bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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.
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 populationsFour 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.
Evaluating Parental Cultivars for Use in Hybrids and Heterosis in Barley1
Authors: Gebrekidan Brhane , Rasmusson D. C. 
Published: July 2010

Nine cultivars were crossed to ‘inbred’ and single cross testers in a study of methods of evaluating parental cultivars for potential use in hybrids of barley, Hordeum vulgare L. The cultivars were ranked in about the same order in testcrosses to inbreds, testcrosses to single crosses, and in the cultivar per se comparison for four of six characters — kernel number, kernel weight, days to heading, and height. The data did not provide a good basis for deciding among the three methods of evaluating potential parental cultivars for yield or number of heads. However, cultivar per se evaluation is recommended for initial screening of potential parental cultivars.Twenty of the 27 hybrids that were evaluated in four environments exceeded their high parent in yield, and 16 of them exceeded ‘Traill,’ the highest yielding of the cultivars. Heterosis, on the high parent basis, ranged from –26 to 47% with a mean of 11%. Four hybrids had a mean yield 17% higher than Traill. High yielding cultivars produced a larger proportion of high yielding hybrids than did low yielding cultivars, whereas, maximum heterosis occurred in crosses among low yielding cultivars. Heterosis, on the high parent basis, was negligible for characters other than yield.
Inheritance of a Self‐Compatibility Response to Temperature and the Segregation of S Alleles in Diploid Alsike Clover, Trifolium hybridum L.1
Authors: Townsend C. E. 
Published: July 2010

Inheritance of a self‐compatibility response to temperature and the segregation of S alleles were investigated in I2, F1, F2, and BC1 progenies of diploid alsike clover, Trifolium hybridum L. I1 clones, 6‐5 (S3S4) and 7‐1 (S5S6), were the temperature‐sensitive parents and I1 clone 1‐5B (S1S1) was the temperature‐insensitive parent. Percentage of selfed florets setting seed after 3 to 5 days at 32 C was used to measure temperature‐sensitivity. The S alleles in the self‐progeny of clone 6‐5 segregated in a 1 S3S3:2 S3S4:1 S4S4 ratio. The S6S6 genotype was absent in the self‐progeny of clone 7‐1, but the other two genotypes (S5S5 and S5S6) segregated in a 1 : 1 ratio. The expected S genotypes (S1S3, S1S4, S1S5, and S1S6) were obtained equal frequencies in the F1 progenies (S1S1 ✕ S3S4, S1S1 ✕ S5S6, and reciprocals). In all F2 progenies, one homozygous and one heterozygous class (S3S3, S1S3; S4S4 S1S4; S5S5, S1S5 and S6S6, S1S6) were obtained in equal frequency. Only five of 202 F2 plants were S1S1.Although other gene models were considered, the temperature‐sensitive data were interpreted best by a twogene model with an interaction between S allele genotype and temperature‐sensitivity. The proposed temperature‐sensitive genotypes of clones 6‐5 and 7‐1 were T1T1T2t2S3S4 and T1t1T2t2S5S6, respectively. The T gene(s) suppressed the action of the S alleles in the style when the plants were held at a 32 C temperature for 3 to 5 days. Dominance at one T locus was sufficient to give a temperature‐sensitive reaction with the S3, S5, and S6 alleles, but dominance at both T loci was required for such a reaction with the S, allele. Also, there was evidence for the interaction among certain S alleles in the presence of the T loci. The expression of the T loci was influenced by polygenes.Apparently these data are the first from any species to establish the role that specific temperature‐sensitive genes have on the expression of specific S alleles and interactions thereof.
Analysis of Genetic Resistance to Maize Dwarf Mosaic Disease1
Authors: Johnson G. R. 
Published: July 2010

Twenty maize diallel cross experiments, grown as part of a screening program for the isolation of resistance to maize dwarf mosaic virus disease, were analyzed to investigate the genetic basis for MDM resistance and to compare several methods for predicting three‐ and fourway hybrid performance.General combining ability variance accounted for most of the variation among crosses; resistance appeared to be usually transmitted with nearly complete dominance; and midparent heterosis for resistance was observed. The performance of non‐parental single crosses predicted three‐ and four‐way cross performance most accurately.
Studies of Tiller Formation in Reed Canarygrass (Phalaris arundinacea L.) and ‘Climax’ Timothy (Phleum pratense L.)1
Authors: Horrocks R. D. , Washko J. B. 
Published: July 2010

The greenhouse and growth chamber experiments reported herein were set up to investigate the influence of the following factors on tillering of ‘Climax’ timothy, Phleum pratense L., and reed canarygrass Phalaris arundinacea L., (a) stage of development at which the first harvest was removed; (b) clipping height; (e) nitrogen level; (d) day‐night temperature; and (e) shading. Stages of development at the time the first harvest was removed were as follows: for Stages 1, 2 and 3 the growing points were 5, 10 and 20 cm, respectively, above the soil surface; Stage 4 was 2 weeks after Stage 3. Tillering was affected as follows by these treatments: Climax timothy plants from Stages 1, 3, and 4 showed no increase in thc number of tillers formed between the 1st and 2nd harvests, but increased thereafter. Tillering under Stage 2 increased between the 1st and 2nd harvests, and declined between the 2nd and 3rd. Plants clipped leaving 10‐ vs 4‐cm stubble showed a 30% increase in the number of tillers formed. Tillering was increased significantly (18%) by the high rate of N (112 vs 28 kg/ha). Reed canarygrass plants clipped at Stages 1 and 2 demonstrated an increase in tillers of 2.6 times between the 1st and 3rd harvests. Those clipped at Stage 3 and 4 performed similarly to the above stages between the 1st and 2nd harvests, but showed no increase thereafter. Plants clipped leaving 10‐ vs 4‐cm stubble produced 26% more tillers. No N treatments were applied to reed canarygrass.The number of tillers formed under high day‐night (32–27C) temperatures was less than the number under the 21–15.5C regime for both species. Climax timothy was more susceptible to injury when subjected to the higher temperature. Both species produced more tiller when shaded (40% of full light intensity received) regardless of whether the day‐night temperature was 32–27C or 21–15.5CDry matter production of reed eanarygrass was approximately equal regardless of whether the first harvest was removed at Stage I or Stage 4, or whether the clipping height was 4‐ or 10‐cm. Climax timothy produced less dry matter when the first harvest was removed at the two earlier stages of maturity, but no difference was found between the 4‐ and 10‐cm clipping heights.
Improvement of Seedling Vigor of Smooth Bromegrass (Bromus inermis Leyss.) by Recurrent Selection for High Seed Weight1
Authors: Trupp C. R. , Carlson I. T. 
Published: July 2010

Three polycross populations of smooth bromegrass (Bromus inermis Leyss.) derived by recurrent phenotypic selection for high seed weight averaged higher in seed weight and seedling vigor and lower in fertility index than five check varieties. Selection for high seed weight had little effect on mean performance or variability for traits other than seed weight and seedling vigor. Seed and forage yields were maintained at high levels.In average seed weight over 2 years, the three successive selected populations were, respectivdy, 6, 20, and 30% higher than the mean of two check clones selected to represent the mean of the initial material. Close agreement was obtained between space‐planted and seeded‐row tests for relative seed weight (r = .98). Phenotypic variance for seed weight increased with each successive cycle of selection.Selection for increased seed weight resulted in superior seedling vigor as measured by ability to emerge from a 5‐cm planting depth, weight per seedling, and seedling yield per unit area. The seedling vigor advantage of large‐seeded strains was greatest during early stages of seedling growth. Topcross progenies of 50 plants selected for high seed weight and seed set from cycle 3 were 45% higher in average weight per seedling 1 month after planting in the field than were five check varieties.
Chromosome Numbers, Microsporogenesis, and Mode of Reproduction of Seven Paspalum Species1
Authors: Burson Byron L. , Bennett Hugh W. 
Published: July 2010

SummaryPaspalum pumilum Nees had a chromosome number of 2n = 20. The chromosome number in P. arechavaletae Hack., P. cromyorhizon Trin. ex Doell., P. exaltatum F. & C. Presl, P. guenoarum Arech., and P. lividum Trin. ex Schlecht. was 2n = 40; and in P. mandiocanum Trin. it was 2n = 60. Meiosis was regular in P. pumilum, P. arechavaletae, P. exaltatum, and P. mandiocanum with primarily bivalent pairing. P. cromyorhizon and P. guenoarum had frequent quadrivalents, and meiosis in P. lividum was the most irregular with lagging chromosomes and micronuclei. A study of megasporogenesis and embryo sac development in each species showed that P. pumilum and P. arechavaletae were sexual and the other five species reproduced by apomixis. The type of apomixis was apospory and, with the exception of P. mandiocanum, species were pseudogamous.
Seasonal Nutrient Uptake and Accumulation Patterns in Soybeans1
Authors: Harper James E. 
Published: July 2010

Field hydroponic gravel culture systems were used to determine nutrient uptake and accumulation in soybeans (Glycine max (L.) Merr.). Uptake of N, P, K, Ca, and Mg were low during the first 30 days after emergence. At initial flowering, nutrient uptake increased sharply, reaching maximum uptake rates between full bloom and midpod fill. Uptake of N, P, and K generally declined through later development stages while Ca and Mg uptake remained high or even increased. The difference in uptake patterns of the macronutrients during later development stages appeared to reflect differences in mobility and translocation of the nutrients.Percent N in the total tops gradually declined from the seedling stage and leveled off shortly after full bloom. Phosphorus concentration increased during the first 30 days after emergence, peaked at initial flowering, declined until mid‐pod fill, and leveled off through the remaining sampling dates. Phosphorus toxicity symptoms were evident at initial flowering with the highest nutrient level imposed. Percent K increased slightly from the seedling stage until full bloom and then declined. Calcium concentration increased until initial flowering, then declined and leveled off during later growth stages while the Mg concentration decreased gradually from the seedling stage through the green bean stage. The concentration of micronutrients (Fe, Mn, Zn, Cu, and B) generally declined from the seedling stage through the green bean stage.
Leaf Angles, Leaf Area, and Canopy Photosynthesis1
Authors: Duncan W. G. 
Published: July 2010

For leaf area indices (LAI) of less than approximately 3.0, differences in leaf angle are predicted by computer simulation to have only small effects on canopy photosynthetic rates. For higher LAI values, layers of vertical and horizontal leaves can be arranged to give both the highest and lowest possible rates of canopy photosynthesis for the conditious assumed. These arrangements of leaf layers and angles are not much affected by leaf type or latitude within usual limits.The ratio of highest to lowest photosynthetic rate varied from 1.14 at LAI 3.0 to 2.0 at LAI 10.0. Calculations with one set of corn (Zea mays L.) descriptions indicate that canopy photosynthetic rates may range from 92% of theoretical maximum at LAI 3.0 to 76% at LAI 7.0.
Size and Frequency of Leaf Stomata in Cultivars of Triticum aestivum and Other Triticum Species1
Authors: Teare I. D. , Peterson C. J. , Law A. G. 
Published: July 2010

Lines of Triticum, representing diverse sources of germplasm, were characterized for stomatal frequency. Wheat leaf variation between the first, second, third, and fourth leaves on a tiller, sampling position at the base, center, and tip of each leaf, and sampling position in relation to adaxial or abaxial surface of the leaf were measured.Stomatal frequency was always greater on the adaxial than on the abaxial surface. Mean ratios (abaxial/adaxial) were .748 for the first leaf and .728 for the second leaf on a culm. Frequencies ranged from 9,219 to 6,372 stomata cm‐2 for the adaxial and 8,024 to 3,487 for the abaxial surface of the first leaf. For the second leaf frequencies ranged from 8,875 to 4,597 for the adaxial and 8,172 to 3,487 for the abaxial surface. Stomatal frequency decreased in relation to position of leaf insertion on the culm. The first leaf had the greatest stomatal frequency, the second had the next greatest, and the fourth had the least. The leaf base contained the most, and the tip, the fewest stomata per unit of leaf area.Plants grown on Cercosporella‐inoculated plots had more stomata per unit of leaf area than did those grown on the control plots.No general relation was found between grain yield and number of stomata cm‐2 of leaf surface nor between grain yield and bn (the product of stomata length and stomata per unit of adaxial leaf area).