bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inheritance of Resistance to Bacterial Wilt in Two Alfalfa Gene Pools: Qualitative Analysis1
Authors: Viands D. R. , Barnes D. K. 
Published: July 2010

Bacterial wilt caused by Corynebacterium insidiosum (McCull.) H. L. Jens. is a serious disease of alfalfa (Medicago sativa L.). Inheritance studies were conducted with germplasm from two diverse gene pools, MSA and MSB. Two sets of six‐parent diallels with reciprocals and selfs were produced within each gene pool. Two sets of parents from one gene pool were crossed with two sets of parents from the other. Eleven‐week‐old seedlings of progenies were inoculated with C. insidiosum and transplanted to the field. Fifteen weeks later the taproot of each plant was cross‐sectioned and scored for the amount of yellow‐brown discoloration.MSA contained one dominant gene, BW1, for resistance. In the absence of other genes for resistance, plants with the genotype BW1… were classified as resistant and bw1bw1bw1bw1 plants were classified as susceptible. In addition to the BW1 gene, we believe that MSA contained two other genes, BW2 and BW3 with additive and smaller gene effects than those from BW1. The BW3 gene had a larger effect than the BW2 gene. The MSB gene pool did not contain resistant alleles at the BW1 locus, but it did contain resistant alleles at the BW2 and BW3 loci. Based on the genetic origins of the two gene pools, we suggest that the BW1 gene originated from ‘Turkistan’ and/or ‘Ladak.’ The BW2 and BW3 genes were probably from Chilean origin.
Distribution and Transformation of Soluble Carbohydrates during Germination Growth of Sorghum1
Authors: Newton R. J. , Baltuskonis D. A. , Goeschl J. D. , Meckenstock D. H. , Miller F. R. 
Published: July 2010

Soluble components of sorghum (Sorghum bicolor (L.) Moench) seedlings growing in distilled water‐sand media were quantified with gas‐liquld‐chromatography. In light, peak levels of soluble component accumulation occurred in the roots in 4 days, in the endosperm in 8 days, and in the shoots in 10 days. Sucrose (2 µg/mg) was the predominant component in the dry seed. In 4‐day‐old seedlings, glucose and fructose levels were 15 and 20 µg/mg, respectively, in both shoots and roots. At l0 days, dhurrin levels in the shoot were 35 to 40 µg/mg and comprised 51% of the total soluble component while glucose accounted for 21%.In the dark, dhurrin levels in 10‐day‐old shoots were 27% of the total solubles and glucose levels were 45%. Dhurrin levels were highest in the coleoptile‐shoot primordium region (90 µg/mg) and the upper, growing portion of the mesocotyl (28 µg/mg). Monosaccharide levels were highest in the upper, mesocotyl region with glucose at 74 µg/mg and fructose at 51 µg/mg. In 4‐day‐old scutella, sucrose to glucose ratios were greater than 3.Dhurrin and monosaccharide levels were reciprocally related; this indicated the precursor roles of both glucose and fructose in glycoside synthesis. The detection of a glycoside with gas‐liquid‐chromatography has several distinct advantanges over the traditional, enzymatic‐colorimetric assay.
A Method for Rating Freezing Inhibitor Activity of Barley Genotypes Using Seed and Crown Tissue Mucilages1
Authors: Olien C. R. , Kuhna A. S. 
Published: July 2010

An infrared assay is described for rating activity of cell wall mucilages as inhibitors of freezing kinetics. It requires 1% of the sample needed for the flow freeze assay previously used to rate mucilages extracted from wheat seed (Triticum aestivum L.). The reduction of sample size makes it feasible to assay polymers from crown tissue in genetic and plant breeding research. This is especially important for barley (Hordeum vulgare L.) because assay of seed extracts does not reliably indicate inhibitor activity in crown tissue for this species.Mucilages from both seed and crown tissues of eight Ethiopian barleys, Introduced into the USDA World Collection as possible sources of genetic diversity, were compared with those from a commercial barley. The introductions did produce more mucilage in their seed than did the commercial barley but did not produce effective inhibitors of freezing kinetics in their crowns.
Effect of Temperature and Glandular‐haired Medicago species on Development of Alfalfa Weevil Larvae1
Authors: Johnson Kathleen J. R. , Sorensen Edgar L. , Horber Ernst K. 
Published: July 2010

We evaluated annual glandular‐haired alfalfa diploids (Medicago disciformis DC., M. blancheana Boiss.) and tetraploids [M. rugosa Desr., M. scutellata (L) Mill.] for resistance to alfalfa weevil larvae [Hypera postica (Gyllenhal)] under three temperature regimes in growth chambers. Perennial M. sativa L. control cultivars were ‘Arc’ (tolerant to weevil larvae) and ‘Lahontan’ (susceptible).The tetraploids, M. scutellata and M. rugosa, were highly resistant over all temperature regimes. Larval mortality was complete during the first instar.Although the diploids were less resistant than the tetraploid annuals, they caused consistent larval mortality at all three temperatures. Mortality of first instar larvae was higher on M. blancheana than on M. disciformis. However, the mortality of ≽second instar larvae or pupae was highest on M. disciformis. Fewer larvae matured to adults on our diploids than on M. sativa. More larvae matured to adults on M. disciformis than on M. blancheana. The mean weight of adults developing on M. disciformis was less than that on M. blancheana and M. sativa, which did not differ in adult weights.The rate of weevil development increased with temperature on the resistant diploid annuals and on the alfalfa cultivars Arc and Lahontan. At each temperature, larval development was slower on the glandular‐haired diploids than on the alfalfa cultivars. Plant resistance did not alter the length of the pupal stage. However, this stage was shorter at high than at low temperatures.
Dry Matter Accumulation in Kernels of Maize1
Authors: Frey Nicholas M. 
Published: July 2010

Selection in a breeding program for physiological traits should not be initiated without knowledge of critical growth stages for the crop. The granin yield of maize (Zea mays L.) is the integral of kernel dry matter accumulation over time. The rate and duration of kernel fill have been suggested as factors which might be improved through selection and result in yield improvement. The purpose of these experiments was to follow kernel development at three positions on the ear when treatments were imposed which altered assimilate supply to the ear.Two maize hybrids, Pioneer brand '3388' and '3369A,' which differed in the yield components, kernel rows ear‐1, and kernel weight, were grown in field plots. Treatments were applied at 50% stand density, shoot bagging ears to allow complete pollination on a single day, and 50% leaf area removal. Kernel growth rates were determined for kernels at the base, middle, and tip regions of the ears. Hybrid 3369A had more rapid rates of kernel dry matter accumulation than did 3388 in both years.Treatments which affected assimilate supply, i.e., thinning and leaf area removal, affected kernel number (ear row)‐1through variations in the cessation of kernel development at the tip of the ears. Rates of kernel dry matter accumulation were similar for kernels from basal and middle regions of the ears, regardless of assimilate supply. Tip kernels may have filled at slower rates than did kernels from the other two regions. Altered duration of the linear phase of kernel dry matter accumulation due to treatments affecting assimilate supply was suggested as one cause of variations in kernel weight on an ear as well as between ears of the same hybrid. A critical stage in the development of maize that is highly dependent on assimilate supply is the 2‐ to 3‐week period after 50% silking; the period when final kernel number is determined.
The Effect of DNBP on the Accumulation of 14C‐Sucrose and the Transport of 14C‐Assimilates in Corn1
Authors: Pitombeira Joao B. , Housley T. L. , Ohlrogge A. J. , Counce Paul A. 
Published: July 2010

Subtoxic rates of DNBP (2‐sec‐butyl‐4, 6‐dinitrophenol) sprayed on corn (Zea mays L.) have been reported to stimulate dry matter accumulation in the grain in some situations. The purpose of this work was to evaluate the short‐term effect of the application of DNBP on the accumulation of sucrose and the translocation of 14C‐assimilates.Premerge 3 (Dow Chemical Company) as a source of DNBP was sprayed on the 4‐ to 5‐week old leaves of green‐house‐grown corn, 16 to 24 hours prior to leaf disc sampling or 14CO2 labeling. Leaf discs were also floated on DNBP and DNP prior to 14C‐sucrose accumulation studies.The accumulation of 14C from a 10 mM 14C‐sucrose solution in discs from untreated leaves was significantly greater than that of discs from leaves sprayed with DNBP or floated on 14C‐sucrose containing 0.7 mM DNBP or DNP. Efflux of 14C from the treated leaf discs indicated a pool of 14C easily leached from the discs. 14C retained was five times greater in untreated leaf discs.The transport of 14C‐assimilates in DNBP treated and untreated leaves suggested an inhibition of long distant transport with 18.7% of the assimilated 14C transported in 30 min in treated leaves and 29.5% of the assimilated 14C translocated in untreated leaf discs. A significantly greater percentage of 14C was recovered in the sink of untreated plants than was found in the sink of DNBP sprayed plants.These experiments support the hypothesis that DNBP acts as an inhibitor of 14C‐sucrose accumulation and the movement of 14C‐assimilates from the source leaf in corn.
Nitrogen Fixation of Alfalfa in the Seeding Year1
Authors: Heichel G. H. , Barnes D. K. , Vance C. P. 
Published: July 2010

Alfalfa (Medicago sativa L.) obtains N from the soil and from the atmosphere by symbiotic nitrogen (N2) fixation. It is necessary to identify the contribution from each N source to evaluate N2‐fixation of different alfalfa germplasms. Field experiments were undertaken using 15N as a tracer of N metabolism to determine the N2‐fixation of two alfalfa populations in the seeding year. Additional objectives were to investigate the effects of establishment method, stage of plant development, and non‐uniform distribution of isotope in the plant on assessment of N,‐fixation capability.During the seeding year the two populations averaged about 43% of their N needs from symbiosis and fixed an average of 148 kg/ha of N during the growing season. The isotope‐dilution and A‐value methods gave similar assessments of performance over four harvest intervals. Nitrogen fixation measured by isotope dilution was least (8 to 20 kg/ha) in the first and fourth harvest intervals when 25 to 30% of the N needs were met by symbiosis; it was greatest (47 to 87 kg/ha) during the second and third harvest intervals, when the populations derived more than 60% of their N from symbiosis.The proportion of N derived from symbiosis for whole plants of seeded and transplanted materials differed significantly (P<0.05) among harvests, but the average over all harvests was not different for plants established by the two methods. A significant (P<0.05) interaction of sample type (herbage vs. whole plant) with harvest in transplants showed that equilibration of isotope in initially unlabeled seedlings occurred slowly early in the growing season.In contrast to glasshouse evaluations of nitrogenase activity, significant (p<0.05) differences in rates of N2‐fixation per plant were observed between the two populations at several harvests and over the growing season. However, a 14% difference in average plant stand precluded differences between populations in N2 fixation on a land area basis. The rates of N2 fixation of field grown plants mirrored growth rates, which varied with the changing field environment and especially with onset of fall dormancy. The use of stable N isotopes can be a powerful technique in assessing progress in breeding alfalfa for increased N2‐fixation capability.
Effect of Flowering Date on Accumulation of Dry Matter and Protein in Soybean Seeds1
Authors: Gbikpi Pascal J. , Crookston R. Kent 
Published: July 2010

The objectives of this study were to determine the effect of time of flowering on the rate of dry matter and protein accumulation in soybean [Glycine max (L.) Merrill] seeds, and to evaluate the relationship between these accumulation rates and the duration of the lag, linear filling, and plateau phases of soybean seed growth.Field studies were conducted on a well‐drained Waukegan silt loam (Typic Hapludoll) at St. Paul, Minn. In 1978 the cvs. ‘McCall’ (Maturity Group 00) and ‘Hodgson 78’ (Group I) were used. In 1979, ‘Altona’ (Group 00) and ‘Steele’ (Group I) were added. On 1 day during both the early and late stages of flowering, 250 flowers were tagged on several plants of each cultivar. During pod filling, pods from these tagged flowers were harvested at weekly intervals for determination of seed dry matter and protein accumulation rates, as well as the duration of the lag, linear filling, and plateau phases of seed growth.We concluded that meaningful relationships between soybean seed growth rate, duration of seed growth phases, and seed size do not exist. However, late maturing seeds of all cultivars consistently had faster (+ 32%) rates of dry matter accumulation, and even faster (+ 42%) rates of protein accumulation in both years of the study. Possible explanations of these fast accumulation rates are discussed.
Inheritance of Male Sterility in Flax Involving Nuclear‐Cytoplasmic Interaction, Including Methods of Testing for Cytoplasmic Restoration1
Authors: Burnham Charles R. , Phillips Ronald L. , Albertsen Marc C. 
Published: July 2010

An interaction between cytoplasm and nuclear genes affecting the inheritance of male sterility in flax (Linum usitatissimum L.) was reported first by workers in England in the 1920s in crosses between procumbent and tall plants and later by a worker in Poland using Linum floccosum. Previously unpublished data are reported on a similar case involving a large‐seeded flax from Crete. The interaction was discovered in all cases by noting that crosses using procumbent, L. floccosum, and Crete as female parents with most other stocks as male parents had fertile and male‐sterile plants in F2; whereas the reciprocal crosses had only fertile plants.For certain crosses using Crete as the female parent, the F2 segregation ratios were for a single gene difference. Other crosses may have involved two genes complementary either for restoration of pollen fertility in F1 or for incomplete restoration. Either of two hypotheses will explain the difference in behavior between reciprocal crosses. One hypothesis is that procumbent, L. floccosum, and Crete have a dominant fertility allele, Ms, and a non‐restorer [N] cytoplasm. Most other stocks have the recessive male‐sterile, ms ms, nuclear genotype but a cytoplasm [c R] that restores fertility. The cross of male steriles [N] ms ms with maintainer [c R] ms ms stocks would produce all male‐sterile progeny. Crossing these male steriles with Ms Ms would produce hybrid seed.The second hypothesis that may explain the difference in behavior between reciprocal crosses assumes that procumbent, L. floccosum, and Crete have cytoplasmic male sterility [cms] together with a nuclear gene for restoration of pollen fertility (Rf). Most other flax stocks would have a normal non‐male‐sterile cytoplasm [N] and the non‐restorer gene, rf. Male‐sterile plants would be [cms] rf rf and maintainer stocks would be [N] rf rf.Tests using genetic male sterility to identify lines with cytoplasmic restoration of fertility are discussed, together with methods of distinguishing the possible nuclear genotypes.For any species in which most stocks have the nonrestorer [N] type of cytoplasm and the restorer type [c R] is rare, an advantage of this system for producing hybrid seed is the ability to produce large quantities of seed that will give only male‐sterile plants yet not transmit a unique cytoplasm to the hybrid seed offered to farmers. Development and maintenance of the parental stocks can be accomplished by conventional breeding techniques.
Effect of Atrazine Carryover on Malting Quality of Barley1
Authors: Brinkman M. A. , Langer D. K. , Harvey R. G. , Burger W. C. 
Published: July 2010

This study was a continuation of an earlier study which showed that spring barley (Hordeum vulgare L. and H. distichum L.) produced higher grain and straw yields in soil containing atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) carryover than spring oats (Avena sativa L.). and spring wheat (Triticum aestivum L.). The objective of this study was to evaluate the effect of atrazine carryover on malting quality of barley.In 1976 and 1977, six barley genotypes were grown to maturity in soil containing atrazine carryover, and the seed was analyzed for malting quality. Atrazine treatments (0, 1.12, 2.24, 3.36, and 4.48 kg of active ingredient/ha) had been applied postemergence to corn (Zea mays L.) 1 year prior to growing the barleys.Light atrazine carryover had a minor effect on malting quality, but heavy carryover reduced quality considerably. Heavy atrazine carryover reduced kernel weight, kernel plumpness, kernel color, malt extract, and wort color, and increased barley and wort protein percentages, diastatic power, and alpha amylase activity. With the possible exception of the increases in the two enzyme systems, all of these changes detracted from malting quality.Although genotype × atrazine level interactions were significant for several quality parameters, only one interaction had special importance. In both years, the genotype ‘Morex’ maintained a high malt extract despite increasing atrazine carryover.
Corn Yields as Related to Legumes and Inorganic Nitrogen1
Authors: Fleming A. A. , Giddens J. E. , Beaty E. R. 
Published: July 2010

High corn (Zea mays L.) yields require heavy N applications. Sources of inorganic N fertilizer have become less dependable and prices more expensive. A 3‐year study was initiated to evaluate the use of winter legumes and inorganic N as sources of N for corn production under modern culture. The experiment included three whole‐plot clover treatments (arrowleaf, Trifolium vesiculosum Savi; crimson, Trifolium incarnatum L; and fallow) and five inorganic split‐plot treatments ranging from 0 to 180 kg/ha N.Significant whole‐plot × split‐plot interactions occurred in 1975 for both grain yield and dry stover. Corn following clover produced 318% more grain than corn following fallow in 1975. When no N was applied, corn yield on fallow averaged 25 q/ha and increased 272% and 364% when grown following arrowleaf and crimson, respectively. The 180 kg/ha N did not increase corn yields significantly when compared with 90 kg/ha N with or without clover. Differences in stover yields between the 90 and 180 kg/ha N were not significant in any of the whole‐plot treatments in any year.Crimson clover produced in a 2‐year average about 1600 kg/ha more dry‐weight forage than arrowleaf. Total forage N at time of turning averaged 163 and 131 kg/ha, respectively, for crimson and arrowleaf. Differences in forage yield and in N content of the clovers were attributed to differences in maturity at time of turning.Growing a winter legume to replace all or part of the N may become a viable alternative in double‐cropping systems for corn production and conserving soll in the southern U.S. and in developing countries.
Inheritance of Crown Rust Resistance in Tall Fescue1
Authors: Wofford D. S. , Watson C. E. 
Published: July 2010

Crown rust caused by Puccinia coronataCordn. is a major disease of tall fescue (Festuca arundinacea Schreb.) in the southern United States. The objectives of this study were to examine the inheritance of crown rust resistance in tall fescue and to determine if it is possible to select for crown rust resistance using a greenhouse seedling technique.In the first experiment a six parent diallel cross was evaluated for crown rust resistance. General (GCA) and specific combining ability (SCA) were both significant sources of variation for rust resistance. Significant SCA effects indicated that there was some nonadditive gene action for rust resistance among these six parents. In most cases, resistant ✕ resistant crosses had high levels of resistance, susceptible ✕ susceptible crosses had no resistance, and resistant ✕ susceptible crosses had intermediate levels of resistance.In the second experiment, eight cultivars of tall fescue were subjected to a single cycle of mass selection for crown rust resistance. All eight cultivars were found to have some resistance to crown rust with the Mediterranean cultivars having the highest levels of resistance. There was a wide range of variation in the realized heritabilities (0.07 to 0.52) for crown rust resistance in these cultivars. Cultivars of related origin exhibited similar heritabilities and it appeared that different populations had different gene systems controlling crown rust resistance. It appears that mass selection is an efiicient means of improving the level of rust resistance in some cultivars.
Effects of Natural Selection in Segregating Soybean Populations Exposed to Phytophthora Rot or Soybean Cyst Nematodes1
Authors: Hartwig E. E. , Kilen T. C. , Young L. D. , Edwards C. J. 
Published: July 2010

A study was conducted to determine the effects of natural selection in soybean [Glycine max (L.) Merr.] populations segregating for reaction to phytophthora rot (caused by Phytophthora megasperma Drechs. var. sojae Hildeb.) and soybean cyst nematode (SCN) (Heterodera glycines Ichinohe). Plantings of an F2 population of ‘Forrest’ ✕ ‘Tracy’ and 10 backcross F3 families of Forrest (2) ✕ Tracy were made at Stoneville, MS, where phytophthora rot caused injury to susceptible genotypes and at Ames Plantation in west Tennessee where SCN race 3 was present. The parent cultivar, Forrest, is resistant to SCN race 3 and moderately resistant to phytophthora rot, and Tracy is susceptible to SCN and resistant to phytophthora rot, races 1 through 9. The populations were advanced in bulk at each location for four generations.Natural selection was not effective in increasing the percentage of plants having major genes for resistance to phytophthora rot in Stoneville plantings where susceptible cultivars show injury from the disease. The failure of natural selection to be effective was attributed to the presence of field resistant plants in the segregating population which competed effectively with plants having major genes for resistance.Segregating populations grown on SCN infested soil showed a distinct increase in percentage of resistant plants as compared with populations grown on non‐infested soil. On the basis of three recessive genes and 1 dominant gene being necessary for resistance to SCN race 3, 5.5% of the population would be expected to be resistant after the F5 generation. The population of Forrest ✕ Tracy grown on non‐infested soil had 5% resistant plants after the F5 generation, while the population advanced on SCN race 3 infested soil had 40% resistant plants. Backcross families of Forrest (2) ✕ Tracy also had a distinctly higher percentage of SCN resistant plants when grown on infested soil than when grown on non‐infested soil.