bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sunflower Performance Relative to Size and Weight of Achenes Planted1
Authors: Robinson R. G. 
Published: July 2010

The research was undertaken in response to a common concern of sunflower (Helianthus annus L.) researchers and seedsmen as to whether various achene‐size fractions of a seed lot will produce crops differing in performance.The objective was to compare crops produced from large, medium, small, heavy, and ungraded achenes in yield and quality. Twelve seed lots of the major types of sunflower were separated into five grades by sieves and wind. An extra large grade representing 3% and a trash grade representing 2% of the original seed lot were additional grades included with one seed lot. Trials were planted at Rosemount, Minn., and thinned to a uniform seedling population of 61,000 plants/ha.Sunflower achenes ranged from 18 to 52% pericarp. However, large, medium, and small achene grades contained, respectively, large, medium, and small seeds. Correlation between achene size and seed size exceeded + 0.95.Crops produced from large, medium, small, or heavy achenes did not differ significantly in achene yield, hectoliter weight, or oil percentage. Large achenes produced significantly (5% level for human food varieties, 1% level for birdfeed varieties, and 20% level for oilseed varieties) larger achenes than the small grade, and the medium grade was intermediate.If size‐graded achenes are used in varietal trials, bias may occur in rating varieties for achene size unless the achenes planted are from similar size‐fractions of the original seed lot.
Male‐Sterile Wheat Seed Production in North Dakota1
Authors: Miller J. F. , Rogers K. J. , Lucken K. A. 
Published: July 2010

Normal and male‐sterile lines of an experimental bread wheat, Minn. II‐54‐30 (Triticum aestivum L. em. Thell. and T. aestivum L. em. Thell. with T. timopheevi (Zhuk.) Zhuk. cytoplasm), were planted in a systematic arrangement of alternate drill strips to evaluate seed production of the male‐sterile line. Approximate ratios of 1:1, 2:1, and 3:1 of male‐sterile to normal were tested over seven environments in 1971 and 1972. Drill‐strip widths of the male‐sterile ranged from 3.1 to 11.0 m. Overall mean yields from strips of the male‐sterile were 18.2, 14.6, and 12.8 q/ha (quintals/ha) for the 1:1, 2:1, and 3:1 ratios, respectively. These yields of the male‐sterile represent 64.4, 51.5, and 45.7% of the normal yields, respectively. Seed set distribution within the male‐sterile in the 2:1 and 3:1 ratio drill widths showed a distinct, though not constant, pattern of decrease toward the center of the strips.A production unit concept was used to compare the efficiencies of the three different ratios from a commercial perspective. Actual yields of male‐sterile from a production hectare were 9.1, 10.1, and 9.9 q for the 1:1, 2:1, and 3:1 ratios, respectively. However, when yield of the normal lines was considered, total yields (normal and male‐sterile) from a production hectare were 23.3, 18.7, and 16.4 q for the three respective ratios.The data from this study were used to evaluate the relationship between seed production yields and relative profit from growing hybrid wheat. The relative profit decreased as production yields decreased, particularly when yields were below a calculated critical level. Hybrid wheat seed production practices that tend to maintain yields above this critical yield level possibly should have priority over alternative practices that can give maximum yields but are vulnerable to production stresses.
Effects of Temperature and Clipping on Growth, Carbohydrate Reserves, and Root Exudation of Western Wheatgrass in Hydroponic Culture1
Authors: Bokhari Unab G. , Singh J. S. 
Published: July 2010

The objective was to investigate the influence of three temperature regimes (13/7C, 24/13C, 29.5/18C day/night) and clipping (moderate and severe) treatments on the growth, total nonstructural carbohydrates (TNC), and root exudations of western wheatgrass (Agropyron smithii Rydb.). The mean growth rate of unclipped plants continued to increase with increasing temperature (from 13/7 to 29.5/18C) up to 50 days followed by a decline during subsequent growth at 24/13 and 29.5/18C. The growth rate of clipped plants was higher than the unclipped controls except for the short duration of 10 days following the clippings. Greatest growth rate occurred under moderate clipping and the next greatest under severe clipping compared to the unclipped (control) plants; crown and root growth of clipped and unclipped plants was greater at 24/13 than at 13/7 or 29.5/18C. Shoots of clipped plants continued to grow throughout the 80‐day experimental period, but those of unclipped plants ceased to show any positive dry matter accumulation after 50 days.The TNC concentrations in the shoots, crowns, and roots of control plants were greater at 24/13 than at 13/7 or 29.5/18C. Concentrations in the three organs of clipped plants declined following clippings, more so in severely than in moderately clipped plants. Severe clipping and high temperature treatments appeared to have a stimulatory effect on root exudations.This study indicated that decline in the growth rate of this cool season grass following maturity was more marked at higher temperatures (29.5/18C) than at lower temperatures, giving a higher overall growth rate for plants at 13/7C. In general, clipping treatments stimulated shoot growth and also increased the potential growth period of the plant. Evidence suggested that reserves in crowns and roots were not utilized to any marked degree for the regrowth of shoots following clipping.
Evaluation of the World Collection of Safflower, Carthamus tinctorius L. IV. Yield and Yield Components and Their Relationships1
Authors: Ashri A. , Zimmer D. E. , Urie A. L. , Cahaner A. , Marani A. 
Published: July 2010

A study of a collection of 903 varieties of safflower (Carthamus tinctorius L.) for the mean yield per plant and the three major yield components, number of heads per plant, number of seeds per head, and seed weight, revealed marked differences in the potential of lines from different origins. Because of the mutual compensation of the yield components, the differences in yield were not as marked as they were for the components. The collection contains an abundance of genetic variability which is available for breeding higher‐yielding safflower varieties. There were regional differences in the components due to human and/or natural selection.A multiple stepwise regression analysis showed that the most important yield component was the number of heads per plant. The number of seeds per head was of little importance, except for lines from Iran. Seed weight had no effect on yield per plant, except for a minor influence in the Iranian lines. The number of heads per plant had negative but negligible correlations with oil content. Yield per plant was not correlated with season length or oil content. Since the findings were obtained under spaced nursery conditions, they are not necessarily applicable directly to dense field stands.
Genotype ✕ Environment Interactions in Burley Tobacco Variety Tests1
Authors: Gupton C. L. , Legg P. D. , Link L. A. , Ross H. F. 
Published: July 2010

The objectives of our study were to estimate the components of variance for burley tobacco (Nicotiana tabacure L.) grown at six locations for 3 years and to determine their implications on testing procedures.Eleven commercial hurley tobacco cultivars were grown at 6 locations in 4 states for 3 years. For each experiment we recorded the number of days to flowering; number of leaves and plant height after topping; length and width of fifth leaf from the top; internode length; yield of cured leaf; percent total nitrogen; percent α‐amino nitrogen; water‐soluble acids; pH; and percent ash, K2O, nicotine, and secondary amine alkaloids. Estimates of variance components and correlations among years and among locations were computed for each variable.Estimates of variance components for cultivars were highly significant for all traits. Cultivar ✕ location and cultivar ✕ year interactions were relatively small for all traits. Second‐order interactions were large relative to first‐order interactions for most variables, but in most instances were much smaller than the component for cultivars.The cultivars source of variation for yield was subdivided to elucidate the variance among F1 hybrids and pure lines and their interactions with environments. The location ✕ hybrid mean square was statistically significant, but the one for location ✕ pure lines was not. These results suggest that some hybrids may not have as much internal buffering capacity as pure lines in burley tobacco.Our results show that years and locations may be considered random environments and may be used interchangeably. Adding more years costs more in time and money than does adding locations; therefore, using several locations for 2 years seems best for testing burley tobacco.
Expected and Actual Gains in Economic Value of Oat Lines from Five Selection Methods1
Authors: Eagles H. A. , Frey K. J. 
Published: July 2010

Grain and straw are the two marketable products of the oat (Avena sativa L.) crop in the midwestern United States. Five methods of selection for increasing economic value of the crop and its two component traits, grain and straw yield, were compared in a population of F9, derived lines of oats. The five methods were: (a) selection for increased grain yield; (b) selection for increased straw yield; (c) a selection index calculated to maximize expected genetic gain in economic value; (d) a base selection index, where the traits were weighted by their relative economic values/gram; and (e) a procedure of independent culling levels. Expected gains from selection were computed by use of data from three test sites individually and means of the three sites for 1 year, and actual selection gains were computed with data from the same sites in a second year. Two selection intensities, 10 and 25%, were used and the methods were compared in terms of expected and actual gains.Selection for one trait only, was superior for improving that trait, but the indexes and method of independent culling levels tended to be superior for improving overall economic value. The superiority of the latter methods was most evident when means across sites were used.For selecting lines with superior economic values, the base index, (d) above, was preferred because of its simplicity, freedom from need for estimating population parameters, and the equivalency of grains from this method.
Transgressive Segregation for Root‐Knot Nematode Resistance in Cotton1
Authors: Shepherd R. L. 
Published: July 2010

F6 families of Gossypium hirsutum L. ✕ ‘Mexico Wild’ (a root‐knot tolerant primitive G. hirsutum from Mexico) were advanced through F10, with selection in greenhouse tests for resistance to root‐knot nematodes [Meloidogyne incognita acrita (Kofoid & White, 1919) Chitwood, 19491. A disinfected larval screening technique effectively classified 85% of the F6 families as intermediate to highly susceptible, even though they had been selected in F2 through F4 in the field for root‐knot resistance in highly infested soil.Two F10 lines, designated A623 and A61, having the highest resistance known to root‐knot in G. hirsutum, were developed. These lines were transgrassive segregates for resistance. Root‐knot resistance in the F1 generation from resistant A623 ✕ susceptible ‘Stoneville 213,’ ‘Coker 201,’ and ‘Dixie King II’ was incompletely dominant.Fusarium wilt [Fusarium oxysporum Schlecht. f. vasinfectum (Atk.) Snyd. ✕ Hans.] resistance in the above material was highly associated with root‐knot resistance. Therefore, it may be possible to breed for fusarium wilt resistance by breeding solely for high root‐knot resistance.
Single Dw3 Height‐Gene Effects in 4‐ and 3‐Dwarf Hybrids of Sorghum bicolor (L.) Moench1
Authors: Schertz K. F. , Rosenow D. T. , Johnson J. W. , Gibson P. T. 
Published: July 2010

Four‐dwarf, heterozygous 3‐dwarf, and homozygous 3‐dwarf hybrids of grain sorghum [Sorghum bicolor (L.) Moench] differing at the Dw3 locus were compared for height and other characteristics to elucidate this locus. This should not be confused with the Dw2 locus for which commercial hybrids may differ. The two female parents were derived from a 4‐dwarf line and a tall mutant from it and the male parents were derived from a 4‐dwarf doubled haploid and a tall mutant from it.The homozygous and heterozygous tall 3‐dwarf hybrids exceeded the short 4‐dwarf hybrid in height, grain yield (not statistically significant in 1 of 2 years), and kernel weight. Hybrids from 3‐dwarf males were taller and had heavier kernels than hybrids from 4‐dwarf (short) males. Hybrids from 3‐dwarf females were taller than hybrids from 4dwarf (short) females, but grain yield comparisons were inconsistent. Homozygous and heterozygous 3‐dwarf hybrids did not differ significantly except in height.
Hybrid Performance of Selected Maize Lines from Reciprocal Recurrent and Testcross Selection Programs1
Authors: Russell W. A. , Eberhart S. A. 
Published: July 2010

We evaluated three maize (Zea mays L.) crosses among BSCBI(R)C5, BSSS(R)C5, and BSSS(HT)C6 populations in six environments. BSCBI(R)C5 and BSSS(R)C5 improved populations from reciprocal recurrent selection, and BSSS(HT)C6 was obtained from testcross selection with a double‐cross tester. Also, we used five selected S3 lines from each of BSCBI(R)C5 and BSSS(R)C5 and five selected S3 or S4 lines from BSSS(HT)C5 in three sets of line ✕ line crosses among the sources. Average yields of the population crosses were essentially equal, which was unexpected for BSSS(R)C5 ✕ BSSS(HT)C6 Most of the variation among crosses in each set was accounted for by average line performance (general combining ability) in all traits.Average yield of line crosses in a set was significantly higher than the population cross in each set and in the BSCBI(R)C5 ✕ BSSS(R)C5 and BSCBI(R)C5 ✕ BSSS (HT)C6 sets, the best cross yielded 35% more than the population cross. Two BSCBI(R)C5 ✕ BSSS(R)C5 crosses yielded significantly higher than B37 ✕ Oh43, and one of these crosses was equal to B37 ✕ Oh43 for lodging resistance. None of the crosses in the other two sets was equal to B37 ✕ Oh45 for all traits, mainly because of lodging. A modified reciprocal recurrent selection procedure using an inbred tester is proposed as a more efficient method of simultaneously improving breeding populations and developing elite single crosses.
14C‐Photosynthate Translocation in C3 and C4 Plants as Related to Leaf Anatomy1
Authors: Gallaher R. N. , Ashley D. A. , Brown R. H. 
Published: July 2010

This study was performed to investigate the relationship between 14C photosynthate translocation and phloem cross‐sectional area in C3 and C4 plants. Spots 5 mm in diameter were labeled by 14CO2 exposure on fully expanded leaves of two monocots (Panicum maximum Jacq., a C4 species and Panicum milioides Nees ex. Trin., a C3 species) and two dicots (Amaranthus retroflexus L., a C4 species and Glycine max Merrill, a C3 species). The spots were removed after 3 hours of translocation and equally divided. Half of the spots were used for 14C analysis and half for anatomical study of cross sectional areas of phloem and other tissues.In all cases percent translocation from and cross‐sectional area of phloem tissue in labeled spots were higher in C4 than in C3 plants. P. maximum had 100% greater translocation out of and 96% more phloem tissue in the labeled spots than P. milioides. A. retroflexus translocated 48, 91, and 45% more 14C out of spots over the midvein, secondary, and tertiary veins, respectively, than G. max. A. retrollexus had 5, 92, and 66% more phloem tissue in the above respective spots than G. max. Photosynthesis rates were higher in C4 than in C3 plants, but differences were not as great as those in translocation.Data from this study indicate that C4 plants have both a greater translocation capacity and larger cross‐sectional area of phloem than C3 plants.
Translocation Patterns in Soybeans Exposed to 14CO2 at Four Different Time Periods of the Day1
Authors: Russell W. J. , Johnson D. R. 
Published: July 2010

Field grown soybeans [Glydne max (L.) Merr.] were exposed at the mid.bloom stage to 14CO2 for 1 hour beginning at either 9 AM, 11 AM, 1 PM, or 3 PM CDT to evaluate the effects of time of day when exposed to 14CO2 on the translocation and distribution of labeled assimilates. Plants were harvested 0, 1, 3, 6, and 24 hours after labeling. By the end of the labeling period, 16.9% of the total recovered 14C had been exported from the leaves and 36.9% had been exported by the end of 24 hours (averaged over the four exposure times).Leaves labeled during the time periods associated with the highest net C fixation rates (11 to 12 AM and 3 to 4 PM) assimilated more 14C, translocated more to the stems and roots, and exhibited a higher rate of export from the leaves. Percent 14C recovered in each component (except nodules) was significantly different between the 9 to 10 AM and 3 to 4 PM exposure periods. Differences between the two midday exposures were relatively small, averaged over all harvest times and increased only when compared immediately and 24 hours after labeling.Carbon‐14 labeling and translocation experiments should be conducted during relatively constant time periods to allow nonconfounded intercomparisons between data when experimental technique dictates multiple times of exposure to 14C, especially between the early morning and late afternoon exposure periods.
Response of Soybeans to a Morphactin1
Authors: Clapp J. G. 
Published: July 2010

Morphactins (a group of plant growth regulating chemicals) were observed to inhibit apical growth on soybeans [Glycine max (L.) Merr.] in North Carolina during 1971. One material, EMD‐7301 (containing 12.5% of methyl‐2‐ chloro‐9‐hydroxyfluorene‐(9)‐carboxylate) was evaluated under field conditions to determine the effects on plant height, lodging, seed weight, pods/plant, seed/pod, maturity, and grain yields.Foliar applications of EMD‐7301 at rates of 12.4, 24.7, 49.4, 98.8, 197.7, and 790.7 ml/ha at flower initiation failed to increase soybean yields over a 2‐year period. A 10.5% yield increase occurred during the first year of study with the 49.4 ml/ha rate. Plant height was reduced by all application rates. Lodging was reduced by the 98.8 ml/ha rate. The highest rate of application (790.7 ml/ha) delayed maturity by 10.5 days, reduced the number of pods/plant by 54.5% and seed/pod by 19.4%, and had no effect on seed weights.
Evaluation of Selection Potential for Earworm Resistance in Two Corn Populations and Their Cross1
Authors: Widstrom N. W. , Wiseman B. R. , McMillian W. W. 
Published: July 2010

Variances and expected selection progress for reduced injury by the corn earworm [Heliothis zea (Boddie)] and for husk tightness were estimated in two corn (Zea mays L.) populations and their F1 and F3 generations. A half‐sib mating design was used to test all populations during each of two successive years. Heterosis estimates for earworm injury and husk tightness were less than 5%, except for an estimate of 13.9% for husk tightness in the F3. Estimates of genetic variance showed that dominance for corn earworm resistance was of less significance than that for husk tightness.Additive variance for earworm injury in the F3 was higher than the mean variance of the parents. This difference may be caused by factors such as multiple alleles, coupling linkages, and segregation of genes in the F3 for which alleles are fixed in one or both of the parents. On the basis of expected selection progress for the characters measured and a highly significant positive correlation between resistance to earworm injury and husk tightness, the authors suggest improvement of these populations by selecting primarily for low earworm injury, while requiring the selections to meet prescribed standards for husk tightness and yield.
Role of Awns in Photosynthesis, Respiration, and Transpiration of Barley Spikes1
Authors: Johnson Richard R. , Willmer Colin M. , Moss Dale N. 
Published: July 2010

To assess the role of awns in photosynthesis, respiration, and transpiration, the water vapor and Co2‐exchange rates were measured on spikes of barley (Hordeum vulgare L.) genotypes ranging from awnless to those having several meters of awn/spike. The plants were grown in large pots in the field and brought into the laboratory for measurement. An increased amount of awn tissue resulted in greater rates of net photosynthesis, dark respiration, and transpiration per spike. The awns of all genotypes remained photosynthetically active throughout grain filling, although some reached maximal activity soon after emerging from the flag leaf sheath, while others had peak rates only a few days before maturity.The total length of awn tissue of each spike remained constant throughout the grain‐filling period, but the awn dry weight of the full‐awned genotypes increased during that period. Awn dry weight, rather than awn number or awn length, best described the amount of photosynthetic tissue present. The genotype which had the dense spike character had a lower photosynthetic efficiency (mg CO2 fixed per g awn dry weight) than did the other genotypes. Removing the top two leaves on each culm to reduce the assimilate supply to the grain increased synthetic rates of the spikes slightly, but not sufficiently to compensate for the leaf area removed.
Correlated Responses and Responses to Index Selection Involving Yield and Ear Height of Maize1
Authors: Moll R. H. , Stuber C. W. , Hanson W. D. 
Published: July 2010

Replicated selection studies were undertaken to evaluate the predictability and repeatability of correlated responses and responses to selection indexes. In each of six samples of the variety ‘Jarvis’ (Zea mays L.), first generation families were selected for five criteria; yield, ear height, and three indexes based on both yield and ear height. In three additional samples, families were selected for yield alone. Each sample was composed of 300 full‐sib families evaluated in a different location‐year environment.Evaluation of responses to divergent selection showed that responses of both traits were generally symmetrical. Large average deviations from predictions were observed for correlated responses and responses to index selection. Variation among replicates for correlated responses was no greater on the average, than variation for direct responses. Responses of component traits to index selection were more variable in general, than responses to singletrait selection. Therefore, index selection responses tended to be less repeatable than responses to single trait selection. Although correlated responses to single trait selection deviated considerably from expectation, they appeared to be as repeatable as the direct responses, which agreed satisfactorily with expectation. Further investigation of the relationship between the two traits suggested a nonlinear association. Failure to account for this nonlinearity in predictions and indexes may have contributed to the discrepancies between observed and expected results.