bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recurrent Selection for Lint Percent within a Cultivar of Cotton (Gossypium hirsutum L.)1
Authors: Meredith William R. , Bridge R. R. 
Published: July 2010

We conducted this study to determine if a modified form of recurrent selection for lint percent within a cotton (Gossypium hirsutum L.) cultivar, ‘Deltapine 523,’ could improve lint yield. Three cycles of selection, beginning in 1965, were completed, with selection for lint percent being practiced first on a plant basis and then on a progeny‐row basis. Plant populations of 430, 828, and 800 plants were used to initiate the S1, S2, and S3 populations, respectively. From each population, 16 progenies were ultimately selected on the basis of high lint percent, and 8 crosses were made among them to initiate the next cycle. In each cycle, an equal number of seeds from each of the 16 selections were combined to form the bulk populations tested in 1971. Eight progenies selected in the S3 for higher 2.5% span length were bulked and designated as the S3L. population.In 1971, Deltapine 523 (S0) and the four selected populations were grown in replicated experiments at four locations. Mean lint precent was 33.8, 35.4, 36.6, 38.0, and 37.1 for the S0, S1, S2, S3, and S3L. populations, respectively. The S2, S3, and S3L populations produced significantly greater lint yield than did S0 and S1. As lint percent was increased by selection, there were concurrent decreases in seed index and 50 and 2.5% span length. Selection for fiber length in the S3 population restored most of the fiber length previously lost. As lint percent was increased by selection, there were simultaneous increases in lint index, seeds per boll, and Micronaire. No consistent trend or change was observed for boll size, number of bolls per plot, fiber strength, and fiber elongation. The primary cause of the increase in lint yield resulting from selection for lint percent was the association of lint percent with increased number of seeds per boll and higher lint index.The genetic variability for lint percent within the S1 and S2 populations was found to be 188 and 83%, respectively, as compared to that of the S0 population. The genetic variability for an unselected trait, boll size, was similar, with the S1 and S2 populations expressing 233 and 186%, respectively, as much variability as that of the S0 population.
Symbiotic Nitrogen Fixation in Soybeans. I. Effect of Photosynthetic Source‐Sink Manipulations1
Authors: Lawn R. J. , Brun William A. 
Published: July 2010

Symbiotic nitrogen fixation of two field grown soybean [Glycine max (L.) Merr.] varieties, ‘Chippewa 64’ and ‘Clay,’ was measured at 7 to 10 day intervals starting at flowering, using the acetylene reduction assay. At he end of flowering, treatments were applied which were designed to alter the relationship between the photosynthetic source and sink components in the plants. The treatments were supplemental light, 25% shade, 50% depodding, 60% defoliation, and control.Total acetylene reduction activity per plant increased in both varieties during the flowering period, reached a maximum near the end of flowering, and then declined markedly during the early podfilling stage. The activity decline was due to a decline in the specific activity of the nodules, and occurred immediately prior to the time when the growth rate of the pods (including seed) exceeded that of the total plant tops in the respective varieties. Treatments designed to enhance he photosynthetic source/sink ratio (supplemental light and depodding) maintained nodule activity well above the control in both varieties. Conversely, treatments designed to reduce the source/sink ratio (shading and defoliation) decreased nodule activity below the level of the control. Treatment effects on total plant protein recovered at maturity closely reflected the treatment effects on total nodule activity. The results of this study are interpreted as evidence that symbiotic nitrogen fixation in these varieties declined during podfilling as the result of inadequate assimilate supply to the nodules.
Symbiotic Nitrogen Fixation in Soybeans. III. Effect of Supplemental Nitrogen and Intervarietal Grafting1
Authors: Lawn R.J. , Brun William A. 
Published: July 2010

Two field experiments were conducted to determine the effect of 1) grafting onto root genotypes with different nitrogen fixation rates, and 2) supplemental nitrogen applied at the time of declining nodule activity (end of flowering), on nodulation, seed yield, and protein yield of ‘Chippewa 64’ and ‘Clay’ soybeans (Glycine max (L.) Merr.). The experiments were conducted in situations of low available soil nitrogen to ensure a strong reliance on symbiotic nitrogen fixation. In the first study, seedling shoots of both varieties were grafted onto four roofstocks: ‘Wayne’, ‘Altona’, Chippewa 64 and Clay.Differences were evident among root genotypes, independent of shoot genotype, for acetylene reduction activity per plant, but not for nodule fresh weight. for Chippewa 64 shoots, seed yield and seed protein content were significantly altered by grafting onto other rootstocks, whereas for Clay shoots only seed protein content was significantly changed from that of the selfgrafted controls. The effects of the root genotypes on seed yield were related in part to the respective differences in ability to support nitrogen fixation.In the second study, supplemental nitrogen (0, 224, and 448 kg per ha) was applied as ammonium nitrate at the end of flowering to Chippewa 64 and Clay soybeans. The application of nitrogen caused a decline in acetylene reduction activity for both varieties. Seed yield and seed protein content for Clay, and seed protein content and vegetative protein yield for Chippewa 64, were all increased by the application of nitrogen.
Recurrent Selection for Seedling Vigor in Birdsfoot Trefoil1
Authors: Twamley B. E. 
Published: July 2010

In 1969, a program of recurrent selection for seedling vigor in ‘Leo’ birdsfoot trefoil (Lotus corniculatus L.) was initiated. Seed for all tests was garnered from openpollination nurseries, small‐seeded lines were discarded, and seedling vigor tests were conducted indoors on the remainder. In each cycle the most vigorous seedlings from the most vigorous lines were selected to be the parents of the next cycle. Three cycles were completed. In 1972, nursery material representing cycles 0, 1, 2, and 3 was established and harvested for seed.Three types of experiments were used to evaluate progress: 1) random seed samples from each cycle were bulked within cycles to provide four treatments, including the check; 2) pedigree test—18 lines from each cycle, randomly chosen from within seed weight classes, were tested; and 3) a series of routine tests were used primarily to identify superior lines. In these routine tests only lines that were at least average in seed size were included.In the bulk test the percentage improvement in seedling vigor for cycles 1, 2, and 3 over the cydc 0, or Leo population, was 10, 34, and 40%, respectively. For the pedigree test it was 20, 36, and 36%. For four routine tests the average improvement was 30, 47, and 52%. The average improvement in seed size was 36%. Inbreeding and a relaxation of selection pressure were considered responsible for the lack of progress in cycle 3 compared to cycle 2.Possible uses of seedling vigor tests to provide information on breeding methods are discussed.
Ozone Damage to Wheat Varieties at Anthesis1
Authors: Shannon J. G. , Mulchi C. L. 
Published: July 2010

Two wheat (Triticum aestivum L.) cultivars, ‘Arthur 71’ and ‘Blueboy,’ were exposed to 0.2 ppm ozone at anthesis for 4 hours/day for a week in a growth chamber. Yields were reduced by about 30 and 23% for Arthur '71 and Blueboy, respectively. However, the reduction for Blueboy was not statistically significant. Reductions in seed per plant and seed per head were not significantly different in the ozone treatment as compared to the controls.Cultivars did not always respond in the same way to ozone for the characteristics studied. Ozone only slightly reduced kernel weight in Blueboy as compared to a significant, 17.4% reduction for Arthur '71; however, seed set was significantly reduced by 22.1% in Blueboy compared to 8.3% for Arthur '71. Since the ozone levels used in this experiment are often attained in fields near urban areas, the responses to ozone for wheat yield and yield components for the varieties studied should be comparable to actual field conditions.
Genetic Effects for Mean Yield and for Yield Responses to Environments in Three‐Way and Single‐Cross Hybrids of Grain Sorghum1
Authors: Patanothai Aran , Atkins R. E. 
Published: July 2010

Grain yields of three‐way and single‐cross hybrids of sorghum (Sorghum bicolor L. Moench) were obtained from experiments grown in nine environments in Iowa during 1969 through 1971. The purpose of the study was to obtain, estimates of the relative impact of various types of geneuc effects on mean grain yield and on stability of yield over environments. Analyses of the data indicated that differences among the entries for mean yield were ascribable to both additive and dominant gene effects. Variations among parameters that describe stability of yield over environments could be attributed largely to additive gene action. Significant epistatic effects were not indicated for the expression of either mean yield or stability of yield.A second objective of the study was to compare observed and predicted values for grain yield and yield stability of the three‐way crosses. Relative effectiveness of five prediction methods generally was in accord with significance of the genetic effects included in the prediction equation. The method analagous to Jenkins's Method B (J. Amer. Soc. Agron. 26:199–204, 1926) for predicting the yield of a double cross seemed preferable to the other methods because of its simplicity and its suitability for use with any set of crosses.
Effect of an Alien Cytoplasm and Fertility Restoring Factor on Growth, Agronomic Characters, and Chemical Constituents in a Male‐Sterile Variety of Flue‐Cured Tobacco1
Authors: Hosfield George L. , Wernsman Earl A. 
Published: July 2010

Experiments conducted with cytoplasmic male‐sterile lines of flue‐cured tobacco (Nicotiana tabacum L.) have shown that male‐sterile inducing cytoplasms can adversely affect plant growth rate and agronomic characters.In the present study isogenic lines of a cytoplasmic male sterile and two fertility‐restored male steriles (N. suavveolens Leh. cytoplasm) were compared with normal fertile tobacco to determine the effect of fertility restoration on growth rate, agronomic performance, and chemical characteristics. The two fertility‐restored tobacco lines possessed N. suaveolens cytoplasm and were homozygous and heterozygous, respectively, for a chromosomal segment from N. suaveolens marked by a factor for fertility restoration.The N. suaveolens cytoplasm exerted a retarding effect on growth rate, causing plants to be taller, to mature later, and to produce more leaves. Nevertheless, the effect of the cytoplasm per se did not cause yield or quality reductions in cured leaf.Genetic activity associated with the N. suaveolens chromosomal segments in the fertility‐restored lines overcame some of the suppressing effects of the cytoplasm on growth rate, yet their final productivity was inferior to the male sterile and normal fertile control. A dosage effect of the introgressed chromosomal segment was evident since the fertility‐restored heterozygote deviated less from the control than the homozygote.Differences among treatments for chemical constituents in cured leaf were minimal, although all entries with N. suaveolens cytoplasm had lower quantities of reducing sugars and the fertility‐restored lines exhibited a twofold increase in nornicotine over the control.
Breeding Root‐Knot‐Resistant Gossypium hirsutum L. Using a Resistant Wild G. barbadense L.1
Authors: Shepherd Raymond L. 
Published: July 2010

Three screening techniques for resistance to the rootknot nematode (Meloidogyne incognita acrita Chitwood & Oteifa 1952) were compared. These were agar, infested soil, and disinfected larvae. The latter was the most effective in differentiating between resistant and susceptible entries.Using the disinfected larval technique, 173 BC3F5 families were screened for resistance. These were from Gossypium hirsutum L. ✕ a wild, root‐knot‐resistant G. barbadense L., followed by three backcrosses to G. hirsutum. In the order of backcrossing, backcross parents were Z106 (a doubled haploid), var. ‘Empire,’ and var. ‘Auburn 56.’ The first two backcross parents were highly susceptible, and the last was moderately resistant to M. incognita acrita. Pedigree‐selection, recurrent‐selection, and progeny‐testing procedures were followed. Three lines (S3, S22, S28), intermediate in resistance between Auburn 56 and G. barbadense, were developed. These lines represented signficant progress in breeding G. hirsutum with a higher level of resistance to M. incognita acrita than presently grown varieties.
Influence of Drought on Tillering and Internode Number and Length in Alfalfa1
Authors: Perry L. J. , Larson K. L. 
Published: July 2010

‘Vernal’ and ‘Sonora’ alfalfa (Medicago sativa L.) plants were grown from seed in the greenhouse under two soil water levels, 49 and 100% field capacity as defined. Vegetation of the primary growth was harvested at the vegetative, 5 to 10% bloom, and seed pod stages. Top growth was again harvested when the regrowth was at 5 to 10% bloom. ‘Travois’ and ‘Lahontan’ were included in a subsequent experiment and were harvested only at the 5 to 10% bloom stage of the primary and recovery growth.Stem number per plant, number of internodes per stem, and individual internode length of the primary stem were greatly reduced by water deficits (49% field capacity) for all cultivars at each harvest. The cold‐hardy cultivars, Travois and Vernal, had significantly more internodes per stem under both soil water levels than the nonhardy cultivars, Lahontan and Sonora. Length of the internode between the unifoliolate and first trifoliolate leaves on the primary stem of Travois and Vernal under both soil water levels was significantly less than that of Lahontan and Sonora. The pattern of morphological differences among hardy and nonhardy cultivars was the same with or without drought stress.
Relationship of Protein Percent with other Phenotypic Characters in Interspecific Oat Crosses1
Authors: Spilde LeRoy A. , Albrechtsen R. S. , Rumbaugh M. D. 
Published: July 2010

Protein percentage and its relationship with 15 other agronomic characteristics were studied in F5 generation progenies of F4 plants from crosses between Avena sterilis L. Var. Maxima Perez Lara and five A. sativa L. cultivars in an attempt to determine the relationships among factors involved in the improvement of oat quality. Mean percent protein of the progenies was intermediate between their parents. Transgressive segregation was present for both percent protein and yield in four crosses. The possibility of simultaneous improvement of these characteristics is suggested.Simple correlation coefficients indicated percent protein was positively associated (P<.01) with characters typical of A. sterilis. Regression analysis indicated yield had the most influence on percent protein of the characters studied.
Influence of Sorghum Seed Weight on the Performance of the Resulting Crop1
Authors: Suh Hyoung W. , Casady A. J. , Vanderlip R. L. 
Published: July 2010

Crops grown in 1971 and 1972 from sorghum [Sorghum bicolor (L.) Moench] seed of two different weights were compared to determine the influence of seed weight on the resulting crop. The lighter seed weighed about 86% as much as the heavier seed. Genetic differences were essentially eliminated and quality differences minimized between the two seed weights.Characteristics of the crops studied were emergence percentage; seedling weight; days to 50y0 bloom; leaf blade width, length, and area; culm diameter; plant height; number of nodes; test weight; kernel weight; kernels per panicle; panicles per plant; and grain yield. Except for a difference of 0.03 cm in culm diameter in 1971 and a difference of 0.6% in emergence in 1972, the crops from the two seed weights did not differ significantly for the characteristics studied.
Influence of Herbicides on Root Rot in Processing Peas1
Authors: Harvey R. G. , Hagedorn D. J. , DeLoughery R. L. 
Published: July 2010

The interaction between eight herbicides and the susceptibility of processing peas (Pisum sativum L.) to common root rot was studied under field, greenhouse, and laboratory conditions. In the field, methyl bromide fumigant was applied in a split‐plot design in order to provide pathogen‐free reference treatments. None of the following herbicides increased susceptibility to common root rot: atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine], cyanazine {2‐[4‐chloro‐6‐(ethylamino)‐ s‐triazin‐2‐yl]amino‐2‐methylpropionitrile}, dalapon (2, 2‐ dichloropropionic acid), dinoseb (2‐sec butyl‐4, 6‐dinitrophenol), EPTC (S‐ethyl dipropylthiocarbamate), MCPB {4‐[(4‐chloro‐o‐toly)oxy]butyric acid}, propachlor (2‐ chloro‐N‐isopropylacetanilide). However, trifluralin (α, α,α‐trifuoro‐2, 6‐dinitro‐N,N‐dipropyl‐p‐toluidine) appeared to reduce the disease injury.When peas were planted in pathogen infested soil in 1973, trifluralin at 0.56 kg/ha followed by 5.6 kg/ha of propachlor increased shelled pea yields 29% above that of controls. Higher trifluralin rates did not improve yields, but did reduce root rot symptoms. Methyl bromide fumigation increased pea stands, but reduced yield of shelled peas. In the greenhouse trifluralin at rates of 1.12 kg/ha or more, resulted in nearly complete prevention of root rot in peas. The 0.56 kg/ha rate provided partial control. In culture, trifluralin at 10 mg or more per liter of medium, reduced mycelial growth and zoospore production of Aphanomyces euteiches, but had no effect on the fungus at rates similar to those used in the field applications.
Effects of Daylength and Temperature on Soybean Development1
Authors: Major D. J. , Johnson D. R. , Tanner J. W. , Anderson I. C. 
Published: July 2010

Dates of emergence, flowering, beginning pod fill, termination of flowering, and physiological maturity were recorded for two soybean [Glycine max (L.) Merr.] cultivars from each of the maturity groups I to V. The cultivars were planted in five dates at three Missouri locations in 1971–73; at weekly intervals from April to August at Columbia, Mo., in 1972 and 1973; and at weekly intervals from May to July at Ames, Iowa and Elora, Ont. in 1973. An iterative regression analysis (IRA) technique was used to develop mathematical equations relating the rate of development to daylength and temperature. The IRA equations predicted development more accurately than calendar days or “growing degree days” at all of the locations studied.The IRA equations were also used to assess the relative effects of daylength and temperature on soybean development. Cooler temperatures and longer daylengths encountered at northern latitudes were additive in their delaying effects on flowering. The effects of cool spring temperatures on flowering predominated in the early part of the season whereas daylength predominated in plantings after June 1. Hastening effects of short days on maturity were greater than delaying effects of cool autumn temperatures. The most obvious difference among genotypes was found for sensitivity to daylength in the flowering period; later maturing cultivars were more sensitive than early cultivars.
Aflatoxin Production in Aspergillus flavus Inoculated Ears of Corn Grown at Diverse Locations
Authors: Lillehoj E. B. , Kwolek W. F. , Vandegraft E. E. , Zuber M. S. , Calvert O. H. , Widstrom N. , Futrell M. C. , Bockholt A. J. 
Published: July 2010

Normal and opaque‐2 endosperm counterparts of two Zea mays L. hybrids were grown during 1973 at locations in Illinois, Missouri, Georgia, and Texas; 20 days after silking test ears were inoculated with Aspergillus flavus Link ex Fr. spores. Other ears were mechanically damaged or untreated. Sample ears were harvested 15, 30, 45, and 70 days after treatment. After shelling the corn was ground, examined for bright‐greenish yellow (BGY) fluorescence, and assayed for aflatoxin. The number of aflatoxin‐positives in 128 inoculated ears/plot increased generally from North to South: Illinois, 28; Missouri, 86; Texas, 111; and Georgia, 117. The mean levels of aflatoxin B1 in toxin‐contaminated ears showed a similar geographical pattern: Illinois, 2.4 ppb; Missouri, 22.5 ppb; Texas, 114.5 ppb; and Georgia, 133.9 ppb.Almost all the toxin production occurred during the initial 30 days after inoculation. Fewer toxin‐contaminated ears were found in the doublecross hybrid than in the single cross, but no significant difference in aflatoxin incidence was observed between endosperm types (normal vs. opaque). Sixty of 512 damaged uninoenlated ears and 21 of 512 untreated control ears contained aflatoxin; 80% of the aflatoxin‐positives associated with physically damaged or control ears were observed in corn from the Georgia location.
Comparison of Early Generation Yield Testing and a Single Seed Descent Procedure in Wheat Breeding
Authors: Knott D. R. , Kumar J. 
Published: July 2010

AbstractTwo breeding procedures were compared in two spring wheat (Triticum aestivum L. em. Thell.) crosses. Both procedures were started from the same selected F2 plants in each cross. In one procedure, a single seed was taken from each F2 plant to produce the F3 generation, the process was repeated for the F4. The F5 lines were then produced from the seed of individual F4 plants (single seed descent method, SSD). In the second procedure, the F3 lines were yield‐tested and a pedigree method followed in the F3 and F4 (YT method). Each F4 line was bulked to provide seed for a yield test in the F5. The F6 SSD lines and F5 YT lines were then compared in yield tests.The mean yield of the YT lines was significantly higher in both crosses, mainly because there were fewer, very low yielding YT lines. The correlations between the F3 and F5 yields of the YT lines were significant in both crosses, but were not particularly large (0.29 and 0.14). The yield of the F5 YT lines, derived from the highest yielding 20% of the F3 lines, was compared with the highest‐yielding 20% of the Fo SSD lines. In each cross, the SSD lines were at least as good as the YT lines. Although selection based on F3 yields would have had some effect, it is doubtful that it was worth the labor involved. The SSD procedure appears to have considerable merit
Shrunken Endosperm Mutants in Barley1
Authors: Jarvi A. J. , Eslick R. F. 
Published: July 2010

AbstractSix spontaneous shrunken endosperm mutants in barley (Hordeum vulgare L.) were identified and described. Five of the mutants (se1 through se5) were inherited as maternal plant monofactorial recessives and one mutant se6 was inherited as a monofactorial recessive expressing xenia. The mutants varied in fertility, seed weight, and seive size assortment. Four mutants were located on chromosome one, one on chromosome three, and one on chromosome six, by using translocation breakpoints as markers. Mutants similar to se1 through se5 could be used as males in commerical hybrid seed production. Mutants similar to se6 could be used as preflowering selective genes for the female stock for hybrid seed production.