bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Depth and Duration of Burial on Shattercane Seed1
Authors: Jacques G. L. , Vesecky J. F. , Feltner K. C. , Vanderlip R. L.
Published: July 2010

Shattercane and grain sorghum [Sorghum bicolor (L.) Moench] seeds were buried at three depths for various times. Few grain sorghum seeds were viable 4 months after burial regardless of burial depth. None were viable 8 months after burial.

Only a few shattercane seeds from compact panicles were viable 4 months after burial, but some remained viable 3 years, mostly at the deeper burial depths (30.5 to 38.0 cm). Light was not a major requirement for germination after seeds were retrieved from burial regardless of time buried.

Some shattercane seeds from open panicles germinated after retrieval from all three burial depths even after 3 years. In general, number of viable seeds increased as depth of burial increased regardless of time buried. Germination, light‐dependent in many wild cane seeds from open panicles, increased in light dependence with length of burial.
Genetic Control of Relative Calcium, Phosphorus, and Manganese Accumulation on Chromosome 9 in Maize1
Authors: Naismith R. W. , Johnson M. W. , Thomas W. I.
Published: July 2010

Marker genes and supernumerary translocations on chromosome nine were utilized to locate genetic loci which influenced calcium, phosphorus, and manganese accumulation in the mid‐leaves of selected inbred lines of maize (Zea mays L.). Data obtained from the backcross of tester inbreds to marker gene stocks indicate that genetic loci influencing Ca, P, and Mn accumulation exist on chromosome 9. Crosses of the tester inbreds with supernumerary translocatipu stocks were used to confirm these findings. Results of this study indicate the absence of a common genetic mechanism for the control of Ca, P, and Mn accumulation.
Growth and Nitrate Assimilation in Oats as Influenced by Temperature1
Authors: Peterson David M. , Schrader L. E.
Published: July 2010

The effects of several day/night temperature regimes on growth and nitrate assimilation of three cultivars of oat (Avena sativa L.) plants from planting until panicle emergence were studied. Panicles emerged first in ‘Jaycee,’ then in ‘Portal,’ and last in ‘Froker’ at all temperatures. More tillers were formed at 13/13 C day/night temperatures than at warmer temperatures, except that Froker tillered most at 28/23 C. At cooler temperatures, Jaycee had more tillers than the other cultivars, and at warm temperatures, Froker had the most. Dry weights of culm plus leaf sheath fractions were similar for all cultivars, but dry weights of leaf blade fractions were greater for Froker than for Portal or Jaycee. This difference increased with increasing temperature. Reduced‐N (total‐N minus nitrate‐N) concentrations of vegetative parts at panicle emergence did not vary greatly with cultivar or with temperature, except at the high and low extremes. Reduced‐N concentrations of leaf blades were higher than those of culms and leaf sheaths. Froker exceeded the other cultivars in total reduced‐N per shoot, especially at warmer temperatures, largely because of greater leaf blade dry matter.
Resistance of Cotton Cultivars to Verticillium Wilt and Its Relationship to Yield1
Authors: Bassett D. M.
Published: July 2010

Twenty‐eight to 35 upland cotton cultivars (Gossypium hirsutum L.) representing a wide range of resistance to the fungus Verticillium albo‐atrum (microsclerotial form) were grown in six tests spanning a 3‐year period on moderately to severely infested fields. Various assessments of foliar or vascular damage to each of the cottons were made during the course of the season.

Ratings based on visual estimates of foliar damage made in either August or September were most closely related to yield performance, accounting for 35 to 65% of the yield variation among the cottons in five of the six tests. Percentages of plants showing early season foliar symptoms were less well correlated with yield, while postharvest vascular ratings showed virtually no yield correlation.
Seed Transmission of Viruses in Soybean1
Authors: Demski James W. , Harris H. B.
Published: July 2010

Varietal differences, time of inoculation, and time of planting were evaluated for effects on the transmission of tobacco ringspot virus (TRSV) through soybean [Glycine max (L.) Merr.] seed at Experiment, Georgia. Also, evaluations were made on the transmissibility of peanut mottle virus, cowpea chlorotic mottle virus, and soybean mosaic virus through seed.

All 10 soybean varieties tested had a high percentage seed transmission of TRSV with no evidence of varietal differences. Seed transmission of TRSV was high and seed germination reduced when inoculation occurred before flowering. Seed transmission of TRSV was less than 1% from soybeans planted in late August and seed germination increased. A marked increase in seedling vigor was noted in progeny from late August plantings. Soybean mosaic virus was transmitted through the seed at a low rate (lye or less depending on variety). Peanut mottle virus and cowpea chlorotic mottle virus were not transmitted through the seed.
Effects of Granular Ethephon on Male Sterility in Wheat1
Authors: Fairey D. T. , Stoskopf N. C.
Published: July 2010

Granular ethephon (2‐chloroethylphosphonic acid) was studied as a gametocide on three winter and six spring wheat (Triticum aestivum L.) cultivars. Applications were made during four stages in ontogeny viz, seeding, primary tiller emergence, initiation of spikelet primordia on the main culm, and during the early‐boot phase, in rate categories of 2 to 8, 26.9 to 109.2, and 164.5 to 822.0 kg a.i./ha. Sterility levels reached mean values of 65 (range 10 to 95), 71 (range 48 to 94) and 89% (range 36 to 100) for the respective rate categories. These values are means of pot/plot data and include different order tillers. Mean sterility levels rose with increase in the rate of gametocide; it was most effective when applied at the highest rate during reproductive development on the main culm. At low rates of application, winter cultivars were more responsive than spring cultivars perhaps because of their increased uptake with a more extensively developed root system.

The granular form of ethephon may be more suited to practical use than the liquid form because the latter demands precision in the time of spraying and causes undesirable side effects. No apparent morphological or physiological abnormalities were observed with the granular form even at the very high rates used in these studies. A better understanding of the site and form of uptake may permit the use of lower rates with effective gametocidal action.
Alkaloid Concentration in Plant Parts of Reed Canarygrass of Varying Maturity1
Authors: Hagman J. L. , Marten G. C. , Hovin A. W.
Published: July 2010

These experiments were conducted to assist plant breeders and forage management researchers who need to know the primary site of alkaloids within reed canarygrass (Phalaris arundinacea L.) forage at specific stages of plant maturity. Alkaloids appear to be responsible for the relatively poor palatability and potential toxicity of this grass to ruminants. We determined alkaloid distribution in leaves and stems of reed canarygrass at various growth stages. Leaf blades (both tip and base parts) contained more than twice as much alkaloid as leaf sheaths and stems in both greenhouse and field studies. The alkaloid concentration of the leaf blades increased with advanced plant maturity of the first growth, but the concentrations in the stems and leaf sheaths decreased. The concentrations decreased in blades, sheaths, and stems with advanced maturity of the regrowth.

The upper third of the total herbage had the highest and most uniform alkaloid concentration when compared to the middle and lower thirds. High correlations (r = 0.94 to 0.98) between alkaloid concentrations in the upper third and in the total herbage enable us to recommend sampling only the upper third of herbage canopies for routine alkaloid screening of reed canarygrass genotypes. This procedure will be most convenient and most precise for use in breeding programs.
Inhibition of Corn, Soybean, and Wheat Seedling Growth by Amino Acid Analogs1
Authors: Singh Mahendra , Widholm J. M.
Published: July 2010

The inhibitory effects of the amino acid analogs DL‐5‐methyltryptophan (5MT, tryptophan analog), S(2‐aminoethyl)‐L‐cysteine (AEC, lysine analog), L‐ethionine (Eth, methionine analog), and DL‐methionine‐DL‐sulfoximine (MS, methionine analog) on the growth of corn (Zea mays), soybean (Glycine max), and wheat (Triticum aestivum) seedlings were determined when the compounds were supplied in the nutrient solution. Twenty ppm 5MT, 20 ppm Eth, or 50 ppm AEC inhibited seedling growth; this inhibition could be reversed by 350 ppm L‐tryptophan, 150 ppm L‐methionine, or 240 ppm L‐lysine, respectively. The growth inhibition caused by 5MT was specifically reversed by the corresponding natural amino acid.

Ethylmethane sulfonate‐treated seeds were allowed to growth to maturity and the seeds collected. The screening of 100,000 wheat seedlings (M2) in inhibitory 5MT concentrations (20 ppm) has resulted in the recovery of 5 plants resistant to this analog. These plants are being studied further.

Growing wheat plants to maturity in nutrient solution containing 2.5 mM L‐tryptophan, resulted in a 13‐ fold increase in free tryptophan in the mature seed.
Survey of Maize Selections for Endosperm Lysine Content1
Authors: Zuber M. S. , Skrdla W. H. , Choe Bong‐Ho
Published: July 2010

Lysine and protein content from 364 white endosperm maize (Zea mays L.) plant introductions showed that 12 accessions had lysine values ≥ 0.22%. The 364 accessions included 195 dent, 28 floury, 9 popcorn, and 132 flint types. Very little difference was noted among the four types for mean lysine content. Two of the 195 dent, 22 of the 28 floury, none of the 9 popcorn, and two of the 132 flint types had opaque endosoerms. Lysine content from the whole kernel was significantly correlated (r = 0.67) with lysine content of the endosperm for 47 accessions. This indicates that about 45% of the variation in lysine content in the whole kernel can be explained by variation in endosperm lysine content. Several of the accessions should be good germplasm sources for cyclic breeding programs for increasing lysine content in normal corn without specific major endosperm mutations or as sources for upgrading the lysine level in the opaque‐2 mutant types.
Inheritance of Oil Percentage in Interspecific Crosses of Hexaploid Oats1
Authors: Frey K. J. , Hammond E. G. , Lawrence P. K.
Published: July 2010

Groats from F2‐derived lines of oats (in the F3 generation) from three crosses between Avena sativa L. ✕ A. sterilis L. cultivars, and samples from the parents, were analyzed for oil percentage using the nuclear magnetic resonance method. Oil percentage was inherited polygenically, with high oil content being partially dominant. Transgressive segregates were found in one cross. Oil percentage showed no correlation with groat weight, heading date, or plant height.
Manganese Toxicity Effects on Leaf Cell Multiplication and Expansion and on Dry Matter Yield of Sugar Beets1
Authors: Terry N. , Evans P. S. , Thomas D. E.
Published: July 2010

Sugar beet (Beta vulgaris ‘F58‐554HI’) plants were cultured hydroponically (pH 6.0) for 3 weeks in a greenhouse with 10 concentrations of Mn in culture solutions; 0.44, 4, 8, 16, 32, 64, 128, 256, 550, and 1,000 mg Mn/liter. Dry weights of roots and leaves, numbers of cells, and mean call volume/leaf were unchanged with increases in Mn from 0.44 to 16 mg/liter in the culture solution or with tissue Mn up to about 5,000 mg/kg dry matter. With further increase to 30 or 40 mg Mn/liter in the culture solution dry matter yields were diminished by 50%, with tissue Mn concentrations of about 20,000 mg/kg. Manganese toxicity reduced the numbers of cells/leaf and the average leaf cell volume and produced smaller leaf and root dry weights.
Inheritance of Seed and Seedling Color in Sweetclover1
Authors: Gorz H. J. , Specht J. E. , Haskins F. A.
Published: July 2010

Eight seed colors, conditioned by two independent pairs of genes, were identified in sweetclover (Melilotus alba Desr.). The seed colors resulted from all combinations of two embryo and four seed coat phenotypes. Only four of the seed colors were recoverable in true‐breeding form. Conventional genetic tests revealed that Y/y alleles determined the absence or presence, respectively, of green pigmentation in both the embryo and seed coat of fully mature seeds. Absence of green was dominant in both seed parts. The C/c alleles conditioned the presence or absence, respectively, of brownish pigmentation in the seed coat and red pigmentation in seedlings with the presence of pigmentation being dominant.
Relationship of Seed/Boll to Other Yield Components and Fiber Quality of Pima Cotton1
Authors: Kittock D. L. , Pinkas Leonard L. H.
Published: July 2010

The relationship of number of seed/boll to other yield components and fiber quality of two cultivars of Pima cotton (Gossypium barbadense L.) was investigated as part of a study of the effects of environment on the variability of these cultivars in three tests. A fourth test had only one cultivar. Bolls examined contained from 1 to 31 seed. Environment of the four tests strongly influenced the proportion of bolls in the different seed number classes. Plants grown under favorable production conditions, such as lower summer temperatures, productive soil, and a wet irigation regime, produced a higher percentage of large bolls (more seed) than those grown less favorable environments. Cultivars did not differ in seed/boll. An increase in the number of seed/boll was associated with the following: decreased mean seed wt, increased lint wt/seed, decreased fiber length and uniformity, and increased micronaire, but strength was unaffected. The unexpected increase in lint wt/seed with a decrease in seed size can be explained by the observed concomitant increase in fiber coarseness.
Isogenic Analysis of Productivity in Barley: Interaction of Genes Affecting Awn Length and Leaf‐spotting1
Authors: Schaller C. W. , Qualset C. O.
Published: July 2010

A dominant leaf‐spotting mutation (Sp sp) was studied in combination with two genes that control awn development in barley (Hordeum vulgare L.). Eight isogenic lines, normal green and spotted in each of four awn genotypes (‘Awnless’ and ‘Quarter,’ ‘Half,’ and ‘Full‐awned’) of ‘Atlas,’ were evaluated in field experiments for 3 years. Leaf‐spotting was expressed similarly in all awn genotypes (i.e., about 1.5% leaf coverage in the seedling stage and 15.6% in the adult stage). Mean grain yield was reduced 13.6% in the spotted genotypes compared to green, but the effect decreased linearly with increasing awn length (16.9, 14.7, 13.1, and 10.1% for Awnless and Quarter, Half, and Full‐awned, respectively). Kernel size and plant height showed a similar pattern, but the effect of spotting on total and fertile floret numbers was the opposite, being increased linearly with increasing awn development. Tillering was unaffected by either the awn or leaf‐spot loci. The developmental effects of leaf‐spotting on yield were similar to those caused by stress environments such as drought, disease, or high temperature conditions. Awn development during seedling growth apparently imposes developmental stress, thus long‐awned types are detrimental when additional stress conditions are present. However, if stress is applied later in development, the awn with its assimilatory activities, can minimize the stress effects on yield.
Inflorescence Gas Exchange and Seed Weight of Blue Panicgrass1
Authors: Abernethy Rollin H. , Wright L. Neal
Published: July 2010

Blue panicgrass (Panicum antidotale Retz.) selections from six cycles of recurrent selection for heavy and lightseed weight were evaluated to establish the relationship between photosynthesis and respiration rates of inflorescences and seed weight. Selections with light seed weight had lower apparent photosynthesis and higher dark‐respiration rates of inflorescences. Data suggest that differences in seed weight of plants grown from heavy and light‐seed weight can be attributed partly to availability of less assimilate for storage during development of seed of lightseed weight selections.
Fruiting Behavior of Insect‐resistant Cotton Strains in an Insect‐free Environment1
Authors: Thomas Robert O.
Published: July 2010

Nectariless and frego bract strains of cotton (Gossypium hirsutum L.) were compared with background‐related strains or cultivars Bayou Sm 1, ‘Deltapine 16,’ and ‘Stoneville 7A’ on the basis of productivity and maturity in an insect‐free greenhouse environment. The nectariless strain of Deltapine 16 was similar to its parent cultivar, whereas nectariless Bayou D2Sm and Stoneville 7A were more productive from late flowers than their background‐related nectaried counterparts. La Frego 2 was similar to its Stoneville 7A parent, whereas La Frego 3159 was more productive from midseason flowers, and La Rak Frego 3161 yielded less and was earlier than Stoneville 7A. Neither trait differed consistently in fruiting behavior compared to that of its background‐related nectaried and normal bract counterparts. Thus, the observed differences may be due to heritable factors not associated with the trait per se, or to selection during the backcross program.
Genetic Recombination in Maize as Affected by Ethylenediaminetetraacetic Acid and Dimethyl Sulfoxide1
Authors: Ihrke Charles A. , Kronstad W. E.
Published: July 2010

Recombination frequencies for seven selected regions on five chromosomes of maize (Zea mays L.) were measured to ascertain the effect of complexing agents on recombination. Ethylenediaminetetraacetic acid (EDTA) and dimethyl sulfoxide (DMSO) were used in three concentrations singly, and in all combinations. Plants heterozgous for linked genes governing endosperm and seedling characteristics were treated with premeiotic foliar spray of EDTA and DMSO for two durations. Appropriate crosses were made and recombination values were calculated from data resulting from test cross and sib cross progeny.

The complexing agents were found to influence the frequency of recombination in each of the regions tested. Increases in recombination frequencies were significant in six of the seven chromosome's regions when treated with several concentrations of the two complexing agents. Reduction in recombination was observed in two regions treated at high concentrations of the chemicals and at the longer duration. In these latter cases, it was concluded that a threshold had been reached causing interference with crossing over or with recovery of recombination products.

Changes in recombination frequency were found to be of similar magnitude whether the complexing agents were used alone or in combination, and it was concluded that the two chemicals did not have a synergistic effect in changing recombination frequency. Although the two agents differ in cation affinity both were shown to influence crossing over, indicating that the action was by a mechanism other than removal of a specific cation from the chromosome. A relationship was shown between length of crossover region and effect of the chemical treatment. No such relationship was found between specific locations in chromosomes and response to complexing agents for the seven regions tested.
Seedling Survival from Cottonseed Treatment Experiments at Several Locations1
Authors: Minton Earl B. , Fest Gary A.
Published: July 2010

Cottonseed treatment containing both experimental and commercial seed protectants used alone and in combination with systemic fungicides were evaluated for their effects on percent seedling survival of Gossypium hirsuturn L., ‘Stoneville 213,’ at several test sites. Although differences among fungicide treatments were not significant within some individual tests, the combined analysis of the data across tests at the same site; with different methods of delinting; with both methods of delinting and sites; or with one method of delinting at several sites, usually showed significant differences among fungicide treatments.

The combined analysis of the data across sites should more clearly define those fungicide treatments effective over a wide range of environments and soil types than did the individual‐test analyses, because the combined experiments were conducted over a wide area. Analyses of the data within tests, across tests at the same site, and across sites, showed that fungicides for coating cotton. seed, enabling higher stands than the standards, are being developed. Combination treatments, two or more fungicides, usually gave higher stands than treatments containing one fungicide. Some experimental materials, when used either alone or in combinations, gave stands equal to or better than the stands for the standards. By use of these methods of analysis, the time, cost, and amount of treated seed required to evaluate seed protestants would probably be reduced, because ineffective treatments could be identified and eliminated early in the research program, while effective treatments could be carried forward.
Method for Screening Sorghum Genotypes for Stomatal Sensitivity to Water Deficits1
Authors: Henzell R. G. , McCree K. J. , van Bavel C. H. M. , Schertz K. F.
Published: July 2010

Twenty‐three genotypes of Sorghum bicolor (L.) Moench were screened with a leaf‐resistance porometer for stomatal sensitivity to water deficits. Plants were grown and tested in a controlled‐environment chamber, at solar levels of lighting and under warm, moist conditions. Plants were grown until the sixth leaf was fully expanded, at which time watering ceased. Measurements of leaf diffusive resistance of the sixth leaf of each plant, and soil water potential of each pot were taken several times daily during the subsequent drying period. The stomatal sensitivity to water stress of a genotype was then compared to that of a check genotype grown in the same pot. The 23 genotypes varied considerably in relative sensitivity to soil‐water potential.
Tiller Bud Inhibition by Young Foliage Leaves in Jointing Wheat1
Authors: Laude Horton M.
Published: July 2010

Young foliage leaves have been associated with bud inhibition in dicotyledonous plants. Whether or not young leaves influence tiller buds in a grass is important, and particularly so in species repeatedly mown or grazed for herbage since the regrowth arises primarily from new tillers. ‘Sonora 64’ wheat (Triticum aestivum L.) during the jointing stage possessed the tiHering characteristics desired for this investigation.

The influence of removing selected leaf laminae on stems retaining the shoot apex was studied on plants in the greenhouse and on uprooted culms in growth chambers. Basal axillary buds on these culms were exposed by stripping off the sheaths of lower leaves. The greatest bud elongation was obtained on culms devoid of foliage leaf blades. Less bud elongation occurred in the presence of an intact flag leaf, and still less if several of the younger leaves retained laminae. On plants in the greenhouse, removal of the younger leaves delayed tiller senescence,i ncreasedt he numbeorf tillers surviving the heading stage, and resulted in the resumption of tillering after heading. These responses were indicative of conditions favoring tiller growth. Tiller bud elongation in Sonora 64 was suppressed on culms retaining the younger foliage leaves. Such leaf influence should be considered among the factors regulating tillering.
Physiological Significance of the In Vivo Assay for Nitrate Reductase in Cotton Seedlings1
Authors: Radin J. W. , Sell C. R. , Jordan W. R.
Published: July 2010

In vivo assay techniques for nitrate reductase activity were evaluated for their ability to predict nitrate assimilation rates of germinating dark‐grown cotton (Gossypium hirsutum L.) seedlings. Activity was measured with four in vivo assay techniques: either aerobic or anaerobic, and either with or without added nitrate in the assay medium. Assays without added nitrate in the medium allowed closer estimates of reduced N accumulation than did assays with added nitrate. Additionally, in the absence of added nitrate, the anaerobic assay provided a better estimate than the aerobic assay because of O2‐stimulated nitrite reduction. The results suggest that the in vivo assay for nitrate reductase best approximated nitrate assimilation rates with only endogenous nitrate as substrate.
Gray Leaf Spot‐Resistant Lupinus Angustifolius L. Germplasm from Plant Exploration in the Western Mediterranean Region1
Authors: Forbes Ian , Gladstones John S. , Wells Homer D.
Published: July 2010

During a plant exploration in the western Mediterranean region in 1973, seeds of wild blue lupine (Lupinus angustifolius L.) ecotypes were collected from 126 sites to increase the amount of germplasm available for blue lupine crop breeding in the United States and Western Australia. These ecotypes were tested for gray leaf spot reactions by artificial inoculation with mixed inoculum from Stemphylium solani Weber and S. botryosum Wallr. in the greenhouse. High percentages of the wild ecotypes from Morocco—81.8%, Spain—70.8%, and Portugal—66.7% were resistant. These data and other reports of resistant wild ecotypes from Portugal, Spain, and Palestine indicate that resistance is widespread and prevalent among wild ecotypes in the Mediterranean basin, which comprises L. angustifolius' natural range. The Stemphylium species that cause gray leaf spot occur in the Mediterranean region and are probably active in preserving host genes for resistance. One ecotype from Morocco gave a previously unknown, intermediate (I‐type) flecklike reaction when inoculated. This reaction differs from the immune reaction conditioned by the known gl1 and gl2 host genes. The identity, country of origin, and disease reaction of each ecotype are listed.
Differential Reaction of Kentucky Bluegrass Cultivars to the Bluegrass Billbug, Sphenophorus Parvulvs Gyllenhal1,2
Authors: Kindler S. D. , Kinbacher E. J.
Published: July 2010

Fifteen cultivars of Kentucky bluegrass, Poa pratensis L., were evaluated in the field for resistance to the bluegrass billbug, Sphenophorus parvulus Gyllenhal; none escaped infestation or damage. The correlation between infestation counts and damage index was significant at the 5% level (r=0.585). A range in resistance to billbug infestation and damage was recorded among the cultivars. ‘Nebraska common,’ ‘Park,’ and ‘South Dakota certified’ had the lowest number of billbugs/unit area.
Glycine canescens F. J. Herm., a Wild Relative of the Soybean1
Authors: Newell C. A. , Hymowitz T.
Published: July 2010

An accession of Glycine canescens F. J. Herm was studied with respect to morphological, cytological, and chemical characteristics. This species, a wild relative of cultivated soybeans G. max (L.) Merr., was collected near Alice Springs, Northern Territory, Australia and has not previously been available in the United States for examination.

Morphologically the accession did not conform unequivocally to the published description of the species, possibly due partly to greenhouse growth conditions. Also, one accession should not be considered representative of the species as a whole. Scanning electron microscopy was employed to investigate external characteristics of seed and leaf surfaces. Cytological analysis of mitosis and meiosis gave a chromosome number of 2n = 40, with regular bivalent formation at diakinesis. Chemical characteristics such as seed oil, protein, and fatty acid content fell within the range previously determined for the subgenus. Preliminary screening of wild Glycine species for disease resistance suggested that G. canescens was resistant to powdery mildew, Microsphaera diffusa Cke. and Pk.
Persistence of the Glandless Genotype in a Composite Cross of Upland Cotton on the Texas High Plains1
Authors: Quisenberry J. E. , Ray L. L. , Rummel D. R.
Published: July 2010

A composite‐cross population, grown for 10 generations, was used to evaluate the amount of natural selection on the glandless genotype of Upland cotton (Gossypium hirsutum L.). The results suggested that the glandless genotypes was not at a selective disadvantage when compared with the glanded genotype on the Texas High Plains.
Detection of Epistatic, Additive, and Dominance Variation in Winter Wheat (Triticum aestivum L. em Thell.)1
Authors: Ketata H. , Smith E. L. , Edwards L. H. , McNew R. W.
Published: July 2010

The objectives of this study were to determine whether epistasis plays a significant role in the genetic systems for selected traits among several winter wheat (Triticum aestivum L. em Thell.) cultivars and to evaluate the importance of additive vs. dominance gene action for traits not influenced by epistasis. In each of two replicated experiments, two cultivars (referred to as testers L1 and L2) and their F1 (L3) were crossed to each of 10 other cultivars and evaluated in a single field experiment. The deviations (cultivar ✕ L1 + cultivar ✕ L2 — 2 cultivar ✕ L3) were analyzed to provide a test for epistasis. An additive‐lominance model was fitted to the data for those characters not affected by gene interactions.

Results of the two experiments were generally consistent with respect to the detection of epistasis. Epistasis affected the expression of heading date, kernels/spikelet, and grain yield, but not of plant height, protein content, tiller number, spikelets/spike, and kernels/spike in both experiments. Epistasis was indicated for kernel weight in one experiment but not the other. Expression of epistasis was influenced by particular cultivars, indicating that a limited number of cultivars may not be sufficient to detect nonallelic interactions for a character within this species.

Additive gene action was predominant in both experiments for protein content, spikelets/spike, and kernels/spike, suggesting that improvement of those characters can be achieved through standard selection procedures. Evidence for dominance gene action was obtained for plant height and kernels/spike in one experiment.

The results of this study indicated that epistasis may be a nontrivial factor in the inheritance of agronomic traits. Genetic models neglecting epistasis may result in biased information.
Transport of 14C‐Assimilates to Cottonseed: Integrity of Funiculus During Seed Filling Stage1
Authors: Benedict C. R. , Kohel R. J. , Schubert A. M.
Published: July 2010

Early work suggested the vascular connection from the ovary wall to the ovules in cotton plants (Gossypium hirsutum L.) degenerates 32 days after fertilization. A minimum of 50 days after fertilization is required for the maturation of cottonseed. From a yield viewpoint, it is important to establish if leaf assimilates are transported to the developing cotton ovules throughout the seed maturation period.

The incorporation of 14C‐assimilates into ovules in different age cotton bolls was measured by: (i) pulse‐labeling cotton plants (which contained a wide distribution of different age cotton bolls at a plant stage of maximum fruit load) with l4CO2 for 10 min, and (ii) allowing photosynthetically assimilated 14CO2 to be transported to the different age bolls for 20 hours.

The rate of incorporation of 14C‐assimilates into fibers in different age cotton bolls was similar to the rate of dry weight increase in the different age bolls. The 14C‐assimilate was incorporated into the fibers during a period of active cellulose deposition in these fibers. 14C‐assimilate was incorporated into ovule wall, sugars, amino acids, organic adds, oil, and protein in 1‐ to 45‐day‐old bolls. This incorporation of photosynthate into the ovules probably reflects transport of 14C‐assimilate through the vascular connection. An alternate route of assimilate transport through the carpel wall, into the locule cavity, and absorption by the ovules, is not important because (iii) the carpel wall chloroplasts do not fix 14CO2 into 14C‐assimilate, and (iv) the transport of leaf and bract 14C‐assimilate to the carpel wall is completed in 30‐ to 35‐day.old bolls.

The boll opening period for these cotton plants was 49 to 56 days after anthesis. The results in this paper show that assimilates are transported to cottonseed throughout the maturation period. The majority of this incorporation occurs through the vascular connection and the funiculus does not break 32 days after fertilization.
Soil Reflectance Effects on Net Carbon Dioxide Exchange Rates of Sorghum1
Authors: Hiebsch C. K. , Kanemasu E. T.
Published: July 2010

Net carbon dioxide exchange (NCE) rates of sorghum (Sorghum bicolor (L.) Moench) canopies were measured in the field using large plastic chambers and an infrared gas analyzer to assess the effect of soil reflectance on photosynthesis. Increasing soil reflectance, by applying white reflective clay, kaolinite, to the soil surface enclosed by the chambers, increased NCE by as much as 16% when crop cover was sparse. The effect decreased as crop coverage increased.

Spectral‐reflectance data taken over kaolinite‐treated and nontreated soil showed that reflected light over the treated plots decreased as crop cover increased so by 2 August treated and nontreated plots differed little in the amount of reflected light. Increases in NCE as calculated from spectral‐reflectance data approximated measured values.
Performance of Diallel Crosses and Second Generation Synthetics of Alfalfa Derived from Partly Inbred Parents. I. Forage Yield1
Authors: Rotili P.
Published: July 2010

In an alfalfa (Medicago sativa L.) breeding study conducted under conditions of high competition between plants, combining ability [or forage yield was evaluated from diallel crosses among selected parents which had been partly inbred by selfing. The performance of first and second generation synthetics was studied as well. General combining ability (GCA) variance was considerably larger than specific combining ability (SCA) variance for all generations of parental inbreeding (S0, S1, S2, S3, and S4). In general both GCA and SCA increased with inbreeding. The best single crosses came from selected inbred parents. Selling and subsequent selection improved the genetic value of the parents and resulted in improved synthetic varieties. Breeding synthetic varieties based on four selected S2. plants might well be an efficient method to improve yield of alfalfa.
Stability and Performance of Hard Red Spring Wheat Bulks for Grain Yield1
Authors: Busch R. H. , Hammond J. , Frohberg R. C.
Published: July 2010

Twenty‐eight hybrid populations resulting from crosses among eight high‐yielding parents of hard red spring wheat (Triticum aestivum L. em Thell.) were evaluated as F1's in one environment, as F2 bulks in six environments, and as F3 bulks in five environments. The average yields of the F2 and F3 bulks were similar to midparent performance across environments. Neither the F2 nor the F3 bulk generations exhibited superior yield performance in stress environments when compared to their midparents. Performance of the bulks varied from 95.9 to 110.9% of midparent across environments. The yield rank of each generation bulk was generally consistent from F2 to F3 (r=0.87, significant at the 0.01 probability level) since the same seven crosses (top 25%) would have been chosen with either generation yield test. The F2 bulk yields also were associated with midparent yields (r=0.73, 0.01 level) and F1 yields (r=0.73, 0.01 level). Parents were included in each trial, however, the Fa bulks were tested together with F2 bulks in only two of the environments. The F2 bulk yields, averaged over environments, correlated as well with the F1 yields as with midparent.

Regression analyses of response to environments for yield indicated that bulks had the same range of b values as parents. Average deviations from regression were smaller for bulks than for parents, but the deviations did not differ significantly. Parental deviations from regression for yield were correlated with gca (general combining ability) effects of their progeny (r=0.72, 0.05 level), but gca effects for response (b) were not significantly associated (r=0.49). Deviations from regression apparently were inherited from the parents in a relatively more predictable manner than response (b) to environments.
Gene Action of Heading Date, Plant Height, and Other Characters in Two Winter Wheat Crosses1
Authors: Edwards L. H. , Ketata H. , Smith E. L.
Published: July 2010

Two winter wheat (Triticum aestivum L. em thell.) crosses were used in this study to determine the type of gene action involved in the expression of a number of agronomic characters. An unweighted least squares procedure was adopted to analyze means of parents, F1, and first generation backcrosses from each cross. Only additive gene effects were significant for plant height, number of tillers/unit area, and kernel weight, indicating possible improvement of these characters through selection in early generations. Heading date was controlled by genes with additive and dominance effects which indicates that selection for this trait would be more effective if delayed until later generations.
Estimation of a Transformation for the Analysis of Some Agronomic and Genetic Experiments1
Authors: Hinz Paul N. , Eagles Howard A.
Published: July 2010

Crop plants are often compared in replicated trials over a wide range of environments. The average yield and the residual variance estimated in individual environments are often related. This interferes with the statistical tests usually required in such data. A method is described here that uses the means and residual variances from the individual environments to find a transformation of the original scale to one that reduces the dependence of the means and the variances.
Genetic Variance Components and Predicted Response to Selection Under Selfing and Full‐sib Mating in a Maize Population1
Authors: Cornelius P. L. , Dudley J. W.
Published: July 2010

Genetic and environmental variance components in maize (Zea mays L.) Synthetic O.P. were estimated from covariances among 12 generations (1 noninbred, 7 sibmated, 4 selfed) in 1970 and 1971 experiments previously described (Crop Sci. 14:815–819). The results showed: a) significant variance due to multiple alleles for plant height and ear height in 1971 and for grain yield in a 2‐year analysis, b) significant variance due to dominance for plant height and ear height in 1971 and for grain yield in both years, c) satisfactory fit of an additive genetic model for percent moisture at harvest and percent oil, and d) significant lack of fit of an additive and dominance model for kernel weight. The additive, dominance, multiple‐allele model contains three additive components (σ2I, C, σ2A) and 2 dominance components (µ21,σ2D. The relative importance of was roughly proportional to inbreeding depression previously reported. was large for yield but negative for plant height and ear height. for yield was negative and an estimate of average degree of dominance suggested extreme overdominance. This may result from repulsion phase linkages of loci showing partial to complete dominance.

Predictions of response to selection for general combining ability (GCA) and performance of lines per se (LPS) suggested a) at equivalent levels of inbreeding, selection under the two systems will be about equally effective if there has been no prior selection, but cumulative response to selection would be 1.5 to 2.0 times as great under sib‐mating as under selfing, b) a given amount of cumulative progress will be reached at a lower level of homozygosity under sib‐mating, and c) for yield, if substantial improvement in both LPS and GCA are desired, both must be evaluated.
Fertility Restoration in Soft Winter Wheat Hybrids1
Authors: Trupp C. R.
Published: July 2010

The ability of a stable cytoplasmic male‐sterile wheat (Triticum aestivum L.) to produce pollen‐fertile hybrid progeny after pollination with a partially effective restorer parent was termed “ease of restoration” (EOR). Within the limits of measurement error, results using A/R crosses were equivalent to results nsing corresponding maintainer lines as pollen parents in R/B crosses.

Using R/B crosses, EOR was predicted for advanced breeding lines of the Michigan State Univ. wheat breeding program, for current and historical commercial cultivars of Michigan, and for entries of the 1973 Uniform Eastern Soft Wheat Nursery. The materials tested were predicted to vary widely for EOR. Only a small portion of variability in EOR could be accounted for by the presence of minor genes for restoration in the maintainer line. Practical uses of extreme EOR types are discussed. EOR is a genetically controlled trait for which prediction can be accomplished with a fair degree of accuracy using partially effective restorer tester lines as female parents.
Sources and Inheritance of Resistance to Stemphylium Leafspot of Alfalfa1
Authors: Borges O. L. , Stanford E. H. , Webster R. K.
Published: July 2010

Twenty‐three accessions of alfalfa were screened for resistance to Stemphylium leafspot. A high degree of resistance was found in collections of Medicago cancellata M.B., M. falcata L., M. coerulea Less., and M. hemicycla Grossh. However, all of the M. saliva L. introductions were susceptible to Stemphylium botryosum Wallr.

The inheritance of resistance was investigated in selections from M. cancellata (2n=48), M. falcata (2n=32), and M. hemicycla (2n=16). The results showed that resistance in M. hemicycla was determined by a pair of dominant genes with duplicate effects. Our observations indicated that there is a dosage effect of dominant genes on the level of resistance. The mode of inheritance involved in the resistance of the M. falcata and M. cancellata selections was not clear.
Callus Induction and Plant Regeneration in Oats1
Authors: Cummings D. P. , Green C. E. , Stuthman D. D.
Published: July 2010

Callus was initiated from immature embryos of 23 oat (Avena sativa L.) genotypes on Gamborg B5 or Murashige‐Skoog MS media containing 0.5 to 3 mg of 2,4‐dichlorophenoxyacetic acid (2,4‐D)/liter. These cultures were maintained by subculturing to B5 medium with 1 mg of 2,4‐D/liter every 4 to 6 weeks. Callus from the variety ‘Lodi’ has been maintained through 13 subcultures for 1 1/2 years and has retained the ability to regenerate plants. Callus capable of plant regeneration was also obtained from excised apical meristem tissues and germinating mature embryos on B5 medium containing 2,4‐D.

Tiny green buds and leaves which developed from callus of 16 different genotypes formed shoots and plants when transferred to B5 medium without 2,4‐D. Ninety percent of the regenerated plants transplanted directly from culture medium to sterilized soil survived. One hundred thirty‐three plants representing 12 genotypes were grown to maturity. Most plants grew vigorously in the greenhouse and produced viable seed. Seed set ranged from complete sterility to 580 seeds from one regenerated plant. Although the growth of most of the regenerated plants appeared normal, some phenotypic and genotypic variability was observed. Cytological examination of meiotic cells from seven plants showed that two had the normal 21 bivalents at diakinesis while five exhibited aberrant meiotic configurations.

The procedures used to regenerate large numbers of fertile plants from tissue cultures of many oat genotypes may ultimately prove useful in varietal improvement in oats and other species.
Allelism Testing in Barley. II. Allelic Relationships of Three Uzu Genes1
Authors: Tsuchiya T.
Published: July 2010

The allelic relationships among three uzu or semibrachytic mutant genes (uz, uz2, uz3) were studied. The coleoptile length and projection on the coleoptile were used as the representative traits of the uzu gene (uz). F1 and F2 data of five crosses showed that the three uzu‐type mutants are controlled by the same gene (uz), or at least they are allelic to each other. The previous conclusion that there were three different uzu genes (uz, uz2, and uz3) could be explained as follows: the character plant height used by the previous workers was not only affected by the uzu gene but also by pleiotropic effects of L vs. 1 for spike density and probably other modifier(s) as suggested by Takahashi (1951. Ber Ohara Inst. Landwirtech. Forsch. 9:383–398).
Influence of Lint Percentage on Yield, Boll, and Fiber Characteristic in Acala strains of Upland Cotton1
Authors: Woodward William T. W. , Malm Norman R.
Published: July 2010

Yield, boll, and fiber characteristics were studied in low, intermediate, and high lint percentage groups of Acala strains of upland cotton (Gossypium hirsutum L.). Three genotypes were used to represent each group. The three groups did not differ significantly in yield of seed cotton or seed, but the high lint percentage group produced significantly more lint yield, lint/plant, lint/boll, lint/seed (lint index), and fiber elongation than did the low lint percentage group. The high lint percentage group produced significantly less seed/boll, seed cotton/boll, and five‐lock bolls and smaller seed (seed index) than the low lint percentage group. Seed, lint, and seed cotton yield were highly correlated as were those three characters with bolls/m2.
Preferential Selection for Wheat‐rye Substitutions in 42‐Chromosome Triticale1
Authors: Gustafson J. P. , Bennett M. D.
Published: July 2010

A survey of available data indicates that many 42‐chromosome triticale varieties (X Triticosecale Wittmack) have one or more D(R) genome substitutions (wheat‐rye, respectively) which are the result of natural and/or artificial selection. In general, there appears to be natural selection acting on chromosome size and/or estimated DNA content which favors the substitution of most of the D‐genome chromosomes from hexaploid wheat for the much larger, homocologous rye chromosomes whose DNA contents exceed those of any wheat chromosome. The order and frequency of fixation of the seven possible homoeologous D(R) genome substitutions during the history of triticale breeding appears not to occur on a tandem basis. The observed pattern of fixation reflects artificial selection pressure for desirable agronomicharacters, and may also have been determined by natural selection pressure distinguishing between the different DNA content of individual rye chromosomes.
Facultative Apomixis in Eragrostis curvula1
Authors: Voigt P. W. , Bashaw E. C.
Published: July 2010

Previous reports indicate that weeping lovegrass, [Eragrostis curvula (Schrad.) Nees], reproduces either sexually or by obligate apomixis (diplospory). Recent studies have shown that certain plants of this species are facultative apomicts. Our research objective was to determine the cytological basis for facultative apomixis in weeping lovegrass and to relate reproductive cytology to performance of progeny from lovegrass parents and hybrids. We observed enlarged or late megaspore mother cells (MMC), as determined by integument size, in apomictic strains. Development from these MMCs occurred in either of two ways: 1) direct formation of the embryo sac (diplospory), or 2) delayed meiosis resulting in the formation of a linear tetrad. Progeny tests of plants with both types of reproductive cytology suggests that these patterns indicate facultative apomixis. We did not observe late, greatly enlarged megaspore mother cells or delayed meiosis in sexual plants. Hybrids between sexual plants and highly apomictic common weeping lovegrass were observed to reproduce either sexually or by facultative apomixis. Sexual plants, when self‐pollinated, produced no apomictic offspring. Therefore, we concluded that the sexual plants studied probably lack all the necessary genes for expression of apomixis. The uniformity observed in most experimental lines, the low level of sexuality in some apomictic hybrids, and the reduced vigor of many of the aberrant plants suggest that varietal development and maintenance in E. curvula should not be hindered too greatly by facultative apomixis.