bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Genetic Heterogeneity Within Two Soybean Populations. II. Competitive Responses and Variance Due to Genetic Heterogeneity for Nine Agronomic and Chemical Characters1
Authors: Byth D. E. , Caldwell B. E. 
Published: July 2010

Effects of genotypic heterogeneity within relatively homozygous lines of soybeans evaluated in three environments were essentially additive for most traits when averaged over populations of lines within a cross. This was related to equivalence of competitive advantages and disadvantages expressed by genotypes within these populations of heterogeneous lines; that is, competitive effects were compensatory.Such additivity apparently held, on the average, for individual heterogeneous lines in the simpler agronomic and chemical characters. However, effects of heterogeneity on character development were non‐additive in individual lines for yield, height, and seed size. Differential responses for characters and crosses were related to differences in the degree of heterogeneity within the lines. In general, interactions among relatively diverse genotypes conditioned more extreme responses, and interactions among relatively similar genotypes conditioned less extreme responses than expected, on the basis of additivity of genotypic effects.Substantial over‐ and under‐compensatory competitive responses occurred for yield, and competitive response was positively correlated with heterogeneous line performance in both crosses. Some implications of these responses, and potential biases introduced into bulk population breeding procedures as a result of their action, are discussed.
Water Requirement and Its Association With Growth Components and Protein Content of Alfalfa (Medicago sativa L.)1
Authors: Cole D. F. , Dobrenz A. K. , Massengale M. A. , Wright L. Neal 
Published: July 2010

Two experiments were conducted in a greenhouse environment at Tucson, Ariz., to investigate the water requirement of five cultivars and two experimental lines of alfalfa (Medicago sativa L.) at the seedling and mature stage of plant development. Another experiment was conducted to investigate differences in water requirement among genotypes within the cultivars ‘Mesa‐Sirsa’ and ‘Ladak.’Significant differences were found in water requirement among cultivars in both the seedling and mature stages of plant development. Significant differences were found among plants of different cultivars in dry forage and transpired water in the seedling stage; however, no significant differences for these factors were found among cultivars in the mature stage of plant development.Greater variation in water requirement was found within cultivars than was found among cultivars.Dry forage production, leaflet to stem and petiole ratio, leaf area, and percentage protein of stems and petioles were each significantly associated with water requirement when averaged over all cultivars.
Heritability Estimates of Quantitative Characters in Mung Bean (Phaseolus aureus Roxb.)1
Authors: Empig L. T. , Lantican R. M. , Escuro P. B. 
Published: July 2010

Heritability (broad sense) estimates of nine quantitative characters were obtained in the F2 of five crosses of mung bean strains. The estimation procedure used was the direct method wherein environmental variance was approximated with the use of the parents. Days to maturity had the highest heritability estimate with a mean of 71.2% for the five crosses. Mean estimate of heritability of 8.6% for seed yield was the lowest.In the F3, heritability (broad sense) estimates for seed yield and its components, namely, pods per plant, seeds per pod, seed weight, and seeds per plant were calculated by variance component analysis in one of the five crosses. Seed weight had the highest estimate of heritability which was 85%, whereas number of seeds per plant had the lowest value of 26%. Seed yield had an estimate of 47%.Based on the F2 data, maturity range had the highest expected genetic progress (37% of the mean) obtainable by selecting the top 5% of the F2 progenies. Seed yield had only 5% expected genetic progress.The implications of these results to breeding programs designed to maximize yield levels in mung bean were discussed.
Genetic Control of a Photoperiod—Temperature Response for Time of Flowering in Beans (Phaseolus vulgaris L.)1
Authors: Coyne Dermot P. 
Published: July 2010

In the first experiment conducted in the field on the inheritance of date of flowering in the cross between the early flowering ‘G.N. 1140’ and the late flowering PI 165078 cultivars of Phaseolus vulgaris L. it was found that this trait was controlled primarily by a single major gene with late flowering being recessive. The symbol fd was assigned to this recessive gene.In a second experiment conducted in growth chambers it was observed that PI 165078 flowered at a later date than G.N. 1140 when grown under long days (14 hours), and 29.4 C and 26.7 C (day and night) temperatures, but that there was no significant difference in date of flowering of the varieties under the 14‐hour photoperiod, and 26.7 C and 21.1 C. The increase in temperature under a 14‐hour day produced a differential response in date of flowering of the varieties.
Oat Varietal Differences in Length of Lower Internodes1
Authors: Nittler L. W. , Kenny T. J. 
Published: July 2010

Six oat, Avena sativa L., varieties grown in sand in a growth chamber were supplied with a complete nutrient solution. Consistent and highly significant varietal differences developed in length of internodes. Although length of internodes was affected by photoperiod, temperature, age, spacing, and planting depth, this is not considered a serious obstacle to use of internode length in varietal purity testing provided environmental conditions can be controlled.Plants of the ‘Russell’, variety grown with continuous light and a temperature of 27 ± 2 C had first leaf internodes (above the first foliar leaf node) three to five times as long as those of other varieties. Second leaf internodes of ‘Orbit’ were nearly twice as long as those of ‘Garry’ or ‘Niagara.’ Both Orbit and ‘Rodney’ had long third leaf internodes whereas ‘Clintland’ had the longest fourth leaf internodes.
Yields and Chemical Composition of Timothy (Phleum pratense L.) Plants Derived from Summer and Winter Tillers1
Authors: Knievel D. P. , Smith Dale 
Published: July 2010

Summer (nonvernalized) and winter (vernalized) timothy (Phleum pratense L.) tillers were grown at 18 C day/10 C night temperatures and harvested at anthesis. Inflorescence production and canopy heights were similar for both plant types, but the summer plants reached anthesis 12 days later. Yields of green leaf‐blade, stem plus sheaths, stem base, root fractions, and total plant dry matter accumulation rate of the summer plants were significantly greater than corresponding parameters of winter plants. Similarly, number of leaves and green leaf‐blade area per pot were significantly greater for the summer plants.Percentages of total nonstructural carbohydrates and fructosans were significantly higher in the summer plant parts, while percentages of total N were significantly higher in the winter plants. Reducing sugar, sucrose, starch, nitrate N, and crude fat percentages were similar among plant parts and between plant types. In vitro digestible energy of the primary shoot green leaf‐blades and of the primary and secondary shoot stems was significantly higher for the summer plants. In vitro digestible energy of the green leaf‐blades on the secondary shoots was similar for both plant types.
Effects of Selection for Lower Ear Height in Synthetic Populations of Maize1
Authors: Vera G. A. , Crane P. L. 
Published: July 2010

Two populations of maize (Zea mays L.) [Antigua 2D ✕ (B10 ✕ B14)] F5 and (Eto ✕ CBC) F5 were used a selection experiment conducted at Lafayette, Ind., to determine the effectiveness of 50% selection intensity in lowering ear height. These two populations were subjected to two cycles of selection, each followed by a generation of random intermating in Florida. The lowereared 50% of the plants in each day of silking was selected to avoid confounding selection for ear height with date of flowering.The evaluations of the subpopulations per se derived by selection and the topcrosses of these subpopulations with five single‐cross testers were made in three locations in 1968.The results showed that selection was effective in lowering the ear height 4.5% per cycle. There was no effect on percent moisture. A slight reduction in yield and a more pronounced reduction in percent lodging were statistically nonsignificant.
Effect of Environmental Conditions on the Growth of Four Perennial Grasses. III. Nucleic Acid Concentration as Influenced by Day‐Night Temperature Combinations1
Authors: Baker Barton S. , Jung G. A. 
Published: July 2010

Timothy (Phleum pratense L.), bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), and Kentucky bluegrass (Poa pratensis L.) were grown under controlled temperatures varying by 3.3 C intervals from 18.3 to 34.8 C during the day and from 1.8 to 18.3 C during the night. The top growth was analyzed to determine the influence of these temperature regimes on ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).Day temperatures exhibited considerably more influence on the nucleic acids than did night temperatures. As the day temperature was increased from 18.3 to 34.8 C the RNA concentration decreased in a near linear manner. The decrease was 43% in timothy and between 21 and 27% in the other three species.When grown at a day temperature of 18.3 C the RNA and DNA concentrations of orchardgrass and bromegrass increased as the night temperature increased. When grown at 34.8 C, however, the concentration of these two components decreased as the night temperature increased. With timothy and Kentucky bluegrass, night temperature had no appreciable influence on RNA, but the DNA concentration tended to increase as night temperature increased. It is proposed that the influence of day temperature on growth in the species used in this experiment may occur in part through its influence on nucleic acids while the influence of night temperature may occur through food reserves.
Inheritance and Trisome Linkage of Seedling Characters in Sorghum bicolor (L.) Moench1
Authors: Hanna W. W. , Schertz K. F. 
Published: July 2010

Segregation ratios of 24 seedling lethals in Sorghum bicolor (L.) Moench indicated that the characters were simply inherited.Some of the genes controlling these characters were tested for linkage with specific chromosomes by using primary trisomic plants. F2 segregation ratios in progenies from crosses of trisomic ✕ genetic stocks showed that the gene w18 was associated with the bottle‐brush trisome and the genes w19 and w20 were associated with the cone trisome. The genes controlling coleoptile color (Rs1 and Rs2) were associated with the small‐glume and stiff‐branch trisomes, respectively.
Influence of Oxygen, Sodium Hypochlorite, and Dehulling on Germination of Green Needlegrass Seed (Stipa viridula Trin.)1
Authors: Frank A. B. , Larson K. L. 
Published: July 2010

Rcsearch was conducted to determine methods for reducing dormancy and tests for predicting germination of green needlegrass seed (Stipa viridula Trim). ‘Lodorm’ and native seed were used in the study. Dehulling new and after‐ripened 1967 seed increased germination 38.5 and 47.4 percentage units, respectively, and of new and after‐ripened 1968 seed by 57.3 and 77.9 percentage units, respectively. After‐ripening occurred independently of the lemma and palea and was nearly complete 8 months after harvest. Treating intact seed with sodium hypochlorite increased germination of 1967 after‐ripened seed from 42.6 to 87.9%, of 1968 new seed from 3.8 to 43.6%, and of 1968 after‐ripened seed from 12.8 to 72.0%. Germinating intact seed in an oxygen‐enriched atmosphere increased germination of 1967 after‐ripened seed from 57.8 to 86.6%, of 1968 new seed from 3.0 to 29.0%, and of 1968 after‐ripened seed from 13.5 to 71.2%.The results obtained from dehulling, sodium hypochlorite, and oxygen treatments indicate that dormancy may be at least partially controlled by the following factors: impermeability of the lemma and palea to gas exchange, a mechanical barrier imposed by the lemma and palea which physically prevents coleoptile and radicle emergence, low seed vigor, or an oxidizable inhibitor present in the intact seed. Tetrazolium viability was a good predictor of germination of dehulled after‐ripened seeds.
Heterosis and Combining Ability in Diallel Crosses of Burley Tobacco, Nicotiana tabacum L.1
Authors: Legg Paul D. , Collins G. B. , Litton C. C. 
Published: July 2010

Twelve burley cultivars of N. tabacum L., the 66 possible F1 hybrids among them, and the 66 F2 populations were evaluated during 1966‐69. Comparisons of the F1 hybrids with the parents indicated that heterosis values were small but significant for several characters. Two hybrids, ‘Ky 10’ × ‘Burley 37’ and Ky 10 × Experimental line 42, yielded more cured leaf than Ky 10, the highest yielding variety in the test. Percentages of inbreeding depression obtained from comparisons of the Fl and F2 generations in 1969 were also small, but they were significant for some characters.Estimates of variances for general combining ability were significant for all seven characters studied. Specific combining ability variances were significant for days to flower, leaf width, and yield.
Response of Alfalfa (Medicago spp.) to Light Interruption of the Dark Period1
Authors: Massengale M. A. , Dobrenz A. K. , Brubaker H. A. , Bard A. E. 
Published: July 2010

The influence of light interruption of the dark period on flowering and certain growth characteristics of alfalfa (Medicago spp.) was studied under field conditions at Tucson, Ariz.One light interruption of 30 min in the middle of the dark period caused significant differences in flowering percentage, height, and dry‐weight production of specific cultivars. Alfalfa plants that were grown under light interruption had smaller crowns, flowered earlier and more profusely, and produced less dry matter compared to plants grown under natural daylength.Seasonal temperatures influenced the effects of light interruption of the dark period. Differences between light treatments with respect to flowering were most evident during shorter natural daylengths which coincided with the cooler growth periods, while differences in production of dry matter were most evident when maximum and minimum temperatures were highest.Light interruption of the dark period can be used to obtain more rapid and complete flowering of alfalfa under field conditions.
Response of Soybean Genotypes to Spacing in Hill Plots1
Authors: Shannon J. G. , Wilcox J. R. , Probst A. H. 
Published: July 2010

Experiments were conducted in a systematic design at 10 spacings ranging from 30 to 122 cm using determinate and indeterminate soybean genotypes (Glycine max.(L). Merrill) of both ‘Clark’ and ‘Harosoy.’ Yield and other characters were evaluated to determine the optimum spacing for evaluating maturity group II and IV soybean genotypes in hill plots. Competition between genotypes was also characterized.Yield consistently increased as spacing between hills increased in all genotypes except the short determinate dt1. In general, the tall determinate, Dt2, and the indeterminate genotypes of each variety matured earlier and lodged least at the intermediate spacings. The dt1 determinates lodged little and tended to mature progressively later as distance between bills increased. Plants, in general, were taller at the closest spacing and progressively shorter as spacing increased. The genotypes of Harosoy differed in response to spacing for seed weight. Seed weight in dt1 increased as spacing between hills increased, while seed weight for Dt2 and indeterminate Harosoy tended to increase as spacing between hills increased. Seed weight in all the Clark genotypes tended to increase as distance between hills increasedCompetition between the determinate and indeterminate genotypes within each variety revealed few significant differences for any character. Competitive effects on yield among genotypes diminished as spacing increased and were nonexistent at 65 cm between hills and beyond.
Effects of Potassium Nitrate on Germination and Respiration of Dormant and Nondormant Kentucky Bluegrass (Poa pratensis L.) Seed1
Authors: Maguire J. D. , Steen K. M. 
Published: July 2010

Respiration rates for germinating ‘Cougar’ and ‘Newport’ Kentucky bluegrass (Poa pratensis L.) seed produced in 1965, 1968, and 1969 (freshly harvested) increased rapidly for 2 to 4 days after imbibition in 0.2% KNO3 and in water, then slowly increased for the remainder of a 7–day period. Cougar seed treated with KNO3 had higher respiration rates than water‐treated seed; only slight increases were obtained with KNO3‐treated New port seed. Seed from 1965 and 1968 took up oxygen more rapidly than the 1969 seed. Respiration rates of 1– and 4–month‐old Newport seed decreased rapidly 3 to 4 days after imbibition.Germination tests of 1969 seed at 1 month after harvest after imbibition showed Newport seed to be more dormant than Cougar. KNO3 increased germination of 1–, 4– and 9–month‐old Newport seed but had no effect on Cougar seed.
Evaluation of Methods for Generation Advance in Bulk Hybrid Soybean Populations1
Authors: Empig L. T. , Fehr W. R. 
Published: July 2010

We evaluated four methods of generation advance in bulk hybrid soybean (Glycine max (L.) Merrill) populations for their ability to maintain superior genotypes and genetic variability for economic traits and for their efficiency in sampling time. The methods used were single seed descent (SSD), restricted cross‐bulk (RCB), maturity‐group bulk (MGB), and cross‐bulk (CB).Method means did not differ significantly at either location, and differences in genotypic variance among methods were not consistent in all crosses. SSD, RCB, and MGB maintained a similar number of high yielding lines, about twice as many as CB. SSD and MGB were the most effective methods in maintaining early lines. However, there were no differences among methods for the frequency of late segregates. SSD was about twice as effective for maintaining large‐seeded lines as the other methods. The four methods did not differ appreciably for the number of lodging resistant lines. RCB had the highest frequency of tall plants.Comparison of the harvest time spent in obtaining samples for the next generation showed that CB was the fastest and RCB the second fastest method. SSD was more time‐consuming than CB and RCB. MGB was the most time‐consuming, since it required pulling plants at several different times to maintain subpopulations restricted in maturity.SSD was the method least influenced by natural selection; therefore, it may be the most useful method in greenhouse or winter nursery environments where a genotype may perform differently than under field conditions in its area of adaptation.
Physiological Changes in Barley Induced by Greenbug Feeding Stress1,3
Authors: Gerloff E. D. , Ortman E. E. 
Published: July 2010

SummaryQuantitative amounts of greenbug (Schizaphis graminum Rondani) feeding stress on the first foliar leaf of barley (Hordeum vulgare L.) caused a severe detrimental decline in chlorophyll content and in the rate of photosynthesis. The stress produced an increase in the rate of respiration but no change in leaf area, fresh weight, or dry weight during 7 days of controlled infestation.
Photosynthetic Rates and Light Saturation Curves of Individual Soybean Leaves Under Field Conditions1
Authors: Beuerlein J. E. , Pendleton J. W. 
Published: July 2010

The effects of leaf age and light acclimation on apparent photosynthesis (AP) rates of single attached leaves of highly productive, field‐grown, ‘Wayne’ soybeans (Glycine max L. Merr.) were determined. AP measurements were made on leaves at nodes along the main stem of plants 5 cm apart in 76‐cm rows (normal canopy plants) and on leaves at different nodes of widely spaced (76 cm ✕ 76 cm) plants without branches. The response to light in the range of 2,000 to 15,000 ft‐c of fully expanded leaves of the two types of plants was also measured.The AP rates of upper and lower leaves of the normal canopy plants averaged 33 and 20 mg CO2/dm2/hour, respectively. AP rates of upper and lower leaves of spaced plants were equal and averaged 50 mg CO2/dm2/hour. Leaves from the upper part of normal, field‐grown canopy plants became light saturated at 10,000 ft‐c but the leaves of spaced plants were not light saturated at 15,000 ft‐c.
Genetic Variances in a Synthetic Variety of Maize Estimated by Two Mating Designs1
Authors: Sentz J. C. 
Published: July 2010

Genetic parameters for a synthetic variety of maize (Zea mays L.) were estimated from Design I (D‐I) Design II (D‐11) matings. Corn borer and stalk rot resistance selection in derivation of lines had no effect upon mean yield or other traits in the D‐II reconstituted population.Additive variance was significant with both designs and of primary importance for all traits. Dominance variance contributed 45% of the genetic variance for yield, but was relatively unimportant for other traits. Greater additive variance estimates with D‐II indicate some epistasis may exist for height and days to tassel. However, additive estimates were less with D‐II for yield, ear moisture, and ear diameter.Genotype‐environment interactions were important for yield and ear moisture, but no consistent rdationships with their respective genetic components were obtained. In the absence of first‐order genotype interactions with years and locations, I pooled the interaction mean squares for D‐I analysis.D‐I was less sensitive than D‐II for estimating genetic variances, particularly dominance variance. Although variance estimates were not large, expected yield increase with half‐sib progeny selection was 6.1 to 8.6%.
Selection in Two Seedling Crops of Four Sugarcane Progenies
Authors: James N. I. , Miller J. D. 
Published: July 2010

Phenotypic correlations were obtained among stalk number, stalk diameter, and Brix, within and among the plant‐cane seedling crop, first‐ratoon seedling crop, and the plant‐cane clonal crop, in progenies of four sugarcane (Saccharum spp.) crosses. Associations among characters within crops were low.The correlation coefficients for stalk number were .378** and .363** between the plant‐cane clonal crop and the plant‐cane and first‐ratoon seedling crops, respectively. Stalk diameter was more closely associated than stalk number between the plant‐cane clonal crop and the plant‐cane seedling crop (r : .618"*). Correlation coefficients for stalk diameter between the clonal crop and first‐ratoon seedling crop were heterogeneous among progenies and ranged from .406** to .673**. Stalk diametera ppearedto be a morer eliable selection criterion than stalk number, particularly in plant‐cane seedlings. Correlation coefficients for Brix among the crops were about equal to those for stalk number, indicating that the two characters were less reliable than stalk diameter, as sdection criteria.Various culling levels imposed on the plant‐cane and first‐ratoon seedling crops indicated that effectiveness of selection was equal when the same selection pressure was applied in both crops. Results were similar with independent and simultaneous selection for the three characters. These data indicated that the most reliable selection criterion was stalk diameter. Stalk numberw as less reliable than either stalk diameter or Brix.Selected populations could be obtained with high frequencies of segregates acceptable for stalk diameter. The trequency of segregates acceptable for stalk numbera nd Brix could be increased by selection, but populations with high frequencies of acceptable segregates could be obtained only when levels of acceptability were low.