bluuebunny/crossref_metadata_2025 huggingface dataset:
Stomatal Resistance to Transpiration in Three Contrasting Canopies1
Authors: Turner Neil C.
Published: July 2010

Profiles of stomatal resistance in canopies of corn (Zea mays L.), yellow‐poplar (Liriodendron tulipifera L.) and flowering dogwood (Comus florida L.) showed increased resistances in the lower portion of the canopy. In corn, this increase was partly the result of reduced illumination and partly the result of senescence. The age of the leaf did not affect its resistance prior to turning yellow. In the woodland species, the stomata closed at lower illumination than in corn, and illumination was the major factor determining the increase of the stomatal resistance within the tree canopics.
Agronomic and Quality Characteristics of Awned and Awnleted Populations of Spring Wheat1
Authors: McNeal F. H. , Baldridge D. E. , Berg M. A.
Published: July 2010

Awned and awnleted populations of spring wheat, Triticum aestivum L. em. Thell., derived by compositing seed from F2 plants and F3 lines classified as homozygous awned and homozygous awnleted, were compared for agronomic and quality performance at two locations. The awned population had heavier kernels and test weight at both locations and a 7% higher yield at one location. The awnleted population headed earlier and had more culms and more spikelets per head. Quality data showed the awnleted population superior in flour yield, loaf volume, farinograph stability, and farinograph valorimeter.

The value of closely related populations for evaluating the effect of simply inherited characters is discussed.
Stomate Density and its Relationship to Water‐Use Efficiency of Blue Panicgrass (Panicum antidotale Retz.)1
Authors: Dobrenz A. K. , Wright L. Neal , Humphrey A. B. , Massengale M. A. , Kneebone W. R.
Published: July 2010

Six clones of blue panicgrass (Panicum antidotale Retz.) representing three diverse sources of germ plasm were used to evaluate the association between stomate density and water‐use efficiency. Silicone rubber impressions were taken on the abaxial and adaxial leaf surfaces of four plants from each clone. Leaves were selected from the top, middle, and base of the culm and impressions were taken at the base, middle, and tip of each leaf.

Stomate density of blue panicgrass clones ranged from 78 to 165 per mm2. Leaves adjacent to the inflorescence had significantly lower stomate density than those at the middle and base of the culm. No difference was found among stomate densities at the three positions on a leaf.

A nonsignificant association was obtained when wateruse efficiency and stomate density were correlated for the six clones. Drouth tolerant clones had fewer stomates per unit area than drouth susceptible clones.
Resistance to Boll Weevil (Anthonomus grandis Boh.) Oviposition in Cotton1
Authors: Jenkins Johnie N. , Maxwell F. G. , Parrott W. L. , Buford W. T.
Published: July 2010

Cotton (Gossypium hirsutum L. and G. barbadense L.) lines were tested for 3 years in small field plots for boll weevil (Anthonomus grandis Boh.) resistance. A total of 23, 29, and 100 lines were evaluated at one location in 1965, 1966, and 1967 respectively. Five frego, four red, and several Sea Island cotton lines received less boll weevil oviposition than the commercial check line. Oviposition under these field conditions may have measured a different component of preference than our standard laboratory test for oviposition factors. In general, however, lines selected in our laboratory test for low oviposition also showed reduced oviposition in the field tests. A covariance analysis adjusted the number of oviposition damaged squares for the number available to the weevil for oviposition. Gains in precision ranged from 49 to 105% from the use of covariance.
Artificial Lighting in the Germination and Early Growth of Sugarcane Seedlings1
Authors: Bull T. A.
Published: July 2010

Young sugarcane (Saccharum hybrid) seedlings receiving 8 hours of full sunlight (ca. 200–300 cal cm−2) did not respond to supplementary lighting. However, the turnover of seedlings up to transplant age may be significantly increased, without extending the glasshouse and constant temperature room area, by using artificial lights.
Effects of 2,3,5‐Triiodobenzoic Acid on the Morphology and Anatomy of Glycine max (L.) Merrill1
Authors: Ghorashy S. R. , Colville W. L. , Ashworth D. L.
Published: July 2010

A foliar application of 75 g/ha of 2,3,5‐triiodobenzoic acid (TIBA) on soybeans at the six‐trifoliolate‐leaf stage modified the morphology and anatomy of the stem, leaf, and petiole. Plants treated with TIBA had a greater number of branches and were shorter than untreated plants. Leaves differentiated after TIBA treatment were smaller, darker green and showed interveinal puckering. Leaves located at nodes 17 and/or 18 exhibited considerable proliferation of vascular bundles. Histological examination of these leaves indicated continuous procambium activity, disorganization of mesophyll tissues and reduced cell size in the laminae. Tetrafoliolate leaves were frequently developed at nodes 17 and 18 on plants receiving TIBA treatments. Petioles developed after TIBA treatment were longer, twisted and in some cases showed tissue abnormalities. Application of TIBA did not increase stem diameter, but altered the pattern of cambium activity throughout the length of the stem.
A Comparison of the Performance of Homogeneous and Heterogeneous Barley Populations1
Authors: Clay R. E. , Allard R. W.
Published: July 2010

Twenty‐three mixtures of barley (Hordeum vulgare L.) varieties were compared with their components for yielding ability and for yield stability at five locations in California over 2 years. The mixtures had a small advantage in yield over the average of the varieties but were inferior to their components in stability of yield. The yield advantage of mixtures decreased when environmental heterogeneity was reduced by excluding data from the most extreme location. The number or diversity of components in a mixture appeared unrelated to its yield. Certain F2 populations, included in the second year, were higher yielding but less stable than their parents. It was concluded that simple varietal mixtures have limited commercial possibilities and that special breeding programs may be necessary if favorable inter‐genotypic interactions are to be utilized.
Effect of Floral Bud Removal on Performance of Soybeans1
Authors: Hicks D. R. , Pendleton J. W.
Published: July 2010

Seed weight was increased such that the yield per plant of soybeans, Glycine max (L.) Merr., was not reduced when all floral buds were removed from any 1/3 section of the plant. When all floral buds were removed from either the upper or lower 2/3 of the plant, the increase in seed weight was not great enough to offset the reduction in the number of pods per plant, and, therefore, the yield per plant was reduced.

Yield and number of pods per plant were reduced when all floral buds were removed from all the branches, but not affected when all floral buds were removed from the main stem. Seed weight was increased by both treatments. The vegetative parts of the plant without pods remained green until killed by frost; other parts of the plant senesced normally.

Removal of floral buds (0 to 60 per plant at random over all nodes) had no effect on the number of pods per plant, seed size, or yield per plant. The protein content of the seed increased and oil content decreased as the number of floral buds removed increased.
Forage Yield and Other Agronomic Traits of High‐ and Low‐Coumarin Isosynthetics of Sweetclover1
Authors: Goplen B. P.
Published: July 2010

A method is described for the development of high‐ and low‐coumarin isosynthetics of Melilotus alba Desr. and M. officinalis (L) Lam. Field studies at four locations were carried out to determine the effect of coumarin content on the agronomic performance of sweetclover. High‐coumarin isosynthetics were superior to corresponding low‐coumarin isosynthetics in forage yield, seed yield, seedling vigor, spring vigor, and winterhardiness and were somewhat earlier in maturity. A greenhouse study corroborated field results on seedling vigor. The basis for the differential behavior is unknown. It was concluded that vigorous and high yielding low‐eoumarin sweetdover varieties might eventually be developed, but breeding efforts must be intensified to overcome the mediocre agronomic performance associated with the low‐coumarin character. The application of the isosynthetic technique to plant breeding programs is suggested.
Effects of Random Intercrossing in a Naturally Self‐Fertilizing Species, Nicotiana tabacum L.1
Authors: Humphrey A. B. , Matzinger D. F. , Cockerham C. Clark
Published: July 2010

Eight varieties of Nicotiana tabacum L. were crossed into an eight‐line synthetic population. This population was random mated for an additional five generations and each random mated generation was selfed for one generation. Comparisons of generation means indicated the presence of epistatic effects for six of eight characters studied. A decrease in yield and narrower leaves with increased generations of random mating suggested that internally balanced chromosomal effects were being disrupted. However, the magnitude was low and this effect would be expected to be more than offset by one generation of selection.
Some Enzyme and Protein Changes Associated with Water Stress in Wheat Leaves1
Authors: Stutte Charles A. , Todd Glenn W.
Published: July 2010

Enzyme changes in soluble protein of wheat leaves (Triticum aestivum L.) subjected to varying amounts of water stress were investigated by using acrylamide gel electrophoresis. Changes in total protein and iron‐containing protein were compared with changes in enzyme patterns. Increased numbers of bands and quantities of iron‐containing proteins appeared with severe wilting while under these same conditions lactic dehydrogenase was found in fewer bands. Certain peroxidase bands disappeared and new ones appeared with increasing water stress. Total peroxidase activity per unit of protein increased with water stress while total soluble protein decreased drastically with increasing water stress as was shown previously.
Effect of Thinning on Stand, Yield, and Plant Height in Maize1
Authors: Hallauer Arnel R. , Sears J. H.
Published: July 2010

We conducted experiments at two locations for 4 years to determine the effect of thinning on stand, yield, and plant and ear height of maize (Zea mays L.). We included a control (no thinning) and over‐planting and thinning at three stages of plant development (2 to 3, 5 to 8, and 9 to 11 leaf‐stages) in all experiments. Average stand improvement was 8% over the control regardless of the stage of thinning. Thinning at the 5 to 8 and 9 to 11 leaf‐stages resulted in significantly lower yields than thinning at the ''. to 3 leaf stage. Yields of the control plots were not significantly different from the yields obtained on the plots thinned at the 5 o 8 leaf‐stage, the latter having 8% higher stands. Plant and ear height also decreased with the later stages of thinning. The experiments showed that over‐planting and thinning was justified for improving stands, but that thinning at different sages did affect yield of grain significantly.
A Rapid Method for Plant Leaf Area Estimation in Maize (Zea mays L.)1
Authors: Francis C. A. , Rutger J. N. , Palmer A. F. E.
Published: July 2010

Total plant leaf area of individual maize plants (Zea mays L.) at anthesis was estimated by multiplying the area of leaf number seven, the best estimator in these studies based on correlation analyses, by an appropriate “leaf area factor.” This factor was determined by dividing total plant leaf area by the area of leaf seven, which was the largest or nearly the largest leaf for the 23 genotypes studied. For precise estimation, a factor should be determined for the largest leaf of each genotype or treatment in each population and each year. A very close correlation between estimated and actual leaf areas was observed when the leaf area factor was used.

To minimize the error incurred by plant‐to‐plant variation, at least five plants should be completely measured to determine the leaf area factor for a given genotype. This method of estimation could be applied widely to leaf area measurements in maize and should make it possible to determine leaf areas in yield trials, breeding nurseries, and extensive field tests.
Inbreeding Depression in Diploid and Induced‐Autotetraploid Crested Wheatgrass1
Authors: Dewey Douglas R.
Published: July 2010

Forage and seed yields of diploid crested wheatgrass, Agropyron cristatum (L.) Gaertu., were reduced sharply by selling. Some progenies were much more sensitive to selfing than others. Vigor and fertility reductions averaged 44.9 and 43.4%, respectively, in 15 S1 progenies. Inbreeding depression of induced‐autotetraploid crested wheatgrass was much less than that of comparable diploids. Forage yields of seven induced‐tetraploid S1 progenies declined 17.3%, compared with a 54.9% reduction for their exact diploid counterparts.

Possible causes of rapid loss of vigor in natural autotetraploids are discussed. Newly synthesized autotetraploids—includiug crested wheatgrass; corn, Zea mays L.; Italian ryegrass, Lolium multillorum Lam.; and alsike clover, Trifolium hybridnm L.—show a much lower degree of inbreeding depression than old natural autotetraploids such as alfalfa, Medicago sativa L.; orchardgrass, Dactylis glomerata L.; and crested wheatgrass, Agropyron desertorum (Fisch. ex. Link) Schult. An accumulation of chromosome aberrations and unfavorable gene combinations in species buffered by autoploidy is offered as a major cause of excessive inbreeding depression in natural autotctraploids. The degree of inbreeding depression in natural autotetraploid species may give an indication of their relative ages.
Genetic Studies of Induced Mutants in Melilotus alba. I. Short‐Internode Dwarf, Curled Leaf, Multifoliolate Leaf, and Cotyledonary Branching1
Authors: Gengenbach B. G. , Haskins F. A. , Gorz H. J.
Published: July 2010

Information obtained from the F1 F2 and F3 generations of crosses between the normal annual M. alba progenitor line and the four mutants, short‐internode dwarf, curled leaf, multifoliolate leaf, and cotyledonary branching, indicates that each character is conditioned by a single pair of alleles. The multifoliolate leaf character is dominant over the normal phenotype; the other three mutant characters are recessive. The symbols dw, cl, Mf, and cb are proposed as designations for the respective mutant genes.
Location of a Gene in Maize Conditioning Susceptibility to Atrazine1
Authors: Scott Gene E. , Grogan C. O.
Published: July 2010

F2 populations from 16 reciprocal chromosomal translocation crosses were used to locate the chromosome arm of corn (Zea mays L.) that carries the gene conditioning the susceptibility of the Mississippi strain of inbred GT112 to atraiine. This gene is located on the long arm of chromosome 8.
Inheritance of the Capacity for Chloride Inclusion and Chloride Exclusion by Soybeans1
Authors: Abel G. H.
Published: July 2010

Roots of Glycine max (L.) Merr. varieties absorb chloride ions in comparable amounts, but subsequent translocations of chlorides to plant tops is genetically controlled. Some varieties accumulate relatively large amounts of chlorides in plant tops; others exclude them almost completely. Chlorides occur in petioles and leaflets, with higher concentrations in leaflets, but whole leaf samples can be used to classify chloride‐accumulating capacity.

The chloride includers growings in the saline soils of the Imperial Valley of California develop severe leaf necrosis from chloride toxicity, whereas the chloride excluders show no necrosis

Crosses between parents with similar chloride accumulating capacity gave F2 and F3 progeny similar to parents in chloride content. In eight crosses from parents dissimilar in chloride accumulation, F2 plants segregated in ratios of 3 chloride excluder to 1 includer. In tests of the F3 progeny from these crosses, the F2 excluder plants segregated in ratios of 1 excluder to 2 segregating, whereas the F2 includer plants bred true.

In backcrosses of the F1 plants from an includer by excluder cross, the segregating ratio was 1 includer to 1 segregating line when the recurrent parent was an includer and 1 excluder to 1 segregating line when the recurrent parent was an excluder.

The gene symbols Nel and nel are proposed as the dominant for chloride excluders and the recessive for chloride includers, respectively.
Influence of Seedling Characteristics on Weed Competitive Ability of Sorghum Hybrids and Inbred Lines1
Authors: Guneyli E. , Burnside O. C. , Nordquist P. T.
Published: July 2010

Competitive ability of 48 sorghum [Sorghum bicolor (L.) Moench] hybrids and 41 parental inbred lines was evaluated using (a) germination percentage and germination rate index, (b) emergence percentage and emergence rate index, (c) seedling vigor, (d) rate of root and shoot development, and (e) cation exchange capacity of roots as selection criteria. Average response of sorghum hybrids was superior to parental inbred lines in all selection criteria. Sorghum lines selected for high and low seedling growth characteristics in laboratory and greenhouse studies showed corresponding competitive advantages over weeds in field studies. Competitive advantage of sorghum over weeds was largely due to rapid germination, emergence, and root and shoot growth during the early stages of sorghum development.
Relationship of Glucose Metabolism to Germinability and Vigor in Barley and Wheat Seeds1
Authors: Abdul‐Baki Aref A.
Published: July 2010

Changes in glucose metabolism of germinating barley (Hordeum vulgate, L.) and wheat (Triticum aestivum L. em Thell.) were determined by following the rate of utilization of uniformly labeled glucose for respiration, and synthesis of proteins and polysaccharides (watersoluble sugars, starch‐hemicelluloses, and cellulose). Small changes in seed germinability or vigor induced by aging, led to a great reduction in glucose utilization as expressed by a reduction in protein and polysaccharide synthesis. The reduction in synthetic capacity greatly preceded any reduction in germination, shoot growth, or respiration.

Besides its ability to detect very early changes in seed germinability or vigor, the glucose‐utilization approach offers a powerful tool for distinguishing dormant from dead seeds on the basis of the great difference in glucose metabolism in the two types of seed.
Modification of the Effects of 2,4‐D Inhibition of Growth and Lethality in Field Beans by Copper Sulfate and Copper Ethylenediaminetetraacetic Acid1
Authors: Huffaker R. C. , Sarquis A. V. , Miller M. D.
Published: July 2010

The toxicity of 2,4‐dichlorophenoxyacetic acid (2,4‐D) on Phaseolus vulgaris L. as modified by two copper compounds was studied. Applying CuSO4 at 10−4 and 10−3M simultaneously with a growth inhibitory concentration of 2,4‐D (10−4M) reduced the inhibition significantly, allowing up to 47% greater dry weight and 44% greater trifoliolate leaf area 18 days after treatment. For maximum effect, only 1/10 as much CuSO4 (l0−3M) was required as the amount of iron compounds earlier found to be needed. CuEDTA began to affect inhibition of growth by 2,4‐D at a lower concentration than did CuSO4, but at maximum effectiveness was only half as effective as CuSO4.

The time required to permanent wilting of primary leaves with 2,4‐D of 6.8 ✕ 10−3M was reduced by both CuSO4 and CuEDTA at concentrations generally ranging from 10−7 to 10−3M. With an added level of l0−2M, CuSO4 did not affect the time course significantly whereas CuEDTA extended it. With 2,4‐D of 1.4 ✕ 10−2M, however, CuEDTA and CuSO4 still reduced the time required to permanent wilting although each was needed in greater concentrations.
Genetic Control of Phytoglycogen Accumulation in Maize (Zea mays L.)1
Authors: Ayers John E. , Creech Roy G.
Published: July 2010

Investigations of the role of the genes ae and su2 in phytoglycogen accumulation in maize endosperms were conducted by quantitating and characterizing the watersoluble polysaccharides (WSP) from the 16 genotypes of endosperm resulting from all possible crosses betweenlines homozygoufso r normal(Ae Su), ae, su1, and ae su1. The WSP was extracted in a mercuric chloride solution and enzymatically hydrolyzed to glucose, then measured as reducing sugar.

Only the endosperms homozygous for su1 contained phytoglycogen. Increased doses of ae decreased the amount of phytoglycogen at 20 days after pollination from 38.8 to 4.2% of the dry weight. The β‐amylolysis limit of the phytoglycogen from the double mutant suggested that it may be a more loosely branched polysaccharide.
A Comparison of Genie Male‐Sterile and Cytoplasmic Male‐Sterile Four‐Way Sugarbeet Hybrids1
Authors: Theurer J. C. , Ryser G. K. , Stout Myron
Published: July 2010

In 1966 and 1967 comparison was made of 12 four‐way sugarbeet (Beta vulgaris L.) hybrids having a cytoplasmic male sterile X pollen restorer male parent, and an equivalent number of hybrids of the same parental lines having a genie male sterile X pollen restorer parent. The genie male sterile X pollinator crosses had a higher sugar percentage and a lower impurity index than cytoplasmic male sterile X pollinator hybrids. Yield of gross sugar and tonnage were similar for the two males averaged over all crosses. The performance of specific male and female parents indicated that good combining ability between cytoplasmic male sterile X restorer pollinators may not necessarily show how equivalent genie male sterile X pollinator crosses will behave.
Genetic Studies of Earliness, Yield, and Fiber Properties in Cotton (Gossypium hirsutum L.)1
Authors: Murray Jay C. , Verhalen Laval M.
Published: July 2010

Earliness, yiekl, and fiber properties in cotton were studied in a series of experiments conducted in Oklahoma from 1961 through 1966. In these studies a very early selection, OK‐86, from an early Yugoslavian strain, PI 235563, and a late commercial variety, ‘Acala 44’, were used as parents. The P1, P2, F1, F2, Bc1, Bc2, F3, and Bc2F4 generations of this cross were investigated. Single plant analyses of the early generation materials gave inconsistent heritabilities. However, progeny row analyses of the Bc2F4 gave predicted genetic advances under selection which corresponded closely with observed selection responses. Selection in this later generation material was highly effective for earliness and fiber length. It probably would have been less effective for yield, fiber coarseness, and fiber strength had selection for those three traits been practiced. The breeding of an early, high‐yielding variety with fiber properties more acceptable than those of the early varieties now available appears feasible, although difficult.
Carbon Uptake and Distribution Before and After Defoliation of Alfalfa1
Authors: Pearce R. B. , Fissel Guy , Carlson G. E.
Published: July 2010

The deposition and redistribution of 14C was followed during the growth of individual alfalfa plants. 14CO2 was administered at 5 weekly intervals (plants were sampled 2 days after each addition of 14CO2). The plants were then defoliated, and the redistribution of 14C was followed during the subsequent growth.

During the 1st week of 14CO2 uptake, only 17% of the 14C in the ]plant was translocated to crown and roots. By the 5th week, 36% of the 14C in the plant was in crown and roots. It was not until the 3rd week that 14C started to accumulate (exponentially) in the “starch” fraction. This coincided with the time that large roots (> 1 mm in diameter) started to increase in dry weight.

After defoliation, 14C changes in the plant best fit a sigmoid curve. The greatest changes occurring between 3 and 15 days after defoliation. During the 28 days of regrowth, 45% of the 14C was lost (respiration, leaching, and sloughing) from the plant, 19% had moved into top growth and large roots had lost 70% of their original 14C content.
Photosynthetic and Morphological Adaptation of Alfalfa Leaves to Light Intensity at Different Stages of Maturity1
Authors: Pearce R. B. , Lee D. R.
Published: July 2010

Leaves of individual alfalfa (Medicago sativa L.) plants were developed under light intensities which were either high (32 to 43 klux) or low (13 to 14 klux). One week after leaf unfolding, half of the plants in each growth chamber were transferred to the other. At 3 weeks, plants were again transferred so that the treatments included all combinations of light intensities and leaf age. Specific leaf weight (SLW = dry weight per unit leaf area) and net photosynthesis (Pn) were determined on leaves at 1, 3, and 5 weeks after leaf unfolding. Both SLW and Pn were higher under high light than low light. The major light intensity effect was that which the leaf had most recently been exposed to. Another was a carryover effect of the light intensity under which the leaf had developed. The SLW and Pn of alfalfa leaves changed with changes in light intensity at all the stages of maturity measured.
Agronomic and Fiber Properties of Smooth, Nectariless ‘Acala’ Cotton1
Authors: Davis Dick
Published: July 2010

Genes for semi‐glabrous leaf and nectariless plant were transferred into ‘Acala 1517’ cotton (Gossypium hirsutum L.) from the insect‐tolerant strain 1514, which carries the Sm1sl, ne1, and ne2 genes. The F2 progeny of this cross approached the midparent in agronomic and fiber properties. A semi‐glabrous, nectariless selection from the above cross was hybridized with a selected experimental strain from Acala 1517. The unselected F2 progeny of the second cross appeared to be essentially equal to the Acala 1517 parent in disease resistance and agronomic and fiber properties.
Eftects of a Single Height Gene (Dw3) of Sorghum bicolor (L.) Moench at 1‐dwarf and 2‐dwarf Height Levels1
Authors: Campbell L. G. , Cassady A. J.
Published: July 2010

Results of a study of isogenic lines of Japanese Dwarf broomcorn (Sorghum bicolor (L.) Moench) that differed only in the dominanto r recessive allele of the Dw3 height gene are reported. Testcrosses positively identified the revertant allel as dw3. The state of the Dw3 gene influenced main head yield; tiller yield; total yield; test weight; kernels per head; heads per plant; grams per 1,000 kenels; length, width, and area of the fourth leaf blade; and head length as well as culm height. Node number was not aftected, indicating that maturity was not influenced. The study was conducted under three environments; significant environment X height interactions were found for main head yield, tiller yield, total yield, test weight, heads per plant, grams per 1,000 kernels, width of the fourth leaf blade, culm height, culm diameter of the fourth internode, head length, and days to 90% bloom.
Nature of Heterosis in Grain Production by the Sorghum Panicle1
Authors: Blum A.
Published: July 2010

Nine grain sorghum (Sorghum bicolor (L.) Moench) hybrids were compared with their parental lines in a field experiment on the manifestations of heterosis in grain production per panicle and each of the panicle weight components (i.e., number of whorls per panicle, number of branches per whorl, number of grains per branch, and weight per grain).

Of all panicle weight components, a significant and consistent effects of heterosis (superiority over best parent) was found only hi the number of grains per branch, and mostly at the lower branches within the panicle. Component interaction did not account for heterosis in the number of grains per panicle, except in RS610 hybrid. It was indicated that heterosis in the weight per grain and in the number of grains per panicle were negatively associated.
Varietal Differences in Net Photosynthesis of Soybean Leaves1
Authors: Dornhoff Gary M. , Shibles R. M.
Published: July 2010

Leaf net CO2 exchange of 20 varieties of soybeans (Glycine max (L.) Merr.) was measured by infrared gas analysis. The varieties differed significantly in net photosynthesis at 100, 200, 300, and 400 ppm CO2. Both stomatal resistance and mesophyll resistance to diffusion of CO2 were different among genotypes. No genotypic differences were found in CO2 evolution into CO2‐free air in light, or in CO2 compensation concentration. Density‐thickness (leaf weight to leaf area ratio), on both dry‐ and fresh‐weight bases, was highly correlated with net photosynthesis. The evidence suggests that varietal differences in net photosynthesis were mainly a result of differences in diffusive resistances.

Net photosynthesis of most varieties began to increase around Aug. 4, at the approximate beginning of seed filling. A linear trend in increasing leaf density‐thickness occurred from beginning of testing. The increase in net photosynthesis is postulated a result of (a) decreased CO2 diffusion resistance within the leaf, and/or (b) increased demandfo r photosynthate for seed formation.
Stomate Density of Alfalfa (Medicago sativa L.)1
Authors: Cole D. F. , Dobrenz A. K.
Published: July 2010

Five cultivars and two experimental lines were used to evaluate stomate density and length in alfalfa (Medicago sativa L.). Plants were grown under similar conditions with respect to light, temperature, and soil‐moisture conditions. Stomate impressions were taken on the adaxial and abaxial leaf surfaces at four leaf positions on plants from all cultivars and experimental lines used in this study.

Average stomate density ranged from 146 per mm2 for ‘Sonora’ to 265 per mm2 for ‘Ladak.’ Stomate density was significantly greater on the adaxial leaf surface compared to the abaxial surface. Terminal leaves of all cultivars and experimental lines had more stomata per unit area than basal leaves.
Genetic Linkage in Soybeans: Linkage Group I1
Authors: Weiss Martin G.
Published: July 2010

Genetic linkage of three genes in soybeans—y12, a seedling chlorophyll deficiency gene, t, a pubescence color gene, and e1, a gene conditioning earliness and shortness—was established in Linkage Group I. The combined recombination value for y12 and el was 20.2 ± 1.1%, for e1 and t was 3.9 ± 0.4%, and for y12 and t was 21.6 — 0.7%. Pubescence color, Tt, and a duplicate locus conditioning cotyledon color, D2d2, previously reported linked, were shown to be inherited independently. The order of genes in Linkage Group I appears to be y12‐e1‐t.
Effect of Endosperm Mutants on Germination and Early Seedling Growth Rate in Maize (Zea mays L.)1
Authors: Nass H. G. , Crane P.L.
Published: July 2010

Endosperm mutants in three near‐isogenic backgrounds of maize (Zea mays L.) were used to determine their effect on germination and early seedling growth. Two environments were utilized: average greenhouse temperature regimes (20 to 25 C) and 15 C in a controlled environment chamber. Floury‐1 had a significantly greater early seedling growth rate than normal in both environments. while sugary‐1 had a significantly slower seedling growth rate in both environments, all mutants showed significantly slower seedling growth rates than normal at 15 C. Shrunken‐1 showed a significantly lower maximum number of plants germinated than normal under greenhouse conditions. Sugary‐1 was significantly different from normal in both environments.
Meiotic Behavior of Wheat‐Rye Addition and Substitution Lines1
Authors: Lee Y. H. , Larter E. N. , Evans L. E.
Published: July 2010

Meiosis was studied in alien addition and substitution lines with common wheat (Triticum aestivum L.) cv. ‘Kharkov’ as the recipient and rye (Secale cereale L.) cv. ‘Dakold’ as the donor. The substitutions 3R(3B), 3R(3D), 6R(6A), and 6R(6D), as well as the disomic addition lines involving either 3R or 6R, exhibited an increased level of meiotic irregularity relative to the Kharkov parent. In contrast, meiosis in the substitution line 5R(5A), and also in the monosomic addition line 5R, was near normal.

In general, univalents and open bivalents observed in substitution and addition lines were identifiable as being rye chromosomes, the wheat complement remaining relatively stable. An exception to this involved 3R(3B), and also the disomic addition 5R, in which the pairing of wheat chromosomes was reduced, presumably as a result of the presence of the alien chromosome(s).
Natural Outcrossing on Genetic Male Sterile Barley1
Authors: Hockett E. A. , Eslick R. F.
Published: July 2010

In 1960, we grew 11 male sterile barley, Hordeum vulgare L., lines at five dryland and three irrigated locations in Montana. Significant differences in mean seed set on male sterile plants were found with different locations (0.7 to 6.2% outcrossing), lines (0.6 to 9.2% outcrossing) and varieties (outcrossing on msms in three different varieties ranged from 1.2 to 6.7%). In 1960 to 1965 natural outcrossing on male sterile plants differed between years at Bozeman in nine male sterile lines.

In 1960, we studied natural outcrossing on single male sterile plants and spikes of 16 male sterile barley lines at Bozeman. We found: (1) the single plant standard error for average seed set per spike was 0.96 seed per spike; (2) the percent seed set on individual spikes which set seed ranged from 2 to 70% and had a standard error of about 11%; and (3) the average number of seed set on primary secondary, and second crop tillers was 3.18, 0.26, and 0, respectively.

Natural outcrossing on male sterile plants was too low in all experiments to allow practical production of hybrid barley in Montana without additional manipulation of pollen shower, female receptivity, and “nicking” time.
Relative Thermal Stability of Malic Dehydrogenase From Heat‐Hardened and Unhardened Phaseolus Sp.1
Authors: Kinbacher E. J.
Published: July 2010

Malic dehydrogenase was extracted from heat‐hardened and unhardened plants of two varieties of Phaseolus vulgaris L., ‘Harvester’ and ‘G.N. Nebraska #1’ and P. acutifolius, Gray var. latifolius Freeman, ‘Tepary Buff.’ The leaf disc heat tests showed that Tepary was significantly the most heat‐tolerant variety and that Harvester was significantly more heat‐tolerant than Nebraska #1. Purified fractions of malic dehydrogenase were exposed to temperatures of 52 to 62 C for 15 min. This thermostability test showed that the enzyme from Harvester was significantly the most thermal stable, and the enzyme extracted from Tepary was significantly the least thermostable for both the heat‐hardened and unhardened plants. Heat hardening increased the thermal stability of malic dehydrogenase extracted from all three varieties. Other data indicate that the leaf disc heat test correctly ranked the varieties for heat tolerance. Since the varieties were not properly ranked for heat tolerance by the thermal stability of extracted malic dehydrogenase, malic dehydrogenase does not appear to be a key enzyme in heat tolerance. The enzyme stability test ranked the two P. vulgaris varieties properly, but Tepary, a variety of P. acutifolius, did not appear to be correctly ranked. Enzyme variation based on species difference may tend to account for the discrepancy in ranking.
Meiosis in Two Species of Trifolium and Their Hybrids1
Authors: Chen Chi‐Chang , Gibson Pryce B.
Published: July 2010

Meiosis in the interspecific hybrid (2n=24) between Trifolium repens L. (2n=32) and T. occidentale D. Coombe (2n=16) was characterized by averages of 4.55 III, 3.45 II, and 3.45 I per microsporocyte at diakinesis and metaphase I. The maximum frequency of eight trivalents and the other chromosome associations suggested close homology between the parent genomes and among chromosomes of the gametic complement of T. repens. Meiosis in T. repens and in 2x T. occidentale was regular. Meiosis in the 32‐chromosome hybrid between T. repens and 4x T. occidentale was similar to meiosis in 4x T. occidentale, which was considered normal for a newly induced autotetraploid. This similarity is considered verification of a close phylogenetic relationship between the two species.
Predicting Yield of Synthetic Varieties1
Authors: Busbice Thad H.
Published: July 2010

Formulae for predicting yield of synthetic varieties are useful in two ways. First, they presumably have predictive value, and second, if they have predictive value, the formulae define those factors that control yield. Such formulae give the relationship of one yield factor to another. In this paper I derive prediction formulae which will, I believe, successfully predict yield. These formulae take into account the effects of ploidy, selfing, number of parents, inbreeding of parents, combining ability of parents, relationship between parents, and the generation of multiplication of the synthetic variety.

The formulae are based upon the observation that heterosis increases with outbreeding and diminishes with inbreeding. A linear relationship between yield and heterozygosity is assumed but the formulae also should be useful when the relationship between yield and heterozygosis is nonlinear, providing a satisfactory transformation of the yield data to fit the linear relationship can be found. The level of heterozygosis is expressed as the coefficient of inbreeding F.
Cytogenetic Studies in Cynodon L. C. Rich. (Gramineae)1
Authors: Harlan Jack R. , de Wet J. M. J. , Rawal K. M. , Felder M. R. , Richardson W. L.
Published: July 2010

In a biosysteiriatic analysis of Cynodon over 700 interspecific and nearly 2,000 intervarietal hybrids were produced. C. barberi, C. arcuatus, and C. plectostachyus proved to be completely isolated from each other and the rest of the genus. C. aethiopicus could be crossed with C. dactylon and C. nlemfuensis, but with great difficulty. Hybrids between the remainder of the taxa could be produced more easily and the chromosome behavior of these hybrids is reported. In all crosses between diploid taxa, the most common configuration is nine pairs. The most common configuration in triploid hybrids is nine pairs and nine univalents regardless of the parentage. Chromosome pairing in tetraploid hybrids is variable. There is little or no genome differentiation among the species that can be crossed. The evidence is discussed with respect to a recent revision of the genus.
Reciprocal Full‐Sib Selection1
Authors: Hallauer Arnel R. , Eberhart S. A.
Published: July 2010

Reciprocal full‐sib selection is a breeding procedure for concurrent population improvement and hybrid development. Reciprocal full‐sib selection should be an efficient procedure for crop species in which non‐additive genetic effects, as well as additive, are important in the expression of hybrid superiority. Full‐sib progenies are yieldtested, and selections are made for improvement of the two parental populations. These same yield trials also are the first season of the evaluation and development of single crosses for each cycle of selection. The use of reciprocal full‐sib selection in a comprehensive breeding program provides a flexible plant‐breeding procedure
Influence of Sample Size on the Estimation of Genetic Variances in a Synthetic Variety of Maize. I. Grain Yield1
Authors: Marquez‐Sanchez Fidel , Hallauer Arnel R.
Published: July 2010

We conducted an experimental study to determine the influence of sample size on the estimation of genetic components of variance for the nested mating scheme (Design I) in maize (Zea mays L.). Estimates were obtained for different numbers of males each mated to a constant number of females and for different numbers of females mated per male. Estimates of the genetic variance (σA2, σD2) components and their standard deviations were calculated for each sample size. Graphs of the standard deviations of the variance components were used to compare the relative precision of the estimates for various sample sizes. It was concluded that at least 4 females per male should be used and that 6 to 8 females mated to at least 48 males would be preferable for estimating components of genetic variance for yield in maize.
Growth Analysis of the Soybean Community1
Authors: Koller H. R. , Nyquist W. E. , Chorush I. S.
Published: July 2010

Growth analysis techniques were used to study components of dry matter accumulation in field soybean [Glycine max (L.) Merrill] communities at Lafayette, Ind. in 1968 and 1969. An analysis was made of dry matter accumulation in leaf, supporting, pod wall, and seed fractions, as well as the total aboveground portion of the crop. General approach with the 1968 data was to select mathematical functions which describe the dry weight and leaf area vs. time relationships and then to calculate, for each day during the growing season, instantaneous values of relative growth rate (RGR), crop growth rate (CGR), net assimilation rate (NAR), leaf area ratio (LAR), and the components of LAR. From the 1969 data, weekly mean RGR's and CGR's were calculated, using traditional growth analysis formulae.

The RGR of each individual plant fraction steadily decreased, at a decreasing rate, as the season progressed, At any given time, the most recently initiated plant fraction had the greatest RGR. The CGR of each fraction rose to a peak and then declined. Growth rate of the leaf component peaked first, followed in sequence by supporting, pod wall, and seed components. Apparently due to late planting in 1968, there was a greater overlap of vegetative and seed growth than in 1969 when planting was earlier.

Total aboveground RGR declined until early August, then rose to a secondary peak in mid‐August. At the same time, there also occurred a peak in total aboveground CGR. The increases in RGR and CGR during August are attributable to a concurrent increase in NAR. The increase in NAR is interpreted as a response of the photosynthetic apparatus to an increased demand for assimilates. The increased demand for assimilates was due to rapid growth of the seed fraction.
C‐14 Labeled Photosynthate Export from Fully Expanded Corn (Zea mays L.) Leaf Blades1
Authors: Eastin John A.
Published: July 2010

The velocity and time course of C‐14 labeled photosynthate export from corn leaves were studied at 15 days after silk emergence. The C‐14 front moved at a velocity of ca. 138 cm/hr. The rate and completeness of C‐14 export from corn leaves was similar to that reported for sugarcane, and more complete than for most species reported in the literature.
Inheritance of Branching in Sunflowers, Helianthus annuus L.1
Authors: Hockett E. A. , Knowles P. F.
Published: July 2010

The inbred parental lines in this study were derived from varieties of sunflowers grown for their large edible seed (Helianthus annuus var macrocarpus (DC.) Ckll.) and from the wild type H. annuus ssp. annuus.

A classification using the following types was found to be adequate for genetic studies of branching in sunflowers: 0 ‐ no branching, 1 ‐ basally branched, 2 ‐ top branched, 3 ‐ fully branched with a central head, 4 ‐ fully branched without a central head (wild type).

Four genes for branching were named in this study: the dominant gene Br2 for top branching; the duplicate dominant genes Br2 and Br3 from the wild type parent; and the recessive genes b2 and b3 which gave a fully branched phenotype only when homozygous for both genes.

The single gene Y for green versus yellow growing point color was found to be linked with the gene Br3 for branching with 11.6 ± 1.0% recombination.
A Convenient High‐Capacity Seed Blower
Authors: James Edwin , Clark D. C.
Published: July 2010

A high‐capacity seed blower has been developed which combines the features of two available blowers. It can effectively clean 250 g of small grain or sorghum seeds, 150 g of small legume seeds, or 50 g of grass seeds. The blower should be an asset to plant breeders where trash or empty glumes are to be removed from small lots of seeds.
Rapid Detection of σ‐Hydroxycinnamic Acid and Beta‐Glucosidase in Melilotus alba1
Authors: Haskins F. A. , Gorz H. J.
Published: July 2010

The tests utilize small samples of leaf tissue crushed on sheets of filter paper. For detection of σ‐hydroxycinnamic acid (σ‐HCA), a crude preparation containing sweetclover β‐glucosidase is added to a spot of crushed tissue to insure hydrolysis of glucosidically bound σ‐HCA. An extract containing cis‐o‐HCA glucoside is added to another tissue spot to serve as the substrate for the detection of β‐glucosidase activity. Finally, all spots are moistened with NaOH and are scored for1 fluorescence under ultraviolet light. Results of qualitative and quantitative tests on plants representing various genotypes are compared. The importance of exposing plants to sunlight before testing for σ‐HCA is discussed. The tests are particularly useful in genetic studies, in the development and maintenance of breeding lines, and in testing for contamination in low‐σ‐HCA sweetclover varieties.
Genetic Variability for Yield after Four Cycles of Reciprocal Recurrent Selections in Maize1
Authors: Hallauer Arnel R.
Published: July 2010

The primary objective of my study was to determine the relative change in genetic variation after four cycles of reciprocal recurrent selection for yield in maize (Zea mays L.). Estimates of additive genetic variance (σ2A) and variance due to dominance deviations (σ2D) were obtained for the original (C0) Stiff Stalk Synthetic and Corn Borer Synthetic #1 populations; for the syn. 3 generation of the reconstituted populations (C4) after four cycles of reciprocal recurrent selection for yield; and for the syn. 3 generation of the hybrid populations formed by crossing the original synthetic varieties (CO ✕ CO) and the CA reconstituted populations (C4 ✕ C4). cross‐classification mating design (Design II) was imposed on each population to form half‐sib and full.sib progenies. Twenty sets were produced, each containing 16 full‐sib progenies formed from crossing four randomly selected S0 males and Sl females, for each population, and grown at three locations.

There was no difference in the estimates of σ2A for the CO and C4 Corn Borer Synthetic No. 1 populations. The estimates for Stiff Stalk Synthetic showed a decrease from the CO to the C4 , which approached the 10% probability level. There was a significant reduction in the estimates of σ2A from the CO ✕ CO to the C4 ✕ C4 hybrid populations. All the estimates of σ2A exceeded twice their standard errors. None of the changes in the estimates of σ2DD was significant between the populations

Four cycles of reciprocal recurrent selection showed an increase in yield of the Stiff Stalk Synthetic and hybrid populations and a decrease in Corn Borer Synthetic No. I populations. It appeared that only modest gains have been made for yield with a reduction in genetic variation.
Effects of Clones, Generation of Inbreeding and Years on Self‐Fertility in Alfalfa1
Authors: Melton Bill
Published: July 2010

Five selected clones of alfalfa, Medicago sativa L., were evaluated for self‐fertility over a period of 9 years. Differences among clones and clone ✕ years interactions were significant but the effect of years on the average self‐fertility of the group was not significant. Correlations of self‐fertility of the clones among years were highly significant. Inbreeding effects on self‐fertility varied between clones. C‐84, the most self‐fertile clone in the group, was significantly reduced in self‐fertility in the S1 generation, whereas the other clones were not affected. Variations in self‐fertility were noted among plants within all inbred generations. The number of self‐sterile plants tended to increase as inbreeding progressed. Pods per flower tripped, seeds per pod and seed per flower tripped were equally effective as measurements of self‐fertility.