bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxicity of Tall Fescue to Rape and Birdsfoot Trefoil Seeds and Seedlings1
Authors: Peters Elroy J.
Published: July 2010

Water extracts from roots and leaves of fescue (Festuca arundinacea elator Schreb.) reduced germination and growth of the roots of rape (Brassica nigra) and birdsfoot trefoil (Lotus corniculatus L.), but effects varied, depending upon how the extracts were prepared. Ethanol extracts of roots and leaves of fescue reduced growth of roots and tops of rape and birdsfoot trefoil seedlings grown in sand containing nutrient solution. Ethanol extract of root‐free soil in which fescue had been grown did not inhibit growth of rape or birdsfoot trefoil seedlings.

Rape and fescue seeds germinated normally in sand with nutrient solution in which rescue was growing. Fescue growing in association with rape plants in nutrient solution or distilled water significantly reduced the growth of rape leaves. When half of the rape and rescue root systems were independently supplied with nutrient solution, and half of their root systems were grown together in distilled “water, rescue inhibited the growth of rape roots in the distilled water. This ruled out competition for nutrients as an explanation of the inhibitory effects of rescue on the growth of rape.
Inheritance of Lint Quality Characteristics in Interspecific Crosses of Cotton1
Authors: Marani A.
Published: July 2010

In interspecific crosses between varieties of upland (Gossypium hirsutum L.) and Egyptian (G. barbadense L.) cotton, tested in Israel from 1959 through 1965, F1 performance for upper‐half‐mean and mean lint length exceeded that of either parent by 10 to 16% and 6 to 13%, respectively. The uniformity ratio of F1 plants was slightly lower than the parental mean. F2 performance for lint length was slightly above parental mean, but a significant F2 deviation was detected for this trait. There were indications that additive, dominance, and additive ✕ additive epistatic effects were operating in the inheritance of lint length.

The tensile strength (1/8‐in. gauge, i.e. T1 of the F1's lint was almost as high as that of the stronger G. barbadense parental varieties. The magnitude of heterosis was 9 to 15% for this trait, with no F2 or backcross deviations. This indicated that only additive and dominance effects were operating in the inheritance of lint strength.

Micronaire measurement of lint fineness was much lower in F1 hybrids than in either parent (a negative heterosis of 12 to 19%). Only the dominance effects were detected as operating significantly in the inheritance of this trait, but there were considerable deviations from the model with no epistasis.

Significant effects of general combining ability were found for lint length and tensile strength. Additive gene‐action was predominant for these traits. Dominance effects were the main cause of heterosis for all the traits of lint quality examined.
Heterosis and Homeostasis in Secale montanum Guss ✕ S. cereale L. Hybrids I. Vegetative Growth and Development1
Authors: Pfahler P. L.
Published: July 2010

F1 hybrids between Secale montanum (P1253956) and three varieties (‘Florida Black,’ ‘Gator,’ and ‘Wrens Abruzzi’) of S. cereale were made with S. montanum the female parent in each cross. F2 populations were produced by interpollination within each F1 population. Forage production and plant weight after final clipping were measured on plants from each population grown under space‐planted conditions in 1965–66 and 1966–67 winter seasons.

or both characters, substantial heterosis was obtained in certain F1 populations with the amount depending on the S. cereale variety involved and the year tested. Heterosis for forage production in all hybrid populations was expressed late in the vegetative development of the plant. The response of the hybrid populations to yearly differences in environment was variable and associated with the character being measured. In comparison to the parents the variation within the hybrid populations was low. In general, the differences between the F1 and F2 populations were small.
Net Photosynthetic Rates, Relative Leaf Growth Rates, and Leaf Numbers of 22 Races of Maize Grown at Eight Temperatures1
Authors: Duncan W. G. , Hesketh J. D.
Published: July 2010

Twenty‐two races of maize (Zea mays L.) and one selection of teosinte (Euchlaena mexicana Schrad) were grown under natural daylight in eight glasshouses where day/night temperatures were maintained from 15/10 to 36/31 C. Differences were found among temperatures and races in net photosynthetic rates, relative leaf growth rates, and leaf numbers. At low temperatures, high altitude races had relatively higher leaf growth rates and dry weights at harvest. At high temperatures high altitude races had relatively lower net photosynthetic rates. Leaf numbers increased with increasing temperatures.
Nodulation Interactions between Soybean Genotypes and Serogroups of Rhizobium japonicum1
Authors: Caldwell B. E. , Vest Grant
Published: July 2010

Soybean genotypes grown successive years in different fields were predominantly nodulated by Rhizobium japonicum strains of specific scrogroups. Chi‐square analyses showed significant differences among plant genotypes in their acceptance of Rhizobium japonicum strains of specific serogroups. Closely related soybean genotypes had similar distributions of R. japonicum in their nodules. The results indicate specific interactions between soybean genotypes and R. japonicum serogroups hi nodule formation.
Karyotype of a David Medicago sativa L. Analyzed from Sporophytic and Gametophytic Mitoses1
Authors: Buss G. R. , Cleveland R. W.
Published: July 2010

Idiograms were constructed for the mitotic chromosomes of diploid Medicago sativa L. (2n = 16). Chromosomes were measured in root tip cells and generative nuclei of pollen tubes. Statistical methods applied to the data did not provide a means for identifying homologous chromosomes; however, a pattern of morphology was found by which chromosomes could be matched by inspection. The haploid complement of eight chromosomes was divided into two groups, four long and four short chromosomes. Within each group the arm length ratios (short arm length ÷ long arm length) increased as total lengths decreased. Only minor discrepancies for this pattern existed. In root‐tips the chromosomes ranged from 3.5 to 4.5 microns in length, and ratios ranged from 0.53 to 0.94. The chromosomes were shorter in pollen tubes (lengths: 2.4‐3.1 microns; ratios: 0.64‐0.95). Idiograms from the two sources agreed in essential form except that the satellited chromosome was not recognizable in pollen‐tube nuclei.
Resistance to Brown Stem Rot in Soybeans1
Authors: Chamberlain D. W. , Bernard R. L.
Published: July 2010

A total of 2,060 soybean strains, screened for resistance to brown stem rot, revealed no immune lines. However, PI 84946‐2, a strain of unknown origin selected from an introduction from Korea, had a very high proportion of disease‐free plants through 12 seasons. When crosses of PI 84946‐2 were made with several commercial varieties, the segregating generations averaged more healthy plants than did the commercial varieties. Lines with resistance similar to that of PI 84946‐2 have been selected from these populations.

We observed that early‐maturing varieties tended to escape infection; locally adapted varieties planted in late June did likewise.

Irradiating the seeds of six soybean varieties with thermal neutrons failed to induce resistant mutants in progeny tests.
Genetic Instability of Ottawa Wheat (Triticum aestivum L.)1
Authors: Urich Max A. , Heyne E. G.
Published: July 2010

Spontaneously occurring off‐type plants susceptible to leaf rust race 9 were found at a high rate (2.61 per 1,000 seedlings tested) in the progeny of self‐pollinated (bagged) spikes of ‘Ottawa’ wheat. They appeared to originate from three different events in a normal, disomic Ottawa population: (1) mutation of the gene for leaf rust race 9 resistance, (2) breakage and loss of a terminal portion of chromosome 6B, which included the gene for resistance, and (3) nonpairing of the two 6B homologues, which resulted in mono‐6B and mono‐6B telo‐6BS aneuploids. A relatively high rate of 6B aneuploids occurred after one generation of self‐pollination (1.58 per 1,000 seedlings) and after two generations of self‐pollination (2.97 per 1,000 seedlings).

Spontaneously occurring white‐glumed spikes ere found at the rate of 1.8 and 2.4 per 10,000 spikes in foundation and registered Ottawa, respectively. Those off‐types had either a ditelo or di‐iso constitution, indicating loss of an arm of chromosome lB. They probably originated from nonpairing of an 1B bivalent and subsequent misdivision and recombination of an 1B univalent.

Nonhomology did not appear to cause nonpairing which was not random but affected chromosomes 1B and 6B more frequently than other chromosomes. This study suggests that Ottawa has some type of genetic malfunction that prevents chromosomes 1B and 6B from pairing in all meiotic cells.
Pachytene Chromosomes of Diploid Medicago sativa L.1
Authors: Buss G. R. , Cleveland R. W.
Published: July 2010

Chromosomes at the pachytene meiotic stage of microsporocytes were measured and characterized in diploid Medicago sativa L. (2n = 16). An idiogram for the eight chromosomes of the haploid complement was constructed including the following details: average total lengths, arm lengths:, arm length ratios (long arm ÷ short arm lengths), and number, position, and size of chromatic areas. The chromosome lengths of the complement ranged from 25.4 to 40.1 microns, and arm length ratio ranged from 1.19 to 3.06. Large degrees of variability in length measurements from cell to cell were noted. Similarly, arm length ratios were also variable, but to a lesser degree. Because of the variability from cell to cell, absolute length was not reliable as an identification criterion. Relative lengths (within the cell), arm length ratios, and chromatic area patterns formed reliable criteria for identification of chromosomes when taken in combination.
Transfer of Diploid Medicago spp. Germplasm to Tetraploid M. sativa L. in 4x‐2x Crosses1
Authors: Bingham E. T.
Published: July 2010

Crosses of 4 male‐sterile tetraploid clones and 13 selected diploids produced 31 triploid and 53 tetraploid hybrid progeny. Transfer of germplasm from diploid Medicago sativa L., M. falcata L., and their hybrids to the tetraploid level was equally efficient and indicated all diploids produced some male gametes with unreduced chromosome numbers. 4x‐2x crosses permitted genes to be transferred from both diploid species and produced triploids and tetraploids. This was in contrast to previously reported 2x‐4x crosses in which the diploid parent was restricted to self‐incompatible M. falcata and the hybrids were mainly tetraploids. All tetraploid hybrids were vigorous and fertile, reflecting the homology of the parental genomes.
Influence of Grain Moisture at Harvest on Seed Yield, Quality, and Seedling Vigor of Rice1
Authors: Oelke E. A. , Ball R. B. , Wick C. M. , Miller M. D.
Published: July 2010

Rice (Oryza sativa L.), Cultivar Caloro, was harvested at 13 levels of moisture content in the grain beginning at 43% and ending at 13%. Seed yields increased rapidly as grain moisture decreased from 43 to 31%. They increased slowly between 31 and 19%, but remained constant thereafter. Weight per seed and liter weight followed the same trend as seed yields. Germination percentage increased steadily as grain moisture decreased. Speed of emergence of seedlings through 10 cm of water was faster when grain was harvested below 20% moisture. Shoot length of seedlings grown on blotters held at a 67° angle in a germinator indicated earlier and faster growth as grain moisture decreased to 13%. Resistance of seedlings to the water mold (Achlya klebsiana Pieters) was optimum when grain was harvested at 13% moisture.
Chromosome Stability in Some Hexaploid Strains of Triticale1
Authors: Tsuchiya T. , Larter E. N.
Published: July 2010

In eight strains of hexaploid Triticale (2n = 42) which had undergone seven to eight generations of selection for improved agronomic characteristics, the mean frequency of aneuploid plants in bulk populations was 11.5%. Most aneuploids were monosomic and differences in the mean frequencies of aneuploids between lines were nonsignificant.

In the immediate progeny of euploid plants, the average aneuploid frequency for eight lines was 8.8%, varying from a low of about 3% in those strains involving Triticum turgidum L. var. dicoccon as one parent, to approximately 11% in those strains with Triticum turgidum L. var. durum or Triticum turgidum L. var. carthlicum (persicum) as parents.
Monosomic Analysis for Bunt Resistance in Derivatives of Turkey and Oro Wheats1
Authors: Schmidt J. W. , Morris R. , Johnson V. A.
Published: July 2010

The “Turkey” factor for resistance to bunt, Tilletia foetida (Wallr.) Liro, in wheat, Triticum aestivum L., has been placed on chromosome 1B through the use of the monosomic analysis technique. Two varieties derived from ‘Turkey’ wheat, ‘Omaha’ and ‘Nebred,’ and two ‘Oro’ wheat derivatives, ‘Bison’ and ‘Kaw,’ were each crossed to monosomic 1B plants of ‘Wichita’ wheat and to one additional randomly available monosomic line. Before seeding, the seeds were dusted with chlamydospores of a collection of bunt maintained at the Nebraska Agricultural Experiment Station. In the field, F2 populations from F1 monosomic IB plants had significantly lower percentages of diseased plants than those from sib F1 disomic plants or from F1 plants monosomic for the other chromosomes. Greenhouse data were less conclusive. As a group, the F2 populations from the monosomic chromosome 1B had significantly lower percentage of diseased plants than either those from sister disomic F1 plants or those from F1 plants monosomic for a chromosome other than 1B.
Relationships of the Clover Root Curculio, Fusarium Wilt, and Bacterial Wilt in Alfalfa1
Authors: Hill R. R. , Newton R. C. , Zeiders K. E. , Elgin J. H.
Published: July 2010

Alfalfa, Medicago saliva L., plants were exposed to larvae of the clover root curculio, Sitona hispidula (F.), the Fusarium wilt fungus, Fusarium oxysporum Schlecht. f. sp. medicaginis (Weimer) Snyd. & Hans., and the bacterial wilt organism, Corynebacterium insidiosum (McCull.) H. L. Jens., in factorial combinations in two greenhouse experiments. S. hispidula and F. oxysporum significantly reduced the growth of alfalfa plants. A higher level of Fusarium wilt was observed when S. hispidula was present than when it was absent. C. insidiosum did not reduce growth of alfalfa. No relation between effects of S. hispidula and C. insidiosum was detected.
Contamination in Denta Sweetclover During Successive Generations of Seed Increase1
Authors: Gorz H. J. , Haskins F. A.
Published: July 2010

Contamination levels observed in the breeder, foundation, and certified seed generations of ‘Denta’ sweetclover (Melilotus alba Desr.) were 0.71, 1.69, and 3.62%, respectively, as measured by the frequency of plants high in content of ο‐hydroxycinnamic acid. Based on a sample of plants tested simultaneously for ο‐hydroxycinnamic acid content and β‐glucosidase activity, a small but consistent decrease in the frequency of cu plants occurred with succeeding seed generations, while shifts in the frequency of b plants were not consistent in magnitude or direction. Contamination through cross‐pollination with CuCuBB plants may be the major factor responsible for the observed decreases in the frequency of cu plants.
Correlations Among Root and Aerial Characteristics of Crosses Between Creeping‐Rooted and Noncreeping Medicago sativa L.1
Authors: Busch R. H. , Davis R. L.
Published: July 2010

Eight creeping‐rooted alfalfa selections, Medicago sativa L., were crossed with random samples of Flemish and non‐Flemish populations. Root and aerial characteristics of progenies were measuredto determinep ossible correlations under competitive row conditions in the field. The low correlations between root and aerial characteristics suggest that it should be possible to develop cultivars whichc ombinet he lateral‐rooted characteristic (and presumably, resistance to heaving) with the vigor of presently grown cultiwars.
Propagation from Proliferated Sorghum Spikelets Caused by Head Smut Infection1
Authors: Casady A. J.
Published: July 2010

Sorghum, Sorghum bicolor (L.) Moench, was successfully propagated from proliferated spikelets caused by head smut, Sphacelotheca reiliana (Kuehn) Glint. Undetached panicles with proliferated spikelets were surrounded with moist soil until the spikelets developed roots. Removing and transplanting the rooted spikelets resulted in the development of normal plants.
Source of Protein Variants in Soybean Seed1
Authors: Larsen A. L. , Caldwell B. E.
Published: July 2010

Samples of soybean seed of breeding lines constituting the parents of currently grown varieties were screened for protein types designated as “A” and “B”. The proteins were classified by polyacrylamide‐gel electrophoresis. In homozygous genotypes the protein types are mutually exclusive and are controlled by a pair of co‐dominnant genes. The source of the A protein was through ‘Mandarin‘, an early‐maturing variety introduced into the United States as PI 36653 from Manchuria in 1911. The disproportionately large numbers of A‐type varieties in northern Maturity Groups can be attributed to repeated use of Mandarin as a parent. However, a possible association of the A protein with some adaptive factor contributed by Mandarin exists.
Water Requirement in Strains of Vine‐Mesquite (Panicum obtusum H. B. K.)1
Authors: Weng Vincent K. , Quinones Ferdinand A.
Published: July 2010

A study of the water requirement of nine strains of vine‐mesquite (Panicum obtusum H. B. K.) was conducted in the greenhouse for 126 days. Three herbage clippings were made. Least‐squares analyses of dry herbage yield, transpiration, and water requirement (a ratio of transpiration to herbage yield) indicated no statistically significant differences among strains in either water requirement or herbage yield during any of the growth periods or in the whole experiment. However, there were significant differences in transpiration by the strains throughout the test. Although large and highly significant negative genetic correlations were obtained between herbage yield and water requirement, the lack of significant differences among strains in these two traits suggests that high herbage yield cannot be used with confidence as a guide in selecting for low water requirement in these accessions of vine‐mesquite.
Self‐Compatibility Studies with Diploid Alsike Clover, Trifolium hybridum L. IV. Inheritance of Type II Self‐Compatibility in Different Genetic Backgrounds1
Authors: Townsend C. E.
Published: July 2010

Inheritance of a type of self‐compatibility, possessing sporophytic and gametophytic characteristics, was studied in different genotypes of diploid alsike clover, Trifolium hybridum L. This type of self‐compatibility was referred to as Type II. The original hypothesis stated that the A1 allele of the A locus in a heterozygous condition suppressed the action of only the S1 allele of the S locus in the pollen to give self‐compatibility. Results from a series of crosses between self‐compatible (SC) and self‐incompatible (SI) plants showed that this postulate must be modified. In some crosses, the A1 allele was found to suppress the action of other S alleles. In other crosses the A1 allele did not suppress the action of any S alleles because all F1 plants were SI. When four of these SI F1 plants were backcrossed to a SC plant, only two of the 46 backcross plants were SC. Thus, the action of the A1 allele was variable. The number of SI and SC plants obtained in some progenies agreed with those expected according to the hypothesis that the A1 allele suppressed the action of only the S1 allele. The frequency of SI and SC plants from two F1 progenies with the same SC male parentage, differed from the frequency obtained in the progenies of the reciprocal crosses. The reason for the discrepancy is not known. In general, the deviation of the results obtained from those expected, and the complete absence of SC plants in some progenies, can be explained by the presence of modifying genes. Consequently, genetic background had considerable influence on the expression of Type II self‐compatibility.
Influence of Supplemental Light on Apparent Photosynthesis, Yield, and Yield Components of Soybeans (Glycine max L.)1
Authors: Johnston T. J. , Pendleton J. W. , Peters D. B. , Hicks D. R.
Published: July 2010

Experiments were conducted to determine the effect on soybean seed yields and yield components of increasing the amount of light available in the soybean leaf canopy and to evaluate the photosynthetic contribution of leaves at different levels in the canopy.

Wide spectrum fluorescent lamps were placed at three levels in the canopies of ‘Amsoy’ and ‘Wayne’ varieties planted in rows 50‐cm and 100‐cm apart. White reflective polyethylene strips were placed between the rows. At harvest each plant was divided into top, middle, and bottom thirds corresponding to the levels of artificial lamps in the canopy.

Measurements of apparent photosynthesis (AP) and respiration of individual soybean leaves were made with a plexiglass single leaf photosynthesis chamber. AP and respiration rates (rag CO2/dm2/hr) were determined by recording the change in CO2 concentration with time in a closed system.

Adding light increased the yields of bottom, middle, and top canopy positions of plants 30, 20, and 2%, respectively. Light‐rich plants had more seeds, nodes, pods, branches, pods per node, seeds per pod, and a higher oil content than normal plants. Protein content and seed size were decreased by adding light.

The rates of AP of bottom and middle soybean leaves were 13 and 60% of the 20.2 mg CO2/dm2/hr rate of top leaves under natural canopy conditions. When exposed to full sunlight, bottom and middle leaves fixed 258 and 50% more CO2, respectively, than when naturally shaded.

Respiration rates decreased with depth in the canopy. Top, middle, and bottom leaves had respiration rates of 6.8, 4.3, and 2.8, mg CORespiration rates decreased with depth in the canopy. Top, middle, and bottom leaves had respiration rates of 6.8, 4.3, and 2.8, mg CO2/dm2/hr, respectively.
Performance of Advanced Generations of Autotetraploid Maize (Zea mays L.) Synthetics1
Authors: Dudley J. w. , Alexander D. E.
Published: July 2010

Four, five, and nine generations, depending on the synthetic, of four autotetraploid maize (Zea mays L.) synthetics created by the “elongate” method were compared for 2 years at Urbana, Ill. In all four synthetics, percent seed set, yield, plant height, and ear height increased with advancing generations. Large increases occurred between particular cycles followed by cycles where no changes occurred. Possible reasons for this type of increase rather than a steady increase over all cycles are discusse
Carbon Dioxide Compensation in Grasses1
Authors: Krenzer E. G. , Moss Dale N.
Published: July 2010

Carbon dioxide compensation concentrations were measured for 325 species of Gramineae. Compensation points of most species of the sub‐family Festucoiaeae were 40 ppm CO2 or greater at 25 C. Exceptions to this were found in the eight genera examined of the Chlorideae tribe of the Festucoideae as well as in the genera Anthephora, Eragrostis, Vaseyochloa and Pappophorum of other tribes, all of which had low compensation concentrations. Compensation concentrations of most species of the sub‐family Panicoideae were 10 ppm CO2 or less. Exceptions to this were found in the genus Panlcum, where species of the subgenus Dichanthelium had high compensation concentrations, while members of the subgenera Eupanicum and Paurochaetium had low compensation concentrations. Interspecific crosses between high and low compensating Panicum species may be possible and, if so, would permit study of the interdependence of photorespiration, photosynthetic carbon pathway, leaf anatomy and capacity for high rates of photosynthesis.
Greenbug Resistance in Sorghums1
Authors: Hackerott H. L. , Harvey T. L. , Ross W. M.
Published: July 2010

Resistance to the C biotype of the greenbug, Schizaphis graminum (Rondani), a pest of recent economic importance on sorghum in the United States, was discovered in Sorghum virgatum (Hack.) Stapf. Otherwise, general susceptibility to the greenbug appeared in a wide array of sorghum germ plasm, including representatives from each of the major groups in the genus Sorghum. On the basis of seedling survival, entries were classified as resistant, intermediate, and susceptible. Classifications were confirmed by plant and greenbug reactions following confinement of greenbugs to seedlings. Tolerance appeared to be the major component of resistance, but resistant and susceptible seedlings could be readily separated on the basis of greenbug populations and injury to plants in greenhouse preference trials. Resistance appeared to be conferred by dominant genes at more than one locus. Preliminary observations indicate the type of resistance discovered may be valuable under field conditions.
Season‐Long Effects of Chilling Treatments Applied to Germinating Cottonseed
Authors: Christiansen M. N. , Thomas R. O.
Published: July 2010

Field growth response of cotton (Gossypium hirsutum L.) to chilling during germination was investigated by laboratory application of controlled dosages of cold, followed by germination in sterile soil and subsequent field culture to maturity. Chilling during germination reduced plant height, delayed fruiting, and reduced fiber quality in a direct relation to the length of exposure to cold.
Leaf Area Relationships and Inheritance in Barley1
Authors: Fowler C. W. , Rasmusson D. C.
Published: July 2010

Five barley, Hordeum vulgare L., populations were used in a study of leaf area. Information was obtained on estimation of leaf area, leaf area relationships on single plants and on inheritance and gain from selection. The formula, leaf width ✕ leaf length ✕ b, where b is the regression coefficient of actual leaf area on the width‐length product, provided a relatively good estimate of leaf area. Our results suggest that a coefficient of b = .69 would be satisfactory for most situations. However, the coefficients that were estimated differed significantly from one population to the other and for different leaves. Area per leaf increased progressively from the flag to the third leaf below the flag in the populations studied. Leaf area of adjacent leaves was highly correlated suggesting that it may be difficult to develop plants that have individual leaves of distinctly different size.

Heritability estimates of leaf area, parent‐progeny method, ranged from .18 to .73 on the F3 and F4 plant basis, and from .24 to .49 on the family or plot basis, without replication. The mean estimates of gain from one generation of selection on the plant basis were 41 and 20% of the mean leaf area for the flag and the first leaf below the flag, respectively. Hence, the results should be encouraging to those who contemplate breeding programs in grass species aimed at altering leaf area.
Sources of Variation in Cynodon dactylon (L). Pers.1
Authors: Harlan Jack R. , de Wet J. M. J.
Published: July 2010

The species Cynodon dactylon is enormously variable and has become truly cosmopolitan as a weed of disturbed habitats. Six botanical varieties are recognized in our classification, but only one is the widespread weed; the others are either narrow endemics or have restricted distributions. The great variability within the cosmopolitan variety appears to have been generated internally by genetic interaction of three of the six varieties and by fragmentation of the gene pool by translocation races.
A Method for Determining Net Photosynthesis and Transpiration of Plant Leaves1
Authors: Nevins D.J. , Loomis R.S.
Published: July 2010

Apparatus and techniques for the determination of photosynthetic carbon dioxide exchange and transpiration of individual leaves are described and evaluated. Stable, high rates of photosynthesis were obtained with attached leaves after preconditioning in the leaf chamber at high levels of illmnination. Particular attention was devoted to providing adequate air turbulence within the chamber and to operating variables, temperature and relative humidity, with regard to their overall effect on CO2 exchange in leaves.
Effects of Rhizobium japonicum Strains on Soybean Yields1
Authors: Caldwell B. E. , Vest Grant
Published: July 2010

Soybean varieties (Glycine max (L.) Merrill) were inoculated with 28 strains and two commercial preparations of Rhizobium japonicum. The effect of each strain on the yield of five varieties was evaluated and significant yield differences were found associated with certain strains. Four different environments were studied and in three of the environments, which were free of R. japonicum, a significant strain ✕ year interaction was observed. No significant strain ✕ variety interactions were indicated. Only 5 to 10% of the nodules on plants grown in a field with an established R. japonicum population were derived from the inoculum introduced into the soil on the seed.
Viability and Leaching of Sugars from Germinating Barley1
Authors: Abdul‐Baki Aref A. , Anderson James D.
Published: July 2010

The relationship of viability to leaching of sugars from germinating barley seeds has been studied with respect to age, accelerated aging, and mechanical injury of seeds. Sugar leaching increased with increased seed age and with increased mechanical injury of endosperm, but it was unchanged by accelerated aging except when viability was severely reduced.

The amount of leached sugars, particularly glucose, even in seeds of high viability was a significant portion of total sugars found in the seed at 4, 8, and 12 hours of germination. Aging the seeds for 2, 5, and 8 years increased sugar leaching and reduced viability. Mechanical injury increased sugar leaching without affecting viability. Accelerated aging treatment up to 12 days did not affect sugar leaching but reduced viability. We conclude that sugar measurements are not a reliable index for seed viability. Furthermore, the leaching of sugars appears to be regulated primarily by the rate of utilization of such sugars during germination rather than by changes in membrane permeability of the dry seed.

Eighty to 90% of the total glucose and sucrose of the seed was found in the endosperm. The remaining 10 to 20 % was found in the embryo. As germination progressed, the total amount of glucose in both embryo and endosperm increased while sucrose decreased. The depletion of sucrose was most pronounced in the embryo.
Rj3 A Gene Conditioning Ineffective Nodulation in Soybean1
Authors: Vest Grant
Published: July 2010

Ineffective nodulation in soybeans (Glycine max (L.) Merrill) inoculated with Rhizobium japonicum strain 33 was found to be controlled by a single dominant gene which has been designated Rj3.
Chemical, Physical and Morphological Properties of Diploid and Tetraploid Sorghum bicolor (L.) Moench Kernels1
Authors: Rooney L. W. , Sullins R. D.
Published: July 2010

Grain produced on diploid (2X) and tetraploid (4X) lines of the sorghum, Sorghum bicolor (L.) Moench, cultivar, Tx 403, was compared for physical, morphological, and chemical properties. Grain from tetraploids was greater in kernel size and protein content and was lower in starch content and test weight than grain from the diploid. Mean values of diploids and tetraploids were 12.8 and 15.7% protein, 72.3 and 68.8% starch, 26.8 and 41.4% g/1,000 kernels, and 74.3 and 70.0 kg/hi respectively. Grain from the tetraploid contained 3.3% less endosperm and a slightly higher proportion of bran than grain from the diploid. The relative proportion of germ was the same. Endosperm cells of the tetraploid were larger than those of the diploid. Kernel density and amino acid composition were similar. Low seed set of the tetraploid plants may partially explain the increase in protein and other differences.
A Partially Male Sterile Strain of Soybean1
Authors: Caviness C. E. , Walters H. J. , Johnson D. L.
Published: July 2010

A partially male sterile strain of soybeans, Glycine max (L.) Merrill, was found in Arkansas in 1964. Grafts involving partially sterile and fertile plants indicated that this character likely was genetically controlled. Only 5 to 10% of pollen from the partially sterile strain appeared to be viable when stained with aceto‐carmine and glycerine. Plants of the F~ generation from a cross between a partially sterile and a fertile strain were completely fertile. Segregation occurred in the F~o generation and gave further evidence for dominance of fertility over partial sterility. Natural cross‐pollination estimates of 11.21% and 0.26% were obtained for the partially sterile and fertile strains, respectively.
Genetic Studies of Induced Mutants in Melilotus alba. II. Inheritance and Complementation of Chlorophyll‐deficient Mutants1
Authors: Gengenbach, B. G. , Gorz H. J. , Haskins F. A.
Published: July 2010

Six ethyl methanesulfonate‐induced mutants of Melilotus alba Desr. were studied. Five of the mutants behaved as monogenic recessives. In the sixth mutant, two independent recessive alleles were responsible for the observed phenotype. Of these two genes, one had a phenotypic effect similar to the five single‐gene mutants. The other (the veined gene) caused a chlorophyll deficiency in which the leaf veins were darker in color than the tissue between the veins. Complementation analysis revealed that five of the seven genes detected in the mutants were nonallelic. Suggested designations for the five genes are ch4, ch5, ch6, ch7, and chv.
Comparative Yields of Single, Three‐Way, and Double Crosses of Maize1
Authors: Weatherspoon James H.
Published: July 2010

In a balanced set of comparisons, 36 single, three‐way, and double crosses, involving nine unrelated inbred lines of corn, Zea mays L., were evaluated for grain yield. Data were also obtained on the variety ✕ environment interaction patterns for the three types of crosses. Average yield of singles was 3.1 q/ha greater than that for three‐ways, and the average for three‐ways was 1.7 q/ha greater than doubles. The range in yields for singles was 12.7 q/ha more than for three‐ways, and 24.2 q/ha greater than for doubles. Hybrids ✕ environments mean square for singles was more than twice that for doubles, and the mean square for three‐ways was intermediate between that for doubles and singles.
Effect of Root Aeration on Amino Acid Levels in Cotton Plants1
Authors: Guinn Gene , Brinkerhoff L. A.
Published: July 2010

Oxygen deficiency in the rooting medium altered amino acid levels in roots, xylem sap, and leaves of cotton plants (Gossypium hirsutum L.). In general, poor root aeration increased amino acid levels in roots and sap, but decreased amino acid levels in leaves. Poor root aeration greatly increased alanine and also increased serine, gamma‐aminobutyric acid, glutamic acid, and glutamine contents of roots and xylem sap. On the other hand, poor root aeration had almost no effect on asparagine content of roots and decreased asparagine contents of xylem sap and leaves.
Cytology, Method of Reproduction, and Fertility of Brunswickgrass, Paspalum nicorae Parodi1
Authors: Burson Byron L. , Bennett Hugh W.
Published: July 2010

Ten introductions of Brunswickgrass (Paspalum nicorae Parodi) had the same chromosome number, 2n=40, and different chromosome associations at diakinesis and metaphase I. Univalents ranged from 0 to 6 with an average of 0.49 per cell; bivalents ranged from 6 to 20 with an average of 16.67 per cell, and quadrivalents ranged from 0 to 7 with an average of 1.48. Some introductions had laggards and micronuclei in 50 to 60% of the cells at anaphase and telophase I and in 70% of the cells during anaphase and telophase II. Stainable pollen averaged 65.7%. Embryo sac studies and uniform progeny obtained from these introductions indicated that the plants were obligate apomicts which reproduce by apospory and pseudogamy. Seed set ranged from 18.6 to 48.0% and 5.2 to 26.4% for open‐ and self‐pollinated conditions, respectively.
Inheritance of Cotyledon Color in Lens Culinaris (Medic.)1
Authors: Wilson V. E. , Law A. G. , Warner R. L.
Published: July 2010

Crosses between lentils with red cotyledons and those with yellow gave F2 ratios of three red to one yellow indicating a simple allelomorphic relationship between genes for cotyledon color with red being dominant to yellow. In white light, colors of lentil (Lens culinaris, Medic.) cotyledons did not show through unbroken seed coats, but in ultraviolet radiation red and yellow cotyledons were distinguishable. Fluorescence made possible an easy, efficient, and accurate means of distinguishing F1 seed from self‐pollinated seed without damaging the seed coats.
Effects of Endosperm Genes on Dry Matter Accumulation and Moisture Loss in Corn (Zea mays L.)
Authors: Nass H. G. , Crane P. L.
Published: July 2010

The effects of nine endosperm mutant genes on dry matter accumulation and percent moisture decrease were studied in three near‐isogenic hybrid backgrounds of corn (Zea mays L.) during the period 35 to 77 days after pollination. Eight of the endosperm mutants were inferior to normal in dry matter accumulation while floury‐l was slightly superior. The shrunken‐1 and sugary‐1 mutants showed the greatest reduction in dry matter, accumulating only 75% and 64% of the total dry matter of normal. The mutants which accumulate greater quantities of sugar and water soluble polysaccharides produced less total dry matter.

It appeared that lower dry matter accumulation was accompanied by retention of more moisture. The floury‐l mutant had a slightly lower percent moisture than normal. All other mutants had a greater percent moisture, sugary‐1 being the highest.
Diallel Analyses of Fatty Acids in Corn (Zea mays L.) Oil1
Authors: Poneleit C.G. , Bauman L.F.
Published: July 2010

Genetic, reciprocal, and environmental variation of oil content and Catty acids was examined in F1 and F2 diallel crosses of nine inbred corn lines. The GCA mean squares were much larger than SCA mean squares for each variable. Relative rank of GCA effects for inbreds could be predicted directly from the inbred means. Breeding systems which effectively use additive genetic variation are suggested as most useful for alteration of either oil quantity or quality. The significant but low correlations found for some of the fatty acids with oil quantity indicate concomitant selection for both quality and quantity should result in progress. Reciprocal differences Cor percent oil were positively correlated with (1) the mean of the F1 crosses and (2) the difference between the parental inbreds of an F1.
Influence of Different Defoliation Systems on the Regrowth of Pearl Millet, Hybrid Sudangrass, and Two Sorghum‐Sudangrass Hybrids from Terminal, Axillary, and Basal Buds1
Authors: Clapp John G. , Chamblee Douglas S.
Published: July 2010

Stubble heights of 8, 10, 15, and 25 un were imposed on ‘Gahi‐1’ pearl millet (Pennisetum typhoides [Burm.] Stapf. and C. E. Hubb.), ‘Haygrazer’ and ‘Sudax SX‐12’ sorghum‐sudangrass hybrids (Sorghum vulgare Pers. ✕ Sorghum sudanense Stapf.), and ‘Trudan II’ sudangrass hybrid (Sorghum sudanense Stapf.) at either the first, second, or third harvest with other harvests being cut to a uniform height. Considering all cultivars tested, marked reductions in yields were obtained when they were defoliated to 8 cm as compared with 25 cm for 21 out of 24 harvests (87% of the harvest). Net gains in yield ranging from 1,203 to 2,039 kg/ha were realized within a 30‐day growth period by raising the stubble height from 8 to 25 cm at a single harvest. Dry matter production was influenced more by variation in stubble heights at the second harvest than when these same variations were imposed at the first or third harvest.

Gahi‐1 pearl millet showed a different regrowth pattern than sorghum‐sudangrass or sudangrass hybrids, as regrowth was more dependent on terminal buds and less on tillering. Regrowth from terminal buds increased for all the summer annual cultivars as the height of defoliation was raised from 8 to 25 cm. Basal and axillary tillering increased as the height of defoliation was lowered from 25 to 8 cm for the sorghum‐sudangass hybrids. The nitrogen content of the forage was not reduced when the harvest height was lowered from 25 to 8 cm at the first or second harvest.
Hybrids of Trifolium pratense × Trifolium pallidum1
Authors: Armstrong K. C. , Cleveland R. W.
Published: July 2010

Triploid hybrids, 2n=22, were produced from crosses of autotetraploid Trifolium pratense L., 2n=28, × diploid T. pallidum Waldst. & Kit., 2n=16. We obtained 194 hybrids from 2,575 hand‐pollinated florets. Many hybrids were vigorous, flowered profusely, and were intermediate to the parent Species in morphology. Chromosomal homology of the parental genomes was slight. At metaphase I the hybrids averaged 7.32 I, 6.34 II, 0.54 III and a very low frequency of multivalents containing more than three chromosomes. The hybrids were male‐ and female‐sterile. A hypo‐autotriploid plant of T. pratense>, 2n=20, was fertile and averaged 1.90 I, 2.89 II, and 4.08 III in microsporocytes at metaphase I.
Competition Among Oat Varieties Grown in Hill Plots1
Authors: Smith Olin D. , Kleese Roger A. , Stuthman Deon D.
Published: July 2010

Five adapted varieties of spring oats, Avena sativa L., were used in a study of intergenotypic competition. All pairwise combinations of the five varieties were grown at two locations at four levels of competition in hills and three levels in rows. Some varieties were enhanced and other varieties suppressed in yield as a result of competition in both hill and row plots at both locations. The maximum effect measured was with the variety ‘Rodney’ which yielded 62% more when surrounded by hills of ‘Goodfield’ than when surrounded by itself. Varieties that were strong competitors yielded more, relative to weak competitors, when grown in single hill plots than in rows or hills bordered by the test genotype (testor). Yield of testors was negatively correlated with differences between testor and competitor height and maturity. However, mature height and date of heading were not significantly influenced by competition. The effects of competition were more pronounced for yield per se than for any of the yield components. Panicle number and number of seeds per panicle were affected more than seed weight.
Growth and Carbohydrate Changes in the Root Wood and Bark of Different Sized Alfalfa Plants during Regrowth after Cutting1
Authors: Ueno Masahiko , Smith Dale
Published: July 2010

Small, medium, and large alfalfa (Medicago sativa L.) plants were allowed to regrow 42 days in the greenhouse following removal of the herbage. Weight of new herbage and total top growth increased steadily during regrowth and was proportional to initial plant size and to numbers of shoots produced per pot. Total root weight for each plant size decreased during the first few weeks and then increased. Weight of root wood was always higher than weight of bark.

Minimum levels (g/pot) of total nonstructural carbohydrates (TNC) in the original plant (crown plus taproot) were reached at 7 days in the small plants and at 14 days in the medium and large plants, but weight of TNC in large plants was nearly as low at 21 as at 14 days. Proportion of the weight of TNC utilized until the minimum level was reached was the same for each plant size (27 to 33%). At the time of minimum TNC level, small, medium, and large plants had utilized 1.50, 0.75, and 0.58 g of TNC during the production of 1 g of herbage dry matter. TNC restoration (g/pot) in the original plant after it reached the minimum level was greatest for the large plants and least for the small plants.

Among the three original plant tissue fractions (crown, taproot wood and bark), highest percentage of TNC was found in the root wood, followed in order by the root bark and the crown. Nearly 55% of the TNC (g/pot) in the original plant was found in the root wood, 20% in the bark, and 25% in the crown at all stages of regrowth regardless of plant size. Of the weight of TNC utilized until the minimum level was reached, 46 to 52% was utilized from the root wood, 21 to 26% from the root bark, and 24 to 28% from the crown regardless of plant size
Visual Selection for Yielding Ability of F3 Lines in a Hard Red Spring Wheat Breeding Program1
Authors: Briggs K. G. , Shebeski L. H.
Published: July 2010

The ability of fourteen plant breeders to visually select the highest yielding plots from a spring wheat (Triticum aestivum L. era. Thell.) nursery containing 828 F3 lines was compared with results obtained by random selection. When a positive selection pressure of 10% was applied a significant improvement in yield over random selection was obtained. Conditions for effective visual selection were optimal in this study with the use of triple row, rod length plots with controls adjacent to each one. Despite these aids, and despite the general effectiveness of visual selection to improve yields, individual selectors demonstrated a rather limited ability to identify the actual highest yielding plots in the nursery. These results support the view that when visual selection is used as a means of screening lines in a plant breeding program the intensity of selection should be relatively low.
Uterotropic Activity and Heritability of Biochanin A and Formononetin in Trifolium medium L.1
Authors: Gourley L. M. , Keim W. F. , Stob Martin
Published: July 2010

The four isoflavones, genistein, biochanin A, formononetin, and daidzein, were identified in zigzag clover, Trifolium medium L. Biochanin A and formononetin were the predominant isoflavones; genisteln and daidzein were present only in trace amounts. The isoflavones were separated by thin‐layer chromatography and quantified spectrophotometrically.

Biochanin A and formononetin concentrations were established for samples collected from two greenhouse and two field harvests of a complete six‐clone diallel cross. Analysis of variance by Griffing's combining‐ability procedure indicated that the significant genetic variance for the isoflavones was primarily explained by general combining ability.

The upper leaflets of zigzag clover contained about 1/3 more biochanin A and formononetin than the lower ones, while the internodes contained about 1/10 as much formononetin as the leaflets, and only a trace of biochanin A.
Effect of Delinting and of Genetical Factors on the Germination of Cotton Seeds at Low Temperatures1
Authors: Marani A. , Amirav A.
Published: July 2010

Acid delinting improved and accelerated the germination of cotton seeds at low temperatures in tests conducted both in an incubator (at 12 C and 14 C) and in the field. All the cultivars of Gossypium hirsutum L. and G. barbadense L., tested in these experiments, exhibited this effect, even though seeds of the latter species were covered only by a negligible amount of fuzz. This indicates that acid delinting increases the permeability of the seedcoat.

Water was absorbed by the fuzz during the first hours after planting, but later acid‐delinted seeds showed a higher rate of water absorption. The inheritance of the ability of cotton seeds to germinate at low temperatures is probably polygenic and primarily additive, with prominent maternal effects which are associated with characteristics of the seedcoat and the fuzz.
Distribution of Total 3‐Beta‐hydroxysterols in Burley Tobaccos1
Authors: Davis D. L. , Legg P. D. , Collins G. B.
Published: July 2010

Phytosterol levels in air‐cured hurley tobacco, Nicotiana tabacum L., ranged from 1.40 to 2.10 mg/g of dry weight. The pattern of sterol distribution in the tobacco plant was characterized by a linear increase from the base to the apex. Within a leaf, the sterol distribution was also linear with increasing levels from the basal section to the tip of a leaf.