bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen Consumption Rates Predicted from Respiration, Permeability and Porosity Measurements on Excised Wheat Root Segments1
Authors: Luxmoore R. J. , Stolzy L. H. 
Published: July 2010

Respiration rates were determined at 3.9, 20.8, and 79.9% oxygen concentration for consecutive excised root segments of ‘Ramona,’ ‘Inia,’ and ‘Yecora’ wheat (Triticum aestivum (L.) em Thell.). From these data, the maximum respiration rate, the O2 concentration at which respiration was half of the maximum rate, and the root permeability to O2 were derived for segments up to 9 cm from the root tip. The gas filled porosity of each segment was measured by the pycnometer method.Maximum respiration rate and permeability decreased with distance from the root tip to a relatively constant value at 2 to 3 cm from the tip, whereas root porosity increased to a maximum value of about 10% at 3 cm from the root tip. The O2 concentration for half maximal respiration rate was about 10% for root segments of Ramona and Inia cultivars and about 7% for Yecora. The data for Yecora were more variable than for the others.These root characteristics were used in a model of root O2 relations to obtain estimates of mean respiration rate of wheat roots under simulated field conditions at three soil temperatures. Mean root O2 consumption rate decreased with increase in root length to a relatively constant value for roots longer than 50 cm. Under well aerated conditions, O2 consumption rates were higher for roots with smaller radii, whereas with flooded conditions respiration rates increased with root radii. Predicted mean respiration rate was higher with increase in soil temperature.
Estimates of Genetic Effects of Heading Date, Plant Height, and Grain Yield in Durum Wheat1
Authors: Amaya A. Arnoldo , Busch R. H. , Lebsock K. L. 
Published: July 2010

A weighted least squares analysis of parental, F1, bulk F2 and F3, B1C, and B2C means was used to estimate genetic effects of plant height, heading date, and grain yield in four crosses of durum wheat (Triticum durum Desf.). F3 lines from randomly harvested F2 plants from each cross were included in replicated tests in three of four environments.The F1 hybrids exceeded their high‐yielding parents by an average of about 25% in grain yield; expression of heterosis, however, varied widely among the environments. Heterosis was of less magnitude in the expression of plant height and heading date.Dominance genetic effects ĥ were relatively more important than additive effects (d̂) in the inheritance of grain yield. Additive genetic effects predominated in the expression of plant height and heading date. Epistatic effects were detected in some crosses when analyzed in individual environments, but these effects were not detected for grain yield and heading date when data were combined over all environments.Some F3 lines from all crosses were not significantly different from their corresponding F1's in grain yield and more desirable than the F1's in heading date (earlier) and plant height (shorter).
Crosses between Hordeum Jubatum L. and Taeniatherum Asperum (Sim.) Nevski to Determine Genomic Relationships
Authors: Schooler A.B. , Bell A.R. , Nalewaja John D. 
Published: July 2010

Fl hybrids were obtained from crosses between Hordeum jubatum L. (2n=28) and Taeniatherum asperum (Sim.) Nevski (2n=14). The F1 hybrids had a chromosome complement of 2n=21 and were self‐sterile. Chromosome behavior was irregular in microsporocytes of the hybrids examined. Chromosome doubling was induced in Fl hybrids by colchicine treatment and partially selffertile amphiploid intergeneric hybrids (2n=42) were produced. Cytological observations showed many micronuclei in the microspores which resulted from chromosome fragmentation during meiosis II.The F1 intergeneric hybrids and amphiploid resembled the Hordeum parent more closely than Taeniatherum but were smaller than either parent in most morphological characteristics. There was only slight evidence of a genome relationship between the two genera.
A Path Coefficient Analysis of Some Yield Component Interrelations in Field Beans (Phaseolus vulgaris L.)1
Authors: Duarte Rodrigo A. , Adams M. W. 
Published: July 2010

A path‐coefficient analysis was performed in field beans of the direct and indirect effects of leaf number and leaf size upon number of pods per plant, number of seeds per pod, and seed weight, and of the latter components upon yield. The data on which the analysis was based were obtained from F3 and F4 families in a recurrent selection experiment grown at three locations. Selection had been practiced for each component separately, at three levels of expression (high, modal, low), in sub‐populations maintained at each of the three locations.The chief findings were: 1) Pods/plants exerts a preponderant effect upon yield in every set of families studied.2)In families where selection had produced divergent types with respect to seed number per pod, and seed weight, these components also assumed major roles in determining yield.3) Leaf number was highly associated with pod number per plant and leaf size was highly associated with seed size in families selected for high, modal, and low levels of expression of the two leaf area components.Interpretations of these findings are given, based first on a common genetic program regulating the number of main stem internodes, and secondly on another genetic program regulating leaf cell number and/or rate of expansion. The rationale connecting these fundamental characteristics with the first‐ and second‐order yield components is given.
Effects of Mass Selection and Irradiation in Corn Measured by Random S1 Lines and Their Testcrosses1
Authors: Harris R. E. , Gardner C. O. , Compton W. A. 
Published: July 2010

Two populations of corn (Zea mays L.) improved by nine cycles of mass selection for yield and the unselected parent variety, ‘Hays Golden,’ were evaluated in 1969 and 1970 using random S1 lines and their testcrosses to related and unrelated single‐cross testers. One selected population received thermal neutron seed treatment prior to the first and third selection cycles.S1 lines of the selected populations, per se and in testcrosses, demonstrated significant superiority in mean yield over lines of the parent variety in each year. Like progenies of the two selected populations produced similar yields. Selection evidently eliminated radiation‐induced deleterious mutants from the “irradiated” population while increasing frequencies of favorable yield genes common to both selected populations. This apparently produced similar germ plasm reservoirs much more suitable for the extraction of superior inbred lines than the parent variety. Indications are that selection also reduced genetic variability in yield and combining ability.Prolificacy resulting from selection for yield was evident in S1 lines but not in the testcrosses. Since inbreeding did not reduce prolificacy in the selected populations, results are interpreted to mean that tester genes masked recessive genes which induce prolific potential when homozygous. All phenotypic correlations between S1 and testcross yields were too low to be of much predictive value; but in general, lines of the selected populations exhibited the least correlation with their testcrosses. Genetic correlations were somewhat higher, indicating sizeable environmental fluctuations in individual experiments. We postulate that non‐prolific testers by inhibiting prolificacy in turn limit the expression of genes controlling yield in these populations. Use of a prolific tester might have provided greater yield differentiation, more precise estimates of line genotypes and higher correlations between S1 and testcross progenies.
A Maize Breeding Methods Study in Kenya1
Authors: Darrah L. L. , Eberhart S. A. , Penny L. H. 
Published: July 2010

Four years of reciprocal recurrent selection has produced rapid improvement in one of the parental varieties (‘Ecuador 573’), in the variety cross, and in a commercial topcross maize (Zea mays L.) hybrid. The improved strain of Ecuador 573 is now used as the male parent of the current commercial hybrids, ‘H611C’ and ‘H613C,’ and they yield approximately 25% more than the original versions.Estimates obtained from seven years of the selection trials showed no changes in genetic variances for yield. Hence, this rate of improvement is not expected to change in the near future. Progress from modified ear‐to‐row selection was greater in the introduced Ecuador 573 variety and in KCA, (‘Kitale II’ ✕ Ecuador 573)syn‐4, than in the local Kitale II variety. No improvement was detected in KCA from mass selection. An increased number of ears per plant was associated with yield improvement by reciprocal recurrent selection and modified ear‐to‐row selection. Selection for lodging resistance and blight resistance in the breeding nurseries resulted in slight improvements in the varieties under reciprocal recurrent selection and in the variety cross. Greater attention to ear height and lodging resistance is required to reduce harvesting losses in the commercial maize crop in Kenya.
Effects of Herbicides Applied Postemergence on Weeds and Sunflowers1
Authors: Johnson B. J. 
Published: July 2010

Herbicides were applied as postemergence treatments either as early over‐the‐top spray or late‐directed spray to sunflowers (Helianthus annuus L.) for weed control and crop tolerance determinations at Experiment, Ga. Treatments of RP 17623 (2‐tertiobutyl‐4‐(2,4‐dichloro‐5‐ isopropyloxyphenyl)‐5‐oxo‐l,3,4‐oxadiazoline) were applied to sunflowers in the cotyledon, first leaf, and second leaf growth stages. Several herbicides commonly used on other crops were applied late postemergence directed spray to sunflowers when they were 25 to 35 cm tall.were obtained from early postemergence treatments of RP 17623 when applied as over‐the‐top spray at either the cotyledon or the first‐leaf stage of sunflower growth. Weed control results were similar to RP 17623 from several herbicides that were applied as late‐directed postemergence sprays. Early postmergence treatments with RP 17623 caused some early injury to sunflower plants and a reduction in achene oil percent when compared with achenes from untreated plants, but achene yields were not reduced. None of the herbicides applied as late‐directed postemergence sprays injured sunflowers, reduced achene yield, or achene oil percent.
Chromosome and Genetic Constancy in a Poa pratensis L. Cultivar1
Authors: Wilton A. C. , Wiseman E. , Murray J. J. 
Published: July 2010

Chromosome numbers were determined on genetically identifiable plants to evaluate chromosomal and genetic constancy of the ‘Windsor’ cultivar of the facultative apomict Poa pratensis L. Seed size, seedling pigmentation, and chromosome number were interrelated in most plants but varied within the cultivar.Large seeds produced 93% pigmented seedlings, of which 84% had 70 chromosomes. Small seeds produced 86% nonpigmented seedlings, of which 94% had 49 chromosomes. Although the cultivar consisted largely of these two relatively stable components, chromosome numbers varied among plants with inverse associations of seed size and seedling pigmentation. Throughout the experiment the following chromosome numbers were found: 35, 49, 56, 60's, 70's, 80's, and 105. A set of twin plants occurred, with one member with 49 chromosomes and the other with 74 chromosomes. The wide range of chromosome numbers was accounted for on the basis of classical explanations of agamospermy in facultative apomicts.
Downy Mildew Resistance in Cultivated Sunflower and Its Inheritance1
Authors: Zimmer D.E. , Kinman M.L. 
Published: July 2010

Resistance in sunflower (Helianthus annuus L.) to the widely virulent Red River race of downy mildew, incited by Plasmopara halstedii (Farl.) Berl. et de Toni, was discovered in three inbred lines selected from the cross 953‐88‐3 ✕ ‘Armavirsky 2497.’ All other breeding lines, sunflower introductions, and varieties, including AD 66, CM 90RR, and S‐37‐388RR, which were reported to be resistant in tests in Romania and France, were susceptible. The failure of the breeding lines AD 66, CM 90RR, and S‐37‐388RR to respond the same to downy mildew in our trials as they did in Europe indicates the existence of pathogenic races.Resistance to the Red River race found in HA 61, one of the three resistant lines, is due to a single dominant gene that we have designated Pl2. The Pl2 gene is inherited independently of the gene presumed to be Ra which conditions rust resistance of HA 61. The Pl2 gene is probably synonymous to one of the genes reported to condition resistance of HA 61 to downy mildew in France.
Estimated Gains from Selection for Protein and Yield in the F4 Generation of Six Soybean Populations1
Authors: Shannon J. G. , Wilcox J. R. , Probst A. H. 
Published: July 2010

Seventy‐eight F2‐derived F4 lines from each of six soybean [Glycine max (L.) Merr.] populations were evaluated to determine which population had the best potential for improving yield, protein, and yield and protein in combination. The six populations, one high protein ✕ high protein, four high protein ✕ high yield, and one high yield ✕ high yield, were derived from diallel crosses among two adapted high‐protein (P1 and P2) and two adapted high‐yield parents (Y1 and Y2).P1P2 contained more lines high in percent protein and in protein per hectare, contained more lines that combined high protein with high yield, showed the greatest expected advances for yield and protein per hectare, was exceeded only by P1Y2 for predicted progress in percent protein, and was the only population in which expected advance exceeded parental means for percent protein and protein per hectare. Its highest‐yielding lines, however, were below the highest lines in other populations, particularly P1Y1 and P2Y2.Genotypic and phenotypic correlation coefficients were computed among yield, percent protein, and percent oil. Highly significant negative correlations were observed for protein and oil in all six populations. Correlations between yield and percent oil were positive, but significant in only two populations. Significant coefficients between yield and percent protein were negative in P1P2 and P2Y2 and positive in Y1Y2.
Carbohydrates in Grasses: V. Incorporation of 14C into Plant Parts and Nonstructural Carbohydrates of Timothy (Phleum pratense L.) at Three Developmental Stages1
Authors: Balasko J. A. , Smith Dale 
Published: July 2010

Distribution of photosynthates in forage grasses is important in terms of yield, quality, and persistence. The objectives of this study were to learn more about the distribution of 14C fed to timothy (Phleum pratense L.) at different growth stages and to follow its incorporation into nonstructural carbohydrates of stem bases. Plants at three developmental stages — initiation of stem elongation, ear emergence, and anthesis N were exposed to 14CO2. Plants were harvested at 1, 3, 8, 32, and 168 hr following exposure. Specific activity of 14C in leaf blades, leaf sheaths, inflorescences, stems, stem bases, roots, and yellow leaves was measured. Radioactivity in each plant part was calculated and expressed as a percentage of total plant radioactivity.One week following exposure to 14CO2 at initiation of stem elongation, roots and leaves were primary recipients of 14C. At ear emergence stems and inflorescences were major sinks. One week following feeding at anthesis, stems and roots contained 73% of the total plant 14C. At initiation of stem elongation, very little 14C was incorporated into the fructosan fraction of the stem bases, whereas at ear emergence and anthesis, labelled fructosan was more abundant. Major storage of fructosan took place after most meristematic sinks were satisfied.
Relationship Between Decarboxylation of Glutamic Acid and Vigor in Soybean Seed1
Authors: Abdul‐Baki Aref A. , Anderson James D. 
Published: July 2010

The relationship between seed vigor and decarboxylation of glutamic acid in 16 lots of soybean (Glycine max L. cv. Lee‐68) was determined (i) manometrically by incubating ground seeds in 75 mM solutions of glutamic acid at pH 5.2 and measuring CO2 production, and (ii) isotopically by incubating excised embryonic axes in 1 mM glutamic acid‐1‐14C (0.3 µCi/ml) and measuring 14CO2. Both methods agree in that decarboxylation of glutamic acid, presumably by glutamic decarboxylase, was high in both the low‐ and high‐vigor lots. The high decarboxylation of glutamic acid in dry soybean seeds and the low content of glutamic acid in either the imbibed or nonimbibed seed suggest that glutamic acid concentration limits the decarboxylation rate during imbibition. Comparison of total CO2 produced by whole seeds or seed parts (axes and cotyledons) during early germination with that estimated from glutamic acid decarboxylation suggests that CO2 production by the tissues via glutamic acid decarboxylation accounts for only a small portion of the CO2 produced by the seeds.Vigor of the soybean lots is highly correlated with the ability of the excised embryonic axes to incorporate glutamic acid into water‐soluble protein and maintain a relatively high rate of respiration. The decreased 02 uptake and CO2 production by the low‐vigor lots, pronounced in the axes and negligible in cotyledons, suggests that a search for biochemical indices to measure seed vigor should be focused on embryonic axes rather than on whole seeds.
Cross‐Fertilization of Alfalfa as Affected by Genetic Markers, Planting Methods, Locations, and Pollinator Species1
Authors: Kehr W. R. 
Published: July 2010

Studies were made to determine the extent of crossfertilization of alfalfa, Medicago sativa L., involving genetic markers, planting methods, locations, field cages and isolations, pollinator species, and their interactions. Crossing between alfalfa populations by honeybees, as measured in white‐ and yellow‐flowered populations, varied from 32 to 96%. The average crossing in noninbred populations was about 50%.Crossing percentages were similar for alternate row and alternate plant methods of planting in Idaho and Nebraska and for a yellow‐flowered population in California. However, crossing percentages were significantly higher with the alternate plant method than with the alternate row method of planting for a white‐flowered population in both caged and uncaged areas in California and for another white‐flowered population in California cages.Crossing percentages were similar in caged and uncaged isolations in Nebraska. Honeybee pollination in California and leafcutter bee pollination in Idaho resulted in 50.5 and 51.0% cross‐fertilization, respectively, averaged over kinds of field isolation, planting methods, and markers used at both locations.
Combining Ability and Gene Action Estimates in an Eight Parent Diallel Cross of Sugarbeet1
Authors: Smith G. A. , Hecker R. J. , Maag G. W. , Rasmuson D. M. 
Published: July 2010

Twenty‐eight F1 hybrids from an eight parent diallel cross grown at two nitrogen fertility levels were analyzed for type of gene action controlling 11 sugarbeet (Beta vulgaris L.) characters. Nonadditive genetic variance was of prime importance in controlling root weight under low and high nitrogen levels, accounting for 51% and 68% of the total genetic variance, respectively. For recoverable sugar, nonadditive genetic variance accounted for 67% and 83% of the total genetic variance under low and high nitrogen. Additive genetic variance accounted for most of the genetic variance for sucrose percentage and root/shoot ratio. Both additive and nonadditive genetic variance were significant for percent thin juice purity, but only at the high nitrogen fertility level.Additive genetic variance was predominant for six nonsucrose components of purified juice. In addition, significant amounts of nonadditive gene action were found for all six nonsucrose components at one or both nitrogen levels. Betaine was the least affected by change in nitrogen of all the characters measured.
Black Layer Maturity and Filling Period Variation Among Inbred Lines of Corn (Zea mays L.)1
Authors: Carter M. W. , Poneleit C. G. 
Published: July 2010

Kernels of 20 corn (Zea mays L.) inbred lines were examined for 3 years to determine variation for black layer maturity, filling period, and associated characters. The color of the black layer and the rate at which it developed at maturity varied among the inbreds. For each inbred, the black layer was observed at a time that was coincident with the observed maximum dry weight accumulation. Moisture content at the time of black layer maturity varied among the inbreds from 15.4 to 35.0%. Differences among inbreds were significant but year means did not differ. There was a significant year ✕ inbred interaction.The growing degree days required to reach black layer maturity varied from 1337 to 1808 and the growing degree days required for kernel filling varied from 512 to 821. Year differences were significant; however, interaction of inbreds with years was found to be minor. The variability among inbreds was always much greater than among years. The growing degree days required for the filling period had positive phenotypic and genotypic correlations with the growing degree days required from planting to pollination, but the correlations were small enough to suggest possible selection for types with long filling periods and short time to pollination. The rate of kernel dry weight accumulation during the filling period was significantly different among inbreds and years but had a significant inbred ✕ year interaction. The rate of kernel dry weight accumulation was not correlated with any character other than dry weight at black layer maturity.
Quick Test for Reed Canarygrass (Phalaris arundinacea L.) Alkaloid Concentration1
Authors: Frelich J. R. , Marten G. C. 
Published: July 2010

We modified a generalized, plant‐alkaloid screening procedure to provide a quick, semiquantitative test for concenrtation of total basic alkaloids in reed canarygrass (Phalaris arundinacea L.). The test is based upon ocular assessment of discernible differences in turbidity or precipitates produced by silicotungstic acid added to plant extracts. The extracts are prepared by macerating frozen grass in ammoniacal chloroform and then by partitioning into 2 N H2SO4.Alkaloid concentrations determined by a summation of readings over five dilutions using the quick test were highly correlated (r = 0.94, P ≤ .01) with concentrations determined by the quantitative laboratory test of Simons and Marten (1971). The quick test is about four times faster than the Simons and Marten test and should enable plant breeders to select low‐alkaloid plants or alkaloid‐free plants among large numbers of genotypes.
Bloat Investigations: Determination of Soluble Protein Concentration in Alfalfa1
Authors: Howarth R. E. , McArthur J. M. , Goplen B. P. 
Published: July 2010

A rapid, reliable method for the determination of soluble protein concentration in alfalfa was developed for use in studies on the bloat potential of alfalfa (Medicago sativa L.) and in breeding a low bloat‐causing alfalfa cultivar. A two‐step extraction procedure was used to obtain a crude aqueous extract. The colorimetric, biuret method for protein determination was modified by taking absorbance readings at two wavelengths (550 and 708 nm) to correct for interference by colored substances in the alfalfa extract.By this method the soluble protein concentration in fresh alfalfa was 50 to 70% of crude protein concentration. The correlation (r = 0.36) between soluble and crude protein was low (p > 0.05). The coefficient variation for soluble protein concentration was 10.5% in a population of 289 plants of diverse genetic origin, indicating the possibility of selecting for low soluble protein concentration as a means of developing a low bloatcausing alfalfa cultivar.