bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Various Combinations of Inoculation Pressure and Concentration on Varietal Disease Response of Sorghum Following Spray Gun Inoculation with Maize Dwarf Mosaic Virus1
Authors: Toler R. W. , Miller F. R.
Published: July 2010

Artificial inoculation of sorghum [Sorghum bicolor (L.) Moench] with maize dwarf mosaic virus (MDMV) has led to the release of tolerant inbred lines and hybrids. When a spray gun is used for inoculation, differences in pressure and inoculum concentrations used during inoculatlon could result in a selectively affected disease rating among genotypes. Ten inbred line sorghum genotypes of known MDMV reaction were artificially inoculated at 1:10 and 1:100 (w/v), tissue to buffer concentration at 0, 1.4, 4.2 and 7.3 kg/cm2 pressure and rated on an individual plant basis 21 days after inoculation. Pressure, concentration, and genotype Disease Severity Index (DSI) were varied. Significant interactions were detected between pressure and concentration of inoculum. High pressures increased genotypic susceptibility as did greater virus concentration. In this study, even though DSI varied under different pressure and concentration combinations, genotypes responded uniformly and rankings remained unchanged.
Water Stress Recovery in Soybeans as Affected by Photoperiod During Seed Development1
Authors: Cure Jennifer D. , Raper C. David , Patterson Robert P. , Jackson William A.
Published: July 2010

Since long‐day photoperiods during seed filling can reduce reproductive sink demand of soybeans [Glycine max (L.) Merr.], a study was conducted to determine whether long‐day treatment during seed filling would also enhance the capacity of the plants to recover from a temporary drought stress. Plants of ‘Ransom’ and ‘D72‐8126’, a high protein line, were grown under long or short‐day photoperiods and subjected to a temporary drought stress during seed‐filling stage. Carbon dioxide exchange rates and leaf water potentials were measured during and immediately after the stress treatment. Dry matter distribution and leaf area also were measured throughout the reproductive growth period. Water‐stressed Ransom and D72‐8126 plants grown under long days maintained 45 and 25% of their maximum leaf areas, respectively, vs. 16 and 0% under short‐day conditions. Carbon exchange rates during the period of water deficit were comparable between plants exposed to long and short days, but recovery was 73 vs 38% for Ransom plants grown under long and short days, respectively, and 76 and 0% for D72‐8126 plants grown under long and short days, respectively. In addition, dry matter assimilation efficiency (mg dry matter cm‐2 day‐1) showed no recovery for plants of either genotype under short days, while recovering approximately 77% for Ransom and 100% for D72‐8126 under long days. For Ransom under short days, water stress shortened the seed‐filling period by 9 days and reduced yield by 33%; but under long days, the duration of seed filling was unaffected by the stress and yield was reduced 19%. for D72‐8126, the water deficit occurred late in the seed‐filling period, and no photoperiod differences were observed in the effect of the stress on seed‐filling duration (2 days abbreviation for each treatment) or on yield (a 19 and 17% reduction under short days and long days, respectively). These results demonstrated that drought sensitivity during reproductive growth of soybeans may be reduced, and yield losses may be minimized, through manipulation of photoperiodic responses.
Recurrent Selection for Resistance in Corn to Tunneling by the Second‐Brood Southwestern Corn Borer1
Authors: Williams W. Paul , Davis Frank M.
Published: July 2010

Two cycles of recurrent selection based on individual plant performance using two selection criteria were conducted in a corn (Zea mays L.) population in an attempt to increase the level of resistance to stalk tunneling by the second‐brood southwestern corn borer, Diatraea grandiosella (Dyar). The original population and the populations resulting from each cycle of selection were evaluated for extent of stalk tunneling in 1979, 1980, and 1981 at Mississippi State, Miss. Neither selecting undamaged plants nor those with reduced stalk tunneling was effective in significantly improving the level of resistance in the original population.
Seed Yields from Breeder and Foundation Seed of Eight Alfalfa Cultivars1
Authors: Kehr W. R. , Barnes D. K. , Brown D. E. , Elgin J. H. , Sorensen E. L.
Published: July 2010

The purpose of this study was to compare seed yields from breeder and foundation seed classes of eight alfalfa (Medicago sativa L.) cultivars, ‘Agate’, ‘Arc’, ‘Cody’, ‘Dawson’, ‘Kanza’, ‘Ramsey’, ‘Ranger’, and ‘Vernal’. Breeding methods used in developing the cultivars and generations of synthesis of breeder and foundation seed classes varied among cultivars. Breeder and foundation seed of the eight alfalfa cultivars were seeded at 2.2 kg/ha in a randomized block split‐plot design of cultivars as main plots and seed classes as subplots with three replications in a field near Caldwell, Idaho, in the spring of 1976. The experiment was managed to maximize seed yield. Seed yields were determined in 1977 and 1978. Seed yields obtained from breeder seed averaged over eight alfalfa cultivars were lower than those obtained from foundation seed in 1977 and for the 1977–1978 average. Seed yields obtained from breeder seed were lower than those obtained from foundation seed for two of eight cultivars, Ramsey and Vernal, in 1977 and for the 1977–1978 averages. Alfalfa breeders need to conduct seed yield tests that include at least one commercial seed generation of their experimental cultivars compared with a check cultivar.
Genetic Analyses of the Yellow‐Veins Mutant in Cotton1
Authors: Kohel R. J.
Published: July 2010

Eight virescent and morphological mutants were found in a cotton (Gossypium hirsutum L.) breeding nursery at College Station, Tex., in 1962. Four of those mutants were conditioned by the same recessive allele. The mutant was named yellow‐veins and assigned the symbol yυ. The phenotype of the mutant is described as is variability associated with expression of the trait. Analyses with 38 other mutant loci provided evidence for linkage of yυ with Rugate (Ru) and virescent‐1 (υ1) to establish linkage group XVII, Ru‐37‐yυ‐30‐υ1.
A method for Production of Experimental Quantities of Hybrid Soybean Seed
Authors: Burton J. W. , Carter T. E.
Published: July 2010

The production of F1 seeds is difficult in soybeans [Glycine max (L.) Merr.]. Hand pollinations are tedious and time consuming, and each successful pollination only produces one, two, or three seeds. A method is suggested herein for producing experimental quantities of hybrid soybean seeds by the use of two traits, genetic male sterility (ms1ms1 or ms2ms2) and green seed embryo (d1d1d2d2). The green seed embryo shows through a yellow seed coat to give the soybean seed a green phenotype that can be easily recognized. Male‐sterile maintainer lines marked with green seed embryos would be used as female parents. The male parent could be any cultivar (or strain) that has a yellow seed embryo (D,1‐, D2‐, or both) and that flowers synchronously with the female parent. Cross‐pollination would be effected by insect vectors in blocks where the male and female lines were inter planted. Yellow seeds harvested from green‐seeded, male‐sterile plants would mark F1 hybrid seeds.
Nodule‐Like Structres Induced on Peanut by Chlorosis Producing Strains of Rhizobium Classified as R. Japonicum1
Authors: Devine T. E. , Kuykendall L. D. , Breithaupt B. H.
Published: July 2010

Some strains of rhizobia produce a rhizobitoxine‐induced foliar chlorosis on soybean, Glycine max (L.) Merr., and have a limited ability to nodulate the nodulation restrictive genotype (rj1). This study was undertaken to determine and compare the effect of chlorosisinducing or rj1‐compatible strains and nonchlorosis‐inducing strains on another legume, peanut (Arachis hypogaea L., cultivars ‘Starr’ and ‘Spancross’), in Leonard jar culture. Ten different rhizobial strains that induce chlorosis or nodulate rj1‐plants, produced swellings at the nodulation sites on peanut roots. No rhizobial‐induced chlorosis symptoms developed on either peanut cultivar. Control peanut plants inoculated with six different nonchlorosis‐inducing strains of Rhizobium japonicum (Kirchner) Buchanan did not have swellings. The clustering of three distinctive characteristics, a) ability to nodule rj1 plants, b) the propensity to produce rhizobitoxine‐induced chlorosis symptoms on soybean, and c) the ability to induce nodule‐like swellings on peanut roots, in a common population of rhizobia suggests that these rhizobia may represent a taxonomically distinct group. These strains appear defective in their symbioses with both soybean and peanut, suggesting that they may have a symbiotic homology for a legume host other than either soybean or peanut.
Effects of Nicotine Precursors on Nicotine Content in Callus Cultures of Burley Tobacco Alkaloid Lines1
Authors: Miller R. D. , Collins G. B. , Davis D. L.
Published: July 2010

Callus cultures of four hurley tobacco (Nicotiana tabacum L.) genotypes differing in alkaloid content were grown on three basal media supplemented with compounds known to be intermediates in the biosynthesis of nicotine. The effects of these compounds on nicotine concentrations in the calli were evaluated to determine if one or more of the compounds were limiting to nicotine synthesis in the low alkaloid genotypes. In general, the supplemental compounds tested reduced nicotine concentrations in the calli of all four alkaloid genotypes. Callus cultures of high alkaloid lines underwent more extensive root and shoot differentiation than did cultures of low alkaloid genotypes. However, genotypic and treatment effects were unaffected by state of differentiation present in the calli. Although several of the treatments had a significant effect on the nicotine content of the calll, none eliminated differences between dominant and recessive alleles at both loci known to control nicotine levels in tobacco. Nicotine levels detected in all control and treatment cultures of the four alkaloid genotypes were proportional to nicotine concentration in the respective intact plants. The results of the present study suggest that differences in nicotine concentrations among callus cultures of the four alkaloid genotypes are not due to a biosynthetic block in the formation of the pyridine or pyrrolidine rings of nicotine.
Relationships between Plant Density and Yield in Barley1
Authors: Baker R. J. , Briggs K. G.
Published: July 2010

To determine the effects of plant density on shoot weight and grain yield of spring barley, Hordeum vulgare L., ten cultivars were planted on square grids at densities of 1.56, 6.25, 25, 100, and 400 plants/m2 in each of 3 years, 1977‐1979. Twenty plants were harvested from each plot (one replicate in 1977; two in 1978 and 1979) for determination of total shoot weight and grain yield per plant. The yield/density relationship was best described by the reciprocal regression equation, w‐1 = a + bd, where w was the total shoot weight or grain yield (g/plant) and d was the plant density (plants/m2). Coefficients of determination varied from 66.4 to 99.5% with an average of 90.3% for total shoot weight and from 68.5 to 99.6% with an average of 89.1% for grain yield. The coefficient a, a measure of apparent maximum yield per plant, was influenced primarily by differences among cultivars. On the other hand, b, which is an estimate of the asymptotic yield per unit area, showed a significant cultivar ✕ year interaction for both total shoot weight and grain yield.
Improvement of Fertility and Herbage Yield by Selection within Two‐Allele Populations of Tetraploid Alfalfa1
Authors: Pfeiffer T. W. , Bingham E. T.
Published: July 2010

Two tetraploid alfalfa (Medicago sativa L.) clones were obtained by chromosome doubling two cultivated diploid clones. The doubled plants were selfed and progeny from within each group were sibbed for four generations to develop two populations of tetraploid alfalfa, HG2 and W315, with a maximum of two alleles per locus. Selection was based upon winter survival and differential fertility in the self and first two sib generations. In the third and fourth sib generations visual selection for vigor was practiced. Inbreeding increased from F = 0.33 to F = 0.54. Crosses between the two populations, and with two different male sterile testers, were made with the initial doubled plants and the second and fourth sib generations. Crosses between the advanced generations of the two populations yielded significantly more forage in progeny yield tests than the cross of the initial doubled plants. For the HG2 population progeny from crosses to male sterile testers by the advanced generations yielded significantly more than progeny from similar test crosses using the initial parent. An increase in cross fertility with advancing generations occurred in the same population. Forage yields of clonal rows were two to three fold greater for the fourth sib generation than for the initial doubled plant in the HG2 population. Changes in the W315 population over generations were small and variable but occurred while the level of inbreeding was increasing in the population. Allelic heterozygosity could not increase in these populations. No new dominant alleles were added to mask unfavorable recessives in a linkage block. Assuming that interlocus interactions are absent, improvement must have come from the accumulation of favorable alleles already present due to recombination within linkage blocks.
Evaluation of the Performance and Combining Ability of Selected Lines Derived from Improved Maize Populations1
Authors: Stangland G. R. , Russell W. A. , Smith O. S.
Published: July 2010

Seven cycles of reciprocal recurrent selection for grain yield were completed in maize (Zea mays L.) populations ‘Iowa Stiff Stalk Synthetic’ (BSSS) and ‘Iowa Corn Borer Synthetic No. 1’ (BSCB1). Also, seven cycles of recurrent selection based on half‐sib progeny performance and one cycle based on S2 line performance have been completed for BSSS. Populations BSSS(R)C5 and BSCB1(R)C5 were crossed and random‐mated to give BS6. Then, BS6 had two cycles of recurrent selection based on half‐sib progeny performance. Crosses of the improved populations and four selected S2 lines from each improved population crossed in design II's (six sets) were evaluated for grain yield and moisture and for root and stalk lodging. The average yields for four sets of S2 crosses were not significantly different from their respective population crosses; one set of S2 crosses yielded significantly less than its population cross, BSSS(R)C7 ✕ BS6(RS)C2; and one set of S2 crosses yielded significantly higher than its population cross, BSCB1(R)C7 ✕BS6(RS)C2. Generally, sets of crosses had less grain moisture and better resistance to root and stalk lodging than did their respective population crosses. General combining‐ability effects accounted for 76% of the total genetic variation for yield among S2 ✕ S2 line crosses. Compared with five single‐cross checks, no S2 ✕ S2 line cross yielded as well as the highest‐yielding check, but one had a performance index equal to the best check, and several had performance indices similar to four checks.
Photosynthate Partitioning in Relation to N2 Fixation Capability of Alfalfa1
Authors: Boller Beat C. , Heichel G. H.
Published: July 2010

Although N2 fixation is held to be strongly dependent upon the products of current photosynthesis, the allocation of photosynthate to nodules of forage legumes in comparison with allocation to other metabolic sinks is unknown. Field experiments were undertaken to determine the partitioning of 14C‐photosynthate among various organs over an annual growth cycle of effectively and ineffectively nodulated alfalfa (Medicago sativa L.). Alfalfa genotypes were examined during vegetative growth and at 5% flower at two rates of supplemental N (0 and 100 kg ha−1 as NH4NO3). Across all entries and growth stages, priority for allocation of photosynthate (measured as relative specific activity of tissue 24 h after pulse‐labeling, RSA24) was greatest for young leaves. The RSA24, of effective nodules averaged 44% and of ineffective nodules 11% of that of young leaves over all stages of growth. During vegetative growth of effectively nodulated entries, the RSA24 values of old leaves, stems, and roots for photosyntheate were similar and averaged about 44% that of young leaves. In comparison, allocation of photosynthate to effective nodules averaged only 16% of that to young leaves. At 5% flower of effective entries, RSA24, of old leaves, stems, and roots were similar to those of nodules, or about 54% that of young leaves. Thus, allocation of photosynthate to nodules was greater late in a growth cycle (2 d before harvest) than early in the cycle (2 weeks after harvest). Comparison of effectively and ineffectively nodulated alfalfa showed that capability for N2 fixation was without effect on the partitioning of recent photosynthate to all organs except nodules. Throughout the season photosynthate was mobilized from old and young leaves and partitioned to stems, roots, and nodules. Priority for photosynthate mobilization varied strongly with growth stage in all entries. The results of photosynthate partitioning suggest a relatively weak coupling between supply of current photosynthate and nodule activity.
Alfalfa Response to Soil Water Deficits. I. Growth, Forage Quality, Yield, Water Use, and Water‐Use Efficiency1
Authors: Carter P. R. , Sheaffer C. C.
Published: July 2010

Although many researchers have reported yield increases due to alfalfa irrigation when soil water has been limited, little information is available on alfalfa plant and soil water relationships which might be used to improve water management strategies. Our objective was to determine effects of plant water deficits on alfalfa seasonal growth patterns, forage quality, forage yield, water use, and water‐use efficiency. During 1981, established alfalfa grown on a sandy soil was subjected to four water supply levels designated: high irrigation (H), medium high irrigation (MH), medium low irrigation (ML), and unirrigated, rainfall only (U). Soil water depletions occurred for all treatments to at least 1.9 m. Alfalfa midday plant water potentials in H and MH treatments ranged from −0.7 to −1.3 MPa throughout the season. For alfalfa subjected to ML and U treatments, ψmp reached −2.7 and −4.0 MPa, respectively. Dry weight (DW) accumulations for alfalfa in H and MH treatments increased with successive harvests during the summer while harvest DW for alfalfa in ML and U treatments declined. Relative growth rate (RGR) declined sharply as ψmp decreased. At moderate plant water stress (ψmp of −1.5 to −2.0 MPa), little growth occurred and under severe water stress, (ψmp < −2.5 MPa), RGR were negative due to leaf loss. Reduced soil water availability resulted in increased leaf:stem weight ratios and in vitro dry matter disappearance (IVDMD), but only under severe and long‐term plant water stress. Crude protein (CP) concentration was unaffected by plant water status. It appeared that irrigation water could be used efficiently on coarse‐textured soils by moderate water application to alfalfa at 50% depletion of extractable soil water, an apparent threshold for maintenance of favorable plant water status. A close association between forage yield of individual harvests and cumulative indicates potential for initiation of irrigations when plant measurements indicate soil water depletions to a threshold level.
Streptomycin and Other Inhibitors as Selection Agents in Corn Tissue Cultures1
Authors: Umbeck Paul F. , Gengenbach Burle G.
Published: July 2010

We were interested in developing a tissue culture selection system to use in identifying potential extranuclear genetic markers in corn (Zea mays L.). Streptomycin, kanamycin, chloramphenicol, aurin tricarboxylic acid, rifampicin, and erythromycin were evaluated for inhibition of seedling root growth and nonregenerable callus cultures of the inbred A619(N). All compounds caused inhibition at one or more concentrations in one or both bioassays. In additional tests on established, regenerable tissue cultures of the inbred A188(T), streptomycin and kanamycin inhibited growth at 100 μmol L−1 but not 10 μmol L−1, while chloramphenicol was inhibitory at 10 μmol L−1. Although all six compounds probably could be used as inhibitors in a tissue culture selection system, streptomycin, kanamycin, and chloramphenicol were the most inhibitory and appeared to be the most feasible to use. A188(T) and A188(N) regenerable tissue cultures were exposed to various levels of streptomycin for eight or five culture periods (cycles of selection), respectively. Culture growth was not inhibited at 50 μmol L−1 or less streptomycin, but was at 75 and 100 μmol L−1. Three cycles of selection (40 days each) on 75 or 100 μmol L−1 were required for the cultures to lose all green pigmentation, after which selection for streptomycin resistance could be based on reappearance of green tissues. A culture sector that exhibited green tissues and a faster growth rate was identified after five cycles of selection on 100 μmol L−1 streptomycin. Six plantlets were regenerated from this source, but none developed past the third leaf stage so mature plant tests and progeny were not obtained to verify the resistance of this potentially variant culture line.
Variation in the Low Molecular Weight Proteinase Inhibitors of Soybeans1
Authors: Stahlhut R. W. , Hymowitz T.
Published: July 2010

Two types of proteinase inhibitors exist in soybean [Glycine max (L.) Merr.] seed. The first type is called the Kunitz trypsin inhibitor and the second is a group generally termed the Bowman‐Birk type inhibitors. The objectives of this study were to attempt to separate and purify the Bowman‐Birk type inhibitors in soybean seeds, and to screen for variants in the USDA Named Cultivar and Type Collections. Five Bowman‐Birk type inhibitors were separated from ‘Amsoy 71’ by anion exchange column chromatography. Soybean accessions were screened electrophoretically for variants of the inhibitors. Three variants were identified: 1) lines which appear to be missing fraction III electrophoretic band (F phenotype); 2) lines which appear to be missing fraction V electrophoretic band (S phenotype); and 3) lines in which both electrophoretic bands are present (SF phenotype). Most lines examined (71%) have the SF banding pattern. The S or F banding patterns are less common with only 26 and 3%, respectively, of the lines screened.
Agronomic and Quality Attributes of Sibling Hard White and Hard Red Winter Wheats1
Authors: Paulsen G. M. , Heyne E. G. , Walter T. L. , Hoseney R. C.
Published: July 2010

Hard red winter wheat (Triticum aestivum L.) is the major class produced in the USA, whereas many markets and countries prefer white wheat. Objectives of studies reported here were to determine the agronomic feasibility of hard white winter wheat in the major U.S. wheat area, compare the breadmaking quality of hard white and hard red winter wheats, and identify where hard white wheat might be grown without preharvest sprouting. ‘KS75216’ hard white winter wheat and ‘Newton’ hard red winter wheat were grown with locally‐recommended production practices at 10 Kansas locations during the 1979–1980 and 1980–1981 seasons. Plant, grain yield, grain quality, and flour quality characteristics were determined. Winter survival, maturity, height, and lodging were very similar for the two genotypes. Mean grain yield, test weight, hundred‐kernel weight, and protein concentration were 3383 kg ha‒1, 762 kg m‒3, 2.88 g, and 136 g kg ‒1, respectively, for the white wheat and 3442 kg ha ‒1 775 kg m‒3, 2.82 g, and 133 g kg‒1, respectively for the red wheat. Grain falling number was lower and α‐amylase activity was higher in the white wheat than in the red wheat at several locations, but both were within acceptable limits at all locations, indicating that preharvest sprouting was low. Sedimentation values frequently were lower and flour protein concentrations frequently were higher for the white wheat than for the red wheat, but dough mixing time, loaf volume, and bread quality were similar for the two genotypes. We concluded that hard white winter wheat is as agronomically feasible as hard red winter wheat in the major U.S. wheat area, that both classes are equally suitable for breadmaking, and that preharvest sprouting is not a barrier to white wheat production most years.
A Method for Classification and Evaluation of Testing Environments1
Authors: Brown K. D. , Sorrells M. E. , Coffman W. R.
Published: July 2010

A methodology is presented to improve the efficiency of cultivar testing first by clustering nursery environments based on selected environmental variables and second by identifying optimum selection environments within clusters by linear regression of the performance of genotypes within an environment on mean genotype performance over all environments. First, the site mean response for the trait is regressed on environmental variables at each site to identify the most predictive subset of variables. Next, the selected predictor variables are converted to standard units and then weighted by the sums of squares from the multiple regression. Finally, the weighted predictor variables are used in a cluster analysis to group sites. A genotypic index regression method is proposed to identify sites that are consistently able to discriminate genotypes. The model is a linear regression of the form yij. =aj+bjyi.+eijk, where yij. is the ith cultivar mean response to the jth environment, aj is the jth environment intercept, bj is the jth environment regression coefficient, yi. is the ith cultivar mean response, and eijk is the error term assumed to be from a normal distribution with a mean of zero and a variance of σ2. The mean cultivar response is an index of the genotypic value of the cultlvar. An environment that discriminates well among genotypes will have a high genotypic index regression coefficient (bj) and one that consistently predicts the performance of genotypes at other sites in the cluster will have a high coefficient of determination (r2). An optimum selection environment should have high values for both statistics. The methodology is applied to a set of data from the International Rice Cold Tolerance Nursery.
Variability in Reed Canarygrass Collections from Eastern Canada1
Authors: Sachs A. P. W. , Coulman B. E.
Published: July 2010

Forty‐eight accessions of reed canarygrass(Phalaris arundinacea L.), including 36 collections from eastern Canada, 5 cultivars, and 7 experimental strains, were studied in space‐planted nurseries with the objective of assessing the genetic variability of the collections, and of comparing the performance of the collections with the other accessions. Variance component analysis was used to estimate population parameters for the collections. Significant differences among the collections were found for several growth traits and for seed retention, but not for seed yield or for forage yield. Broad sense heritabilities for fall vigor, spring vigor, heading date, height, panicle number and seed retention were 0.38, 0.47, 0.94, 0.54, 0.49, and 0.67, respectively. Seed retention and maximum seed yield potential did not show a significant phenotypic correlation, indicating the possibility of selecting for both traits simultaneously. The collections had somewhat higher forage yields, but much lower seed retention values, than did the selected accessions. An alkaloid survey of the material indicated that the majority of the plants were free of tryptamines and carbolines.
Inheritance of Resistance to Soil Borne Mosaic in Wheat1
Authors: Merkle O. G. , Smith E. L.
Published: July 2010

A partial diallel of five wheat (Triticum aestivum L.) cultivars was evaluated for inheritance of resistance to soil‐borne mosaic virus. ‘Payne’ was a susceptible parent; whereas ‘Arthur 71’, ‘Homestead’, ‘Newton’, and ‘Tascosa‘ were resistant parents. Resistance was dominant and inherited monogenically. Arthur 71, Homestead and Tascosa have the same gene for resistance, while Newton contains a different gene for resistance.
Genetic and Phenotypic Associations of Agronomic Characteristics in Four High Protein Soybean Populations1
Authors: Simpson A. M. , Wilcox J. R.
Published: July 2010

Four hundred and twelve soybean [Glycine max (L.) Merr.] progenies from crosses between two poorly adapted, high protein strains, ‘Pando’ (49.9% protein) and PI 159,764 (48.7% protein) and two adapted, average protein strains, SL12 (41.8% protein) and ‘Woodworth’ (40.4% protein) were evaluated replicated tests for two years at Lafayette, Ind. Data were recorded on seed yield, protein and oil percentage, and several agronomic characteristics to determine if interrelationships among these characteristics would facilitate or conflict with the development of high yielding, high protein strains with acceptable agronomic characteristics. High yield was positively associated with late maturity, increased plant height, lodging susceptibility, and resistance to shattering. High protein content was also associated with late maturity and increased plant height in progenies of two crosses and with increased severity of seed coat mottling. Because of a strong inverse relationship between protein and oil content, characteristics positively associated with high protein were associated with low oil content. Genetic correlations were large and variable for yield and protein percentage, were small for yield and oil percentage, and were negative for protein percentage and oil percentage. Yield components and yield related characteristics were measured on 52 progenies from one of the crosses. Characteristics closely associated with seed yield were number of seeds, pods, and nodes. Of these, number of nodes was also positively correlated with protein content. Selection for plants with high numbers of nodes should result in the development of base populations or lines where the negative correlation between yield and protein percentage would be negligible. The data indicated that group III or group IV strains combining high seed yield and protein content could be readily obtained from the populations studied. Adverse associations of lodging with both yield and protein were not strong enough to seriously interfere with the development of high yielding, high protein strains with adequate lodging resistance.
Spectrum of Variation in Somaclones of Triploid Ryegrass1
Authors: Ahloowalia B. S.
Published: July 2010

Ryegrass (Lolium spp.) plants regenerated from callus culture were investigated for variation in morphology, chromosome number and fertility. More than 4000 plants were produced from successive subculture of a single callus initiated from a triploid (2n = 21) embryo of hybrid origin, 2x (Lolium multiflorum Lam.‐perenne L.)✕ 4x (L. perenne L.). The first group of plants regenerated from the callus were triploid. However, those obtained from successive callus subculture had chromosome number of 2n = 20,19,18,16,14, and still later regenerates were neartetraploids with 2n = 30, 29, 28, 27, and 26 chromosomes. A number of plants were mosaics with 2n = 21/20,20/19,27/28, 20/30, and 29/30 chromosomes. Some plants had pollen mother cells with variable chromosome number of 2n = 20,40,60,200 and 2n = 19, 38, 57. Meiotic study suggested the presence of reciprocal translocations, deletions, inversions, chromosomal fragmentation and elimination, and polyploidy. Regenerated plants showed wide variation in leaf shape and size, floral development, vigor, and survival. Some plants had novel phenotypes, not produced by conventional breeding. An albino mutant sector of callus produced only albino plants. Regenerated plants originated both via differentiation of shoot primordia and somatic embryogenesis. It is concluded that the observed variation among the regenerated plants resulted primarily from chromosomal instability in the callus subcultures.
Southwestern Corn Borer Growth on Callus Initiated from Corn Genotypes with Different Levels of Resistance to Plant Damage1
Authors: Williams W. P. , Buckley P. M. , Taylor V. N.
Published: July 2010

Development of southwestern corn borer [Diatrea grandiosella (Dyar)] larvae on corn (Zea mays L.) has been shown to be affected by the corn genotype on which they develop in the field. This investigation was undertaken to determine whether larvae could survive and grow on corn callus in the laboratory and, if so, whether the genotype of the callus would affect growth. Callus of several corn genotypes was initiated and maintained on Muashige and Skoog (MS) medium with an addition of 14 mg of 2,4‐D (2, 4 dichlorophenoxyacetic acid) per liter. When approximately 600 mg of callus had developed on each petri plate, three first‐instar southwestern corn borer larvae were added to each plate. After 1 week the larvae were weighed. Larvae developing on some corn genotypes were significantly smaller than those developing on other genotypes. The smaller larvae developed on genotypes which have relatively high levels of field resistance to leaf feeding when infested at the whorl stage of growth or to stalk tunneling when infested at anthesis. Larvae developing on some genotypes showing field resistance, however, were not significantly smaller than those developing on callus initiated from susceptible genotypes.
Evaluation of R‐Lines from the Sorghum Random‐Mating Populations NP3R1
Authors: Otte C. E. , Ross W. M. , Sullivan C. Y. , Voigt R. L. , Miller F. R.
Published: July 2010

Sixty sorghum [Sorghum bicolor (L.) Moench] F1 hybrids produced by crossing two A‐lines (cytoplasmic male steriles) with 30 R‐lines (fertility restorers) were grown in two environments each in Nebraska and Arizona. The primary objective was to compare two sets of related hybrids, one set made with lines derived from a random‐mating population and the other made with component lines of the population. A second objective was to determine the effect of parental line selection environment on hybrid performance. The 30 R‐lines were composed of three groups: 10 well‐adapted component lines of the random‐mating population NP3R, 10 lines selected from the NP3R population in Nebraska, and 10 selected from NP3R in Arizona. The Arizona and Nebraska lines were furlher identified by their origin as being selected under high‐moisture or low‐moisture environments in each state. Hybrids fron3 the selected lines averaged 0.22 Mg ha−1 higher yield than hybrids from the component lines, which was statistically significant. There was no difference between the mean yields of the hybrids produced from the Arizona and Nebraska selections. Hybrids produced from the Arizona low‐moisture selections were 6 to 8 cm taller and 0.20 to 0.45 Mg ha−1 higher yielding than Ihose produced from the other groups. Hybrids from the Arizona selections Itowered 2 days earlier than from the Nebraska selections. Statistical differences also existed among hybrids of the male groups for tillering, 100‐seed weight, and grain protein percentage, but they were not of great practical importance. The study demonstrated that parental lines can be selected from a sorghum random‐mating population that will produce suitable hybrids. Extensive genetic recombination in random‐mating populations makes their use feasible as sources of inbreds.
Association of Weather Variables with Genotype × Environment Interactions in Grain Sorghum1
Authors: Saeed Mohammad , Francis C. A.
Published: July 2010

The objective of this study was to determine the relative contribution of several weather variables during various plant growth stages to variation in environment and genotype ✕ environment (GE) interactions of grain sorghum [Sorghum bicolor (L.) Moench] genotypes in different maturity groups. Three growth stages viz., planting to panicle initiation (GS1), panicle initiation to anthesis (GS2), and anthesis to physiological maturity (GS3), were approximated with three periods of crop season, each with an equal number of growing degree days. Variation in temperature and rainfall accounted for more than half of the environment and genotype ✕ environment interaction sums of squares for yield, and seed number and seed weight components of yield. However, the extent to which these variables contributed to differential genotypic response to environments varied among maturity groups and growth stages. Temperature was the most important factor affecting environmental variability for yield and seed number. Effects of temperature and rainfall in GS2 and GS3 were highly associated with GE interaction effects for yield in all maturity groups. Generally, minimum temperature was more important than maximum temperature especially for the early and the late maturing genotypes. Preseason precipitation contributed more than seasonal rainfall to the GE interaction sums of square for yield and seed number, however, the opposite was observed for seed weight. Variation in weather factors contributed more to GE interaction for yield of the late maturing genotypes than the early and medium maturing genotypes. More information on environmental factors is needed to better understand the nature of GE interaction in grain sorghum.
Prediction of Three‐Way Top Cross Sugarbeet Hybrid Performance1
Authors: Skaracis G. N. , Smith G. A.
Published: July 2010

A fixed set of inbred and pollinator diploid sugarbeet (Beta vulgaris L.) lines was used to synthesize all possible inbred inbred, and inbred ✕ pollinator single crosses, as well as all possible (inbred ✕ inbred) ✕ pollinator three‐way top crosses. Parental lines, and single and three‐way cross hybrids were grown in 1980 and 1981. The primary objective of this study was to develop and evaluate various methods to predict the performance of three‐way top cross hybrids and secondarily to assess the relative importance of different types of gene effects involved in the expression of root yield, sucrose content, and juice purity in the set of lines used. Predictions based on the mean of the nonparental single crosses, involved in each three‐way top cross, were sufficiently reliable and proved equally as good as or better than predictions by other methods investigated. An inbred ✕ pollinator factorial crossing system necessary for this approach also would be compatible with standard sugarbeet breeding procedures. Dominance and additive gene effects proved most important for root yield. Sucrose content and juice purity were controlled only by additive effects. No evidence for significant epistatic effects was found for any of the traits studied.
Divergent Mass Selection for Carotenoids in a Flue‐Cured Tobacco Populations1
Authors: Beatson R. A. , Wernsman E. A. , Long R. C.
Published: July 2010

Leaf carotenoids are important precursors of aroma and flavor constituents in tobacco, Nicotiana tabacum L. In an F2 population resulting from a cross of ‘Hicks’ ✕ ‘Coker 139’, five cycles of mass selection were practiced for high and low total carotenoid concentrations in cured leaf. All 10 selected cycle populations, the original F2 population, and parental cultivars were evaluated at two locations. The effectiveness of mass selection for changing total carotenoids, the divergence and asymmetry of responses between the high and low populations and the correlated changes in other characters were measured. Based on a linear concurrent regression model, response to divergent mass selection for total carotenoids was significant in both directions. Average change per cycle of selection for total carotenoids was 4 μg g‐1 for the high population, and —5.4 μg g‐1 for the low population. Progress in the two populations was symmetric with the high population possessing 41% more carotenoids than the low population after five cycles of selection. Important correlated responses in other constituents occurred as well. Total alkaloids were positively correlated with carotenoid changes, diverging 46% between the high and low populations. Total alkaloids were altered 0.17 and —0.13% per cycle for the high and low populations, respectively. Leaf yields and grade index were negatively related to direction of carotenoid selections and diverged at cycle five by 20 and 45%, respectively. The complexity of cured leaf quality determination in tobacco is apparent from this study. If carotenoid concentrations in cured leaf are to be used as an indirect selection criterion for altering aroma and flavor of tobacco, selection schemes to minimize correlated responses for other chemical constituents may be necessary.
Response of an F1 Interspecific Cotton Hybrid to Nitrogen Fertilization1
Authors: Palomo Arturo , Davis D. D.
Published: July 2010

Response of the high yielding interspecific cotton (Gossypium hirsutum L. × G. barbadense L.) hybrid, ‘NX‐1’, to four N fertilizer levels (0, 55, 110, and 220 kg ha‒1) and 2 years (1979 and 1980) was evaluated. ‘Acala 1517–75’ and ‘McNair 220’, G. hirsutum L. cultivars, were also included as checks. Data recorded included blooming rate, earliness, lint yield, boll characteristics, and fiber properties. NX‐1 was about 9 days earlier to first bloom, compared to the checks, and exhibited a higher blooming rate. NX‐1 also showed the largest increases in floral production with the addition of N in 1980, but not in 1979. The flower production of NX‐1 was increased by the addition of 55 kg of N ha‐1, but not by additions beyond that level. NX‐1 was the earliest genotype as measured by the number of days from planting to first bloom, production rate index, and lint yield at first harvest. A significant genotype ✕ N interaction for lint yield was detected. At zero N level, the lint yield of the hybrid was significantly lower than with added N. McNair 220 and Acala 1517–75 did not show a significant response to N. On the average, lint yield of the hybrid was 38 and 27% higher than for Acala 1517–75 and McNair 220, respectively. NX‐1 had a smaller boll, fewer seed boll‐1, lower lint percentage, and a higher seed index, compared to the checks. The hybrid showed a fiber fineness similar to that of Acala 1517–75, but its fiber was longer and stronger with a higher elongation. Boll characteristics and fiber properties were not significantly influenced by N rates.
Effects of Two Pilosity Alleles on Agronomic and Fiber Traits in Upland Cotton1
Authors: Lee Joshua A.
Published: July 2010

The pilosity alleles H2 and Pilose impart dense pubescence to various plant parts of upland cotton (Gossypium hirsutum L.). The effects of the two alleles on selected agronomic and fiber traits were studied in 1982 in two environments on the background of ‘Empire’, a cultivar which displays a normal density of pubescence. Four entries were compared, i.e., i) homozygous Pilose; ii) normally pubescent siblings of Pilose, designated as C‐l; iii) homozygous H2; and iv) normally pubescent siblings H2, designated as C‐2. The density of pubescence on leaves of Pilose and H2 did not differ, and both were about 2.5 times more pubescenthan the controls. Pilose did differ from the other three entries in having pubescent bolls. Boll weight was virtually the same for all entries, as was lint percentage. Fiber length varied among entries. C‐I had 21% greater 2.5% span length than Pilose (28.4 vs. 23.4 mm). C‐2 displayed 4% greater 2.5% span length than H2 (27.8 vs. 26.7 ram), a difference not significant at the 0.5 probability level. The 50% span length of the entries correlated closely with 2.5% span length (r = 0.89**), and Pilose differed significantly from the other entries in fiber length uniformity index. Micronaire was significantly greater for Pilose than for the other three entires (5.2 vs. 4.4 to 4.5), and the coarser fiber of Pilose was accompanied by a small loss in fiber tensile strength. There were no significant differences in fiber elongation. The possible uses for H2 in breeding for insect resistance were discussed.
Field Evaluation of Seedling Root Length Selection in Oats1
Authors: Barbour N. W. , Murphy C. F.
Published: July 2010

Selections for long and short root length were made on 10‐day‐old oat, Avena sativa L., seedlings from two F2 populations grown in distilled water or in a modified half‐strength Hoagland's solution. F2 derived F3 and F4 progeny were grown in the field in a nonstress environment with a shallow ( 10 to 30 cm) loamy sand or sandy loam A horizon and in a stress environment with a deep (75 to 90 cm) loamy sand A horizon. Seedling root measurements were made on F4 and F5 plants. Root length differences were observed two and three generations after selection following growth in a modified half‐strength Hoagland's solution but differences between long and short root length selections were not consistently maintained for the selections made after growth in distilled water. Trends toward greater grain yield, seed number, and plant height were observed for the long root length selection, especially in the nonstress environment. The technique was not successful in identifying plants with superior performance in a deep sandy soil.
Effects of Nitrate and Plant Development on the Abundance of Nitrogenous Solutes in Root‐Bleeding and Vacuum‐Extracted Exudates of Soybean1
Authors: Herridge David F.
Published: July 2010

In the experiments reported, the relative contents of ureides [(ureide‐N/ureide‐N + nitrate N + a‐amino‐N) × 100] ofxylary exudates and the relative symbiotic dependence of nodulated soybean [Glycine max (L.) Merr. ‘Bragg’] were compared using glasshouse‐grown plants supplied with various concentrations of nitrate ranging from zero to 8.0 raM. Xylary exudates were sampled from the plants by vacuum extraction of detached shoots or as root‐bleeding exudate. Symbiotic dependence for each of the NO−3 treatments was calculated on the basis of total‐plant N and time‐integrated rates of nitrogenase (C2H2 reduction) activities. Analyses of all samples of the two exudates for ureides, NO−3 and α‐NH2‐N and of samples from R2 plants of individual amino compounds revealed only minor differences between the two exudates in the composition of these compounds. Amino acids and amides contributed slightly more and ureides and NO−3 slightly less to total N of vacuum‐extracted exudate relative to root‐bleeding exudate. The photosynthetic amino acids, alanine and serine, were more evident in stem exudate. Effects of NO−3 supply and plant age on the relative contents of ureides were similar for both exudates. These data were combined with the data on the effects of NO−3 supply on N2(C2H2) fixation to describe standard curve relationships between the symbiotic dependence of the plants and the relative contents of ureides for each of eight phases of growth.