bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photosynthesis, Stomatal Resistance, and Enzyme Activities in Relation to Yield of Field‐grown Dry Bean Varieties1
Authors: Peet M. M. , Bravo A. , Wallace D. H. , Ozbun J. L. 
Published: July 2010

Photosynthetic rates, stomatal resistances and the activities of three enzymes; ribulose bisphosphate carboxylase (RuBPCase), malate dehydrogenase (MDH), glycolate oxidase (GAO) were determined for nine fieldgrown dry bean (Phaseolus vulgaris L.) varieties. Measurements were made during several developmental stages; vegetative growth, flowering, early pod set, and late pod set. All data were compared to biological and seed yields using seasonal averages as well as using data from each developmental stage separately.Photosynthetic rates and RuBPCase activities were highest at early pod set, which was the only developmental stage where they were significantly correlated with biological yields. Also at pod set MDH activities were significantly correlated with both seed yield and harvest index, and GAO activity was correlated with biological yield. GAO activity was highest at flowering. The amount of the increase in photosynthesis from flowering to pod set of each variety was correlated positively with its final seed yield.While photosynthetic rates at pod set were positively correlated with both biological and seed yield in eight of the varieties, in one variety high seed yields were associated with very low photosynthetic rates. This variety, however, also had an exceptionally high harvest index and high MDH and GAO activities. Thus high seed yields are not necessarily associated with high photosynthetic rates but may result from a more efficient utilization of photosynthate.
Sunflower Moth Damage and Inheritance of the Phytomelanin Layer in Sunflower Achenes1
Authors: Johnson A. L. , Beard B. H. 
Published: July 2010

Inheritance of the phytomelanin layer in sunflower (Helianthus annuus L.) achenes was studied in association with resistance to the sunflower moth (Homoeosoma electellum Hulst.). The F2 and F3 populations of four crosses between resistant lines with the layer and a susceptible line without were evaluated for presence of the layer and moth‐damaged seeds.Segregation ratios for the layer indicated a single locus with a dominant allele determining its presence and recessive alleles determining its absence. There was no indication of differences due to modifying egnes. We suggest Pml pml as symbols for these alleles.Seed damage was determined from natural and artificial (hand) infestations. Each method has advantages and disadvantages, but with either method there was less larval damage in seeds with the layer than in seeds without.In laboratory tests older larvae were able to penetrate nearly mature seeds, even those with the phytomelanin layer; but the damage was greater on seeds without the layer. Younger larvae could penetrate immature seeds (1 to 3 days after pollination) but penetration appeared to become more difficult as the seeds developed. Seeds with the phytomelanin layer were not penetrated by young larvae 13 to 15 days after pollination.
Water Relations and Growth of Soybeans in Drying Soil1
Authors: Heatherly Larry G. , Russell W. J. , Hinckley T. M. 
Published: July 2010

Soybean plants (Glycine max (L.) Merrill ‘Hill’) were grown in moist soil in ll4‐1iter containers for 63 days in the greenhouse, and then subjected to a 9‐day drying cycle to evaluate water relations and growth in a drying soil. On day 1 of the drying cycle, measurement of xylem pressure potential (P), leaf diffusive resistance (RL), area, soil water potential (SWP), and root dry weight was initiated. Measurements were made at 0500 to 0630, 1000 to 1200, and 1400 to 1600 hours (CDT) on days 1, 3, 5, 7, and 9. The earliest time period was before sunrise. Atmospheric demand was calculated for each sample period.Xylem pressure potential at each time period of each day decreased linearly with, and was significantly related to (R2 = 0.97, 0.92, and 0.93, respectively) decreasing base (presunrise) SWP of the drying soil for the duration of the experiment. The data indicated the possibility of estimating P of plants growing in a drying soil from base values of SWP. Extremes in atmospheric demand, as well as SWP, influenced levels of P of plants growing in wet soil. The largest decline in P occurred between the presunrise and 1000 to 1200 hour time periods of each day in both soil environments. Presunrise wilting of plants growing in the drying soil occurred at day 7, when the corresponding base (presunrise) P was about —18 bars. No establishment of a water potential gradient between upper‐ and mid‐canopy leaves occurred in either soil environment. Decline in leaf enlargement corresponded to a base P of about —4.5 bars, and cessation of enlargement occurred when base P was between —10 and —12.9 bars.As SWP and P declined, RL increased. Vapor pressure deficit (VPD) was the most significant single determinant of RL (R2 = 0.56) at the 1400 to 1600 hour time period; however, the interaction between VPD and P influenced RL more than either variable singly at this time period (R2 = 0.67). The interactions between VPD and base and between VPD and base SWP both influenced RL above the level of single variable effect at both the 1000 to 1200 and 1400 to 1600 hour time periods.
Relationship of Stalk Morphology and Chemical Composition to Lodging Resistance in Sorghum1
Authors: Esechie H. A. , Maranville J. W. , Ross W. M. 
Published: July 2010

Lodging reduces grain yields significantly in most grain crops. Therefore, selection of lodging‐resistant lines might alleviate the lodging problem. Several factors are associated with lodging resistance, but attempts to quantitate these factors are either very few or lacking for grain sorghum (Sorghum bicolor (L.) Moench). Morphological and stalk composition measurements were made in 2 consecutive years using 30 lodging‐resistant and 30 lodging‐susceptible lines in order to quantify these factors and to assess their value as an index of selection.Lodging resistance was associated with larger diameters of basal internodes and peduncles, shorter peduncles, shorter plant height, higher weight of 5‐cm basal and peduncle stalk sections, and a thicker rind. When external force was artificially applied in the field, those lines classified as lodging resistant required more force to effect stalk failure.Lodging‐resistant sorghums contained higher total nonstructural carbohydrates (TNC) and lower stalk potassium and protein concentrations. The resistant types also appeared to be more perennial in habit and thus were resistant to senescence of cell tissues after freezing. High TNC was directly associated with resistance to post‐freeze senescence and/or with longer maturity, and indirectly with lodging. Resistant types were generally later maturing, and the results indicated that resistance probably can be obtained without sacrificing yield.
Reaction of Reed Canarygrass Genotypes to the Leafspot Pathogens Stagonospora foliicola and Helminthosporium catenarium1
Authors: Zeiders K. E. , Sherwood R. T. 
Published: July 2010

Our objectives were to determine the range of reactions to tawny blotch (caused by Stagonospora foliicola (Bres.) Bubak) and Helminthosporium leafspot (caused by H. cateranium Drechs.) among diverse genotypes of reed canarygrass (Phalaris arundinacea L.), to assess the relationships among lesion size, lesion frequency, leaf size, and tawny blotch severity ratings, and to assess the feasibility of selecting for resistance as a means of improving this highly productive forage species.The 24 clones varied from resistant to highly susceptible to S. foliicola or H. catenarium in artificial inoculations. Differences among disease severity means for both pathogens were significant at P < 0.01. Resistance to S. foliicola was controlled independently from resistance to H. catenarium. One clone was resistant to both pathogens. There was a wider range of reaction among clones to S. foliicola than to H. catenarium.Differences in lesions per leaf, lesions per cm2, and lesion size rating for S. foliicola were significant at P < 0.01. There was a significant negative correlation (r = −0.60) between leaf area and lesions per cm2. Lesions per leaf and lesion size were correlated (P < 0.01) with disease severity ratings (r = 0.69), thus supporting the validity of our disease severity evaluations. The results indicate that the prospects for developing lines with resistance to either or both pathogens are good.
Histological Evidence for a Cotton Genotype with Opposite Leaves and Fruiting Branches at a Main Stem Node1
Authors: Gausman H. W. , Namken L. N. , Heilman M. D. , Dilday R. H. 
Published: July 2010

Cotton (Gossypium hirsutum L.) usually has one fruiting branch emerging at each main stem node. ‘Tamcot SP‐37’ plants often have two branches emerging opposite each other. Frequency of plants with two fruiting branches per node increased following selection of Tamcot SP‐37 plants that had opposite leaves at nodes five or six, rather than the conventional spiral (alternate) leaf arrangement. We sought histological data concerning this previously unreported anomaly in phyllotaxis and fruiting emergence.We compared the main‐stem apical meristems and vascular systems of anomalous Tamcot SP‐37 plants with those of ‘Stoneville 213’, a standard cultivar that does not exhibit this phenomenon. Comparative anatomy indicated no internode at the level(s) where Tamcot SP‐37's two leaves and two fruiting branches emerge and develop. This anomaly in Tamcot SP‐37 has not been reported previously and may be useful in the future for developing earlier maturing and higher yielding cotton cultivars.
Inheritance of Gossypol Level in Gossyplum. III. Genetic Potentials of Two Strains of Gossypium hirsutum L. Differing Widely in Seed Gossypol Level1
Authors: Lee Joshua A. 
Published: July 2010

Genetic potentials for the production of terpenoid aldehydes (gossypol in the present material) were compared in two stocks of Gossypium hirsutum L. differing widely in their capacities to produce these substances. In the line, 3‐T, the dimeric genotype, Gl2Gl2Gl3Gl3, averaged 2.78% gossypol in dried seed meal, whereas the same genotype in ‘Acala 4‐42’ averaged 0.90%. Most of the genetic variance generated by the substitution of mutant for normal alleles at the two loci was additive for both cottons.In 3‐T, the monomerics, Gl2Gl2gl3gl3 and gl2gl2Gl3Gl3, produced an average of 3.03 and 1.18% gossypol, respectively, whereas the same genotypes in Acala 4‐42 averaged 0.69 and 0.24%. Thus the ratio of gossypol production for the monomerics was nearly the same for both cottons.In 3‐T, the Gl2 monomeric proved to be duplex sufficient; that is, monomeric plants produced as much seed gossypol as dimerics. The Gl2 allele in Acala 4‐42 was not duplex‐sufficient, but became so after transfer to the 3‐T background.Analysis of individual seed lots from 84 dimeric F2 plants from a cross of the two cottons produced a symmetrical curve of gossypol value spanning the distribution between the parents. This result was interpreted to mean that potentials for the alleles, Gl2 and Gl3, are similar in high and low gossypol cottons, and that observed differences in recovery of seed terpenoids results from variation in numbers, or effectiveness, or modifier alleles.
Screening of Flax Species for New Sources of Genes Resistant to Melampsora lint (Ehrenb.) Lev.1
Authors: Wicks Z. W. , Hammond J. J. 
Published: July 2010

The control of rust (Melampsora lini (Ehrenb.) Lev.) in flax (Linum usitatissimum L.) has been by development of rust resistant cultivars. Because genes for rust resistance are continually being rendered ineffective by new races of rust, the isolation of new genes is essential.Hybridization of the common flax cultivar ‘Bison’ was attempted with available species of flax with chromosome numbers of n = 15. Ten accessions representing four successfully hybridized species were immune to cultures of race 371. Of these, two were immune to all known races of rust in North and South America. Inv munity of each of these accessions was conditioned by a single gene located at or near the L locus. Because the genes for rust resistance were both found at the L locus and both conditioned immunity to all known North and South American races of rust, it was impossible to determine if they were the same or different alleles located at the same locus. These genes have not been reported previously in the literature, and we propose to designate them L12‐l and L12‐2.
Water Relations of Tall and Short Cultivars of Winter Wheat1
Authors: Kirkham M. B. , Smith E. L. 
Published: July 2010

Water potential, osmotic potential, stomatal resistance, and leaf temperature were measured for 8 weeks in spring under field conditions, on the top and bottom green leaf of eight cultivars of winter wheat (Triticum aestivum L.). Four cultivars were adapted for the Southern Great Plains (‘Payne,’ ‘Scout 66,’ ‘Sturdy,’ and ‘Turkey’) and four for Europe (‘Burgas 2,’ Bulgaria; ‘David,’ Austria; ‘F23‐71,’ Romania; ‘Odesskaya 51,’ U.S.S.R.). Four cultivars were tall (F23‐71, Odesskaya 51, Scout 66, and Turkey) and four were short (Burgas 2, David, Payne, Sturdy). Soil was moist and plants were not under moisture stress.Tall and short cultivars reached a maximum height of 114 and 84 cm, respectively. Water potential and osmotic potential of top leaves of tall cultivars averaged 4.8 and 3.3 bars less (more negative), respectively, than those of top leaves of short cultivars. Water potential and osmotic potential of bottom leaves of tall cultivars were similar to those of bottom leaves of short cultivars (about _7 and _16 bars for water and osmotic potentials, respectively). Stomatal resistance of the upper surfaces of top leaves of tall cultivars (5.8 sec/cm) was similar that of upper surfaces of the top leaves of short cultivars (5.3 sec/cm). Stomatal resistance of the upper surfaces of bottom leaves of tall cultivars (9.1 sec/cm) was less than that of upper surfaces of bottom leaves of short cultivars (13.2 sec/cm). Because plants were not water stressed, temperature of all leaves was always cooler than air temperature (0.4 to 0.9 C cooler than air). Average yields of short and tall cultivars were 3,260 and 2,950 kg/ha, respectively. The better yield of short cultivars appeared to be related, in part, to the lower tension with which water was held in the top leaf of the short plants compared to the top leaf of the tall plants.
Influence of Intergenotypic Competition on Seed Yield of Heterogeneous Soybean Lines1
Authors: Gedge D. L. , Fehr W. R. , Cox D. F. 
Published: July 2010

Two experiments were conducted to determine if overcompensation or undercompensation due to intergenotypic competition is preferentially associated with high or low‐yielding heterogeneous soybean (Glycine max (L.) Merrill) lines. In Experiment 1, yield of 40 random F2‐derived lines, four F5‐derived lines from each F2 line, and a blend of the four F5 lines (F5 blend) were evaluated for two crosses. Linear regression was used to compare the yield of the F2 lines and F5 blends with the mean yield of the four F5 lines. In Experiment 2, four F5‐derived lines were selected from each of six high and six low‐yielding F2‐derived lines in the two crosses. The four F5 lines were evaluated for yield in pure stands, in the six possible two‐component blends, and in a four‐component blend. Yields of the blends were compared with average performance of the components in pure stands.In both experiments, overcompensation or undercompensation was not preferentially associated with high or low‐yielding heterogeneous lines. The results indicated that early generation testing for yield in soybeans should not be biased significantly by intergenotypic competition within heterogeneous lines.
Heterosis, Inbreeding, and Line Performance in Crosses of Adapted Spring Wheats1
Authors: Cregan P. B. , Busch R. H. 
Published: July 2010

Eight adapted high‐yielding spring wheat (Triticum aestivum L.) parents were crossed in a diallel to produce 28 hybrid populations. The F1, F2 through F5 bulks, and a varying number of F5 lines/cross were grown at two locations. The F1 yields exhibited midparent heterosis from 5 to 58% (x̄ = 20%) and highparent heterosis from _17 to 41% (x̄ = 8%). Compared to the respective highest yielding line (HL) from each cross, F1 yields ranged from 75 to 119% (x̄ = 99.4%). The three highest yielding entries were Fl's even though the average HL and F1 over all crosses were similar.Significant general combining ability (GCA) mean squares for yield were noted in the combining ability analyses of the F1, F2 through F5 bulks, HL, and the x̄ of F5 lines from each cross (x̄F5L). Significant specific combining ability (SCA) mean squares were detected the analyses of the F, and x̄F5L. The significant SCA mean square for x̄F5L suggested the presence of additive ✕ additive epistasis. The GCA effects generally were positively correlated across the various hybrid generations, which indicated consistent performance of the parents when measured by bulks or F5 lines.The regression analysis of F1 and F2 through F5 bulk yields on heterozygosity detected a highly significant mean square (r2 = 0.947). The mean yield of the 28 crosses decreased at a linear rate of 0.23% per 1% decrease in heterozygosity with a maximum rate of 0.4% in one cross. Even this maximum rate was less than the lowest reported in maize (Zea mays L.) suggesting lesser amounts of dominance genetic variance in these materials.The significant F1 heterosis and SCA for yield and the significant inbreeding depression indicated the possible desirability of F1 hybrids to maximize yield in these materials. However, since no F1 hybrid significantly outyielded the best F5 line tested, it was unclear if increased yield would best be obtained via pureline or F1 hybrid development.
Physiological Response of Three Alfalfa Cultivars to One Chilling Night1
Authors: Peoples T. R. , Koch D. W. 
Published: July 2010

Most studies involving photosynthetic efficiency have compared species or cultivars that were grown under fixed day/night temperature regimes. Researchers attempting to improve photosynthetic efficiency and productivity of a crop may also need to consider genotype response to adverse factors, such as temporary chilling, which have been shown to reduce subsequent photosynthetic rates.Three alfalfa (Medicago sativa L.) cultlvars, representing a range of environmental adaptation, were grown in a greenhouse at 22/18 C (day/night), and then were exposed for one night to 5 or 18 C to determine the effect of low temperature on physiological processes the following morning. The CO2 exchange rate (CER) of all three cultivars was reduced following a 5 C night. A greater reduction in CER occurred in ‘Mesa‐Sirsa’ and ‘Saranac’ (69.1 and 60.2% less than 18 C, respectively) than in ‘Kane’ (36.7% less than 18 C). Transpiration rates were significantly reduced following chilling exposure of Mesa‐Sirsa only (75.5% less than 18 C). This reduction in transpiration was associated with a 50% increase in leaf diffusive resistance and a 4.3 bar decrease in xylem water p6tential. Increased leaf diffusive resistance was not observed in Saranac and Kane following a chilling night. A greater leaf carbohydrate concentration and reduced l4C‐photosynthate translocation from leaf tissue was noted in all cultivars following a 5 C night.These data suggest a feedback inhibition of CER in alfalfa following one 5 C chilling night. A water stress inducing an increased leaf diffusion resistance and decreased transpiration was found in Mesa‐Sirsa only.
Diallel Analysis of Ear Height and Associated Characters in Corn1
Authors: Harville B. G. , Josephson L. M. , Kincer H. C. 
Published: July 2010

Early and late low ear corn (Zea mays L.) synthetics were developed by sib‐mating for lower ear height over 12 cycles of selection. Cycles 1, 3, 5, 7, 8, 9, and 10 were crossed in a diallel set for a study on inheritance of ear height and associated characters.Ear height was reduced an average of 3.20 cm per cycle in the early synthetic and 2.98 cm in the late synthetic. Plant height remained fairly constant in both synthetics. The plant‐to‐ear height ratio increased from 3.03 to 4.84 in the early synthetic and from 2.96 to 4.56 in the late synthetic.Lower ear placement was associated with a change from a fewer number of nodes below the ear to a greater number of nodes above the ear in both synthetics. Over 12 cycles of selection, ears were lowered more than one node in each synthetic. Therefore, the lower ear heights were due to placement on the stalk as well as shorter internodes.Large general combining ability mean squares indicated that the characters were controlled by additive gene action. Significant changes of the estimate of the general combining ability effects were less with each succeeding cycle of selection, indicating less progress in lowering ear height with each succeeding cycle.
Gas Exchange of Finger Millet Inflorescences1
Authors: Tieszen Larry L. , Imbamba Simeon K. 
Published: July 2010

The growth and development of finger millet [Eleusine coracana (L.) Gaertn.] inflorescences is described. The respiration rate on a dry weight basis remained uniform until it decreased during the later stages of seed filling and drying. On an inflorescence basis, the respiratory production of CO2 increased until the “mature” stage because of the large increase in the mass of the inflorescence with time.The inflorescence was photosynthetically active at all stages and at “early an thesis” accounted for about 41% of the C reguirements. The photosynthetic contribution of C was less in both later and earlier stages of development. Inflorescences possessed low resistances to mass transfer, were a significant source of water loss, and appeared to possess poor stomatal control. The quantitative importance of this source of CO2 for grain filling and yield remains to be established.
Selection Responses, Genetic‐Environmental Interactions, and Heterosis with Recurrent Selection for Yield in Maize1
Authors: Moll R. H. , Cockerham C. Clark , Stuber C. W. , Williams W. P. 
Published: July 2010

Populations of maize (Zea mays L.) and their hybrids derived from full‐sib family selection and reciprocal recurrent selection for increased yield were compared with the corresponding original populations over a range of environments. The populations derived from six selection cycles were evaluated in 12 year‐location environ. ments, and the eight cycle populations and their hybrids were evaluated in a separate study in five year‐location environments.Results of the two studies were in good agreement. Genetic environmental interactions were largely accounted for by responsiveness to environmental variation. Improved populations which were the direct result of selection were more responsive than the original populations. Other populations in which improvements resulted from indirect effects of selection showed less consistency in their responsiveness.Heterosis was increased after reciprocal recurrent selection and decreased slightly after full‐sib family selection. Changes in heterosis were found to be compatible with a simple dominance genetic model.
Outscoring Rates in Oat Species Crosses (Avena sativa L. ✕ A. sterilis L.)1
Authors: Shorter R. , Gibson P. , Frey K. J. 
Published: July 2010

Outcrossing percentages were estimated in F3 oat populations from four matings of Avena sativa L. ✕ A. sterilis L. The populations were generated from the original cross and backcross 1 to 5 to the A. sativa parent in each mating. Mean outcrossing averaged across generations ranged from 1.8 to 8.7% for the four matings. Outcrossing values were 2.8, 10.7, 9.1, 4.7, 2.4, and 4.9% in the Bc0, Bc1, Bc2, Bc3, Bc4, and Bc5, respectively.Calculations showed that outcrossing in oats has a much greater relative effect on retaining heterozygosity in the F5 to F10 generations than it has in F1 to F5.