bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth and Yield of Wheat under CO2 Enrichment and Water Stress1
Authors: Sionit Nasser , Hellmers H. , Strain B. R. 
Published: July 2010

Growth and yield responses of a semi‐dwarf spring wheat (Triticum aestivum L.; cv. GWO 1809) to two CO2 concentrations and two water stress regimes were studied in controlled environment chambers of the Duke Univ. Phytotron. Groups of plants in low (350 ppm), or high (1,000 ppm) CO2 environments were subjected to water stress By withholding irrigation starting at the 10th day after the beginning of anthesis. A second drying cycle beginning 5 days after termination of the first cycle was also given to some of the plants. Water potential of the flag leaves of the main stem of the plants in each CO2 environment reached a minimum of −13 bars at the end of the first drying cycle and −17 bars at the end of the second cycle.Under well‐watered conditions high CO2 enhanced the rate of tiller production by 43% and significantly increased grain yield, total dry matter, and number and size of the grains.As water stress developed, the osmotic potentials of the high CO2. plants decreased at a faster rate and resulted in maintenance of higher turgor pressures at the end of each stress cycle compared to the low CO2 plants. Osmotic potentials of the leaves of both high and low 2 plants decreased faster in the second drying cycle than in the first.Significantly fewer and smaller grains were produced on the plants grown under water stress in both CO2 concentrations compared to unstressed plants. In general, high CO2 plants under water stress conditions had a grain yield and total dry matter production equal to the unstressed, low CO2 plants. Thus, CO2 enrichment increased the yield potential of the water limited wheat plants due probably to osmotic adjustment by an increased concentration of solutes in their leaves.
Selection for Root and Crown Rot Resistance in Alfalfa1
Authors: Richard C. , Michaud R. , Frève A. , Gagnon C. 
Published: July 2010

Root and orown rot cause extensive damage to alfalfa (Medicago sativa). In this study, Fusorium solani followed by F. oxysporum, F. roseum, and F. tricinctum were most frequently isolated.Two techniques of inoculation, with one isolate of F. roseum var. acuminatum, were used for screening alfalfa for Fusarium root rot resistance. Both techniques were effective in producing a high percentage of infection. The application technique used on 3‐month‐old plants gave 5.9% resistant plants in the cultivar ‘Europa.’ Only 3.2% resistant plants were found when the bareroot‐soak technique was applied on 3‐week‐old seedlings. Resistance was evaluated by measuring the vertical discoloration in the split taproot. Plants with less than a 5mm spread of internal browning from the wound site were saved and intercrossed.The populations developed through each technique were established in the field at three locations in the spring of 1977 and rated for root rot in the fall of 1978. The two populations selected for resistance showed consistently less root rot than the unselected one although differences were not statistically significant.In a greenhouse study we were able to detect significant variation for root rot infection among as well as within polyerossed progenies of the selected genotypes suggesting that resistant genes for this disease are present in alfalfa. Narrow‐sense heritability was estimated at 22%. Some specific crosses were made between resistant (R) and susceptible (S) plants. The cross S ✕ S showed almost twice as much root rot infection as the cross R ✕ R. R ✕ S was better than expected based on mid value of R ✕ R and S ✕ S.Based on the results of this study, we believe progress is possible toward developing a crown and root rot resistant alfalfa.
Effect of 2,4‐D on Cotton Yield, Floral Nectar, Seed Germination, and Honeybee Visits
Authors: Moffett Joseph O. , Stith Lee S. , Morton Howard L. , Shipman Charles W. 
Published: July 2010

In Arizona honey bees, Apis mellifera L., frequently visit cotton flowers, Gossypium hirsutum L., in sufficient numbers to adequately pollinate the male sterile flowers and produce hybrid cotton seed. Yet in some other states and at times in Arizona, honey bee visits to cotton flowers are low or erratic. Since hybrid cotton seed may be in demand in the near future, this study was made to determine how spraying 2,4‐D [(2,4‐dichlorophenoxy) acetic acid] on cotton plants affected honey bee visits, seed yields, and nectar secretion.Small concentrations of 2,4‐D were sprayed on five cotton cultivars at three locations in Arizona from 1975 to 1977. Each year, 1 ppm applied in 187 liters of water/ ha at the beginning of bloom increased the volume of floral nectar more than 30%. An application of 10 ppm was harmful to the plants. Application of 2,4‐D when plants started to flower increased the amount of nectar more than application 3 weeks earlier or application at both times. One ppm of 2,4‐D had no significant effect on cotton yields or sugar concentration of the floral nectar.This dosage also had no significant effect on honey bee visits during the only year, 1977, that visits were counted. However, this year the visits were relatively high in both the check and unsprayed plots. Results might be different when the bees are not visiting the flowers well. None of the levels of 2,4‐D applied (0.01, 0.1, 1.0, and 10.0 ppm) affected germination or weight of the seeds produced or caused damage to seedlings grown from the sprayed plants.
A Compendium of Information about Named Genes for Low Reaction to Puccinia recondita in Wheat1
Authors: Browder L. E. 
Published: July 2010

Thirty‐five genes for low reaction to Puccinia recondita Rob. ex Desm. (Lr genes) in wheat, Triticum aestivum L., have been studied and named in a sequential number series by different authors. This paper summarizes information about these named Lr genes. Information on origin, chromosome location, characteristic low infection types, relative environmental sensitivity, synonymy, reference host lines, and reference cultures is summarized.Five Lr genes, Lrl2, Lrl3, Lr22a, Lr22b, and Lr26 can be detected only by inoculating adult plants with an avirulent culture; the others can be detected by inoculating seedling plants with an appropriate cullture. Characteristic low infection types conditioned by Lr genes and their corresponding Lr genes range from 01C, where only very small flecks occur, to 56X to 78X where extensive sporulation occurs. Post‐infection Temperature influences the expression of all Lr genes; but some, Lr11, Lr12. Lr13, Lrl4a, and Lrl8 are especially sensitive to high temperatures. The name Lr genes have been shown to occur on 13 different chromosomes, in all 3 common wheat genomes. Lr genes and their corresponding genes for pathogenicity are the basis for storing and retrieving information about specificity in the P. recondita:Triticum system.
Effect of the Ethoxy Analog of Rhizobitoxine on Nodulation of Soybeans1
Authors: Devine T. E. , Breithaupt B. H. 
Published: July 2010

A common property of Rhizobium japonicum strains that are able to nodulate the nodulation restrictive soybean [Glycine max (L.) Merr.] genotype rj1 rj1 is the ability to produce rhizobitoxine (2‐amino‐3‐hydroxypropoxyvinylglycine). The ethoxy analog of rhizobitoxine (aminoethoxyvinylglycine) was tested for potential to modify the nodulating ability of strains of Rhizobium japonicum (Kirchner) Buchanan with Clark rj1rj1 soybeans. The analog was added to broth cultures of Rhizobium at concentrations of 0, 5 ✕ lO−10, 5 ✕ 10−8, 5 ✕ 10−6, 5 ✕ 10−6 and 5 ✕ 10−4 M, 30 hours before being used to inoculate seeds planted in Leonard jars.The analog did not enhance nodulation at any of the concentrations tested. Genetic modification of the rhizobial microsymbiont appears to be a more promising approach for obtaining Rhizobium strains capable of successfully nodulating the rj1 rj1 genotype.
Effect of Awn Length and Naked Caryopsis on Malting Quality of Betzes Barley1
Authors: McGuire Charles F. , Hockett E. A. 
Published: July 2010

Plant breeders at the Montana Agruicultural Experiment Station developed four isogenic ‘Betzes’ lines from a Betzes*7/‘Sermo’ barley (Hordeum vulgare L.) cross. The four isogenes were long‐awned covered (Lk2Lk2NN), long‐awned naked (Lk2Lk2nn) short‐awned covered (lk2lk2NN), and short‐awned naked (lk2lk2nn). These lines and Betzes were grown in a total of 11 environments in the western United States in 1970 and 1973.Of the four experimental isogenic lines, the two covered types produced the most grain and were similar to Betzes in this trait. The long‐awned naked line produced 91%, and the short‐awned naked 89%, of Betzes. Grain from each location was malted separately. Long awns produced significantly heavier kernels, higher percentage of plump kernels, lower diastatic power, and lower alpha amylase activity than short awns. Naked caryopsis conditioned significantly higher barley protein content, higher malt extract, a higher finecoarse grind extract difference, lower kernel weight, lower percentage of plump kernels, lower kernel color score, lower wort color, lower wort N:malt N, lower diastatic power, and lower alpha amylase activity than the covered caryopsis. Genotypes with the covered allele averaged about 10% greater grain yield than did the naked genotypes.
Recurrent Selection in Soybeans. III. Selection for Increased Percent Oil in Seeds1
Authors: Burton J. W. , Brim C. A. 
Published: July 2010

Three cycles of recurrent selection to increase seed oil percentage were conducted in a soybean [Glycine max (L.) Merr.] population segregating for male sterility (ms1ms1). The base population was planted single plant hills to allow for natural cross pollination of male‐sterile plants by male‐fertile plants. At maturity, male‐sterile plants with the highest seed oil percentages were selected from this crossing block. The halfsib families from the selected plants w.ere grown to maturity in the greenhouse, and the individual within each half‐sib family with the highest seed oil percentage was selected. A new cycle was begun by a natural intermating of the progeny of theselected individuals in the field.The selected progenies from each cycle of selection were evaluated in composite populations and singly as lines. The combined composite and lines tests showed cycles of selection, at an average rate of 0.35 ± 0.03/cycle. There was a nonsignificant increase in total oil from 444 to 460 kg/ha. Protein percentage decreased at a rate of −0.52 ± 0.08/cycle. Changes in yield and total protein were not statistically significant.An investigation of variation within the selection populations showed that genotypic variation among the mass selected lines did not change through three cycles of selection. Variation among the within half‐sib family selected lines was greater than the variation among mass selected lines in cycle one and two but not three. Realized heritability estimated from the observed response to mass selection was 0.28 ± 0.03, and the heritability estimated from the within family selection response was 0.20 ± 0.04. The difference between the two was attributed, in part, to differences in phenotypic variance.The results showed that both mass and within family selection contributed to the overall progress. The segregation of genetic male sterility in the population proved to be a convenient and inexpensive way to allow natural random mating of selected individuals and to provide half‐sib families.
Effects of Daylength Response and Semidwarfism on Agronomic Performance of Spring Wheat1
Authors: Busch R. H. , Chamberlain D. D. 
Published: July 2010

Semidwarfism and daylength insensitivity have advantages for winter increase in southern latitudes and to allow wider potential use in breeding programs around the world. To determine if these traits have adverse effects in the upper Midwest, the progenies from a cross of ‘Justin,’ a tall daylength‐sensitive spring wheat (Triticum aestivum L.), by ‘Ciano 67,’ a semidwarf daylength‐insensitive cultivar, were separated into four phenotypic classes: tall‐insensitive (TI), tallsensitive (TS), semidwarf‐insensitive (DI), and semidwarf‐sensitive (DS). Each phenotypic class was represented by 28 F6 lines, randomly derived with the exceptions of their response to daylength and plant height. The lines were grown in three environments after normal time of seeding and one environment after late seeding to obtain information on the effects of semidwarfism and daylength‐insensitivity on various traits in different environmental conditions.As expected, the insensitive classes headed earlier than the sensitive classes, while the tall classes and semidwarf classes headed similarly. The sensitive classes were slightly taller than the insensitive classes.The tall classes yielded more than the semidwarf classes in the two environments where yields were highest but did not differ over all locations. The sensitive classes were superior to the insensitive classes in three of the four environments, but they did not differ following late‐seeding. Individual high‐yielding lines were observed in each phenotypic class, except in the TI class.The DS class had considerably lower test weight than all other classes. However, reduced test weight did not appear to be closely associated with semidwarfism since the DI class had test weight equal to the mean of the two tall classes.The DS class was lowest in protein percentage, but the DI class was equal to the TS class. Thus lower protein percentage did not appear closely related to the semidwarf trait.Late seeding did not reduce the performance of the semidwarf or the insensitive classes relative to the other classes. The TS and DI classes represented parental types and apparently had higher frequencies of favorable gene combinations for yield. Consequently, for future studies, intercrossing may be beneficial to help distribute favorable gene combinations. Using these genetic materials, no severe deleterious effects were observed to be tightly associated with semidwarfism or daylength‐insensitivity.
Heritability of Canopy‐Apparent Photosynthesis and Its Relationship to Seed Yield in Soybeans1
Authors: Harrison S. A. , Boerma H. R. , Ashley D. A. 
Published: July 2010

Selection based on canopy‐apparent photosynthesis (CAP) may be a means of improving the effectiveness of selection for seed yield in soybeans [Glycine max (L.) Merr.]. The present study was undertaken to determine the heritability of CAP and to determine the relationship of CAP to seed yield in F3‐derived lines from two soybean crosses.In 1977 and 1978, 34 F3‐derived soybean lines from each of the crosses, ‘Dare’ × ‘Forrest’ (Cross V) and ‘Tracy’ × ‘Davis’ (Cross VI), were planted in a randomized complete block design with three replications. Two CAP determinations/plot were made during the period of pod and seed development. Significant genotypic variation and transgressive segregation for CAP occurred at each measurement for both crosses. Heritabilities based on variance component estimates were 41% for CAP and 28% for seed yield in Cross V and 65 and 14% for Cross VI.Seed yield and CAP were significantly related (r=0.55 and 0.54) in both crosses. The average yield improvement over the 2 years of indirect selection based on CAP rate, using a 15% selection intensity, was 79% of direct selection for yield in Cross V and 146% in Cross VI. Based on the 2‐year means, 6 of the 10 highest yielding lines in Cross VI were among the 10 lines with the highest CAP rates. With the techniques used in our experiment, the cost and time of measuring CAP greatly exceeded that for measuring yield. The value of selecting for increased CAP to increase seed yield will be determined by the adaptability of current and future technology to determine CAP on fieldgrown soybeans.
Breeding for Early Maturity and Verticillium Wilt Tolerance in Upland Cotton1
Authors: Cano‐Rios Pedro , Davis Dick D. 
Published: July 2010

Inheritance of earliness of crop maturity and Verticillium wilt (Verticillium dahliae Kleb.) tolerance and the relationship between the two characters, was investigated using seven strains of cotton (Gossypium hirsutum L.). Maturity rank was consistent over the two locations used, Las Cruces, N.M., USA, and Matamoros, Coahuila, Mexico.Only general combining ability effects (GCA) were significant for either character. The strains Nectariless and Stahmannh ad the largest GCA effects for crop earliness, indicating that these cottons are potentially useful sources of germplasmin earliness breeding programs. Yugoslavian and ‘Deltapine 16’ exhibited the largest GCA effects for Verticillium wilt tolerance.Yugoslavian and Stahmann showed the largest GCA effects for lint yield, suggesting that these strains could have value in developing wilt tolerant cultivars with good fiber yields. The strong association between wilt tolerance and lint yield at Las Cruces suggested that selecting for wilt tolerance among progenies stemming from these cottons on wilt‐infested soil might also increase lint yield.Simultaneous selection for earliness of crop maturity and wilt tolerance, using Stahmannas a donoro fearliness, could be accomplished using the pedigree method of breeding.
Cell Dynamics in Leaf Meristems of Contrasting Tall Fescue Genotypes1
Authors: Volenec J. J. , Nelson C. J. 
Published: July 2010

Leaf elongation rate is a factor associated with yield per tiller and rate of canopy development. Elucidation of the mechanism by which leaves elongate may assist plant breeders and crop managers in optimizing agronomic performance. Our objectives were to locate the leaf intercalary meristem of tall rescue (Festuca arundinacea Schreb.) and to assess the relative contribution of cell division, cell elongation rate, and mature cell length to leaf elongation rate. Both cell division and elongation occurred in an intercalary meristem located with a lignin‐sensitive stain in the basal 30 mm of the elongating leaf. Growth rates within the elongation zone were ascertained by placing equispaced ink dots on the epidermis of the exposed meristem region and then measuring their displacement after 24 hours of growth. Growth occurred between dots placed 2 mm above the point of the previous leaf's attachment and those placed 13 and 26 mm above in genotypes exhibiting low (LYT) and high (HYT) yield per tiller, respectively. Maximum elongation rate occurred from 6 to 7 mm and from 9 to 14 mm above the point of the previous leaf's attachment in the LYT and HYT genotypes, respectively. In these regions, elongation rate of leaf tissue of the LYT genotype averaged 1.0 mm mm‐1 day ‐1, which was 40% higher than that of the HYT genotype.Microscopic measurement of epidermal cell lengths throughout the elongation zone, and measurement of leaf elongation rate (LER), permitted an assessment the relative contribution of both cell division and elongation. The LER of 26 mm day‐1 of the HYT genotype was 44% higher than that of the LYT genotype. The HYT genotype also had a 100% longer cell elongation zone and produced 185 epidermal cells day ‐1 cell column‐1 which was 24% more than that produced by the LYT genotype. The 145 µm length of mature epidermal cells of the HYT genotype was 22% longer than those of the LYT genotype. The elongation zone of the HYT genotype contained 509 epidermal cells which was 94% more than the LYT genotype, but each epidermal cell expanded at a rate that was 20% slower. This resulted in a duration of elongation of 2.8 days cell‐1 for the HYT genotype, which was 56% longer than that of the LYT genotype. The large number of cells and long duration of cell elongation in the HYT genotype overcame the slow rate of cell elongation. This resulted in more and larger matured cells which led to the more rapid LER and high yield per tiller characteristic of the HYT genotype in comparison with the LYT genotype.
Breeding Potentials of Noncultivated Cottons. V. Productivity of Cultivars, Race Stocks, and F1 Hybrids among Them in Long‐ and Short‐Day Environments1
Authors: Wilson F. D. , George B. W. 
Published: July 2010

Twelve primitive race stocks of cotton (Gossypiura hirsutum L.), four Upland cultivars, and 24 race stock ✕ cultivar F1 hybrids were grown in three replicated tests in the summer at Phoenix, Ariz. and in the winter at Isabela, Puerto Rico. Objectives of this research were to compare productivity, to study hybrid expression of agronomic properties, and to determine the effects of cultivar ✕ race stock and genotype ✕ environment interactions on parents and their F1 hybrids when grown in long‐ and short‐day environments.Six of the 12 race stocks produced no bolls at Phoenix and few boils at Isabela. Hybrids of four of the six also produced no boils at Phoenix, but produced more bolls than either parent at Isabela. The other six race stocks, representatives of race latifoliura (from which Upland cotton was derived) produced from 2 to 29 bolls/plant at Phoenix. Five of the latter six produced more bolls at Isabela than at Phoenix; two of these five produced more bolls than the cultivars at the Puerto Rican location. None of the latifolium race stock ✕ cultivar hybrids produced more boils than the cultivars at Phoenix, but 5 of the 12 produced a larger number at Isabela.Genetic variability among the hybrids was caused by differences among the race stocks. Lack of cultivar ✕ race stock interactions suggested that the genetic variability may be attributed largely m additive effects. Numerous instances of heterosis, however, also suggested the presence of nonadditive genetic effects. for hybrids from 8 of the 12 race stocks, location ✕ race stock interactions were significant for all six agronomic characters studied, indicating the inconsistency of hybrid performance for those traits between the two locations. For the other four hybrids, however, the location ✕ race stock interaction was significant only for lint yield/plant, but not for its components. Significant location ✕ cultivar interactions were much more infrequent than location ✕ race stock interactions. Positive heterosis for F1 vs. cultivar comparisons was shown by 26% of all hybrid/character combinations at Isabela and by 9% of those combinations at Phoenix. Several race stocks, potentially useful for specific characters, were noted for future breeding efforts.
Agronomic Performance of Soybeans with Differing Levels of Iron Deficiency Chlorosis on Calcareous Soil1
Authors: Froechlich D. M. , Fehr W. R. 
Published: July 2010

There are marked differences among soybean [Glycine max (L.) Merrill] cultivars for susceptibility iron deficiency chlorosis on calcareous soils. Our objective was to determine the relationship between agronomic performance and the amount of iron deficiency chlorosis that soybean cultivars sustain. Fifteen cultivars ranging from highly resistant to highly susceptible to iron chlorosis were tested on calcareous and noncalcareous soils in five Iowa environments during 1978 and 1979.There was a significant linear relationship between percentage yield reduction and visual chlorosis scores. The average percentage yield loss increased by 90% for each unit increase in chlorosis score. There also was a significant linear relationship between percentage yield reduction and percentage height reduction, with a 1.6% yield loss for each 1% reduction in height. Because of the reduction in height, lodging was reduced as chlorosis symptoms increased. Maturity was delayed for cultivars that had severe chlorosis symptoms. Seed weight and protein and oil content were not significantly influenced by chlorosis expression. The results should facilitate the assessment of potential yield reduction from iron deficiency chlorosis for planning appropriate control measures.