bluuebunny/crossref_metadata_2025_split huggingface dataset:
Agronomic and Genetic Analysis of Tarnished Plant Bug Tolerance in Cotton1
Authors: Meredith William R. , Laster M. L. 
Published: July 2010

We investigated at Stoneville, Miss., in 1973, the effects of heavy and light infestations of tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), on six genetic populations of cotton, Gossypium hirsutum L. Mustard Brassica juncea (L.) Czern, planted in rows adjacent to cotton, was used to attract and accumulate large numbers of plant bugs. The light infestations of plant bugs were maintained by six early‐season insecticide applications. The genetic populations used were ‘Stoneville 213,’ ‘Coker 201,’ their reciprocal F1 and F2 hybrids, and the reciprocal F1 backcrosses to the recurrent parents. Lint yield, six yield components, and five fiber properties were determined for plants harvested on four dates: September 12 and 21, October 4, and November 9.The presence of plant bugs resulted in more terminal damage on small plants, and higher lint percentage and decreased boll size and seed/boll on mature ones. Plant bugs had no effect on seed index, lint index, and fiber properties. The reduced number of bolls/plot caused by plant bugs resulted in decreased lint yields. Lint yield and bolls/plot of the more tolerant cultivar (Stoneville 213) were not appreciably reduced by plant bugs until the last harvest. However, in the less tolerant cultivar (Coker 201) yield and number of bolls/plot were reduced most in the first two harvests.No reciprocal genetic effects were detected for any characteristic in this study. An analysis of generation means indicated that additive gene action and additive Χ additional epistasis, were both significant in accounting for terminal damage. Analyses of generation means for lint yield and bolls/plot indicated that additive gene action was responsible for conferring tolerance to plant bugs. No dominance or epistatic effects involved in tolerance to plant bugs were detected. Once the plants had recovered from the early‐season plant bug damage, significant dominance for late‐season production was detected.
Genotypic Response to Potassium in Soybeans1
Authors: Walker A. K. , Schillinger J. A. 
Published: July 2010

Soybean [Glycine max (L.) Merr.] genotypes usually yield about the same under high K fertility as under moderate K fertility. The objective of this study was to verify the results of a preliminary screening test, which revealed that the FC31702 and ‘Lincoln’ genotypes were responsive and nonresponsive, respectively, to high K fertility.FC31702 and Lincoln soybeans were grown under moderate (approximately 130 kg K/ha) and high (approximately 193 kg K/ha) K fertility on a Beltsville silt loam soil for 3 years. ‘Cutler,’ a recommended cultivar for Maryland, also was included the last 2 test years. Seed yield and percent K in the leaves during the growing season were determined.FC31702 had a significant increase in seed yield when grown under high K fertility as compared to moderate K fertility. Lincoln and Cutler had no yield increase. The response in yield of FC31702 to high K fertility was associated with higher K percentages in the leaves during the growing season.
Yield Potential in a Dwarf Spring Wheat and the Effect of Shading1
Authors: Fischer R. A. 
Published: July 2010

A dwarf spring wheat (Triticum aestivum ‘Yecora 70’) was grown under irrigation and optimal agronomy in northwest Mexico during four winter seasons. Single shading treatments of approximately four (1971, 1972), three (1973), and two (1974) weeks duration and various intensities were used to elucidate the importance for grain yield of radiation and crop photosynthesis at different stages of development.Shading always reduced crop growth, approximately in direct proportion to the reduction in radiation. Grain yield reduction was however curvilinearly related to radiation such that small reductions had little effect on yield at any developmental stage. Yield reductions with heavier shading only occurred with shading after about 60 days after seeding and were greater before anthesis (90 days) than after anthesis, especially in 1973.The shorter shading treatments indicated that the period of rapid spike growth, approximately 35 to 5 days before anthesis, was that showing greatest sensitivity to shading. Shading then led to fewer spikes/m2 (lower tiller survival) and fewer grains/splkelet (fewer florets produced), hence reduced grains/m2Responses to post‐anthesis shading suggest that the degree of yield limitation by post‐anthesis photosynthesis is not constant for a given genotype, varying substantially from year to year. Thus in 1973 immediate pre‐anthesis conditions were unfavorable due to cloudiness, grains/m2 was low, and yield was entirely limited by this factor. In other years, yield was more sensitive to post‐anthesis shading. However it is concluded that grains/m2, hence crop photosynthesis in the immediate pre‐anthesis period, is the key to higher yield in this cultivar.
Photosynthetic Responses of Tall Fescue to Selection for Longevity below the CO2 Compensation Point1
Authors: Nelson C. J. , Asay K. H. , Patton L. D. 
Published: July 2010

There have been many attempts to identify efficient C3 plants by survival in CO2 environments below their normal CO2 compensation point (Γ). Thus far there have been no reports on characteristics of final survivors from such a treatment. Our objective was to determine relationships between CO2 exchange parameters in tall fescue (Festuca arundinacea, Schreb.) and to determine if selection for longevity under sub‐Γ conditions would be feasible for decreasing photorespiration or increasing net carbon exchange (NCE).About 4,400 seedlings of ‘Alta’ and 2,200 of ‘Kentucky 31’ were exposed to sub‐Γ conditions for seven to eight days and 36 and 22 final survivors, respectively, were selected. In both cultivars, the selected population was not different from the base in rate of NCE in 21% O2, NCE in 0% O2, or photorespiration estimated as NCE enhancement in 0% O2 over 21% O2. Rate of dark respiration was significantly increased in both Alta (P < 0.01) and Kentucky 31 (P < 0.10).Rate of dark respiration was not correlated with rates of other CO2 exchange parameters except in the base population of Kentucky 31, where it was positively correlated (P < 0.05) with photorespiration, NCE in 21% O2, and NCE in 0% O2. Rate of photorespiration was positively correlated (P < 0.01) with NCE in 21% O2 in all four populations and regression coefficients were similar. Combining all populations gave an overall correlation coefficient of 0.649 (P < 0.001) and a regression coefficient of 0.54.This suggests that in plant breeding programs selection for increased NCE will probably also increase photorespiration, unless genetic control is independent and selection pressure is placed on both characters.
Estimation and Utilization of Inter‐cultivar Competition in Peanuts1
Authors: Beg Akhtar , Emery D. A. , Wynne J. C. 
Published: July 2010

Competition among three peanut (Arachis hypogaea L.) cultivars: ‘NC 5,’ ‘NC 17,’ and ‘Florigiant,’ was measured in replicated hill and row‐plot field designs for purposes of predicting optimum proportions of the components in seed blends. The three cultivars are adapted to the Virginia‐North Carolina peanut belt, but differ in maturity and growth habit. Competition was determined by calculating the coefficients of regression for mean plant, fruit, and seed characters on numbers of competing plants or rows.Three‐year trials provided evidence of inter‐cultivar competition. Fruit yield, fruit number, and plant weight of NC 17 were found to increase (overcompensate) significantly over that of pure stands when grown in competition with Florigiant. Coefficients tended to be negative, small in magnitude, and nonsignificant when Florigiant was in competition with NC 17. NC 5 and NC 17 frequently had reduced numbers, sizes, and weights of fruit when grown in competition with each other. Overcompensation was not found when the coefficients for the regression of NC 17 performance on number of competing plants or rows of Florigiant were summed with coefficients based on reciprocal arrangements of the cultivars.Yields of cultivar blends could not be predicted using data from competition tests.
Results of Breeding for Tolerance to 2,4‐D in Birdsfoot Trefoil1
Authors: Devine T. E. , Seaney R. R. , Linscott D. L. , Hagin R. D. , Brace N. 
Published: July 2010

To develop a weed control system for birdsfoot trefoil (Lotus corniculatus L.) utilizing an effective, inexpensive, and relatively safe herbicide, 2,4‐D, a recurrent selection program was undertaken to breed a strain of trefoil tolerant to this herbicide. We believe that this is the first report of the successful use of recurrent selection to develop herbicide tolerance.A series of tests established that five cycles of field selection had been effective in developing a strain substantially more tolerant to 2,4‐D than commonly used trefoil cultivars. After 2,4‐D treatment, green weight of the lowest yielding progeny line of the tolerant strain was five times that of ‘Viking.’ Survival percentage of the resistant strain was significantly higher than Viking, ‘Empire,’ ‘Mansfield,’ ‘Granger,’ and ‘Tana.’ Fresh and dry weight, plant N composition, and surface wax accumulation were significantly less affected by 2,4‐D in the tolerant strain. Evidence is presented that the 2,4‐D tolerant strain is resistant to the 2,4‐D homologs as well as the parent compound. It was suggested that evaluation of early seedling growth during exposure to herbicides in petri dish culture may prove to be both an effective and efficient screening device in breeding programs to develop tolerance to specific herbicides.
Quality Factors Affecting the Nutritive Value of Bean Seed Protein1
Authors: Kelly J. D. , Bliss F. A. 
Published: July 2010

Seeds of four bean (Phaseolus vulgaris L.) strains with a range in protein content from 21.5 to 31.9% were selected and analyzed for their constituent amino acids. Differences in the levels of certain essential amino acids were detected. Total methionine and microbiologically available methionine, each as percent of protein, were similar in three of the four strains, but one strain had a lower level of available methionine, suggesting that part of the total methionine was unavailable.Correlation between protein efficiency ratio (PER) for rats and available methionine as percent of protein in the four strains was positive and significant, while similar correlations between PER and total methionine as percent of protein with or without cystine were not significant.The microbial assay used in determination of available methionine levels is outlined and its value in a breeding program for improving nutritive quality of beans is discussed.
Characteristics and Performance of Interspecific Hybrids Between Kentucky Bluegrass and Canada Bluegras1
Authors: Dale M. R. , Ahmed M. K. , Jelenkovic G. , Funk C. R. 
Published: July 2010

Interspecific hybridization involving four Poa pratensis L. selections as female parents in crosses with P. compressa L. produced 2,104 hybrids. Crosses using the highly sexual Kentucky bluegrass cultivar, ‘Warren's A‐20,’ and selections, Warren's A‐25 and Warren's A‐26, produced a very high frequency of hybrids.Many of these hybrids showed considerable first year vigor with more abundant panicle production than generally found in Kentucky bluegrass. However, these particular plants produced a very few or no viable seeds. Cytological studies indicated that these mostly sterile hybrids originated from the fertilization of reduced female gametes by reduced male gametes.The 54 interspecific hybrids produced using highly apomictic ‘Belturf’ Kentucky bluegrass as the female parent showed moderate to good floret fertility, acceptable seedling vigor, and some produced rather attractive turf. Cytological studies indicated that these fertile hybrids originated from the fertilization of unreduced eggs by reduced male gametes. These “triploid” F1 hybrids are moderately to highly apomictic.
Effect of Recurrent Selection for Combining Ability with a Single‐Cross Tester in Maize1
Authors: Horner E. S. , Lutrick M. C. , Chapman W. H. , Martin F. G. 
Published: July 2010

To obtain additional information on the effectiveness of recurrent selection for specific combining ability in maize (Zea mays L.), we evaluated seven cycles of selection for combining ability with the single‐cross tester F44 ✕ F6. Grain yield, lodging resistance, and low ear height were the main selection criteria.Seed of the selected population from each cycle was stored and later evaluated for combining ability with the original tester, F44 ✕ F6, and with an unrelated synthetic. The evaluation with F44 ✕ F6 indicated that the seven cycles of selection resulted in 18% more grain yield, 9% lower ear height, and 35% less lodging. Performance was similar when the same selected populations were crossed with an unrelated synthetic. This suggests that gains for all traits resulted from increasing the frequency of genes with additive effects.These results and others previously reported for inbred testers suggest that narrow‐base testers are effective for improving general as well as specific combining ability, and that it is possible to change such testers in a recurrent selection program with little loss in accumulated improvement.
Harvest Index in Spaced Populations and Grain Weight in Microplots as Indicators of Yielding Ability in Spring Wheat1
Authors: Fischer R. A. , Kertesz Z. 
Published: July 2010

A set of 40 adapted homozygous spring wheat (Triticum aestivum L.) genotypes were grown under similar conditions of irrigation and high fertility utilizing large plots and microplots seeded at normal densities, and spaced plants (60 × 60 cm grid). The objective was to see how well spaced plant traits, especially grain weight and harvest index, and microplot yields predicted true yielding ability as measured with the large plots. Phenotypic correlation coefficients were calculated using genotype means.Microplot yield was highly correlated (r = 0.67 at the 1% level) with large plot yield but explained less than half of the variation between the genotypes. Much of the residual was probably related to the highly significant genotype Χ plot type interaction. With spaced planting, yield/plant was correlated (r = 033 at the 5% level) with crop yield. Better correlations with crop yield were obtained with plant and shoot harvest indices (r = 0.56 and 0.66, respectively, at the 1% level). No numerical components of yield measured on spaced plants gave better correlations with crop yield than yield per plant itself.These results emphasize the major effect that the degree of interplant competition, probably primarily for light in this case, has on the performance of a genotype. As the degree of competition declined going from crop plots to spaced plants, genotypes which can more fully occupy the increased space available were favored; thus, the performance of non‐erect genotypes improved noticeably relative to erect ones. We conclude that harvest index measurement offers promise as a predictor of yielding ability where the seed available is limited.
Selection Among and Within Full‐sib Families to Develop Single‐crosses of Maize1
Authors: Hoegemeyer T. C. , Hallauer Arnel R. 
Published: July 2010

Systematic genetic advance in maize (Zea mays L.) hybrid yields depends on the improvement of breeding populations and the efficient extraction of inbred lines. We evaluated the efficacy of selection among and within fullsib families produced in two 2‐eared populations for the extraction of lines and for the identification of superior yielding hybrids. Intra‐ and interpopulation crosses were made among selected and unselected lines developed from ‘Iowa Two‐ear Synthetic’ (BSI0) and ‘Pioneer Prolific Composite’ (BSll). The selected lines were superior paired‐plant interpopulation crosses tested from the S0 ✕ S0 through S4 ✕ S4 generations. Six sets, each containing 28 crosses, produced from selected and unselected lines, were grown in three locations for 3 years.Interpopulation crosses averaged 5.8 quintals/ha (7.4%)greater yields than intrapopulation crosses, and the crosses of selected lines yielded 8.7 quintals/ha (11.2%) more than crosses of unselected lines. On the average, the tested paired‐plant crosses yielded 3.7 quintals/ha (4.2%) more than the untested crosses among selected lines and the specific combining ability (SCA) effects tended to be strongly positive for the tested line pairs. The yields of the previously untested crosses among the selected lines also showed that the selected lines expressed high general combining ability (GCA) with other selected lines.If the five best single‐crosses from each set were selected (9% selection intensity), 28 of 30 were from interpopulation crosses, 23 of 28 from selected lines, and II of 23 from the tested‐line pairs. If only the selected interpopulation crosses were grown (96 entries), 23 of the best 30 hybrids were identified from 336 entries. The method of selection, therefore, does develop an elite group of lines having high SCA with its tested mate and also high GCA with other elite lines with a minimum of testing. Thus selection among and within full‐sib families seems to be an efficient method of developing superior parental lines for hybrids.
Chlorogenic Acid Content of Meal from Cultivated and Wild Sunflowers1
Authors: Dorrell D. G. 
Published: July 2010

The chlorogenic acid (CA) content of dehulled and defatted sunflower (Helianthus annuus L.) seeds was determined on a portion of the germplasm maintained at the Modern Research Station. This material represented 167 inbred accessions, 387 highly inbred Morden lines, and 42 North American wild H. annuus collections.Cultivated sunflower seeds contained from 1.1 to 4.5% CA with an overall mean of 2.8% and a normal distribution. Approximately 6% of the cultivated inbreds contained 2% or less CA. The wild sunflower lines averaged 2.1% CA with almost half containing less than 2% CA.There was a highly significant correlation between CA content and oil content in all populations. Seed size was not related with CA content. In the wild population, low CA content was highly significantly correlated with high hull content. Although there was no association between country of origin and CA content for the cultivated inbreds, wild sunflowers collected in the southern USA contained lower levels of CA than those collected north of 40°N latitude.
Relationship of Yield, Seed Quality, and Fiber Properties in Upland Cotton1
Authors: Turner John H. , Ramey Harmon H. , Worley Smith 
Published: July 2010

Seed and fiber samples of four Upland cotton (Cossypium hirsutum L.) cultivars, grown at 17 locations in the 1973 Regional Cotton Variety Test, were examined for yield, seed quality, and fiber quality. Correlation coefficients were calculated among eight agronomic and quality parameters.No significant correlations were found between yield and oil content or yield and protein content. Three of the cultivars showed positive correlations between oil content and fiber maturity and negative correlations between oil content and percent immature seed. The strongest correlation for protein was a negative relationship with fiber maturity. ‘Lockett 4789A’ gave a high positive correlation between oil content and seed index. ‘Acala 1517–70’ showed a strong negative relationship between protein and fiber maturity. Both of these cultivars showed positive correlations between yield and fiber strength.The feasibility of using Micronaire readings (fiber maturity) as indicators of oil content for cottonseed in the various production zones are discussed.
Photoperiodic Control of Seed Filling for Soybeans1
Authors: Thomas Judith F. , Raper C. David 
Published: July 2010

Soybean plants [Glycine max (L.) Merr. ‘Ransom’] were grown in the controlled‐environment rooms of the phytotron at N.C. State Univ. to investigate the effects on floral and pod development of the morphological stage of plant development upon initial exposure to inductive short days, number of consecutive short days, and temperature. All plants were initially grown under long‐day photoperiods and at day/night temperatures of 18/14, 22/18, 26/92, and 30/26 C. In Experiment I, groups of plants were transferred to an inductive short‐day photoperiod at three stages of development: expansion of paired primary leaves, unfolding of third trifoliolate leaf, and unfolding of sixth trifoliolate leaf. Plants from each group were returned to the long‐day photoperiod upon appearance of the first open flower, when pods were becoming visible, or retained under the short‐day photoperiod until termination of the experiment. Measurements of vegetative and reproductive growth were made of all plants at 63 days after planting. In Experiment II, groups of plants were transferred to short‐day photoperiods either upon expansion of paired primary leaves or unfolding of sixth trifoliolate leaf. Plants from each group were returned to long‐day photoperiods after 0, 10, 15, 95, 30, and 50 consecutive short‐days. Measurements of vegetative and reproductive growth were made of all plants, regardless of when returned to long‐day photoperiod, at 50 days after initial exposure to short‐day photoperiod.Pod production efficiency (number of pods set/total number of flowers initiated) was greater for plants initially exposed to short days upon expansion of paired primary leaves than for plants exposed at a later morphological stage. However, the numbers of both flowers and pods/plant were increased by delay of exposure to inductive photoperiods due to increased numbers of main stem and axillary branch nodes. As thermoperiod was decreased, maximum pod production efficiency was achieved with fewer consecutive short‐days. An increased number of short‐day photoperiods beyond that required for efficient pod set was disruptive to vegetative growth. Dry weight of vegetative tissues and area of leaves generally was decreased, and pod weight was increased correspondingly, by increased numbers of consecutive short‐days. These data support a conclusion that the rate of seed‐fill for soybeans is responsive to photoperiodic conditions.