bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Soybean Seed Oil and Protein as Influenced by Manganese Nutrition1
Authors: Wilson D. O. , Boswell F. C. , Ohki K. , Parker M. B. , Shuman L. M. , Jellum M. D.
Published: July 2010

Manganese deficiency is known to severely reduce growth and yield of soybean [Glycine max (L.) Merr.] plants, but little is known about the effects of Mn deficiency on soybean seed quality factors. Seed from field‐grown soybean plants containing leaf Mn concentrations ranging from 4 to 58 ppm were analyzed for oil and protein percentage. Seed oil and seed protein from selected treatments containing 4 to 44 ppm leaf Mn were analyzed for fatty acid and amino acid percentages, respectively.

Severe Mn deficiency (less than 15 ppm Mn in the leaves) increased seed protein percentage and decreased seed oil percentage. Seed from plants with extremely low leaf Mn levels contained higher percentages of linoleic, palmitic, linolenic, and stearic acids and a lower percentage of oleic acid. The percentages of seed protein, seed oil, and fatty acids changed markedly at low leaf Mn levels but remained relatively constant above leaf Mn concentrations of 15 to 20 ppm. Percentages of amino acids in seed protein were relatively unaffected by Mn.

The results show that several soybean seed quality factors can be markedly altered by deficient levels of Mn. These changes could have a significant influence on the quality of products derived from soybean seed.
Seasonal Changes in Nonstructural Carbohydrate Levels of Wheat and Oats Grown in a Semiarid Environment1
Authors: McCaig Thomas N. , Clarke John M.
Published: July 2010

Nonstructural carbohydrate (NSC)levels of vegetative tissues were examined in two cultivars of wheat (Triticum aestivum L.) and of oats (Avena sativa L.) to determine the seasonal distribution patterns and amounts of NSC present in these crops when grown under the dryland conditions of southwestern Saskatchewan. Ethanol (95 %) was used to extract short chain carbohydrates while oligosaccharides were extracted with water. Both fractions of carbohydrates were more prevalent in the stems than in green leaves; only low levels were found in dead leaves. The green‐leaf carbohydrate levels were relatively stable throughout the growing season and did not fluctuate in response to seasonal rainfall. Carbohydrates accumulated in the stems to a maximum (25 to 48% of the dry weight) about anthesis and then declined toward maturity. Significant differences in stem carbohydrate levels were observed between wheat and oats and between cultivars within a species. Although similar trends were found in both years of this experiment, stem carbohydrate concentrations differed. The results support the concept that the stem may act as a temporary storage organ for NSC to correct a phase difference between the time of maximum photosynthate production by the plant and the time of maximum requirement for carbohydrate by the developing grain.
The Effect of Rhizobium trifolii Strains and Crimson Clover Genotypes on N2 Fixation1
Authors: Smith G. R. , Knight W. E. , Peterson H. L. , Hagedorn C.
Published: July 2010

The effects of crimson clover (Trifolium incarnatum L.) genotype and strain of Rhizobium trifolii on dry weight yield and N2 fixation were investigated in a factorial experiment. The treatments were arranged in a randomized complete block design with eight replications. The clover‐Rhizobium combinations were grown in plastic pouches with a N‐free nutrient solution. A growth chamber was used to maintain 24/19 C diurnal temperatures and a 12 hour photoperiod.

After 60 days of growth, the combinations were assayed for N2 fixation using acetylene reduction and the plant tops were harvested and dried. Plant lines, strains of Rhizobium and line ✕ strain interaction were all significant sources of variation for both acetylene reduction rate and dry weight yield. Strains had the largest effect, in terms of variance components, on dry weight yield followed by plant lines and strain ✕ line interaction, respectively. Strains also had the largest effect on acetylene reduction rate followed by strain ✕ line interaction and plant lines, respectively. Strain TA1 of R. trifolii was highly variable in its effect on the different plant lines. Response of different inbred lines with this strain ranged from efficient to inefficient.
Quantitative Inheritance of Ozone Resistance in Potato1
Authors: De Vos N. E. , Hill R. R. , Pell E. J. , Cole R. H.
Published: July 2010

The inheritance of foliar resistance to ozone was studied in 14 cultivars of Solanum tuberosum L. using two sets of 7 × 7 diallel crosses. Resistant, intermediate, and susceptible parents were included in each diallel. In each of four runs for each diallel, parent clones, parents selfed, and reciprocal F1 hybrids were simultaneously exposed to 774(μg/m3 (0.40 ppm) ozone for 3 hours in a controlled environment chamber at 21 C and 70% relative humidity.

General and specific combining ability were significant in both diallels, accounting for over 70 and 20%, respectively, of the variation among hybrids. Maternal effects were significant in one diallel, but accounted for less than 5 % of the variation among hybrids in either set of crosses. Single‐locus, autotetraploid genetic models for complete additivity, complete dominance for suceptibility, and complete dominance for resistance were tested by comparing the observed and expected relationships between parent, S1, and offspring means. Complete dominance for resistance accounted for the results better than any of the simple models tested; however, no adequate test for digenic and trigenic models could be determined, and no model with more than one locus or multiple alleles was examined.
Genotype ✕ Environment Interactions for Leaf Area Parameters and Yield Components and Their Effects on Wheat Yields1
Authors: Borojevic Slavko , Williams William A.
Published: July 2010

Genotype × environment interactions for parameters characterizing source and sink capacity and their effects on grain yield of three divergent wheat (Triticum aestivum L.) cultivars were studied over a 10‐year period.

The mean square in the number of spikes/m2 due to genotype × year interaction (g × y) was greater than the mean squares due to years or genotypes alone. The mean square for leaf area index (LAI) and leaf area duration (LAD) due to years was greater than the mean squares due to genotypes and g × y interactions. The mean squares due to genotypes were greater than the mean squares for years and g × y interactions for number of kernels/spike, 1,000‐ kernel weight, disease and lodging resistance, as well as for grain yield. Environmental factors exhibited greater effects on the parameters of source capacity than on the parameters of sink capacity.

The LAD showed the highest positive relative contribution to grain yield for each cultivar over the 10‐year period. Direct effects of other variables differed among the cultivars; some exhibited positive and some negative direct effects on grain yield. Using seven variables, 83% of variation of grain yield could be “explained” for the cultivar ‘Sava,’ 75% for ‘Bezostaia,’ but only 34% for ‘Bankut,’ as shown by the coefficient of determination.

For climatic variables the only significant relation was a positive association between grain yield and hours of sunshine in May and June, i.e., during gamete formation, fertilization, and the grain filling period.

Bezostaia showed the greatest stability in yield performance, but Sava gave the highest grain yield in all years. Since a grain producer is interested in having high grain yields at his location, the preference in the choice of cultivars should be given to the meangrain yield rather than to the other stability parameters.
Genotype ✕ Year Interaction for Length and Rate of Grain Filling in Oats1
Authors: Wych R. D. , McGraw R. L. , Stuthman D. D.
Published: July 2010

In spring oats (Avena sativa L.) the sensitivity of grain yield to environmental stresses during grain filling varies among genotypes that differ in days to heading. The main objective of this study was to evaluate the relationship between grain yield, grain‐filling rate (GFR), and grain‐filling period (GFP) of oats in two contrasting field environments. A secondary objective was to assess the validity of estimating “vegetative growth rate” (i.e., preheading crop growth rate) from straw weight at maturity and days to heading.

Twenty oat genotypes selected for diversity in days to heading and percent groat protein were grown in consecutive years that differed in air temperature during the GFP and in rainfall distribution during the growing season. Average grain yield in 1980 was 8% lower than in 1979. The genotype × year (G × Y) interaction for grain yield resulted from increases from 1979 to 1980 for earlier heading genotypes but decreases from 1979 to 1980 for later heading genotypes. Compared to 1979, the 1980 GFP was shortcned for all genotypes, but was changed the most for later heading genotypes. Relative to 1979 values, GFR in 1980 increased for 12 of the earlier heading genotypes, but decreased for six of the eight later heading genotypes. Kernel weight and groat percentage were also lower in 1980 than in 1979 for all 20 genotypes, supporting the interpretation that kernel growth, and hence grain filling, were curtailed prematurely in 1980.

Straw weight declined between heading and maturity for only one genotype in 1979 but for seven genotypes in 1980. Since the occurrence and magnitude of post‐heading change in straw weight are subject to G × Y interaction, vegetative growth rates estimated by dividing straw yield at maturity by days to heading may be invalid. Two alternate methods for more accurately estimating vegetative growth rate are discussed.
Inheritance Pattern for Secreting and Nonsecreting Glandular Trichomes in Tobacco1
Authors: Nielsen M. T. , Jones G. A. , Collins G. B.
Published: July 2010

Crosses were made between Tobacco Introduction 1406 (‘Virgin A Mutant’), a Nicotiana tabacum L. breeding line susceptible to the tobacco flea beetle, Epitrix hirtipennis (Melsheimer), and three tobacco flea beetle tolerant burley tobacco cultivars. The parents, F1, F2, and BC1 generations were evaluated for secreting or nonsecreting glandular trichomes to determine the inheritance of secretory activity. Tobacco Introduction 1406 did not possess secreting trichomes. Secreting trichomes were present on the three burley cultivars. Segregation patterns revealed that presence or absence of secreting trichomes was controlled by alleles at a single locus. Secreting trichomes were produced on leaves of the homozygous and heterozygous plants while nonsecreting trichomes were present on leaves of the homozygous recessive genotype. The locus was designated as the Te locus. Quantitative determination of exudate amounts in secreting plants were not made although visual differences in exudate levels were noted.
Successful Wide Hybridization Between the Soybean and a Wild Perennial Relative, G. tomentella Hayata1
Authors: Newell C. A. , Hymowitz T.
Published: July 2010

An important source of genetic diversity that has been employed effectively in a variety of breeding programs is that provided by wild relatives of crop plants. In this paper, we report that hybrids between the soybean [Glycine max (L.) Merr.] and a wild perennial relative, G. tomentella Hayata, were obtained for the first time through in vitro ovule culture. The F1 plants were vegetatively vigorous and resembled the wild male parent morphologically. The chromosome numbers were consistent with a hybrid origin. The plants flowered profusely but were sterile. The data suggest that the use of wild perennial members of Glycine might become feasible for broadening the germplasm base of the soybean.
Chromosome Numbers of Released Cultivars of Switchgrass, Indiangrass, Big Bluestem, and Sand Bluestem1
Authors: Riley R. D. , Vogel K. P.
Published: July 2010

Chromosome numbers of cultivars of switchgrass (Panicum virgatum L.), indiangrass (Sorghastrum nutans L.) and the tall bluestem complex of big bluestem (Andropogon gerardi Vitman.) and sand bluestem (Andropogon hallii Hack.) were determined. Ploidy levels of these cultivars have not been reported previously even though these grasses have been reported to have two or more ploidy levels. Switchgrass cultivars ‘Pathfinder’, ‘Blackwell’, and ‘Nebraska 28’ were hexaploids (2n = 54), while ‘Summer’ and ‘Kanlow’ were tetraploids (2n = 36). Indiangrass cultivars ‘Nebraska 54’, ‘Oto’, ‘Osage’, and ‘Holt’ were all tetraploids (2n = 40). Big bluestem cultivars ‘Pawnee’ and ‘Kaw’ and the sand bluestem cultivar ‘Goldstrike’ were hexaploids (2n = 60). Meiosis was normal with bivalent pairing for most plants examined from all three grasses.
Genotype × Environment Interactions for Protein in Glycine max × Glycine soja crosses1
Authors: Erickson L. R. , Beversdorf W. D. , Ball S. T.
Published: July 2010

One hundred fifteen F3 families chosen from four crosses between Glycine max (L.) Merr. and its wild relative, Glycine soja Sieb. and Zucc., were used in two studies to evaluate the effect of genotype × environment interactions on the protein content of soybean seeds. The families ranged in protein content from approximately 40 to 50%.

The first study was a variance component approach composed of 15 F3 families grown at two locations in 2 years. The family variance component estimate was highly significant (p≤0.01). Estimates of the variance components for the family × year and family × location interactions were nonsignificant. The estimated variance component for the family × year × location interaction was significant (p≤.05), although approximately one‐fourth the magnitude of the family and within‐plot variance components. Broad sense estimates of heritability for protein content calculated on a single plant, plot, and entry‐mean basis were 0.45, 0.58, and 0.90, respectively.

The second study was composed of 100 F3 families conducted at two locations during a single growing season. Highly significant (p≤0.01) differences among the families were observed. Despite a highly significant (p≤0.01) correlation for protein content between locations, a few families with high protein content at one location had much lower protein content at the other location.

Progress from selection among the families from these four crosses for protein content should be possible. Although the lower 50% of the families could be safely discarded on the basis of data from one location, selection among the higher protein genotypes should involve at least two environments.
Genetic Resistance and its Residual Effects for Control of the Root‐Knot Nematode‐Fusarium Wilt Complex in Cotton1
Authors: Shepherd Raymond L.
Published: July 2010

Two cotton (Gossypium hirsutum L.) cultivars and a breeding stock (‘Deltapine 16’, ‘Auburn 56’, and Auburn 623 RNR, respectively), having in order low, intermediate, and high resistance to the root‐knot nematode‐fusarium wilt disease complex [caused by Meloidogyne incognita acrita (Kofoid & White) Chitwood and Fusarium oxysporum Schlecht. f. vasinfectum (Atk.) Snyd. & Hans.], were grown in nematicide, DBCP (1,2‐dibromo‐3‐chloropropane), treated vs. untreated plots for 3 years.

Fumigation did not significantly increase lint yield of Auburn 623 RNR compared with 36 and 77% increases for Auburn 56 and Deltapine 16, respectively. Auburn 623 RNR without fumigation was more effective for controlling root‐knot nematodes than Auburn 56 and Deltapine 16 with fumigation and was equally effective as those cottons with fumigation for controlling fusarium wilt disease. In unfumigated plots, Auburn 623 RNR vs. Auburn 56 and Deltapine 16 also had lower root‐knot nematode numbers (83/500‐cm3 of soil vs. 717 and 1,581, respectively) and lower fusarium wilt percentages (5% vs. 47%, respectively). In the fourth year of the study, susceptible ‘Stoneville 213’ cotton was grown without fumigation in all plots where the above cottons had been grown. Stoneville 213 following unfumigated Auburn 623 RNR had 147 kg/ha (21%) and 270 kg/ha (47%) higher lint yields than following unfumigated Auburn 56 and Deltapine 16, respectively. Stoneville 213 had smaller root‐knot nematode populations following unfumigated Auburn 623 RNR than following fumigated Deltapine 16 and no greater incidence of fusarium wilt disease than when it followed fumigated Auburn 56 and Deltapine 16. If the high level of resistance exhibited by Auburn 623 RNR can be bred into cotton cultivars, it should reduce much of the present root‐knot nematode and fusarium wilt damage to cotton and to susceptible crops following resistant cotton in rotations.
A Genetic and Breeding Study of Pink Bollworm Resistance and Agronomic Properties in Cotton1
Authors: Wilson F. D. , George B. W.
Published: July 2010

A breeding stock of upland cotton (Gossypium hirsutum L.) designated as AET‐5, consistently sustains less seed damage by pink bollworm(PBW)[Pectinophora gossypiella (Saunders)] than do cultivars.This stock is deficient in most agronomic and fiber properties, with the exception of lint percentage. Wec rossed AET‐5 to DES 24‐8ne, an advanced breedingl line which lacks extrafloral nectaries [nectariless (2 ne1, ne2)], a morphologicalt rait whichi mparts resistance to PBW in large field plantings. Parents and hybrid generations were compared for 2 years in insecticide‐free environments. The objectives of these studies were to determine the inheritance of the AET‐5 level of seed damage and of several agronomic properties and to predict the ease of transfer of the low seed damage and high lint percentage into a desirable agronomic background by backcrossing. The seed damage expected in a stock combining the AET‐5 type of resistance with the nectariless character should be lower than in stocks carrying only one of those two resistance characters. Analyses of tests grown for 2 years indicated that gene action was primarily additive for both seed damage and lint percentage, that narrow‐sense heritability estimates were significant, and that few genes conditioned those properties. A combined analysis of variance revealed that genotype ✕ environment interactions were not significant for those traits. Therefore, it should not be difficult to transfer the AET‐5le vel of resistance and its associated high lint percentage into desirable backgrounds. Additive effects were also shownin two of the three tests for the other agronomic properties measured. Dominance, epistasis, or both were also shown. Heritability estimates were not consistently significant. Those non‐additive effects shouldn ot be regarded as obstacles to breeding progress because our ultimate objective is to transfer by backcrossing only low seed damage and high lint percentage, but otherwise to reconstitute the phenotype of the nectariless parent.
Soybean Seedling Response to Anaerobiosis1
Authors: Turner F. T. , Sij J. W. , McCauley G. N. , Chen C. C.
Published: July 2010

Death and stunting of soybean [Glycine max (L.) Merr.] seedlings in soils with excess water is generally thought to be a response to low oxygen (O2) levels in soils. To evaluate the effect of low soil O2 level on root development of selected soybean cultivars, soybean seedling roots or roots and shoots, were exposed to a nitrogen gas (99.995% N2) environment (anaerobiosis) for up to 16 hours. The resulting data indicate that soybean seedling roots can survive anaerobiosis better than anticipated. Data suggest that when the seedling shoot is in air, O2 may diffuse down the stem, providing an unaerated root with sufficient O2 to elongate at approximately 14% of the rate obtained in air. When entire seedlings were enclosed in a N2 environment taproot elongation was inhibited. Recovery from anaerobiosis (in terms of root elongation) was inversely proportional to anaerobiosis duration. Exposing the entire developing seedling to 14 hours of anaerobiosis killed the elongating taproot tip of the less‐tolerant cultivars in some experiments. There also appeared to be cultivar differences in root elongation rate after anaerobiosis. ‘Semmes’ and ‘Dowling’ cultivars recovered more rapidly than ‘Biloxi’ and ‘Bragg’. The roots of Semmes soybean seedlings recovered more quickly from 4 hours of anaerobiosis than the roots of two cotton [Gossypium hirsutum L.] cultivars (‘Deltapine 61’ and ‘Tamcot SP37H’) and two rice [Oryza sativs L.] cultivars (‘Caloro’ and ‘Labelle’).
Heterosis in Population Crosses of Alfalfa1
Authors: Hill R. R.
Published: July 2010

A partial diallel cross with 32 parental lines of alfalfa, Medicago sativa L., was evaluated to determine genetic variability and heterosis expressed for forage yield when pest‐resistant, low‐yielding parents were crossed with noninbred, vigorous germplasm. The parental lines included eight half‐sib family seed lines from two commercial cultivars, ‘Apalachee’ and ‘Arc,’ and from two pest‐resistant experimental populations, MSA and MSB. Progenies from the intercross of each of the parental lines were also included in the experiment. Significant mean squares for cultivars from which the parental lines were derived and for lines in cultivars were observed for the intercrosses of the parental lines and for general combining ability. In both cases, the mean square for cultivars was more than 20 times larger than the mean square for lines in cultivars. Significant specific combining ability was not detected. Interactions between genetic effects and years generally were not significant. Crosses had significantly greater yield than the mean of the parental line intercrosses for each of the cultivar combinations. Generally, crosses with lines from MSA or MSB as one of the parents yielded significantly less than crosses between lines from Apalachee and Arc, and crosses between lines from MSA and MSB yielded significantly less than crosses from any other cultivar combination. The intercrosses of parental lines from MSA had greater average yield than those from MSB, but parental lines from MSA had lower combining ability than those from MSB.
Chromosomal Location of Genes for Resistance to Greenbug in ‘Largo’ and ‘Amigo’ Wheats1
Authors: Hollenhorst Margaret M. , Joppa Leonard R.
Published: July 2010

The greenbug (Schizaphis graminum Rondani) causes significant economic losses to wheat, oats, barley, and sorghum. Genetic resistance to the greenbug recently has been identified in the germplasm lines ‘Amigo’ (Triticum aestivum L.) and ‘Largo’ (Triticum turgidum ✕ T. tauschii) hexaploid wheats. Amigo has a single dominant gene transferred from rye (Secale cereale L.), and Largo is an amphiploid of ‘Langdon’ durum (T. turgidum L.) and T. tauschii (Coss.) Schmal. Crosses between Largo and Amigo indicated that each parent has a single independent gene for resistance to greenbug biotype C. A set of ‘Chinese Spring’ monosomics were used to determine the chromosomal location of the resistance genes in Amigo and Largo. The F2 plants from monosomic F1s were grown to the two to three leaf stage in 12‐cm‐pots or in flats and infested with greenbug biotype C. We found that the gene in Amigo is located in chromosome 1A and the gene in Largo is located on chromosome 7D. Chromosome pairing data from crosses between the Chinese Spring monosomics and Amigo indicated that Amigo differs from Chinese Spring by two reciprocal translocations which involve chromosomes 6A, 6B, 7A, and 7B.
Combining Ability Effects for Forage Residue Traits in Grain Sorghum Hybrids1
Authors: Ross W. M. , Gorz H. J. , Haskins F. A. , Hookstra G. H. , Rutto J. K. , Ritter R.
Published: July 2010

Combining ability effects of 10 female and 10 male inbred lines were evaluated for agronomic, grain, and forage residue traits in 100 grain sorghum [Sorghum bicolor (L.) Moench] F1 hybrids for 2 years. Traits studied were height, flowering, tillering, seed weight, yield, protein percentage, protein yield of grain, leaves, and stems; and in vitro dry matter disappearance (IVDMD) percentage and digestible dry matter (DDM) yield of leaves and stems. General combining ability (GCA) effects exceeded specific combining ability (SCA) effects for all traits except height in females and grain and leaf yields in males. Both GCA and SCA were low for tillering and stem protein percentage. Genetic ratios, resembling heritability, were higher for GCA than SCA except for height in females and tillering in males. Grain yield generally had no extremely strong negatlve phenotypic correlatlons with any forage residue trait although grain yield correlated with stem protein and stem IVDMD percentages produced negative values that would warrant monitoring in a breeding program. Grain yield, stem and leaf yields, and stem and leaf DDM yields all had moderate to strong positive relationships with each other. A few potentially useful parents were identified having high GCA effects for forage quality characters. Data on protein and IVDMD percentages of leaf and stem fractions from grain sorghum breeding nurseries and hybrid yield trials should be routinely collected.
Metabolic Changes in Senescing Soybean Leaves of Similar Plant Ontogeny1
Authors: Secor Jacob , Shibles Richard , Stewart Cecil R.
Published: July 2010

Delaying the onset or reducing the rate of leaf senescence may be one means of increasing crop productivity. But before senescence can be controlled, it must first be characterized. We compared the onset of leaf senescence, defined as the time at which apparent photosynthesis began to decline irreversibly, with ribulose‐l,5‐bisphosphate carboxylase (RuBPCase) activity, chlorophyll content, total protein content, leaf diffusive resistance, and dark respiration in outdoorgrown soybean [Glycine max (L.) Merr. ‘Amsoy 71’] leaves that had emerged during plant reproduction. We sought to determine which parameter(s) was associated with the onset of senescence. Apparent photosynthesis, as estimated by infrared gas analysis, began to decline about 85 days after planting in leaves at both nodes 12 and 15. There was no change in diffusive resistance, protein content, or dark respiration until about 3 weeks later. On the other hand, RuBPCase activity and chlorophyll content declined concomitantly with photosynthesis. This pattern was similar in both leaves. Thus, we conclude that RuBPCase activity and chlorophyll were best associated with the onset of senescence and that a similar mechanism seems to be operating in both leaves.
Influence of Leaf Anatomy on the Dry Matter Digestibility of C3, C4, and C3/C4 Intermediate Types of Panicum Species1
Authors: Wilson J. R. , Brown R. H. , Windham W. R.
Published: July 2010

Twenty‐eight Panicum species were examined to evaluate the influence of anatomy on leaf digestibility. Eighteen species had Kranztype leaf anatomy (C4 photosynthetic type), seven were non‐Kranz (C3 type) and three were intermediate (designated C3/C4) in their anatomical characteristics. Plants were grown in a greenhouse in summer and were sampled on two occasions for measurement of leaf dry matter digestibility (DMD), cell wall content (CWC) and the percentage of mesophyll, vascular, bundle sheath, epidermis and sclerenchyma tissues in leaf cross section. In rank order the C3 Panicums were high in DMD and low in CWC, the C3/C4 species were intermediate and the C4 species were low in DMD and high in CWC. Average values for the C3, C3/C4 and C4 species were 76, 70 and 69%, respectively, for DMD, and 33, 42 and 50% for CWC. The C3 species, P. rivulare Trin., was an exception with low DMD and high CWC. The average leaf tissue proportions for the C3, C3/C4 and C4 groups were, respectively, 66, 48 and 43% mesophyll, 10, 18 and 20% bundle sheath, 3, 6 and 8% vascular tissue, 22, 26 and 27% epidermis, and 0.5, 1.7 and 1.7% sclerenchyma. Correlations between DMD and proportions of bundle sheath, vascular or mesophyll tissue were highly significant (P < 0.001) for all species or within the C3 group with coefficients ranging from −0.53 to −0.88 for relationships with bundle sheath or vascular tissue and 0.62 to 0.63 for mesophyll. Within the C4 group, variation in gross tissue proportions was not closely correlated with DMD. The results indicate that the gross difference in tissue proportions between Kranz and non‐Kranz anatomy is probably an important factor contributing to the general difference in digestibility between tropical and temperate grasses. Leaf bulk density (dry weight/leaf volume) also appeared to be an important factor the dry matter digestibility difference between groups and within the C4 group.
Heritability of Lodging Resistance and Its Association with Other Agronomic Traits in a Diverse Sorghum Population1
Authors: Prest T. J. , Cantrell R. P. , Axtell J. D.
Published: July 2010

Random advanced lines from the grain sorghum [Sorghum bicolor (L.) Moench] population, PP9, were used to partition the genotypic variances of lodging resistance and other agronomic traits into components due to additive and additive ✕ additive genetic effects. In addition, heritabilities, phenotypic and genetic correlations between characters, and expected gains from S1 progeny selection were calculated. A hierarchical design employing 260 S4 lines tracing to 65 random S1 plants was used. The Sl‐derived families were categorized into three arbitrary height groups, and analysis was conducted over the groups. The characters evaluated were stalk lodging (before and after frost), thickness of third‐internode rind, diameter of third internode, flowering, and grain yield. Additive genetic variance was significant for all traits, whereas additive ✕ additive variances were not significant. Heritability estimates, using S1 progeny as the selection unit, ranged from 0.46 for rind thickness to 0.85 for flowering. Coefficients of variation were large for the lodging estimates. Rind thickness was significantly correlated (−0.46) with stalk lodging (post‐frost), whereas internode diameter and flowering were significantly correlated (−0.31 and −0.25) with stalk lodging estimates taken before frost. Although the pre‐frost lodging estimate had a significant phenotypic correlation with post‐frost lodging, the genetic correlation was not significant. The genes conferring resistance to post‐frost stalk lodging appear to be somewhat unrelated to those conferring resistance to pre‐frost stalk lodging. All characters except lodging (post‐frost) and yield were significantly correlated with flowering. When flowering within years was used as a covariate, heritabilities did not change appreciably.
Inheritance of Resistance in ‘Luso’ Wheat to Hessian Fly1
Authors: Oellermann C. M. , Patterson F. L. , Gallun R. L.
Published: July 2010

‘Luso’, a common wheat (Triticum aestivum L. em. Thell.) cultivar from Portugal, was studied to characterize its resistance to biotypes B and D of the Hessian fly [(Mayetiola destructor (Say)]. All experiments were conducted in controlled climate chambers and ventilated greenhouses at 20 ± 2 C. Progeny rows of self‐pollinated F2 and testcross Ft plants were infested with biotype B or D of the Hessian fly and classified as resistant, segregating, or susceptible. Chi‐square analyses were used to test genetic hypotheses. Luso possessed partial resistance to biotypes B and D of the Hessian fly. A single gene conferred this resistance to both of these biotypes. We found that the Luso gene is distinct from, and probably independent of, all genes previously characterized which confer resistance to biotype D of the Hessian fly (H5, H9, H10, and Hll). Therefore, the Luso factor was designated H12. The H12 gene is most likely located within the A or B genome of wheat.
Inheritance of Ozone Resistance in Tall Fescue1
Authors: Johnston W. J. , Haaland R. L. , Dickens R.
Published: July 2010

Ozone is considered the most important air pollutant affecting vegetation. With progessive urbanization, ozone levels have steadily escalated. Reports suggest that ozone tolerance is a highly heritable characteristic and that the selection of resistant plants and breeding for ozone resistance should be possible. This study was undertaken to gain information on the inheritance of ozone resistance in tall fescue (Festuca arundinacea Schreb.). Progenies from a diallel among six tall fescue genotypes of diverse origin were evaluated for ozone resistance in a fumigation‐chamber. Sixteen‐day‐old seedlings were exposed to 0.5 ppm ozone for 3 hours and scored for injury after 3 days. General combining ability (GCA) and reciprocal effects were both highly significant; however, GCA constituted a major portion of the genotypic variation. Specific combining ability was not significant. The predominance of additive genetic variance observed indicates that breeding for ozone resistance in this tall fescue population should be possible.
A Split‐Root Growth System for Evaluating the Effect of Salinity on Components of the Soybean Rhizobium japonicum Symbiosis1
Authors: Singleton P. W.
Published: July 2010

Study of the effects of salinity on symbiotic nitrogen fixation is complicated by the high degree of integration between shoot and nodules. Shoot photosynthetic capacity determines not only the amount of photosynthate available to the nodule, but the strength of the sink for nodule products. Salinity may also directly affect functional processes within the nodule. Two experiments were undertaken which employed a split‐root solution culture assembly that confined N2 fixation to one‐half of soybean [Glycine max (L.) Merr.] root systems. In one experiment, one‐half of the root system was inoculated with non‐N2 fixing strain (ineffective) of Rhizobium japonicum, SM‐5, 48 hours prior to inoculating the other side with effective strain USDA 110. Nodulation and N2 fixation by USDA 110 when in combination with SM‐5 was significantly suppressed compared to a second treatment where one‐half of the root system was inoculated with USDA 110 and the other half remained uninoculated. Root development was significantly greater on the side producing effective nodules than that of the uninoculated or SM‐5 nodulated half‐root systems. In another experiment, one‐half of the root system was nodulated with USDA 110 and the opposite side with SM‐5. After nodule development, NaCl (120 mM) was added to the nutrient solutions of: 1) neither half, effective nodule (USDA 110) half, 3) ineffective nodule (SM‐5) or 4) both halves of the root systems. Osmotic potentials ;(ψπ) of roots, nodules, and leaves were measured. Leaves of plants with only half their roots salinized had ψπ(−10.3 bar and −11.1 bar treatments 2 and 3 respectively) comparable to the non‐salinized control (−9.3 bar). Leaf ψπ of plants with both root halves in salt solutions was −17.9 bar. Nodules exposed to salt solutions had ψπ values ranging from −9.3 to −12.2 bar while ψπ of nodules in normal solutions ranged from −6.1 to −7.8 bar. Ineffective nodules always had a lower ψπ than similarly treated effective nodules. These results demonstrate that functional components of the soybean Rhizobium japonicum symbiosis can be independently subjected to salinity stress. This methodology can be used to evaluate the relative sensitivity of the components of the symbiosis.
Effect of Secondary Selection on Cyst Nematode Reproduction on Soybeans1
Authors: Luedders V. D. , Dropkin V. H.
Published: July 2010

“Resistance” of soybeans [Glycine max L. (Merr.)] to soybean cyst nematodes (SCN, Heterodero glycines Ichinohe) is determined by the relative number of nematode females or cysts that can develop in the roots of soybeans. Soybean cyst nematode (SCN) populations have been selected for ability to reproduce on soybeans with several sources of resistance and were used to identify genetic differences in both SCN and soybeans. The objective of this experiment was to determine reproductive changes in SCN populations initially selected on ‘Cloud’ or on ‘PI 89772’ after secondary selection on the other, genetically‐different, source of resistance. Response to the secondary selection was rapid; apparently SCN genes for reproductive ability were not fixed by the primary selection. Four cycles of selection or SCN generations on Cloud, of the population initially selected on PI 89772, significantly increased its ability to reproduce on Cloud while concurrently decreasing it on PI 89772. When the SCN population initially selected on Cloud was then selected on PI 89772, it could reproduce relatively better on PI 89772 but less well on Cloud. Thus, SCN genes for ability to reproduce on specific soybeans are not independent. Williams, the “susceptible” check, may have at least one of the same genes for resistance as Cloud. Evidence from SCN populations selected from four other field populations indicates that at least some of the SCN genes for reproduction on genetically different soybeans probably are alleles. By judicious deployment of the soybean genes, we may be able to keep SCN populations below damage‐threshold levels.
Characteristics of Soybean Seed Maturation: Necessity for Slow Dehydration1
Authors: Adams Clifford A. , Fjerstad Maria C. , Rinne Robert W.
Published: July 2010

Soybean [Glycine max (L.) Merr.] seeds harvested as young as 26 days after flowering (DAF) and allowed to air‐dry in intact pods underwent a maturation process and were viable. Seeds shelled and dried outside the pod lost moisture more rapidly and had poorer viability than seeds slow‐dried in intact pods. Maturation under slow dehydration allowed degradation of chlorophyll but fast‐dried seed remained green. Greater amounts of inorganic phosphate, sugars, and soluble protein were leached from fast‐dried seeds during subsequent imbibition, than from slow‐dried seeds. The activity of several soluble enzymes remained the same in both fast‐ and slow‐dried seed. Freshly harvested seed of all ages did not contain the germination‐specific enzymes malate synthase and isocitrate lyase (of the glyoxylate cycle). When planted in moist sand these enzymes were produced by fresh seed only if they were 54 DAF or older. By contrast seeds as young as 33 DAF produced malate synthase and isocitrate lyase after 4 days germination if they were slow‐dried before planting in moist sand. Seeds slow‐dried 3 days before planting in moist sand produced small amounts of malate synthase and isocitrate lyase but fast‐dried seeds never produced these enzymes. Seed maturation in soybeans is a necessary process brought about by slow dehydration with distinct effects on chlorophyll degradation and influence on the genome to allow production of germination‐specific enzymes.
Effectiveness of Selection for Nectar Volume, Receptacle Diameter, and Seed Yield Characteristics in Alfalfa1
Authors: Teuber L. R. , Barnes D. K. , Rincker C. M.
Published: July 2010

California produces more than 30% of the US alfalfa (Medicago sativa L.) seed crop. The majority of this seed is produced using honey bees (Apis mellifera) for pollination. Strength of reward, i.e. quantity and quality of nectar, is a primary factor in pollinator foraging activity. Positive correlations occur between nectar production and honey bee visitation, and honey bee visitation and seed production. Objectives of this investigation were to determine the effectiveness of phenotypic recurrent selection for increased nectar volume production and receptacle diameter and to determine the relationships among receptacle diameter, seeds/pod, seed production, and nectar volume in alfalfa. Populations of ‘CUF‐101,’ ‘Team,’ and ‘Vernal’ origin were developed by two cycles of phenotypic recurrent selection under either greenhouse conditions for nectar volume and receptacle diameter or field conditions for seeds/pod and seed production. Selection for either nectar volume or receptacle diameter resulted in a significant linear response in receptacle diameter. Nectar volume responded in a linear fashion to selection for nectar volume but did not respond when selection was for receptacle diameter. Selection for seeds/pod produced a significant linear response in nectar volume. Selection for seed production had no effect on nectar volume or receptacle diameter. Initial selection for receptacle diameter followed by nectar extraction should be an effective method of increasing nectar volume production.
Inheritance of Leaf‐Width and Seed Yield Characteristics of Lolium‐Festuca Hybrid Derivatives1
Authors: Buckner R. C. , Burrus P. B.
Published: July 2010

The appearance and acceptance of tall rescue for turf purposes maybe improved by reducing its leaf width. Flag leaf width was used as a criterion for improving turf texture of Lolium‐Festuchay brid derivatives. The objective of the study was to determine whether flag leaf width and concomitant fine texture characteristics of perennial ryegrass (Lolium perenne L.) ✕ tall fescue (Festuca arundinacea Schreb.) and {tall fescue ✕ giant rescue [F. gigantea (L.) Vill.]} ✕ [annual ryegrass (L. multiflorum Lam.) tall fescue hybridd derivatives were heritable. Parents (G0), first (G1), and second (G2) generation progenies were grown as spaced plants, seeded rows, and solid seeded sod plots, respectively. The fine‐leaf characteris genetically controlled having a different expression in competitive stands as compared to spaced plants or rows. Significant differences obtained among lines for leaf width indicated considerable genetic variability for the character. Nonsignificant line ✕ generation and line ✕ year interaction indicated that flag‐leaf width was not influenced greatly by management or environment. Regression of G2 polycross progenies on parents gave an estimated narrow sense heritability value of 0.70 indicating that a large fraction of the phenotypic differences between parents maybe recovered in the offspring. Leaf width of G2 polycross progenies was significantly less than that of widely used commercially available cultivars indicating that progress was made in improving turf texture of the population through breeding. A study of the genetic variability of seed yields of the hybrid derivatives showed that seed production compared favorably with tall rescue, that seed production was heritable, and that sufficient genetic variability exists for improving seed yield of the fine‐leaf turf types through breeding.
Maize Genotype by Cropping Pattern Interactions: Monoculture vs. Intercropping1
Authors: Francis C. A. , Prager M. , Tejada G. , Laing D. R.
Published: July 2010

Breeding programs to develop new crop cultivars for small farm cropping systems must consider the range of intercrop patterns in which these cultivars will be used. Most research in the past has concentrated on selection for monoculture. The objective of this study was to evaluate cultivar by cropping pattern interactions in a set of maize (Zea mays L.) genotypes currently used by the international research centers and the Colombian national maize program. In three consecutive years at the Centro Internacional de Agriculture Tropical station (1,000 m elevation, 47 N Lat.), maize cultivars were planted at optimum densities for monoculture and intercropping with two types of bean (Phaseolus vulgaris L.): a determine bush type and anindeterminate climber type. Optimum production conditions were attempted using irrigation and pesticides where needed. Average monoculture maize yields were about 5,000 kg/ha, with some cultivars producing up to 7,600 kg/ha. Intercropping with bush beans reduced maize yields in one year out of three. Intercropping with the more competitive climbing bean reduced maize yields in all 3 years. Significant yield differences among maize cultivars were found in all 3 cropping patterns each year. The cropping pattern by maize cultivar interaction was not significant for maize yields, however for bean yields there were differences among intercropped maize cultivars and a cultivar by cropping pattern interaction in the second and third years. Highly significant (P<0.01) correlations of maize yields between cropping patterns (r = 0.78 to 0.91) in second and third year data suggest consistency of results from one system to another. The significant difference in bean yields among maize cultivars emphasizes the importance of evaluating cropping patterns in terms of total production or income from both crops before making decisions on the best maize cultivar to recommend for intercropping.
Response of Soybean to Two Levels of Mineral Nutrition in CO2‐Enriched Atmosphere1
Authors: Sionit Nasser
Published: July 2010

Studies conducted with increased atmospheric CO2 usually have the nutritional supply being either optimal or not monitored. The expected increase in growth rate and production by plants in an enriched CO2 atmosphere that is predicted for the future could be limited through the rapid depletion of mineral nutrients in the root media. The objective of this study was to investigate the effect of atmospheric CO2 enrichment on soybean (Glycine max L. Merr. cv. Ransom) plants grown under two nutritional levels. Plants were grown from seed in a mixture of gravel, vermiculite, and tnrface in controlled environment chambers at 350 or 675 ppm CO2 and were irrigated with one‐eighth or one‐half strength Hoagland's solution No. 1. The temperature was 26 C during the 12‐hour day, and 20 C during the 12‐hour dark period. The photosynthetic photon flux density was 550 μE m‐2 sec‐1. Plants grown in one‐half strength Hoagland's solution produced more branches, total leaf area, and total blomass at each CO2 concentration than those grown in one‐eighth strength Hoagland's solution. Specific leaf weight increased with increased CO2 concentration in both nutritional levels. Plants grown in low nutrient supply at low CO2 concentration had a shorter flowering period and produced fewer towers, pods, and seeds due to the abortion of some flowers and senescence of pods. Total plant weight and seed number were greater with the high nutrient level than with the low nutrient level under similar CO2 concentrations. Plants grown at 675 ppm CO2 and receiving one‐eighth strength Hoagland's solution produced more biomass and total seed yield than plants grown at 350 ppm CO2 and one‐half strength Hoagland's solution. Therefore, the limiting effect of nutrient supply could partly be overcome by the increase in atmospheric CO2 concentration.
Effect of Soybean Mosiac on Component Yields from Blends of Mosiac Resistant and Susceptible Soybeans1
Authors: Ross J. P.
Published: July 2010

To gain information on how yield reductions are generated by soybean mosaic under field conditions, experiments were conducted during four seasons to study the competition, as reflected in seed yield, between healthy and mosaic‐infected soybean [Glycine max (L.) Merr.] plants. Three pairs of closely related soybean mosaic virus (SMV)‐ resistant (R) and ‐susceptible (S) sibling soybean lines were planted in blends of 10, 20, 40, 60, and 80% R and complementary S seed. Natural virus sources were present at one location, and at the other location a virus source was provided for aphid transmission into the plots. Using total yields, plant stand counts during August or September, and the R or S reaction of seedlings grown from seed harvested from each plot, average yields per R and S plant were calculated for each blend. Yields per R plant generally increased as the percentage of R plants in the blend decreased, whereas yields per S plant varied only slightly among the various blends. Total yields generally increased with increasing percentages of R plants; however, this yield varied among seasons, locations, and sibling lines. The line with ‘Semmes’ as the recurrent susceptible parent manifested the greatest yield response. Yield compensation by nonlnfected soybean plants in fields with mosaic probably plays a major role in moderating yield loss.