bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utilization of Plant Introductions in Soybean Breeding Populations1
Authors: Schoener C. S. , Fehr W. R. 
Published: July 2010

The relationship between percentage of germplasm from plant introductions (PIs) in soybean [Glycine max (L.) Merr.] populations and their performance for seed yield, height, and lodging was evaluated. Five intermated populations were developed from four PIs selected for their good yield potential, PI 68600, PI 68704, PI 81029, and PI 91150, and four cultivars or experimental lines, ‘Chippewa 64’, C1426, L15, and ‘Calland’. The parents and their hybrid progeny were intermated up to five times to form population AP1 with 100% PI germplasm, AP2 with 75%, AP3 with 50%, AP4 with 25%, and AP5 with 0%. Performance of progeny from 96 random S3 plants from each population was evaluated in three environments in Iowa during 1975 and 1976.Both the linear and quadratic mean squares were significant for differences in yield among the five populations. There was a linear increase in yield from AP1 to AP5; however, AP1 consistently was higher yielding than AP2. AP5 had the highest mean yield and greatest frequency of lines with high yield. AP3 had the greatest amount of genetic variability for yield, AP2 and AP4 were intermediate and AP1 and AP5 had the least. There was a significant linear increase in height from AP1 to AP5 and linear decrease in lodging score from AP1 to AP5.The use of PIs with good yield potential and up to five intermatings before selection did not overcome the superiority of the population developed from high yielding cultivars and experimental lines. The superiority of AP5 was small enough, however, to suggest that evaluation of PIs for yield may permit selection of parents that do not cause a drastic yield reduction in genetically diverse populations. The acceptable mean yield and high genetic variability of AP3 suggested that up to 50% PI germplasm may be suitable for populations intended for long‐term improvement by recurrent selection.
Forage Sampling Factors Influencing the Variability of In Vitro Fermentation Results of Grass Selections1
Authors: Holt E. C. , Ellis W. C. , Engdahl G. R. 
Published: July 2010

Variation in in vitro fermentation estimates of forage digestibility is a problem. Only a few studies have quantified the extent of laboratory variation, and even less information is available on variability associated with sample collection, processing, and storage prior to analysis. A study was designed to evaluate the effects of source of samples and maturation on genotype selection in a breeding program. Variance was partitioned into genotype effects; sampling procedures; effects of handling, drying, grinding, and storing samples; and laboratory analysis. The sampling procedure consisted of collecting bulk and tiller samples of 31‐day regrowth forage of five clones from each of five Panicum coloratum L. and seven Cenchrus ciliaris L. selections (genotypes). Tillers in the early inflorescence stage were selected while bulk samples consisted of the top growth from one‐half of each clone. Each sample was randomly divided in the field, and bulk samples were again subdivided following drying and grinding. Laboratory analyses were run on duplicate 0.5‐g samples.Bulk samples exhibited a wider range of digestibility among selections, and approximately the same genotypic rankings as did tiller samples. Bulk samples collected at three ages (approximately 4, 6, and 8 weeks of regrowth) showed genotype ✕ age interactions, indicating the need to sample at more than one stage of maturation. The largest component of variance (3.01 to 8.1) was associated with selections (genotypes). The second largest component of variance (1.81 to 2.65) was associated with clones. Clones accounted for 14 to 25% of total variance. Relatively little variance was associated with handling, drying, grinding, and storage of samples. From 9 to 22% of total variance was associated with in vitro analysis (duplicate samples). The components of variance for laboratory analysis ranged from 1.18 to 2.38, which is similar to that reported in other studies.The results indicate that for indeterminate plants, and others not varying widely in date of flowering, bulk sampling is acceptable. Improvement in precision of the in vitro procedure may be realized by sampling multiple clones of the same genotype and by multiple laboratory analysis. Grass breeders should sample plants at more than one stage of maturation to gain an improved assessment of forage digestibility potential.
Evaluation of Vigor in Soybean Seeds: Influences of Date of Planting and Soil Type on Emergence, Stand, and Yield1,2
Authors: Yaklich R. W. , Kulik M. M. , Garrison C. S. 
Published: July 2010

Soybean [Glycine max (L.) Merr.] seed lots were evaluated for emergence, stand, and yield. Seven cultivars were analyzed in 1975 and eight in 1976. The seeds were planted 3.8 cm deep at a rate of 6 seeds/0.3 m of row in sandy and heavy type soils. Three planting dates — early, pre‐optimum, and optimum — and four replicates were used for the evaluations. Emergence counts (V2 to V3 growth stage) and stand counts (R6 growth stage) were recorded for the planting dates and sites. Yield was determined on 4.9 m of row for seeds planted on the optimum planting date in the heavy type soil.Each year, seedling emergence and stand were better on a sandy type soil than on the heavy soil and were best for the optimum date of planting. Simple correlation coefficients of emergence and stand counts for both years were high and significant. However, analysis of variance showed seed lots did not perform similarity across sites and planting dates in 1975. A 10 to 15 percentage point difference in emergence was necessary for a significant difference between seed lots, depending on site and planting date. In 1975 and 1976 the correlations between stand and yield were low, rr= 0.361 and 0.311, respectively, but those between stand and yield/plant were high and negative, r = −0.862 and −0.830, respectively. Stand and yield for the cultivar ‘Wayne’ were significantly correlated each year.
Effect of Non‐Milo Cytoplasms on the Agronomic Performance of Sorghum1
Authors: Ross W. M. , Kofoid K. D. 
Published: July 2010

Over 97% of the grain sorghum [Sorghum bicolor (L.) Moench] hybrids in the United States are ipade with male‐sterile (A) lines that have cytoplasm tracing to one sorghum type, milo. Six ‘Combine Kafir‐60’ (CK)‐type A lines, ‘KS34A’ through ‘KS39A’, have non‐milo cytoplasms which are maintained with the same CKB line that maintains CKA, which has milo cytoplasm; but apparently KS34 through KS39 are seldom used.The six A lines and CKA were crossed to ‘Tx 414’ to make F1's, and the F1's were used to make six pairs of modified backcrosses as follows: (KS4‐CKB) ✕ (CKA‐Tx 414) vs. (CK4‐CKB) ✕ (KSA‐Tx 414) which are the same except for cytoplasms. The two sets of crosses, F1's and modified backcrosses, were grown at Mead, Nebr. in 1976 and 1977 in a replicated test to determine effects of the non‐milo cytoplasm on yield and other agronomic characters.No significant differences among entries were found for flowering, plant height, grain yield, heads per plant, 1,000‐seed weight, or seed number per head in either the F1's or the backcross group. The non‐milo cytoplasms apparently had neither adverse nor beneficial effects on the agronomic performance of the crosses. In consideration of the possible hazards that exist with one cytoplasm, widely used females should be extended into KS34 through KS39 cytoplasm bases for potential use in hybrid seed production.
Potato Leafhopper Resistance in Glandular‐Haired Alfalfa Species1
Authors: Shade R. E. , Doskocil M. J. , Maxon N. P. 
Published: July 2010

Five glandular‐haired alfalfa (Medicago) species were evaluated for resistance to the potato leafhopper (Empoasca fabae (Harris) in cages under greenhouse conditions. Preference was based on the percentage of time adults were observed on the plant rather than on the cage surface. Data showed that adults spent significantly less time on M. blancheana Boiss. and M. disciformis DC. than the adults did on the glabrous control (M. sativa L. ‘Vernal’). Adult mortality occurred at a higher rate on all five glandular‐haired species than on the control. Highest rate of mortality (100%) occurred on M. noeana Boiss. within 3 days, compared with 53% mortality on the control after 9 days.Total nymphal production, which reflects the over‐all influence of the plant on the potato leafhopper, was significantly less on all five glandular‐haired species than on the control. Glandular‐haired species were nearly immune to the first instars, as all nymphs produced were found dead in the first stadium and trapped in glandular hair exudate.
Speed of Germination as a Criterion of Seed Vigor in Soybeans1
Authors: Pinthus M. J. , Kimel U. 
Published: July 2010

The effect of germination speed on the development and seed yield of soybean [Glyclne max(L.) Merr.] plants was investigated. Seedlings from graded ‘Clark’ soybean seeds were geminated in individual turf pots and grouped according to speed of germination. The pots of each group were planted in separate lots in greenhouse and field experiments.In both experiments, foliage development, dry matter accumulation, and seed yield of the rapidly germinating plants exceeded those of the slowly germinating plants. In the field experiment, the average seed yield of the plots planted with seedlings germinating 4 and 5 days after sowing exceeded the yield of the plots planted with seedlings germinating 6, 7, and 8 days after sowing by 22%. Through tests of the progenies of the different groups it was ascertained that the differences in the speed of germination were not heritable.
Inheritance of Prolificacy in Maize1
Authors: Sorrells M. E. , Lonnquist J. H. , Harris R. E. 
Published: July 2010

The inheritance of prolificacy and the relationship of multiple ear development to time intervals between developmental stages of reproductive structures were studied in maize (Zea mays L.) in three different experiments using both quantitative and qualitative methods of genetic analysis.A six‐line diallel involving unrelated parents, F1's, and F2's were grown at population densities of 17,200 and 34,400 plants/ha over 2 years. General (GCA) and specific (SCA) combining ability effects were significant for both ear number and multiple‐ear‐weight index (MEWI). This index is defined as the total grain weight minus first ear grain weight divided by total grain weight. The ratio of GCA to SCA fixed‐effects variance ranged from 3.7:1 to 7.4:1 for ear number and from 2.5:1 to 7.2:1 for MEWI. Higher ratios were usually associated with the low population density. Phenotypic correlations and the correlations of GCA effects were strongly positive for the time intervals, first‐to‐second ear shoot emergence, and first‐to‐second silk. Also, silking interval was negatively correlated with both ear number and MEWI.In a second experiment, six unrelated parents and 15 F1's were dissected daily and the dates of initiation of tassel and ear shoot meristems recorded. General combining ability effects were highly significant for the time periods tassel‐to‐first ear shoot initiation and first‐to‐second ear shoot initiation. Only the time period between initiation of the first and second ear shoot was correlated with ear number (−0.57**) and MEWI (−0.63**).In an experiment involving related inbred lines, their F1's, F2's, and backcrosses, additive gene effects were highly significant for ear number and MEWI, and dominance effects were significant (0.05 level) for MEWI. Negative correlations were observed between both ear number and MEWI and the time periods, ear shoot emergence‐to‐pollen‐shed, first‐to‐second ear shoot emergence, and first‐to‐second silk. For the F1 and segregating generations of one pair of related lines, a greater frequency of second ears occurred on plants having fewer nodes above the first ear. In both experiments prolificacy factors segregated in a manner predictable from the penetrance and genetic segregation inferred from parents and F1's. The genetic analysis on two pairs of related lines indicated that a single locus or group of linked loci account for the majority of the variation in ear number an their segregating generations.
Resistance to Mexican Bean Beetle and Corn Earworm in Soybean Genotypes Derived from PI 2276871
Authors: Smith C. M. , Brim C. A. 
Published: July 2010

Progeny of three advanced soybean [Glycine max (L.) Merr.] backcross populations {‘Forrest’ ✕ [‘Bragg’ (2) PI 227687]). {Bragg ✕ [Bragg (3) ✕ PI 227687]} and {Bragg X [Bragg (3) ✕ PI 227687]) were sc reened for resistance to Mexican bean beetle (MBB) (Epilachna vorivestis Mulsant) and corn earworm (CEW) [Heliothis zea (Boddie)] defoliation in 1977 and 1978. Of the 258 progeny evaluated, 53% were similar to the resistant check PI 227687 in MBB resistance, but only 7% exhibited dual resistance to MBB and CEW. The level of MBB resistance differed significantly (P ≤ 0.05) among the 17 CEW‐resistant progenies from the three populations. Visual estimates of CEW feeding preference accurately indicated resistance in 73% of all observations, as compared to resistance ratings based on weight of leaf tissue consumed.Results of the study indicated that levels of MBB and CEW resistance equal to or greater than that of PI 227687 exist in progeny from the three backcross populations tested, and that evaluation of CEW leaf feeding resistance by visual estimate appears to be a useful method of rapidly eliminating large amounts of susceptible germplasm. The low incidence of progeny with CEW resistance among those with high MBB resistance suggested that indirect selection for resistance to CEW leaf feeding by screening for MBB resistance may be ineffective, and that future breeding efforts should utilize direct selection for resistance to CEW defoliation.
A Comparative Analysis of Nuclear‐determined Resistance to Helminthosporium maydis Races T and O in Maize1
Authors: Caunter Ivor G. , Gracen V. E. 
Published: July 2010

Nuclear gene resistance to Helminthosporium maydis races T and O was studied using diallel analysis. Plants were artificially inoculated in the field and ratings based on measurements of lesion length and lesion area were obtained. Resistance to both races was basically determined by the same set of nuclear genes. Deviations in the relative rankings of certain inbreds suggested that resistance genes functioned both additively and on a gene‐for‐gene basis with pathogenicity factors.Gene action conditioning resistance was similar for both races. Additive gene action was primarily involved in determining resistance, but dominance effects were also significant. The results suggest that several, possibly the majority, of genes that condition resistance to race T of H. maydis in the resistant lines, Mol7 and C103, also contribute to resistance to race O.
Nitrate‐N and Rhizobium Strain Roles in Alfalfa Seedling Nodulation and Growth1
Authors: Heichel G. H. , Vance C. P. 
Published: July 2010

Alfalfa (Medicago sativa L.) seedlings grown for 14 day with initial levels of 0, 10, 25, and 50 µg N/ml as nitrate and inoculated with individual strains of Rhizobium meliloti or a mixture of these strains were investi. gated to learn how seedling growth and nodulation are mediated by nitrate N levels similar to those found in soils during alfalfa establishment. With a mixed Rhizobium culture, the proportion of the seedlings that nodulated declined from 84% at zero N to 53% at 50 µg N/ml. Significant (P = 0.05) differences in frequency of seedling nodulation occurred among individual Rhizobium strains at each N level, and significant (P = 0.05) strain × N interactions were observed.At 0 and 10 µg N/ml, number of nodules per seedling elicited by inoculation with the mixture of strains was significantly (P = 0.05) higher than with any of the five constituent strains. At 25 and 50 µg N/ml, number of nodules per seedling was similar with the strain mix. ture and with individual strains. At all N levels, seedlings inoculated with a strain mixture consistently developed more leaves and longer roots than uninoculated controis. Individual strains significantly (P = 0.05) differed in stimulation of leaf and root development at 0, 10, and 25 µg N/ml, but not at 50 µg N/ml.Variance analysis, leaf growth, and nodulation frequency experiments suggested that one of the five Rhizobium strains was less effective than the other four or than the mixture. The results suggest the possibility of improving alfalfa nodulation by selecting for increased nodule numbers in the presence of nitrate N, or by the identification of Rhizobium strains with maximum effectiveness at ambient N levels.
Inheritance of Three Groups of Indole Alkaloids in Reed Canarygrass1
Authors: Marum P. , Hovin A. W. , Marten G. C. 
Published: July 2010

Certain tryptamine alkaloids and their derivatives appear to cause the severe diarrhea seen in sheep and sometimes in cattle that graze reed canarygrass, Phalaris arundinacea L. This malady is either absent or less prevalent in animals that graze trytamine‐carboline‐free, gramine‐containing clones. Our objectives were to study the mode of inheritance and genetic relationships among indole alkaloid phenotypes in this species.We characterized three groups based on chemical structure and occurrence in breeding materials of seven of the nine known indole alkaloids. Group G consisted of gramine; group T included N‐methyltryptamine (NMT), N,N‐dimethyltryptamine (DMT), and 2‐methyl‐l,2,3,4‐tetrahydro‐β‐ carboline (MTHC); and group MeO included 5‐methoxy‐N‐methyltryptamine (5‐MeO‐NMT), 5‐methoxy‐ N,N‐dimethyltryptamine (5‐MeO‐DMT) and 2‐methyl‐ 6‐methoxy‐l,2,3,4‐tetrahydro β‐carboline (6‐MeO.THC).A genetic model was proposed on the basis of data obtained from progeny analysis following self‐pollination and hybridization within and between alkaloid groups. The model was tested by analyzing F1 and F2 families from separate crosses between groups G and T, within group G, and testcrosses to group G of selected F1 plants. The results verified a two‐gene model in which a single dominant allele T at one locus controls synthesis of alkaloids for phenotypes in group T and a single dominant allele M at a second locus controls synthesis of alkaloids for phenotypes in group MeO. Phenotypes in group G are produced only when both recessive alleles m and t are homozygous.The M allele is epistatic to T and the two loci appear to be closely linked. Unidentified modifying factors appear to affect this interpretation in certain genetic backgrounds, and require further studies to ascertain their mode of inheritance. Alleles M and T had frequencies of 0.21 and 0.01, respectively, in the diverse reed canarygrass source, NCRCI.The fact that gramine is synthesized only in the presence of the double recessive will enable plant breeders to select directly for this type without progeny testing to verify the genotype.
Plant Water Stress Effects on Irrigated Grain Sorghum. II. Effects on Nutrients in Plant Tissues1
Authors: Eck H. V. , Musick J. T. 
Published: July 2010

A field study was conducted to determine nutrient concentration and dry matter and nutrient accumulation patterns in grain sorghum [Sorghum bicolor (L.) Moench] plants and to determine the effects of plant water stress on these parameters. Grain sorghum hybrid ‘Pioneer 8311’ was grown under five irrigation treatments to givestress periods varying in timing and duration.Samples were collected at weekly intervals from plants grown with and without stress from (i) early boot until early grain filling, (ii) heading until late grain filling, (iii) early grain filling until near physiological maturiy, and (iv) from early boot until mid‐grain filling. Plants were partitioned into component parts for dry matter estimation and analysis for N, P, K, Ca, Mg, and NO3. Plant water stress reduced N and P concentrations in leaves and increased N concentration in stalks and heads, but did not affect NO3−N, K, Ca, and Mg concentrations.In unstressed plants, dry matter accumulation proceeded at a near constant rate from about 40 days after planting until physiological maturity. Nutrient accumulation rates tended to be near‐constant from 40 days after planting until flowering and then slowed somewhat. At flowering, plants had accumulated 59, 77, 72, 90, 88, and 65% of their total dry matter N, P, K, Ca, and Mg, respectively. Plant water stress reduced dry matter and nutrient accumulation. Nitrogen and P were affected more than K, Ca, and Mg.
Elongation Force of Seedlings of Leguminous Crops1
Authors: Inouye J. , Tanakamaru S. , Hibi K. 
Published: July 2010

Using an unbonded strain gauge transducer and a null balancing recorder, the vertical elongation or lifting forces of 3‐ and 5‐cm tall seedlings of 12 leguminous species grown in darkness at about 23 C were measured. The elongation force (El) gradually increased after initially setting the cotyledons of hypogeous seedlings or plumular hooks of epigeous seedlings against the receptor of the transducer. The maximum force was reached 20 to 50 hours after the initial setting, with a gradual decrease thereafter.The maximum Ef differed significantly among species and among cultivars within species. The mean value for the maximum Ef of a species was positively correlated with seed weight (0.787** in 3 cm, and 0.816** in 5 cm tall seedlings). Furthermore, in seedlings 3 cm tall, highly positive relationships were found between stem area at the center portion‐of the seedling and seed weight (0.787**) or the mean value for the maximum Ef of a species (0.971**). The results indicate that the large seeded species produce large stems and therefore a large Ef.The maximum Ef per unit mass of seed was smaller in species which produced an epicotyl such as broad bean (Vicia faba L.), pea (Pisum sativum L.), and azuki bean (Phaseolus radiatus L. vat. aurea Prain.) compared to species which produced a hypocotyl such as peanut (Arachis hypogaea L.) and soybean (Glycine max (L.) Merrill). Among species which produce a hypocotyl, the elongation force was less in soybean and sword bean (Canavalia gradiata DC.) than in other species tested.
Convergent‐Divergent Selection for Area Improvement in Maize1
Authors: Lonnquist J. H. , Compton W. A. , Geadelmann J. L. , Loeffel F. A. , Shank Boyd , Troyer A. F. 
Published: July 2010

The development of basic breeding populations that are adapted to a wide area and have at least some resistance to crop hazards in a region is important to breeders. A program designed to develop such a population of maize (Zea mays L.) for the northern Cornbelt is described. Six breeders in the area contributed germplasm samples (convergence) which were intercrossed. Samples of the resulting population were sent to each collaborator (divergence) who practiced mass selection for healthy, productive plants. In subsequent years, harvested samples (balanced composites) sent to Wisconsin (the convergent phase) were subdivided and redistributed (divergence) in such a way that seed for each location did not include seed harvested from that location the previous year.Results from the first four cycles of selection were evaluated in performance trials at all locations over a 2‐year period. Significant increases in productivity (gram yield) and reduction in grain moisture at harvest were obtained. Evidence of increased stability was noted over the four cycles of selection.