bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytogenetics of Stem‐Rust Resistance in an Agrotricum Line1
Authors: Shank A. R. , Schmidt J. W. , Morris R.
Published: July 2010

Low transmission of resistance to stem rust and to adult‐plant leaf rust in crosses between the Agrotricum line NE66536 and Triticum aestivum L. em. Thell. prompted this cytogenetic study. Monosomic analysis showed that stem‐rust resistance was carried on an Agropyron chromosome which had substituted for chromosome 6D of wheat but could also substitute for 6A. Pollen with the Agropyron chromosome instead of 6D was slightly less competitive than pollen with a complete set of wheat chromosomes. Transmission of stem‐rust resistance in crosses to ‘Chinese Spring’ was a good fit to expected segregation ratios for plants having two independent univalents in place of a bivalent. Transmission of resistance in crosses to ‘Omaha’ was considerably lower than expected. It is proposed that differential alien chromosome instability in different genetic backgrounds leads to variability in the rate of univalent misdivision and somatic loss, resulting in variable transmission rates.
Linkage and Inheritance Studies Involving an Annual Pollen Restorer and Other Genetic Characters in Sugarbeets1
Authors: Roundy T. E. , Theurer J. C.
Published: July 2010

An annual pollen‐restorer sugarbeet (Beta vulgaris L.) inbred, was studied to determine if its cytoplasm had changed from sterile to fertile. Data showed that the fertility expressed by the restorer inbred was the result of genetic factors and not cytoplasmic reversion. Linkage tests with the restorer gene (Rf2)showed independence with five other sugarbeet characters of the YRB (yellow root, red hypocotyl, annualness) linkage group, m (monogerm), and vi4 (virescens).
Sources and Inheritance of Resistance to Brown Planthopper in Some Breeding Lines of Rice1
Authors: Martinez C. R. , Khush Gurdev S.
Published: July 2010

The inheritance of resistance to the brown planthopper (Nilaparvata lugens Sial.) in three breeding lines of rice (Oryza sativa L.), IR747B2‐6, IR1154‐243, and IR4‐93, was studied. Seven‐day‐old seedlings were infested with second‐ and third‐instar nymphs of brown planthopper and seedling injury was recorded 7 to 8 days after infestation.

The resistance of IR747B2‐6 was conditioned by a single dominant gene which was allelic to the dominant gene of the variety ‘Mudgo’ (Bph 1). The resistance of IR1154‐243 and of IR4‐93 was governed by the same recessive gene which was also allelic to the recessive gene conditioning the resistance of ‘ASD 7’ (bph 2). IR4‐93 inherited its resistance from ‘H‐105.’ But both parents of IR747B2‐6 and of IR1154‐243 were susceptible. We concluded that ‘TKM 6,’ one of the parents of IR747B2‐6, is homozygous for Bph 1 but is also homozygous for a gene, I‐Bph‐1, which inhibits Bph 1. ‘Zenith,’ one of the parents of IR1154‐243, may also have a similar inhibitor gene.
Abscission of Cotton Floral Buds and Bolls as Influenced by Factors Affecting Photosynthesis and Respiration1
Authors: Guinn Gene
Published: July 2010

The effects of some environmental factors on abscission (shedding) of young cotton (Gossypium hirsutum L.) fruits were investigated because excessive shedding is sometimes a problem in cotton production. Increasing the concentration of CO2 in the atmosphere from 350 to 1,000 ppm decreased shedding, increased the glucose and fructose contents of leaves, and lowered the average node number of the first bolls. Increasing the daily photoperiod from 8 to about 14 hours had similar effects. Conversely, shedding was increased by warm nights (30 C) and by low light intensity.

These results indicate that factors that decrease photosynthesis or increase respiration may delay fruiting and decrease retention of floral buds (squares) and bolls. Low light intensity could become critical with high plant populations (more than 100,000 plants/ha), cloudy weather, rank growth, or a combination of the above conditions.
Effects of Zinc Deficiency on the Multiplication and Expansion of Sugarbeet Leaf Cells1
Authors: Spiller Susan , Terry Norman
Published: July 2010

The effects of zinc deficiency on cell number, mean cell volume, and dry weight of sugarbeet (Beta vulgaris L.) leaves was determined using plants cultured hydroponically in growth chambers. Zinc deficiency reduced the number of cells in the first‐formed leaf (leaf 1) 48 to 70% of the control and in the fourth‐formed leaf (leaf 4) 39 to 43% of the control. Mean cell volume was not significantly changed by zinc deficiency in leaf 1 but was decreased 30 to 38% of the control in leaf 4. Leaf dry weight was decreased more by zinc deficiency in leaf 4 than hi leaf 1. The results showed that zinc deficiency, in its initial stages, retarded cell division and dry matter accumulation of leaves but had little effect on cell expansion. As zinc deficiency became more severe, cell expansion was also decreased.
Variety Synthesis in Alfalfa1
Authors: Lowe C. C. , Cleveland R. W. , Hill R. R.
Published: July 2010

We compared performance of conventional synthetics, double‐cross synthetics, and the parental components of the double‐cross synthetics in a series of field experiments of alfalfa (Medicago sativa L.). Nine clones that had been selected for high general combinging ability were used as parents for the nine 4‐clone combinations studied. Synthetics were produced by several methods of synthesis. The forage yield of the synthetics, measured in broadcast‐seeded trials at three locations in New York and Pennsylvania, was used to compare the methods of synthesis. All seeds were produced in cage isolations in California and New York. Honeybees (Apis mellifera L.) were used as pollinators.

Conventional 4‐clone synthetics consistently yielded slightly more than the double‐cross synthetics. True double‐cross hybrid varieties from these parents would probably yield about 104% of that of the double.cross synthetics or about equal to the conventional synthetics. Advanced generations of 2‐clone synthetics (components of double.cross synthetics) were consistently lower yidlding than any 4‐clone synthetic which had the same two clones in its parentage. This agrees with theoretical expectations on inbreeding. Permutations of parent clones in synthesis of double‐cross synthetics affected performance but no permutation exceeded the corresponding conventional synthetic. Double‐cross synthetics made from Syn 2 generations of 2‐clone synthetics as parent lines yielded the same as those made from the Syn 1 generations of the parent lines. Differences observed in performance of synthetics produced in California and New York were attributed to differences in methods of establishing the plantings in seed production cages.
Mutations Induced in Vegetatively Propagated Turf Bermudagrasses by Gamma Radiation1
Authors: Powell Jerrel B. , Burton Glenn W. , Young Jonh. R.
Published: July 2010

Most improved cultivars of turf bermudagrass (Cynodon sp.) are vegetatively propagated because of trlploid‐induced sterility or poor seed‐setting characteristics. Further improvement of these specialized turfgrasses is unlikely because they cannot be hybridized or easily constructed from parental stocks. New techniques are needed to circumvent these breeding barriers. Physical or chemical mutagens offer a practical approach.

Rhizomes of two turf bermudagrass cultivars were treated with gamma rays to evaluate the mutation‐breeding technique for these vegetatively propagated grasses. Dosages of 9,000 and 11,300 rads produced 71 distinct mutations in the treated material screened. Mutations to dwarfism and changes in color hue of the stolons were most frequently noted. Gamma‐ray induction of mutations was of such frequency as to recommend use of this approach for the practical and successful breeding improvement of vegetatively propagated turf bermudagrass. Methods reported here also apply to the forage bermudagrasses and other vegetatively propagated grasses.
Model for Predicting Emergence of Grain Sorghum1
Authors: Horrocks R. D. , Cloninger F. D.
Published: July 2010

Six planting depths (1.3 to 7.6 cm in 1.27‐cm increments) and five day/night temperature regimes (17/7C to 37/27C in 5/5C increments) were used to develop a model capable of predicting grain sorghum (Sorghum bicolor (L.) Moench.) emergence. Polynomial components in the analysis of variance indicated that 24 variables were significant at the 1% level. Regression analysis showed that these 24 variables accounted for 92% of the variation in the observed emergence. The standard error of the estimate was 11.0%. The model generally predicted less emergence at the lower temperatures and more at the higher temperatures than was observed. Only recently have some physical, biological, and physiological processes relating to plant growth been defined mathematically. The quantification reported here adds to the growing list. Its utility lies in three areas: 1) in its present form we are able to make reasonably accurate estimates of emergence if the soil water supply is adequate; 2) it can serve as a definition for one of the steps in the complete plant‐production system; and 3) it will serve as a basis for developing a more sophisticated model as additional data become available.
Growth Analysis of Soybeans Treated with TIBA1
Authors: Tanner J. W. , Ahmed Shabir
Published: July 2010

A growth analysis study was employed in an attempt to understand the mechanism by which the growth regulator 2,3,5‐triiodobenzolc acid (TIBA) increases soybean [Glycine max (L.) Merrill] yields. Four soybean cultivars were sprayed at flowering time with an aqueous solution containing TIBA. Under good growth conditions, seed yields were increased by the treatment; no yield response was shown when conditions were poor for growth. Latermaturing cultivars responded more than early‐maturlng cultivars. Total dry matter production and rate of total dry matter production were not altered by TIBA; however, both seed yield and rate of reproductive dry matter production were greater on treated than on control plots. The data support the theory that TIBA acts by slowing vegetative growth and increasing reproductive growth rather than the theory proposing that the increase occurs as a result of improved canopy efficiency. Breeding implications are discussed.
Amylolytic Activity of Orchardgrass and Starch and Sucrose Contents of Orchardgrass vs Pangola Digitgrass Leaf Blades as Influenced by Night Temperature and Gibberellic Acid1
Authors: Carter J. L. , Garrard L. A. , West S. H.
Published: July 2010

This study was made to determine differences in sucrose and starch contents and amylolytic activities between Orchardgrass (Dactylis glomerata L.) and ‘Pangola’ digitgrass (Digitaria decumbens Stent.). This information could help explain why growth of tropical grasses is severely reduced by suboptimal night temperature (10C) whereas temperate species are much less affected.

Orchardgrass and Pangola were treated with gibberellic acid (GA) and subjected to 30 or 10C 12‐hour nights with SOC days, after which sucrose and starch were determined. The starch‐degrading enzymes of Orchardgrass leaf blades were separated by means of polyacrylamide gel electrophoresis. Amylolytic enzyme activity was determined from densitometer tracings and by a colorimetric assay. In the case of Orchardgrass extracts, densitometer tracings of gels negatively stained by starch‐iodine showed the presence of 18 bands regardless of plant treatment. This was hi contrast to similar data previously obtained for Pangola. The temperate grass was found to contain more amylolytic isozymes and greater total amylolytic activity than Pangola. Neither the 10C night regime nor GA application affected total amylolytic activity or starch content of Orchardgrass, whereas both treatments affected amylolytic activity and starch content of Pangola. GA application did not affect the number of amylolytic isozymes in the leaf blades of either plant. Sucrose appeared to accumulate in leaves of both grasses during 10C exposure, in the presence and in the absence of GA. In the case of Orchardgrass, GA appeared to reduce leaf sucrose content at 30C.
Inheritance of Barley Stripe Mosaic Reaction in Crosses Among Three Barley Varieties1
Authors: Vazquez Gregorio , Peterson G. A. , Timian R. G.
Published: July 2010

Inheritance of reaction to three strains, “Type” (PV43), NDI, and CV52, of barley stripe mosaic virus (BSMV) was studied in F1 and segregating populations of a diallel cross of barley (Hordeum vulgare L.) varieties ‘Traill,’ ‘Modjo 1,’ and ‘Moreval.’ A multiple allelic series was proposed for reaction to the Type strain, with the susceptible allele of Traill dominant to the resistant allele of Modjo 1, but recessive to the resistant allele of Moreval. A single gene conditioned reaction to strain NDI, with susceptibility of Traill and Modjo 1 dominant to resistance of Moreval. Varietal genotypes proposed for reaction to the Type strain of BSMV were Sm3bSm3b for Traill, Sm3aSm3a for Modjo 1, and Sm3cSm3c for Moreval. Genotypes Sm5Sm5 for Traill and Modjo 1 and sm5sm5 for Moreval were proposed for reaction to BSMV strain NDI. All three varieties were susceptible to strain CV52, and segregation was not observed hi hybrid populations. Genes controlling reaction to the Type strain of BSMV were inherited independently of genes for stem rust reaction, aleurone color, spike row number, and rachilla hair length. In a few instances, the BSMV used in the study proved unstable or mixtures of virus strains existed.
Genetic Analysis of Virescent Mutants in Cotton
Authors: Percival A. E. , Kohel R. J.
Published: July 2010

Seven potential yellow‐foliage mutants were found in Upland cotton (Gossypium hirsutum L.), and progeny tests proved three to be genetically controlled. These three mutants were classed as virescents, two of which were found to be alleles of known virescent mutants, virescent‐2 (v2) and virescent‐4 (v4). However, results indicate that the remaining mutant is not an allele of any of the known virescent‐yellow mutants. It is a complete recessive and is controlled by a single locus that causes virescent‐yellow foliage when the recessive alleles are homozygous. Linkage tests indicate that it is an independent mutant, not linked to any of the known mutants tested. It is proposed that this new virescent mutant be named virescent‐3 and assigned the gene symbol v3; the homozygous mutant genotype will thus be v3v3.
Refractive Index as a Basis for Assessing Fatty Acid Composition in Segregating Populations Derived from Infraspecific Crosses of Cultivated Peanuts1
Authors: Khan A. Rahman , Emery Donald A. , Singleton John A.
Published: July 2010

Refractive indexes of oil were converted to calculated iodine values (C.I.V.'s) and used to assess the fatty acid composition of hybrid and segregating populations of six crosses of cultivated peanuts (Arachis hypogaea L.). Two subspecies (hypogaea and fastigiata), three botanical types (Virginia, Spanish, and Valencia), and four market types (Virginia, Southeastern Runner, Spanish, and Valencia) were represented in the four parents.

Highly significant statistical effects of locations and genotypes on mean C.I.V.'s were noted. Parent by location interactions were statistically significant, but hybrid by location interactions were nonsignificant.

The use of a refractometer as a practical, rapid, inexpensive, and objective means of assessing the fatty acid composition of peanut oil was demonstrated. Significant positive correlation coefficients between C.I.V.'s and the actual linoleic acid compositions of oils from 40 F2 plants supported the use of the refractometer method.

The wide range of genetic variability for C.I.V.'s in F2 populations of infraspecific crosses indicated selection potential for the improvement of quality and stability of seed oil within specific botanical plant types.

C.I.V. appears to be highly heritable, and its expression is controlled by a few additive genes.
Seed Production of Stylosanthes humilis as Influenced by Origin and Temperature During Flowering1
Authors: Schoonover H. C. , Humphreys L. R.
Published: July 2010

Ten selections of the tropical annual pasture legume Stylosanthes humilis, grown in controlled‐environment cabinets, were induced to flower at a common time and then subjected for 60 days to 31/24, 24/17, or 17/10C, day/night temperatures. Mature seed were not formed on inflorescences differentiated at 17/10C. This regime also decreased inflorescence number and floret number. Seed production at 31/24 and 24/17C was similar, but selections differed in their response to temperature and in the pathways through which response was reflected. The cultivar ‘Lawson’ and a selection from Dayboro, Queensland, were superior. Ecological implications are considered.
Semidwarfness, Stem Solidness, and Tillering of F2 Plants from 17 Spring Wheat Crosses1
Authors: McNeal F. H. , Wallace L. E. , Berg M. A.
Published: July 2010

Combining resistance to the wheat stem sawfly (Cephus cinctus Norton) with semidwarfness and higher grain yields in wheat (Triticum aestivum L.) is a plant breeding objective in Montana. Parental and F2 populations from 17 crosses of 6 standard‐height, solid‐stemmed wheat selections with three semidwarf, hollow‐stemmed selections were evaluated in the field for semidwarfness (plant height), stem solidness, and tillering.

Plant height data from crosses with ‘Bonanza’ suggest additive gene action, whereas skewness for tallness from crosses with ‘Shortana’ and MT 6830 suggest either dominance or some type of epistasis. The lack of dominance hi solid‐stemmed by hollow‐stemmed crosses is considered an indication of genetic additivity for stem solidness. All parents except Shortana tillered equally; Shortana had more tillers than standard height parents ND 681, ND 683, and ND 6850. A negative relationship between plant height and stem solidness indicates that selection of solid‐stemmed, semidwarf types should be possible.

The variation exhibited by these three plant characteristics offers plant breeders an opportunity to combine desirable features of each.
Analysis of Diallel‐Type Competition Studies1
Authors: Rawlings J. O.
Published: July 2010

The basic linear model for diallelic competition studies corresponds to the model for the diallel cross mating design with parents included. It is demonstrated that this model does not allow for unbiased estimation or testing of the average competitive effects unless certain restrictions are imposed on the parameters. Both the “adjusted” and “unadjusted” results of Hanson et al. (1961) are biased with respect to the basic unrestricted model but both are shown to provide unbiased results if alternative sets of restrictions on the [S1(jk)] are imposed. Thus, the two “adjusted” and “unadjusted” analyses may be more appropriately referred to as two alternative models. Two methods of competitor assignment which are consistent with the two sets of restrictions are described and it is left to the experimenter to decide which model more nearly represents his experimental situation. High correlation of results between the two models makes it unnecessary to perform both analyses. Estimators and variances of competitive effects and competition biases are presented for both models.
Genetic Analysis of a New Virescent Mutant in Cotton1
Authors: Kohel R. J.
Published: July 2010

A spontaneous mutant in cotton (Gossypium hirsutum L.) is described, and the results of its genetic analysis are reported. This mutant was called virescent‐splash‐leaf because it showed a typical virescent expression, and portions of the leaf surface had a splash‐leaf appearance resulting from abnormal palisade cell development. Expression of the virescent phenotype was consistent, but the splash‐leaf expression was variable. The incidence of the splash‐leaf expression was associated with cool temperatures.

The mutant was conditioned by recessive alleles at a single locus. Because it was non‐allelic with any known virescent mutants, it was designated as virescent‐8 and assigned the gene symbols v8v8.

Linkage analysis of virescent‐8 did not reveal any significant association with the marker loci: cup leaf, glandless‐1, frego bract, cluster‐1, virescent‐1, Okra leaf, Red plant, Pilose, Petal spot, Yellow petals, Pollen color, Brown lint‐1, Naked seed, or Green lint.
Comparative Leaf Area and Dry Matter Accumulation by Maize and Sugarbeet1
Authors: Snyder F. W.
Published: July 2010

Growth of noncompetitive plants of locally adapted maize (Zea mays L. cv. ‘Michigan 555 3x’) was compared with that of sugarbect (Beta vulgaris L. cv. ‘US H20’) in five experiments, including a 113‐day experiment outdoors.

Maize had larger leaf area per plant at emergence and maintained a larger area until the end of the 113‐day experiment; however, sugarbeet had nearly the same leaf area as maize at 113 days from emergence. The rate of leaf‐area accretion for both species was very similar for the first 50 days. Maize had decelerated to zero by 71 days, whereas sugarbeet continued to accrete leaf area.

Dry‐matter production per plant was greater for maize, ranging from 11.7‐fold greater at 15 days to 1.6‐fold greater at 113 days when it was mature.

The ratio of total dry matter produced per unit leaf area (DM/ULA) for maize:sugarbeet at 15 days was 1.60:1.00 and at 30 days was 1.48:1.00. At 50 days maize had produced no more DM/ULA than sugarbeet; and when the differential rate of leaf‐area accretion between the two species was adjusted, they were about equal at 71 days. At 92 days, maize again produced more DM/ULA than sugarbeet. At 113 days, maize averaged 66.8 mg dry matter cm−2 of leaf area and sugarbeet only 46.4. Thus, in the 113‐day period, the ratio of total DM/ULA for maize:sugarbeet was 1.44:1.00. Individual plants of both species differed markedly in producing DM/ULA. Growth‐rate data are included.
Development of a Nitrogen Balance for Cotton Growth Models: A First Approximation1
Authors: Jones J. W. , Hesketh J. D. , Kamprath E. J. , Bowen H. D.
Published: July 2010

Daily growth values of cotton (Gossypium hirsutum L.) were calculated based on the carbohydrate balance of SIMCOT II, a simulation model of cotton growth and development. The daily N requirements for new growth of leaves, stems, roots, burrs, and seed were calculated based on maximum and minimum N concentration for these plant parts. Daily N absorption depended on the availability of N in the soil pool and new growth requirements. If the absorbed N was less than the required amount, partitioning functions determined the distribution of available N into each sink. During periods of N shortages, some N reserves were supplied for new growth from the breakdown of N compounds in the older leaves and stems. Depending on the level of N shortage, new growth was slowed, bolls and squares were abscised, and some leaves were shed.

The model shows that, based on the N balance, growth can be restricted and reproductive organs aborted after SIMCOT II runs its normal course for a day during the boll setting period. Simulated fruiting characteristics and yield curves were similar to those of real plants.
Starch Content, Test Weight, and Other Quality Parameters of Corn Produced in Different Maturity Areas of Ontario1
Authors: Hilliard Joe H. , Daynard T. B.
Published: July 2010

Industrial buyers have traditionally assumed that the quality of grain corn (Zea mays L.) from shorter growing‐season areas of Ontario is inferior to that of grain produced in longer‐season areas. To test this assumption, we collected grain corn samples in the fall of 1970 and 1971 from 26 country elevators located across the corn‐growing region of the province. We evaluated the samples for test weight, 100‐kernel weight, percent starch, and percent protein. Significant positive correlations were found between test weight and maturity (i.e., number of heat units available for corn production at elevator location) and between 100‐kernel weight and test weight. Correlations of percent starch and percent protein with maturity were not significant. The results indicated that, except for test weight, length of growing season has no consistent effect on the grain quality parameters measured. We would argue that because of the lack of a relationship between test weight and either starch or protein content, lower test weight should not detract from the suitability of shorter‐season corn for most industrial uses.
Inheritance of Yellow Berry Color in Atropa belladonna L.1
Authors: Bhat B. K. , Dhar A. K.
Published: July 2010

A rare yellow berry plant of Atropa belladonna L. was self‐ and sib‐pollinated in a breeding program to improve this important medicinal plant. The normal color is purple‐black. Segregation studies indicated that the yellow berry color was inherited from a single recessive gene. Data are presented from F1, F2, and F3 generations.
Heritability and Interrelationships of Grain‐Protein Content with Other Agronomic Traits of Sorghum1
Authors: Crook Wayne. J. , Casady A. J.
Published: July 2010

Forty grain sorghum (Sorghum bicolor (L.) Moench) hybrids were produced by crossing each of 4 cytoplasmic male‐sterile lines with 10 diverse restorer lines. The parents and their hybrids were grown at four locations in 1972. Characters studied included protein percentage, grain yield, days to 50% bloom, height, panicle exsertion, leaf area, panicles per pl,ant, kernel weight, and test weight.

Location significantly affected all characters except test weight in the hybrid populations. The genetic variance was significant for all characters measured. The specific combining ability, estimated by the male) ✕ female interaction, was significant for protein percentage, days to 50% bloom, height, panicle exsertion, panicles per plant, kernel weight, and test weight.

Heritability estimates were calculated from variance components and midparent‐offspring correlation. High heritability estimates were obtained from correlations for protein percentage, height, and panicles per plant; medium heritability estimates were obtained for yield and kernel weight; and low heritability estimates were obtained for day to 50% bloom, panicle exsertion, leaf area, and test weight. Heritability estimates for all characters were high when calculated from variance components.
Simulated Selection in Autotetraploid Populations. I. Computer Methods and Effects of Linkage1
Authors: Swanson M. R. , Dudley J. W. , Carmer S. G.
Published: July 2010

A computer simulation model for mass selection in a random mating autotetraploid population was presented. Selection was based on a single quantitative trait controlled genetically by 40 genes, 4 on each of 10 chromosomes. The model allowed for arbitrary gene frequency, double reduction, linkage, dominance, epistatic deviations involving two loci, population size, intensity of selection, and environmental variance. Effects of mutation, migration, and natural selection were ignored.

Preliminary results revealed that linkage affected selection response in diploid and autotetraploid populations about equally when genetic variance was primarily additive. With dominance, linkage had a greater effect on diploids.
Simulated Selection in Autotetraploid Populations II. Effects of Double Reduction, Population Size, and Selection Intensity1
Authors: Swanson M. R. , Dudley J. W. , Carmer S. G.
Published: July 2010

Effects of double reduction, population size, and selection intensity on response to mass selection in a random mating autotetraploid population were studied by computer simulation. Results were compared to diploids. Selection was based on a single quantitative trait controlled genetically by 40 loci, ignoring the effects of mutation, migration, and natural selection. Six genetic models, with varying levels of additive, dominance, and epistatic variance were compared.

In models with small dominance effects, double reduction increased heritability by increasing additive genetic variance, thus increasing selection response. In models with dominance deviations, selection response was not affected by double reduction.

Genetic drift was a major factor in limiting total selection response when the effective population size was 10 or less. Diploids were affected more by genetic drift than autotetraploids.

Changes in genetic variance over generations of selection varied with the genetic model, selection intensity, and initial gene frequency. Peculiar trends were noted for some models due to a mix of initial gene frequencies. Of several measures of heritability compared, parent‐offspring regression on a random sample of parents and their offspring predicted selection gain best.
Inheritance of High Lysine in Hiproly Barley and Its Association with the Hiproly Endosperm Gene1
Authors: Helm J. H. , Metzer R. J. , Kronstad W. E.
Published: July 2010

A recombination of 22.45% between the major high lysine gene and a single gene for starch binding in the endosperm (stb) was found in the barley (Hordeum vulgare L.) variety ‘Hiproly.’ This association was found by using a microscopic technique to identify the stb gene and a micro Udy‐Dye binding method to identify the high lysine gene. Both genes give a dosage effect in the 3n endosperm.
Histological Studies on Five Male‐Sterile Strains of Upland Cotton1
Authors: Murthi Anishetty N. , Weaver J. B.
Published: July 2010

Microsporogenesis and pollen development in one cytoplasmic male‐sterile and four genetic male‐sterile strains of Upland cotton (Gossypium hirsutum L.) were studied in comparison with a male‐fertile variety.

In the cytoplasmically male‐sterile Upland cotton with the G. harknessii cytoplasm, there was disorganization of tapetal cells and coalescence of pollen mother cells (PMC's) during the premeiotic stages.

In the Ms4 dominant genetic male‐sterile anthers, degeneration of microsporocytes was observed before or shortly after the initiation of prophase I. The tapetal cells were reduced in size in some of the anthers.

In another dominant genetic male‐sterile, Ms7, meiosis appeared normal in the majority of the PMC's. The abortion of microspores was noticed during formation of the pollen wall. There was no observable malfunctioning of the tapetum.

In the double recessive ms5ms6 male‐sterile anthers, vacuolation of developing microspores led to their degeneration. Nutrient deficiency of several kinds might have been the cause of vacuolation and abortion of pollen.

In Rhyne's double recessive male‐sterile unthers, premature degeneration of the tapetum caused the abortion of pollen in most locules. In a few locules viable pollen was produced but the anthers were nondehiscent. Seeds were produced when pollen from the indehiscent anthers was released by crushing and dusted on other male‐sterile plants.
Diallel Crosses Among Maryland Cultivars1 of Tobacco1
Authors: Fan C. J. , Aycock M. K.
Published: July 2010

Five cultivars and the diallel set of 10 F1 hybrids of tobacco (Nicotiana tabacum L.) were grown at 2 locations in 1967. The diallel was expanded in 1968 to include 7 cultivars and 21 F1 hybrids. Also in 1968, F1 and F2 hybrids from the 5‐parent diallel were grown at one location in order to obtain estimates of inbreeding depression. For both years, a significant heterotic response was observed for four agronomic traits. On the average, the F1 hybrids produced more yield and dollars per hectare, had a higher price ($/kg), and flowered earlier than the cultivars. A significant inbreeding depression was found with the F2 hybrids for value ($/ha), price ($/kg), and days to flower.

From the 7‐parent diallel, estimated variability for general combining ability was significant for 6 of the 10 traits studied, but specific combining ability estimates were small and nonsignificant. F1 hybrids in the 5‐parent diallel did not vary significantly.
Stability Indexes of Radiated and Nonradiated Oat Genotypes Propagated in Bulk Populations1
Authors: Fatunla T. , Frey K. J.
Published: July 2010

Two lines of descent were established from an F3 bulk lot of oats (Arena sativa L.) initiated by mixing seeds from 250 crosses. For one line of descent, seeds were radiated with thermal neutrons or X‐rays from F3 through F6, and these treatments were followed by five generations of bulk propagation with no artificial selection. The other line was propagated for 10 generations with no artificial selection. Twenty random strains from each of four generations from the radiated (F7, F8, F9, and F11) and five from the nonradiated (F3, F6, F7, F8, and F12) line of descent, and ‘Nodaway’ cultivar were used to measure stability indexes for grain yield, plant weight, harvest index, plant height, 100‐seed weight, and seed numbers in the various generations.

Mean regression stability indexes for grain yield decreased from 1.17 to 1.02 in the nonradiated line, and increased from 0.82 to 1.04 in the radiated line of descent over time. Generally, data on oat strains from the radiated line fitted the linear regression model better than those from the nonradiated one. The changes in mean regression stability indexes for plant weight paralleled those for grain yield, but no trends in this statistic occurred for other traits.

Genotypic variances among strains within generations were sporadic for all traits in both lines of descent. for grain yield, seed number, and plant height there were consistent expansions in the genotype ✕ environment interaction variances within generations. This was primarily due to the regression stability indexes among lines becoming more diverse over time. The contributions of deviations from regression to the interaction variance remained relatively constant over generations in both lines of descent.

Means and regression stability indexes for oat strains within generations were highly and positively correlated for grain yield, seed number, bundle weight, and plant height.
Effectiveness of Recurrent Selection for Corn Stunt Resistance in a Maize Variety1
Authors: Scott Gene E. , Rosenkranz Eugen E.
Published: July 2010

Three methods of selecting parents to be used in a recurrent selection program were compared for their effectiveness in increasing the level of resistance to corn stunt within a corn (Zea mays L.) population. Selection methods were: (1) selecting the best plant in the best 10 of 463 S1 progeny rows, (2) selecting the best 23 S3 progenies derived from the original 463 S1 progenies, and (3) selecting the best 10 of 100 S1 progenies that were evaluated in a replicated test. All tests were conducted under conditions of natural infection by the disease agents.

Each method of selection was effective. Selecting parents on the basis of results obtained from a replicated test was the most efficient procedure. In the improved population after one cycle, 21% of the plants were infected with corn stunt, compared with 52% diseased plants in the original population. Our results showed slightly more effectiveness in improving the population for corn stunt resistance than predicted.
Light Intensity During Leaf Growth Affects Chlorophyll Concentration and CO2 Assimilation of a Soybean Chlorophyll Mutant1
Authors: Koller H. R. , Dilley R. A.
Published: July 2010

An evaluation was made of leaf diffusive resistance and chlorophyll concentrations of dark green (normal) and pale green (chlorophyll deficient) phenotypes of a soybean [Glycine max (L.) Merrill] mutant when grown 10‐ and 30‐klux light intensities. When grown at the 10‐klux intensity the two leaf types had similar mesophyll and total CO2 diffusive resistances and similar net photosynthetic rates per unit leaf area at normal ambient CO2 concentrations (e.g., 300 µl/liter). Chloropyhll concentration of the pale green leaf was one‐fourth that of the dark green leaf. On a chlorophyll basis, rate of CO2 fixation was four times faster in the pale green type than in the dark green type. The similarity in net photosynthetic rates per unit leaf area of the two phenotypes when grown at the 10‐klux light intensity was the result of (1) similar CO2 diffusive resistances and (2) the ability of the photosynthetic apparatus of the pale green leaf to fix CO2 as rapidly as that of the dark green leaf, in spite of a much lower amount of chlorophyll.

When grown at the 30‐klux light intensity, chlorophyll concentration of the pale green phenotype progressively declined, to one‐tenth the amount at the 10‐klux intensity. Chlorophyll concentration of the dark green phenotype was not significantly affected by light intensity. Photosynthesis of the pale green leaf grown at the 30‐klux intensity became CO2 saturated at concentrations well below 300 µl/liter. Therefore, light intensity during leaf growth strongly influenced the relative CO2 assimilation rates of the dark green and pale green phenotypes.
Intergenotypic Competition Between Tall and Dwarf Wheats. I. In Mechanical Mixtures1
Authors: Khalifa M. A. , Qualset C. O.
Published: July 2010

Intergenotypic competition was examined in Triticum aestivum L. em. Thell. populations composed of ‘Ramona 50’ (R50), a tall variety, and ‘D6301,’ a short‐statured variety. Their respective relative heights were about 100 and 75% and relative grain yields in pure stands were about 80 and 100%. Replicate equal‐frequency mixture‐bulk populations were synthesized and maintained without artificial selection or reconstruction for four generations. D6301 decreased in frequency over time with a concurrent decrease in the population yield level. Yield and endpoint yield components were examined in three environments for each genotype in a frequency study where the genotypes appeared in all combinations at 0.125 frequency increments. Population yields were predictable on the basis of pure‐stand performance, but the contribution of D6301 to total yield was significantly below expectations at all frequencies. Complementary competition was indicated because R50 showed a corresponding increase in yield over expectations from pure‐stand performance. Reproductive values were strongly frequency‐dependent for both genotypes, with the competition effect becoming increasingly larger either with decreasing frequency of D6301 or increased frequency of R50. The poor competitive ability of D6301 was expressed as a large decrease in number of kernels per spike and possibly decreased spike number, while kernel weight was not affected. R50 attained its advantage by increased kernel weight at lower frequencies and possibly increased spike number; kernel number per spike remained constant over all frequencies.
Effect of Light Intensity on the Development of Field Grown Soybeans1
Authors: Major D. J. , Johnson D. R.
Published: July 2010

Effects of light intensity on days to flowering and postflowering development were recorded on two soybean [Glycine max (L.) Merr.] cultivars from each of the Maturity Groups I to V. A light intensity gradient was produced by a row of lights at one end and perpendicular to rows 25.2 m long. Lights were left on continuously from planting until maturity. Light intensities along the rows ranged from 2 to 100 lux. Days from planting to flowering, final plant height, and internode number increased as light intensity increased but no detectable effects of light intensity were observed on days from flowering to beginning pod fill, flowering to the termination of flowering, flowering to maturity, or final seed yield.
Mitochondrial DNA from Maize Hybrids with Normal and Texas Cytoplasms1
Authors: Shah D. M. , Levings C. S.
Published: July 2010

Mitochondrial DNA (mtDNA) was isolated from two hybrids of maize (Zea mays L.), NC232 ✕ T204N (normal cytoplasm) and NC232 ✕ T204 cms T (Texas cytoplasm). No difference was found in the buoyant densities of mtDNA isolated from the two hybrids. The mtDNA had a buoyant density of 1.706 g/cm3 in CsCl and a molar % guanine plus cytosine of 46.9. Therefore, the cytoplasmic dissimilarities with respect to sterility and disease response between the normal and the Texas cytoplasm cannot be accounted for by detectable alterations in the base composition of mtDNA.
Analysis by Digestion and Colorimetric Assay of Total Nitrogen in Plant Tissues High in Nitrate1
Authors: Cataldo D. A. , Schrader L. E. , Youngs V. L.
Published: July 2010

A method is proposed for analysis of total nitrogen in plant tissues enabling predigestion (to reduce nitrate to ammonium) and digestion to be performed in a Folin‐Wu tube. Following digestion, a sensitive colorimetric assay for ammonium is used to quantitate N‐content in an aliquot of the digest. The proposed method has several advantages: 1) up to 110 tissue samples can be predigested and digested in one batch; 2) small tissue samples (5 to 100 mg) can be accommodated; 3) the colorimetric assay for ammonia is very sensitive; 4) tissues can be predigested to recover all nitrate in the samples; and 5) aliquot size from the diluted digest can be varied to effectively detect as little as 1 µg of N.
Reproduction in Crested Wheatgrass Pentaploids1
Authors: Dewey Douglas R.
Published: July 2010

Pentaploid, 2n=35, crested wheatgrasses [Agropyron cristatum (L.) Gaertn.] and related taxa., were derived by crossing natural and induced tetraploids, 2n=28, with hexaploids, 2n=42. The pentaploids backcrossed readily to tetraploids and hexaploids, but they crossed only rarely with diploids, 2n=14. Chromosome numbers in 5x‐2x, 5x‐4x, 5x‐5x, and 5x‐6x hybrids ranged from 2n=21 to 25, 2n=28 to 35, 2n=28 to 42, and 2n=35 to 60, respectively. Three hyperoctoploid hybrids—2n=58, 59, and 60—from 5x‐6x crosses probably resulted from union of unreduced male gametes, n=42, and reduced eggs, n=16 to 18. The pentaploids produced functional reduced gametes with n=14 to 21 chromosomes, and the gametic chromosome numbers were distributed somewhat normally, with a mean between n=17 and 18. High multivalent associations at metaphase‐I in some hybrids were caused by a combination of autoploidy and structural heterozygosity. Fully fertile tetraploid and hexaploid hybrids were recovered immediately from 5x‐4x and 5x‐6x crosses, respectively. Grass breeders should not find it difficult to transfer genes, chromosomes, or even whole genomes between tetraploid and hexaploid crested wheatgrasses. Genetic transfer between diploid and polyploid races is somewhat more difficult.
Selection in Six Crops of Sugarcane. II. Efficiency and Optimum Selection Intensities
Authors: James N. I. , Miller J. D.
Published: July 2010

Selection was applied for stalk number, stalk diameter, and Brix in six crops of a population of 376 sugarcane (Saccharum sp.) clones with intensities from 2 to 100%. In both cost and land use, efficiency of selection for stalk number was somewhat greater in the plant crop of seedlings and 1.2‐m clonal plots than in the first ratoon crops. For stalk diameter, efficiency was equal in the plant and ratoon seedling crops and greater in the plant crop than in the ratoon crop of 1.2‐m clonal plots. Selection efficiency for Brix was somewhat greater in the ratoon crop than in the plant crop of seedlings and about equal in both crops of 1.2‐m clonal plots.

The optimum intensity for independent selection of stalk number and stalk diameter was 40% in both plant and first ratoon crops of seedlings. The optimum selection intensity for Brix in the plant crop of seedlings ranged from 30 to 50% and in the first ratoon crop of seedlings was 40%. In the plant crop of 1.2‐m clonal plots, the optimum selection intensity was 50% for the three characters. In the first ratoon crop, optimum selection intensities were 60, 40, and 40% for stalk number, stalk diameter, and Brix, respectively.

The optimum simultaneous selection intensity for the three characters in the plant crop of seedlings ranged from 4.8 to 8% and was 6.4% in the first ratoon crop of seedlings. Optimum selection intensities in the 1.2‐m clonal plots were 12.5% and 9.6% in the plant and first ratoon crops, respectively.

At the optimum selection intensities, gains from selection were 8 to 10% for stalk number and diameter and 4 to 5% for Brix.
Inheritance of Kernel Fatty Acid Composition Among Six Maize Inbreds1
Authors: Widstrom N. W. , Jellum M. D.
Published: July 2010

Three single crosses among six dent corn (Zea mays L.) inbreds, and segregating generations, were produced for investigation of the inheritance of five major fatty acid components by the method of single kernel analysis. Generation mean analysis showed that additive variation was predominant for palmitic, oleic, and linoleic acid composition, whereas additive and dominance sources of variation were of about equal importance for stearic acid. Differences were nonsignificant between inbreds for linolenic acid composition; genetic effects could not be determined. Individual kernel analyses showed that differences in palmitic and oleic acids of the inbreds Ab26A and X‐187 were each controlled mainly by a single gene, though probably not the same gene. The gene controlling high palmitic acid in Ab26A was partially dominant whereas the gene controlling high oleic acid composition showed almost complete dominance. The data did not show single‐gene control of linoleic acid in this cross.

A two‐factor hypothesis, with one factor showing partial dominance and the other no dominance for low linoleic acid, best explains the difference in linoleic acid of the inbreds GE82 (low) and R196 (high).
Heterosis and Inbreeding Estimates in Safflower1
Authors: Yazdi‐Samadi Bahman , Sarafi A. , Zali A. A.
Published: July 2010

Estimates of heterosis and inbreeding depression in safflower (Carthcmus tinctorius L.) were obtained for seven traits: flowering time, plant height, yield, seed weight, percentage of empty seeds, embryo percentage, and oil percentage. Selfed and single‐cross hybrid progenies were compared in two experiments, one involving five varieties and the other seven.

In one experiment some of the hybrids were significantly superior to their best parents for height, yield, seed weight, and oil percentage. Inbreeding depression was observed only in about 10% of the cases. In a second experiment significant heterotic effects were observed for flowering time, height, seed weight, and oil percentage. Inbreeding depression was present in about 11% of the cases. Reciprocal effects were not generally significant, suggesting that cytoplasmic effects are not important in safflower.
Distinguishing Characteristics of Crambe Abyssinica and C. Hispanica
Authors: White George A.
Published: July 2010

Morphological characteristics and chromosome numbers were compared to clarify the distinction between Crambe abyssinica Hochst. ex R. E. Fries and C. hispanica L. Chromosome numbers and basal leaf shapes proved to be the most reliable distinctive features. Length and structure of the lower fruit segment do not give a clear species distinction. Three accessions including the cultivar ‘Indy’ that were introduced as C. hispanica were re‐identified as C. abyssinica. PI 370747 is the first recorded wild collection of C. abyssinica from Turkey. C. hispanica var. glabrata (DC.) Coss. differed from C. hispanica in chromosome number (n=15 and n=30), pericarp and seedcoat color, fruit size, and in length of the lower segment of the fruit.

The average erucic acid content, just under 60%, in the seedoils of C. hispanica (PI 337996) and C. hispanica var. glabrata (PI 372928) was quite similar to that of C. abyssinica.
Variation and Covariation of Agronomic and Quality Traits in Two Spring Wheat Populations1
Authors: Dyck P. L. , Baker R. J.
Published: July 2010

Random F5‐derived F7 lines from each of two related crosses of spring wheat, Triticum aestivum (L.) em. Thell., were grown in replicated tests in each of 2 years. Three types of traits were measured: a) classification traits (rust resistance, awnedness, waxiness, spike type, spike density, and lodging resistance); b) agronomic measurement traits (height, maturity, kernel weight, and yield); and c) quality measurement traits (flour nitrogen, sedimentation value, mixograph development time, mixograph peak height, and centrifuge absorption).

There were no significant differences between the two crosses, ‘Manitou’ ✕ R37 and ‘Pembina’ ✕ R37, in estimates of variance components nor heritabilities. Of 60 comparisons between classification and measurement traits, only three were significant in Manitou ✕ R37 and four in Pembina ✕ R37. There was no significant relationship between yield and awnedness nor between yield and nitrogen content. The cross mean differed significantly from the mid‐parent value in only one of 14 cases. Estimates of genetic variances did not differ between crosses for any of the traits studied.