either ‘Starr’ or ‘Florunner’. Start and Florunner had a twofold increase in sound split kernels with extreme (approximately 49 C) compared to recommended (35 C maximum) drying temperatures. The increase in sound split kernels in New Mexico Valencia ‘A’ was nonsignificant. ‘NCFLA 14’ was similar to New Mexico Valencia ‘A’ with recommended drying, but had a significantly higher percentage of sound split kernels with extreme drying. Genetic improvements through breeding should be possible in both subspecies fastigiata and hypogaea of Arachis hypogaea L. Examination of testae by light and electron microscopy revealed that testa thickness, appearance, and structure varied with cultivar, maturity, and area of seed examined. Testae of mature New Mexico Valencia ‘A’ seed were, in general, less compacted and more flexible than those of Starr and Florunner. When dried at 49 C, New Mexico Valencia ‘A’ testae lost some flexibility but did not become brittle like Starr. The middle parenchyma cells of Starr testae appeared crushed and compressed against the thick‐walled inner parenchyma cell layer. Thin inner parenchyma, non‐compact middle parenchyma and relatively thick‐walled outer sclerenchyma cell layers seemed to be primary factors related to maintenance of testa integrity. Testae of mature seed of Florunner and NC‐FLA 14 were similar to Starr and New Mexico Valencia ‘A’, respectively.
Effect of Leaf Width on Responses of Tall Fescue Genotypes to Defoliation Treatment and Temperature Regimes1
Authors: Asay K. H. , Matches A. G. , Nelson C. J.
Published: July 2010

Tall fescue (Festuca arundinacea, Schreb.) genotypes, selected to represent a range in leaf widths, were subjected to several combinations of defoliation treatments and temperature regimes. The effects and interrelationships of characters associated with forage yield were studied with the objective of ultimately developing more meaningful selection indices. Genotypic differences in tillering capacity were associated with leaf width. Number of tillers of genotypes selected for wide, medium, and narrow leaves increased 302, 342, and 406%, respectively, over a 15‐week period in the greenhouse. Increasing stubble height from 4 to 12 cm resulted in increased tillering and energy reserves and lower forage yield. Tillering, dry matter yield, and energy reserves increased as number of tillers left uncut at each harvest increased from 0 to 20%, and they tended to remain constant from 20 to 40% intact tillers.

Genetic and temperature effects on tillering were significant at 17/7, 22/12, 27/17, and 32/22 C (day/night) temperature regimes in controlled environment chambers. Maximum tillering occurred at 22/12 C and declined significantly at higher temperatures. A genotype with narrow leaves from North Africa (194‐24) produced significantly more tillers than genotypes selected from North American strains and cultivars, particularly at lower temperature regimes. Although leaf width and number of tillers were negatively correlated (r = _0.67), neither was significantly correlated with dry matter yield.
Inheritance of Shattering in Wild Rice1
Authors: Elliott W. A. , Perlinger G. J.
Published: July 2010

Wild rice (Zizania aquatica L.) is a native annual aquatic cereal that grows in lakes and streams in the upper great lakes region of North America. Native ecotypes shed staminate florets shortly after anthesis and grain shatters over a 2 to 3 week maturation period. A mutant was found which retains its staminate florets beyond anthesis and has a moderate degree of resistance to seed shattering. Objectives of this study were to determine the mode of inheritance of shattering resistance and to determine the relationship between staminate floret retention and resistance to seed shattering.

Crosses were made between five shattering susceptible plants and five shattering resistant plants. The resulting S1, F1, and F2 progenies were studied. Two complementary dominant genes were proposed to explain the observed segregations. Susceptibility to shattering occurred when at least one dominate allele (Sh− Sh2−) was present at both loci. Shattering resistant genotypes were: sh sh sh2 sh2, sh sh Sh2−, and Sh− sh2 sh2. All F2 plants which retained 100% of their staminate florets at the completion of anthesis were classed as resistant, while all those which lost all of their staminate florets were classed as susceptible. Other plants were observed that retained some staminate florets. Some of these plants were susceptible and some were resistant to shattering. The selection of shattering resistant plants at anthesis can be accomplished by selecting plants having 100% staminate floret retention.
Proline Accumulation in Water Stressed Cotton Leaves1
Authors: McMichael B. L. , Elmore C. D.
Published: July 2010

Greenhouse‐grown cotton (Gossypium hirsutum L.) plants were subjected to a drying cycle when the plants had four true leaves and the proline content of the leaf tissue was determined. Free proline accumulated to about 100 times the concentration of the well‐watered controls as the stress increased. The threshold of the predawn leaf water potential for proline accumulation was about —15 to —17 bars. Total proline content also increased, which suggested that there was some proline synthesis. Free glutamic acid concomitantly decreased. Because proline did not accumulate until the water deficits were quite severe concentration of free proline is not a good indicator of the onset of plant water stress.
Genetic Diversity in Burley and Flue‐cured Tobacco1
Authors: Legg Paul D. , Chaplin J. F. , Williamson R. E.
Published: July 2010

Chlorophyll content in burley and flue‐cured tobacco, Nicotiana tabacum L., is influenced by genetic factors at two major loci. Burley is genotypically yb1yb1yb2yb2 an has a low chlorophyll level in growing plants; whereas, a dominant allele at either locus will give a high level of chlorophyll characteristic of flue‐cured tobacco. A backcrossing program was used to obtain lines that were near isogenic for all genetic factors except alleles at the yb loci. Comparison of converted burley fines (ones carrying a Yb allele) with flue‐cured cultivars and tests comparing the near isogenic lines indicated that most of the genetic differences between flue‐cured and burley tobacco in chemical composition resulted from the influence of alleles at the two yb loci. The only differences between the two classes were for polyphenols and reducing sugars, and these may have been independent of the yb loci. Even these two constituents, however, showed as much diversity within classes as between classes.
A Yield‐Component Selection Experiment Involving American and Iranian Cultivars of the Common Bean1
Authors: Sarafi A.
Published: July 2010

A cross was made between Iranian and American bean (Phaseolus vulgaris L.) cultivars. Five percent of the plants having the most pods per plant in the F2 and F3 generations were selected for production of F3 and F4 lines. Heritability (narrow sense) of yield components was evaluated in F2 and F3 populations. Heritability for pods per plant was 29%, for seeds per pod 38 to 42%, and for 100‐seed weight 33 to 37%. The average dominance of genes for all components suggested partial or nearly complete dominance. To determine genetic advance, F3 and F4 lines were compared with the mid‐parent for pods per plant, seeds per pod, and 100‐seed weight. The differences between mid‐parent and selected F4 lines for pods per plant and seeds per pod were significant. Genetic advance for these characters was 30 and 19%, respectively. The results show that heritabillty for yield components in F2 and F3 populations is high enough to be useful for selection. Selection is usually made directly for yield. In this particular cross selection was made for pods per plant and promising productive lines with important Iranian marketing characteristics were obtained.
Differential Response of Sugarbeet Cultivars to Cercospora Leaf Spot Disease1
Authors: Smith G. A. , Martin S. S.
Published: July 2010

Preliminary observations and data on sugarbeet (Beta vulgaris L.) yield and quality components suggested that a possible differential response to infection by the fungus Cercospora beticola exists among sugarbeet cultivars and genotypes with different inherent levels of resistance and possibly among cultivars with similar resistance. The objectives of this study were: 1) to determine, for cultivars known to vary in leaf spot resistance, the effects of leaf spot disease on sucrose yield components and on extract chemical components which affect sugarbeet juice purity and 2) to examine whether infected cultivars with similar resistance to leaf spot respond in similar or different ways. Eight sugarbeet cultivars ranging from leaf spot resistant to leaf spot susceptible were examined under an artificially induced leaf spot epidemic in a 2‐year field study. With increasing severity of C. beticola infection there was a general increase in nonsucrose chemical components, and decrease in gross sucrose yield, yield components, and purity. Of the chemical components, Na, nitrate, amino N, and total N consistently showed the greatest increases with increased infection by C. beticola. Numerous examples of differential response of the cultivars to C. beticola infection were found for nonsucrose chemical components as well as for sucrose yield and yield components.
Effects of Intergenotypic Competition on Genetic Parameter Estimation1
Authors: Hamblin J. , Rosielle A. A.
Published: July 2010

Genetic parameters are often estimated from mixtures of genotypes, but the models used rarely take into account neighbor effects, and those that do are excessively complicated. We developed a simple model that illustrates the effects of competition on genetic parameter estimation when published data are used. The results show how unreliable predictions from mixed cultures may be for pure culture.
A Factor Analysis of Plant Variables Related to Yield in Dry Beans. I. Morphologic Traits1
Authors: Denis J. C. , Adams M. W.
Published: July 2010

A principal factor analysis was performed on 22 morphological and yield‐determining traits of 16 cultivars and strains of dry beans (Phaseolus vulgaris L.) grown in replicated field plots at two locations in Michigan. in 1970. Factors, representing patterns of variables interpreted as weight (or size), number, and plant architecture were consistently extracted across and within locations in various subsets of the data. These factors were identiifed with the “source” and “sink” constructs of crop psysiologists. It is suggested that the development of higher yielding bean cultivars must be based upon relatively large plants bearing numerous nodes, leaves, and reproductive structures, and with an architectural display of phytomeric units which facilitates more uniform light interception throughout the canopy. We caution that this generalized morphological description of a high yielding plant type is not to be taken as the complete specification of a yield ideotype in field beans.
Zinc Concentration in Soybean as Related to Growth, Photosynthesis, and Carbonic Anhydrase Activity1
Authors: Ohki K.
Published: July 2010

The influence of Zn status on growth, photosynthesis, dark respiration, and carbonic anhydrase was determined to establish the relationship of these growth processes to the critical deficiency level (CDL) for growth of soybean (Glycine max (L.) Merr. cv ‘Bragg’). Soybean was grown in nutrient solution with Zn rates of 10, 20, 50, 100, 200, 500, and 1,000 µg Zn/liter for a period of 36 days after transplanting. Critical Zn deficiency level for top dry weight was determined as 12 µg/g dry weight in recently matured leaf tissue (blade 3 from the top). Maximum photosynthesis was associated with leaf blades containing also 12 µg/g. Zinc deficiency reduced photosynthesis and carbonic anhydrase activity. Minimum dark respiration was attained at the CDL for growth and severe Zn deficiency enhanced respiration.
Relationship of Phloem Size to Leaf Size and Position1
Authors: Segovia A. J. , Brown R. H.
Published: July 2010

Prior studies have shown that phloem cross‐sectional area in leaf bases or petioles may influence the rate of export of photosynthetic products from leaves. Since information could not be found on the variability in phloem size due to leaf size and position, an experiment was conducted to study phloem area in the leaf bases of two grass species and in petioles of two dicots. Leaves were removed from several nodes on each stem when the leaf at each node became fully expanded. Tall fescue (Festttca arundinacea Schreb.), sugarcane (Saccharum officinmrum L.), soybean (Glycine max Merr.), and peanut (Arachis hypogaea L.) were grown outside during the summer in full sunlight. Soybean and peanut were also grown under 50% shade. Lamina base or petiole sections were embedded in paraffin, sectioned, and stained for measurements of phloem cross‐sectional area under the light microscope.

Leaf area increased with leaf position from the stem base toward the top. In peanut, soybean, and tall fescue, however, the distal one or two leaves were smaller than the one just below. Phloem area in the leaf bases or petioles followed a pattern similar to that for leaf area and the two parameters were closely correlated. The increased phloem area in larger leaves was due mainly to an increase in the number of vascular bundles per leaf in tall fescue and sugarcane. In soybean larger leaves had more and larger bundles per petiole and in peanut increased phloem in larger leaves was due to more phloem per bundle, since bundle number was constant at 5. Shading reduced phloem size in soybean even though leaf area was increased. Leaf area was barely affected by shading in peanut, but phloem size was reduced. Leaf weight was reduced to a greater extent than phloem size by shading, so that phloem per unit of leaf weight was increased in peanut and soybean. It is concluded that leaf position, size, and environment have an effect on phloem size that may complicate comparisons of species in studies of photosynthate translocation and anatomy.
Heterosis in Maize as Measured by K Uptake Properties of Seedling Roots1
Authors: Frick Hugh , Bauman Loyal F.
Published: July 2010

The capacity of the primary root of maize (Zea mays L.) seedlings to rapidly alter K uptake rates appears to be of adaptive value to the plant, and is related physiologically to dent corn hybrid vigor. A causal relationship is not implied.

K+(86Rb) uptake rates of seedling roots were measured in freshly excised segments (basal K+ uptake rates) and in segments after 2 hours aeration in buffer (augmented K+ uptake rates). The calculated augmentation potential (augmented rate/basal rate)100, represents the ability to rapidly alter K uptake rates and was used to estimate inbred combining ability and heterosis in 39 single‐cross hybrids, and to predict single‐cross hybrid yield to within 5.7 q/ha better than 75% of the time in our tests of 29 single‐cross hybrids.
Effects of Inbreeding on Field Performance of White Clover Selections1
Authors: Cope Will A.
Published: July 2010

Three selected clones (A, B, and C) of white‐clover (Trifolium repens, L.) that had been selected from old pastures were each crossed with a different set of five clones. Double‐cross and full‐sib matings were made among the progeny to estimate the effect of inbreeding on field performance and variability for resistance to crown rot. One generation of full‐sib mating reduced forage yield by 9 to 15% relative to that of the doublecross matings. Inbreeding depression was much greater for stand loss than for forage yield. By the end of the second summer more than two‐thirds of the sibmated plants were lost compared to slightly over onehalf of the double‐cross plants. Planting the test in a field in which forage legumes had been previously grown for more than 10 years resulted in severe crown rot; this procedure may be useful in future experiments to evaluate crown rot resistance. Differences among fullsib families, among double‐cross families and between these families and the check cultivars were significant for yield and disease tolerance. Inbreeding may be useful in breeding for disease resistance, but one must avoid mating related clones to produce a synthetic cultivar.
Influence of Temperature on Leaf Growth of Diverse Populations of Tall Fescue1
Authors: Nelson C. J. , Treharne K. J. , Cooper J. P.
Published: July 2010

Rate and duration of leaf growth have been suggested as yield determinants in cool‐season grasses. Therefore, our objective was to compare temperature responses of leaf blade growth among diverse populations of tall rescue (Festuca arundinacea Schreb.). Seedlings of three Mediterranean populations, two European populations, and three cultivars were grown at 10, 15, 20, and 25 C with a 16‐hour photoperiod. An additional growth treatment was 8 C with an 8‐hour photoperiod.

Area of leaf blade 3 (3rd complete leaf), and area and weight of leaf blade 5 were maximum, but time interval between leaves was minimum at 20 C. Elongation rate of leaf blade 3 was greatest (about 28 mm/day) at 20 and 25 C. Specific leaf weight of leaf blade 5 was highest at 10 and 15 C (3.4 mg/cm2) and decreased as temperature increased. Specific leaf weight was only 2.6 mg/cm e at 8 C, probably due to lower irradiation and shorter photoperiod than at the other temperatures.

Elongation rate of leaf blade 3, as well as area expansion rate and specific leaf weight of leaf blade 5, was lowest in Mediterranean populations and highest in improved cultivars. However, time interval between leaves for Mediterranean populations was shorter than for other populations. Relative temperature response among populations was similar from 10 to 20 C. At 8 C with an 8‐hour photoperiod, population Bn 272 (from Tunisia) had higher dry weight and area of leaf blade 5 than at 10 C with a 16‐hour photoperiod. At 25 C and a 16‐hour photoperiod, area and weight of leaf blade 5 of continental populations were greater than those of Mediterranean populations. Yield superiority of improved populations may be due partially to their inherently faster leaf growth rate and larger leaves.
Morphology, Cytology, and Fertility of Agropyron podperae and its Hybrids with A. intermedium1
Authors: Dewey Douglas R.
Published: July 2010

Seventy‐three collections of wheatgrass (Agropyron podperae Nabel.) from two sites in Iran were grown at Logan, Utah to determine the morphological, cytological, and reproductive characteristics of this rarely collected taxon. The A. podperae collections were morphologically similar to those of A. intermedium (Host) Beauv., except that A. podperae was caespitose (tufted) and A. intermedium was rhizomatous. Sixty‐nine of 71 A. podperae plants were 2n=42, and the other two were 2n=41 and 43 Agropyron podperae behaved meiotically as a segmental autoallohexaploid and averaged 0.23I, 20.58II, 0.01III, 0.14IV, 0.002VI, and 0.002VIII per cell in 487 metaphase‐I cells. Most plants were moderately to completely self‐sterile; some (11%) were highly self‐fertile.

Agropyron podperae hybridized readily with A. intermedium, with 56% crossing success. Chromosome pairing was almost complete in the F1 hybrids, which averaged 1.17I, 18.57II, 0.27III, 0.68IV, 0.02V, 0.02VI, and O.OO1VII per cell in 681 metaphase‐I cells. The chromosomes of A. podperae differed from those of A. intermedium by structural rearrangements, primarily interchanges. The hybrids produced 10 to 75% stainable pollen and averaged 44%. Although A. podperae does not appear to have much direct potential as a forage grass, it may serve as a useful secondary gene pool for A. intermedium and Triticum aestivum L.

The morphological, ecological, geographical, and cytogenetic differences that separate A. podperae from A. intermedium are on the order of those that distinguish subspecies. It is proposed that A. podperae be relegated to a subspecies of A. intermedium, i.e., A. intermedium (Host) Beauv. subsp. podperae (Nabel.) Dewey comb. nov.
Carbon Dioxide Exchange Rates, Transpiration, and Leaf Characters in Genetically Equivalent Ploidy Levels of Alfalfa1
Authors: Setter Tim L. , Schrader L. E. , Bingham E. T.
Published: July 2010

The influence of polyploidization on CO2 exchange, transpiration, leaf diffusion resistance, stomatal size, stomatal density, and leaf area was examined in diploid (2x = 16), tetraploid (4x = 32), and octoploid (Sx = 64) alfalfa (Medicago sativa L.). Carbon dioxide exchange rates (CER) of intact leaves were measured with an open system by differential CO2 analysis. Leaf resistance to water vapor diffusion was determined by differential water vapor analysis in a flow‐through leaf chamber and leaf temperature measurements. 2x plants derived by haploidy from cultivated 4x alfalfa were colchicine doubled to form 2x – 4x genetically equivalent paired sets. A different group of cultivated 4x alfalfa was chromosomally doubled to the 8x level to form 4x – 8x paired sets. The CER of 4x plants grown in a growth chamber were similar to the corresponding 2x plants, and 8x plants were similar to corresponding 4x plants even though the stomatal densities were higher for the lower ploidy level in each case. Leaf areas, leaf weights, and specific leaf weights generally were unchanged with polyploidization. In an experiment comparing parents and hybrids at respective 2x and 4x levels, hybrids at the 4x level had greater leaf areas, transpiration per leaf, and CER per leaf than their corresponding 2x hybrids, but CER and transpiration per unit leaf area were unchanged with polyploidization. In both hybrids and parents, 2x plants had greater stomatal densities and shorter guard cell lengths than corresponding 4x plants. When Ft progenies (both 2x and 4x) were compared to parents, hybrids generally were higher in transpiration per leaf, CER per leaf, and leaf area.
Soybean Seed Yield Losses Caused by Powdery Mildew1
Authors: Dunleavy J. M.
Published: July 2010

Yield losses in soybean (Glycine max (L.) Merr.) caused by natural infection with Microsphaera diffusa Cke. & Pk., the powdery mildew fungus, have not been determined. The objective of this study was to determine if M. diffusa caused loss of seed yield in soybeans. Three susceptible (‘Harosoy 63’, ‘Kanrich’, and ‘Bonus’) and three resistant (‘Lindarin 63’, ‘Wayne’, and ‘Cutler 71’) cultivars were tested. A spray containing benomyl (methyl 1‐(butylcarbamoyl)‐2‐benzimidazole carbamate) was applied to plant rows until runoff, once a week from 1 July until near plant maturity. Nonsprayed rows served as controls. The incidence of powdery mildew increased rapidly during July, and by the end of the month nearly all leaves of all susceptible cultivars were infected. Seed yield of the susceptible cultivars was significantly (p < 0.01) higher in benomyl‐sprayed than in nonsprayed plants: 9, 15, and 10% higher for Harosoy 63, Kanrich, and Bonus, respectively. Seed yield of the resistant cultivars was not affected by spraying with benomyl, indicating that the higher yield from spraying susceptible cultivars was only from the control of powdery mildew. The mean loss of yield caused by powdery mildew was 10.1%, which suggests that use of powdery mildew resistant cultivars by soybean producers in areas where powdery mildew occurs, would be beneficial.
Gibberellin Studies with Sugarcane. I. Cultivar Differences in Growth Responses to Gibberellic Acid1
Authors: Moore P. H. , Buren L. L.
Published: July 2010

The lowered radiation and temperatures of the subtropical winter season induce a physiological dwarfism in sugarcane (Saccharum spp.). This reduction in growth can be overcome to increase yields by application of gibberellic acid (GA3).

In Hawaii, cultivars are commercially developed for culture in specific environmental zones defined by their mean daily radiation. In this study, cultivars selected for culture under leeward conditions of high radiation and temperatures were more dwarfed by the adverse winter conditions and gave a greater response to GA3 than did cultivars selected for culture under the lower radiation and temperatures of higher elevations and windward zones.
Easy‐To‐Make ‘Leonard Jar’1
Authors: Wacek T. J. , Alm D.
Published: July 2010

The construction and use of sterilizable plastic Leonard jar assemblies is described. The assemblies, which are used for the aseptic growth of plants during the study of Rhizobium or other soil organisms, are made from commercial plastic bottles which are easily cut, able to withstand repeated sterilization, and are unbreakable.
A Technique for Assessing Seedling Emergence under Drought Stress1
Authors: Johnson Douglas A. , Asay Kay H.
Published: July 2010

A procedure involving a cellulose acetate membrane separating a polyethylene glycol‐6,000 osmoticum from a germination medium of soil was modified for use as a plant‐selection tool. This technique avoided direct seed and osmoticum contact, allowed maintenance of a wide range of soil water potentials, and was capable of assessing emergence of large numbers of seedlings. This procedure was used to assess seedling emergence under drought stress of 120 lines of crested wheatgrass—Agropyron desertorum (Fisch. ex Link) Shult., A. cristatum (L.) Gaertn., and A. sibiricum (Willd.) Beauv. Significant differences in seedling emergence at two water stress levels occurred among the crested wheatgrass lines. The genetic variance as greater under the more severe drought stress. However, relative differences among lines were not consistent under the two drought stress regimes, as indicated by the highly significant progeny ✕ stress‐level interaction and the significant, but low, correlation between drought stress levels (r=0.40, 118 d.f.). Although opportunities for genetic improvement may be greater under the more severe moisture stress level, the environment of intended use must be considered during selection.
Genetic Variation for Canopy Architecture and its Use in Wheat Breeding1
Authors: de Carvalho Fernando I. F. , Qualset C. O.
Published: July 2010

Genetic studies showed that two genes control the dense spike (short rachis internodes) of PI 190982 (Triticum aestivum L., sphaerococcum group), a tall wheat cultivar from Spain that has erect and short leaves. Few genes, most likely two or three, controlled most observed differences in flag leaf angle and length. Selection allowed the isolation of erect‐leaved types that yielded about 45% more grain than PI 190982 but about 20% less grain than standard cultivars. Erect and nonerect derived lines did not differ in yields between row spacings of 15 and 30 cm in field experiments in 2 years. PI 190982 appears to be a useful germplasm source for modifying canopy architecture, but the role of leaf erectness in reaching new high yield levels requires additional study.