bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Variation and Breeding Potential of Phytate and Inorganic Phosphorus in a Maize Population
Authors: Lorenz Aaron J. , Scott M. Paul , Lamkey Kendall R.
Published: January 2008

Seed P is predominantly bound in the organic compound phytate, which makes the bioavailability of P low for monogastric animals fed maize (Zea mays L.)‐based diets. Decreasing phytate and increasing inorganic P (Pi, an available form of P) concentrations in maize grain would be desirable to help ameliorate environmental problems associated with high P in feces. Our objective was to investigate the potential of improving the P profile of maize grain through breeding and selection. Ninety S1 families from the BS31 population were evaluated at two locations for phytate, Pi, and other grain quality and agronomic traits. Phytate concentrations ranged from 1.98 to 2.46 g kg−1, and the broad‐sense heritability (H) was relatively low (0.60). Both genetic variance and H (0.84) were much greater for Pi Few unfavorable genetic correlations were observed between either Pi or phytate and other key economic traits. Also, selection differentials of multiple trait indices indicated that the P profile of maize grain and grain yield and moisture could be improved simultaneously. Many cycles of selection will be needed, however, to reach desirable phytate and Pi concentrations, especially when selecting for multiple traits. Regardless, our results are encouraging given that the families evaluated were related S1 families and the number of families was relatively small.
Improving Persistence in Red Clover: Insights from QTL Analysis and Comparative Phenotypic Evaluation
Authors: Herrmann Doris , Boller Beat , Studer Bruno , Widmer Franco , Kölliker Roland
Published: January 2008

Cultivars of red clover (Trifolium pratense L.) often suffer from low persistence, leading to insufficient legume proportions in pluriannual forage stands. Persistence is a complex trait often negatively correlated with other important traits and its phenotyping is laborious. Consequently, persistence is difficult to improve. The objectives of this study were to optimize the phenotypic evaluation of persistence, to identify quantitative trait loci (QTLs) for this important trait, and to investigate the association of persistence with other important traits. A weighted average of vigor scores assessed during two winters and three growing seasons was identified as the optimal method to phenotype persistence. For this index, one QTL explaining 12.2% of the total phenotypic variation was identified. While there was no negative correlation between persistence and seed yield, persistence was positively correlated with length of stem, which in turn was positively correlated with seed yield. Furthermore, QTLs for persistence, length of stem, and seed yield were detected in the same genome region. Improvement of persistence should therefore be possible without adverse effects on seed yield. Moreover, length of stem may present a candidate character for indirect selection of these two traits. The QTLs and the indirect selection criteria identified in this study may substantially assist future breeding efforts for the improvement of persistence in red clover.
Crop Adaptation in On‐Farm Management by Natural and Conscious Selection: A Case Study with Lentil
Authors: Horneburg Bernd , Becker Heiko C.
Published: January 2008

On‐farm management of landraces or older cultivars of crop plants is often recommended to combine conservation and use of genetic resources, but experimental studies on on‐farm management are hard to find, particularly in industrialized countries. To investigate whether on‐farm management results in regional adaptation and enhances crop biodiversity, an experiment with lentils (Lens culinaris Medik.) was designed. Lentil production has almost ceased to exist in central Europe, but lentils may still be found in gene banks and have remained a popular food. Three landraces were evaluated on three farms in Germany; at each farm, three populations evolved, based on three selection methods: (i) natural selection, (ii) visual mass selection, and (iii) selection for yield of single plant progenies. These selection methods were applied for two to four years. The nine populations developed for each landrace (three methods × three locations) were grown in a comparative trial on two of the farms. In most cases, populations selected at a specific location were at this location superior in yield to populations selected at other locations, indicating that on‐farm management can result in site‐specific adaptation. Significant changes in morphological and phenological traits occurred. For one landrace, natural selection increased seed weight. The response to different selection methods largely depended on landrace and selection site, and no method was generally superior. In conclusion, on‐farm management is a useful approach to maintain, use, and develop plant genetic resources. Natural selection as the most cost‐efficient method is recommended.
Coexistence in Maize: Do Nonmaize Buffer Zones Reduce Gene Flow between Maize Fields?
Authors: Langhof Maren , Hommel Bernd , Hüsken Alexandra , Schiemann Joachim , Wehling Peter , Wilhelm Ralf , Rühl Gerhard
Published: January 2008

One approach to ensuring coexistence of genetically modified (GM) and conventional maize (Zea mays L.) is reducing pollen‐mediated gene flow. Field experiments were conducted in 2005 at four sites in Germany to compare a tall sunflower crop (Helianthus annuus L.) vs. a short clover–grass crop (Trifolium pratense L. and Lolium spp.) with regard to their ability to reduce outcrossing when grown as buffer between pollen donor and recipient maize plots. Three different maize test systems were used: (i) quantification of a donor transgene via real‐time polymerase chain reaction (rt PCR), (ii) a nontransgenic test system based on a dominant kernel color trait, and (iii) a molecular marker test system based on rt PCR quantification of a cultivar‐specific nontransgenic DNA sequence. We found that the three test systems yielded comparable results concerning buffer‐crop effectiveness and edge effects. There was no difference in outcrossing rates when comparing the sunflower vs. clover–grass buffer crop. Outcrossing rates downwind beyond 12 m sunflower as buffer crop within adjacent 12‐m‐wide recipient maize were 4.2, 11.7, and 3.8% for the GM maize, the kernel color, and the molecular marker test system compared with clover–grass with 4.3, 9.6, and 3.6%. Pronounced edge effects were detected at the edges of recipient maize fields. Based on the present study, growing sunflower as a tall crop between GM and non‐GM maize cannot be recommended as an appropriate coexistence measure.
QTL Associated with Maize Kernel Oil, Protein, and Starch Concentrations; Kernel Mass; and Grain Yield in Illinois High Oil × B73 Backcross‐Derived Lines
Authors: Wassom James J. , Wong Jeffrey C. , Martinez Edwin , King Joseph J. , DeBaene Jan , Hotchkiss Jay R. , Mikkilineni Venugopal , Bohn Martin O. , Rocheford Torbert R.
Published: January 2008

Illinois long‐term selection strains of maize (Zea mays L.) have been useful for identifying genomic regions controlling kernel oil, protein, and starch concentrations. To identify kernel trait quantitative trait loci (QTL) in a genetic background more relevant to practical breeding, 150 BC1‐derived S1 lines (BC1S1s) were produced from Illinois High Oil and recurrent parent B73. Oil, protein, and starch were measured in BC1S1s and in Mo17‐topcross hybrids (TCs). Kernel mass of BC1S1s and grain yield of TCs were also determined. Starch was positively correlated with mass in BC1S1s (rp = 0.67**, α ≤ 0.01) and with yield in TCs (rp = 0.59**). Oil was negatively correlated with mass in BC1S1s (rp = −0.29**) and with yield in TCs (rp = −0.30**). Oil was negatively correlated with starch in BC1S1s (rp = −0.75**) and TCs (rp = −0.66**). A genetic map with length = 1486 cM was created with 110 markers. Multiple regression models with QTL detected by composite interval mapping (CIM) explained 46.9, 45.2, 44.3, and 17.7% of phenotypic variance for oil, protein, starch, and mass, respectively, in BC1S1s and 17.5, 22.9, 40.1, and 28.7% for oil, protein, starch, and yield, respectively, in TCs. A 22 cM‐interval on chromosome 6 in BC1S1s included oil, protein, and starch QTL, including a QTL explaining 36.7% of the BC1S1 phenotypic variation for oil. No yield QTL were detected in this region. Introgression of this QTL into breeding lines might increase oil while maintaining yield.
QTL for Fatty Acid Composition of Maize Kernel Oil in Illinois High Oil × B73 Backcross‐Derived Lines
Authors: Wassom James J. , Mikkelineni Venugopal , Bohn Martin O. , Rocheford Torbert R.
Published: January 2008

Maize (Zea mays L.) produces high‐quality oil valued for oxidative stability and low concentrations of saturated fatty acids. The nutritional value of maize oil could be improved by increasing the concentration of oleic acid, a “heart‐friendly” monounsaturated fatty acid. To identify quantitative trait loci (QTL) for the major fatty acids constituting oil from maize kernels, we produced 150 backcross1‐derived S1 (BC1S1) lines from donor parent, Illinois High Oil (IHO), and recurrent parent, B73. There was a positive phenotypic correlation between oil and oleic acid (rp = 0.47**, α ≤ 0.01) and negative correlations between oil and linoleic acid (rp = −0.46**), and between oleic and linoleic acids (rp = −0.99**). Multiple regression models with QTL detected by composite interval mapping (CIM) on a genetic map with length = 1486 cM, explained 15.4, 41.6, 51.0, 59.6, and 47.9% of the phenotypic variation for palmitic, stearic, oleic, linoleic, and linolenic acids, respectively. A 6‐cM interval on chromosome 6 (bin 6.04) includes QTL for stearic, oleic, linoleic, and linolenic acids, explains 10.9 to 39.6% of the variation for these fatty acids, and is 10 to 16 cM from QTL for oil. Another region on chromosome 6 (bin 6.01) includes QTL for oleic and linoleic acids and was epistatic with the QTL in bin 6.04. One or both of these two QTL regions on chromosome 6 may be responsible for fatty acid variation previously attributed to linoleic acid1
Testing Wheat in Variable Environments: Genotype, Environment, Interaction Effects, and Grouping Test Locations
Authors: Roozeboom Kraig L. , Schapaugh William T. , Tuinstra Mitchell R. , Vanderlip Richard L. , Milliken George A.
Published: January 2008

Selection of winter wheat (Triticum aestivumL.) genotypes requires testing programs with complementary locations that sample environments of interest with minimal duplication. The goal of the current study was to improve prediction of genotype performance in the highly variable environments of the central Great Plains in the United States by estimating the contributions of genotype, location, and year to wheat yield variability and identifying subgroups of test locations that minimize crossover genotype‐by‐environment interaction. Variance components were estimated from Kansas wheat performance data from 17 locations from 1982 to 2002. Annual data sets balanced for genotypes and environments were used to generate genotype, genotype‐by‐environment biplots that could objectively separate locations into groups with the same top‐yielding genotype. Location, year, and their interaction introduced the greatest proportion of the variability in wheat performance test yields. Frequency of common grouping during the 21‐year period was used to construct six groups of test locations representing unique target environments. Evaluation of the six groups using results from two subsequent years revealed that they generally agreed with location groups observed in the previous 21 years. Smaller regional genotype‐by‐environment variance component estimates compared with statewide estimates further confirmed the effectiveness of the pro posed six regions for reducing genotype‐by‐environment interaction.
Yield and Agronomic Responses of Soybean to Cotyledon and Unifoliolate Node Removal
Authors: Coulter Jeffrey A. , Nafziger Emerson D.
Published: January 2008

Field experiments were conducted over two years at two locations in Illinois to investigate the response of soybean [Glycine max(L.) Merr.] to simulated hail injury applied at the cotyledon (VC) stage. Removal of one or both cotyledons from all plants or of both cotyledons from alternating plants did not reduce mature plant height or yield in any environment. Cutting the stem off just below the unifoliolate node, alone or in conjunction with the removal of a single cotyledon, reduced yield by 11 to 21% in three of the four environments. It appears that soybean cotyledons are of little importance once the unifoliolate leaves have expanded.
Crop Species Diversity Affects Productivity and Weed Suppression in Perennial Polycultures under Two Management Strategies
Authors: Picasso Valentín D. , Brummer E. Charles , Liebman Matt , Dixon Philip M. , Wilsey Brian J.
Published: January 2008

Species diversity can increase natural grasslands productivity but the effect of diversity in agricultural systems is not well understood. Our objective was to measure the effects of species composition, species richness, and harvest management on crop and weed biomass in perennial herbaceous polycultures. In 2003, 49 combinations of seven species (legumes, C3 and C4 grasses) including all monocultures and selected two to six species polycultures were sown in small plots at two Iowa, USA, locations in a replicated field design. Plots were split in half and managed with either one or three harvests in each of 2004 and 2005. Biomass increased log‐linearly with species richness in all location‐management environments and the response was not different between managements. Polycultures outyielded monocultures on average by 73%. The most productive species in monoculture for each management best explained the variation in biomass productivity. The biomass of plots containing this species did not increase with richness in most environments but biomass of plots without this species increased log‐linearly in all cases. Weed biomass decreased exponentially with richness in all environments. On average, increasing species richness in perennial herbaceous polycultures increased productivity and weed suppression, but well‐adapted species produced high biomass yield regardless of richness.
Slow Darkening in Pinto Bean (Phaseolus vulgaris L.) Seed Coats Is Controlled by a Single Major Gene
Authors: Junk‐Knievel Donna C. , Vandenberg Albert , Bett Kirstin E.
Published: January 2008

Postharvest seed coat darkening is a significant problem in pinto beans (Phaseolus vulgaris L.), resulting in product that is undesirable to consumers and that is discounted in the marketplace. There is a range in the rate and extent of darkening among pinto germplasm and recently, slow‐darkening (SD) lines have been identified. Line 1533‐15, an SD line from the University of Saskatchewan, was crossed to CDC Pintium, a regular darkening pinto, and seed of F1 and F2 individuals and F5:6 recombinant inbred lines were assessed for their darkening phenotype. Segregation data indicated that there is a single, recessive gene that controls the SD phenotype. All F2 individuals from a cross between 1533‐15 and Pinto Saltillo, another SD line, were slow‐darkening suggesting that the phenotype is controlled by the same gene in both lines. The simple genetics of this trait should facilitate the introduction of this trait into breeding programs, thereby increasing the quality of pinto beans being developed.
Epistatic Interactions in Crosses of Illinois High Oil × Illinois Low Oil and of Illinois High Protein × Illinois Low Protein Corn Strains
Authors: Dudley John W.
Published: January 2008

Epistasis has been proposed as a possible explanation for the long continued progress from selection in the Illinois long‐term corn (Zea mays L.) selection strains. From the crosses of Illinois High Oil (IHO) × Illinois Low Oil (ILO) and of Illinois High Protein (IHP) × Illinois Low Protein (ILP), 500 S2 lines were developed. Each IHO×ILO line was genotyped for 479 single nucleotide polymorphism (SNP) markers, and each IHP×ILP line was genotyped for 499 SNP markers. Per se and testcross progenies of each S2 line were evaluated for oil, protein, and starch. A large number of QTL were found to control these traits. The objective of this paper is to report the results of analysis of these crosses for two‐way epistatic interactions. More epistatic interactions were significant than expected by chance. The proportion of significant interactions that involved a marker significant in a single marker analysis (SMA) was no greater than expected by chance. The number of markers associated only with significant epistatic effects ranged from 46.3 to 72.2% of the total number of markers significant for either an interaction effect or from SMA. The number of QTL controlling a trait is much greater than will be found by analyzing for significant QTL main effects. Thus, epistasis could contribute to the long continued response to selection in the Illinois long‐term selection strains and also may help explain the continued success of commercial corn breeding.
Intercropping Corn with Lablab Bean, Velvet Bean, and Scarlet Runner Bean for Forage
Authors: Armstrong Kevin L. , Albrecht Kenneth A. , Lauer Joseph G. , Riday Heathcliffe
Published: January 2008

This experiment was designed to determine if intercropping corn (Zea mays L.) with climbing beans is a viable option to increase crude protein (CP) concentration in forage rather than purchasing costly protein supplements for livestock rations. In these experiments, corn was intercropped with three beans—lablab bean [Lablab purpureus (L.) Sweet], velvet bean [Mucuna pruriens (L.) D.C.], and scarlet runner bean (Phaseolus coccineus L.)—or grown in monoculture near Arlington and Lancaster, WI. Corn was sown in early May and late April in 2004 and 2005, respectively, and later thinned to 55,000 (low density) or 82,500 (normal density) plants ha−1 Beans were sown in rows 8 cm on one side of the corn rows at 82,500 plants ha−1 2 or 4 wk after corn planting. Averaged over four environments, mixture forage dry matter (DM) yields were similar. However the velvet bean and scarlet runner bean mixtures produced significantly higher forage DM yield, 1.2 Mg ha−1 and 0.89 Mg ha−1 more, respectively, in the late bean planting treatment. Beans, except scarlet runner bean, which was damaged by mold and insects, increased the CP concentration of all mixtures, with the greatest increases from the lablab bean (13%) and velvet bean (16%). The experiments show that lablab bean grown with corn has the greatest potential of the three beans to increase CP concentration above monoculture corn, without compromising forage yield or calculated milk ha−1 and increasing forage nutrient value.
The Effect of Higher Temperatures on Cotton Lint Yield Production and Fiber Quality
Authors: Pettigrew W. T.
Published: January 2008

An optimal temperature range exists for cotton (Gossypium hirsutum L.). When Mississippi Delta cotton experiences temperatures above the upper threshold, as can occur during the summer, it is not entirely clear what growth parameters are affected by the heat. The objectives of this study were to document differences in agronomic and physiological performance for two cotton genotypes (SureGrow 125 and SureGrow 125BR) when grown under an ambient temperature control and a warm temperature regime (about 1°C warmer). Field studies were conducted from 2003 through 2005. White bloom counts, nodes above white bloom (NAWB) data, dry matter partitioning data, lint yield, yield components, and fiber quality data were collected. Genotypes responded similarly to the temperature regimes. Warmer temperatures resulted in lower NAWB data, indicating a slightly advanced crop maturity. In two out of three years, the lint yield from the warm regime was 10% lower than that of the control. This reduction was primarily caused by a 6% smaller boll mass, with 7% fewer seed produced per boll in the warm regime. Fiber produced in the warm temperature regime was consistently 3% stronger than fiber in the control treatment. When temperatures become too hot, ovule fertilization may be compromised, leading to fewer seeds produced per boll, smaller boll masses, and ultimately, lint yield reductions.
Efficiency of Indirect Selection for Dry Matter Yield Based on Fresh Matter Yield in Perennial Ryegrass Sward Plots
Authors: Conaghan Patrick , Casler Michael D. , O'Kiely Pádraig , Dowley Leslie J.
Published: January 2008

Forage dry matter yield (DMY) is a high‐priority trait in breeding perennial ryegrass (Lolium perenne L.). However, determining dry matter concentration is highly labor intensive. For a similar level of resources, indirect selection based on fresh matter yield (FMY) would allow a greater number of replicates, genotypes, or both to be evaluated. Our objective was to estimate the efficiency of indirect selection for DMY based on FMY of pure perennial ryegrass sward plots. Over a 14‐yr period, replicated trials, containing perennial ryegrass genotypes of similar ploidy and maturity category, were sown in Ireland and assessed for DMY and FMY at each harvest over two consecutive years. Forage was generally surface dry when harvested. The estimated efficiency of indirect selection based on two replicates and comparable selection intensity was high (≥0.80). Simulation models indicated that resources would be used more efficiently by evaluating more genotypes than by increasing the number of replicates. For example, doubling the number of plots to increase the number of replicates from two to four indicated an increase in the efficiency of indirect selection from a mean 0.88 to 0.94. However, doubling the number of plots and including more genotypes, facilitating greater selection intensity, indicated an increase in the efficiency of indirect selection from a mean 0.88 to 1.04. This study indicates that FMY can be used successfully as an indirect selection method of increasing DMY in perennial ryegrass swards.
Evaluation of Elite Exotic Maize Inbreds for Use in Temperate Breeding
Authors: Nelson Paul T. , Goodman Major M.
Published: January 2008

While maize (Zea mays L.) is a highly diverse species, this diversity is not well represented in U.S. maize production acreage. Increased genetic diversity can be obtained through breeding with exotic germplasm, especially tropical‐exotic sources. However, the pool of available tropical germplasm is large and diverse, making choices of tropical parents difficult. The maize breeding program at North Carolina State University has initiated a large‐scale screening effort to evaluate elite exotic maize inbreds, most of which are tropical‐exotic in origin. Here we report screening results for 88 inbreds obtained from various international breeding programs. These lines were tested in replicated yield trials in North Carolina as 50% exotic topcrosses by crossing them to a single‐cross U.S. tester of stiff‐stalk (SS) by non‐stiff‐stalk (NSS) origin. The more promising lines additionally entered 25% tropical topcrosses with SS and NSS testers and were further evaluated in yield‐trials. A handful of tropical inbred lines—CML10, CML108, CML157Q, CML274, CML341, CML343, and CML373—performed well overall. It was further determined that topcrossing to a single SS by NSS tester will suffice for initial screening purposes, allowing for elimination of the poorest performing lines. Topcrossing to additional SS and NSS testers may be of value when determining where, in terms of heterotic patterns, the better‐performing lines will fit into a breeding program.
Planting Date Influence on Soybean Agronomic Traits and Seed Composition in Modified Fatty Acid Breeding Lines
Authors: Ray C. L. , Shipe E. R. , Bridges W. C.
Published: January 2008

A primary focus for soybean [Glycine max (L.) Merr.] breeders recently has been the development of cultivars with improved oil qualities such as reduced palmitic acid (16:0) and linolenic acid (18:3). A backcross breeding program was used to develop five low 16:0, two low 16:0 + 18:3, and one low 18:3 modified fatty acid breeding lines (MFALs). Research objectives were (i) to determine planting date effects on fatty acid content in the eight MFALs and (ii) to compare the MFALs to parental cultivars for seed composition and agronomic traits. The eight MFALs and four control cultivars were evaluated at two planting dates at Clemson, SC, in 2001, 2003, and 2004. Planting dates were chosen to simulate full season and double crop planting dates for South Carolina soybean production. Agronomic traits including seed yield, plant height, lodging, maturity date, seed size, and seed quality were measured, and seeds were analyzed for protein, oil, and fatty acid levels. Planting date had a significant effect on all agronomic variables, as well as on protein, oil, and palmitic and linolenic acid. There was a decrease in palmitic acid at the late planting date, while the early planting date resulted in a decrease in linolenic acid levels. The effect of genotype was significant for all agronomic and seed composition variables measured when averaged across planting dates. It appears that planting date may be manipulated to reduce palmitic or linolenic acid of MFALs, although the extent of the reduction varies with genotype.
Hybridization and Introgression between Two Diploid Wild Relatives of White Clover, Trifolium nigrescens Viv. and T. occidentale Coombe
Authors: Williams W. M. , Ansari H. A. , Hussain S. W. , Ellison N. W. , Williamson M. L. , Verry I. M.
Published: January 2008

Trifolium nigrescens Viv. and T. occidentale Coombe are diploid (2n = 2x = 16) clover species with contrasting habits and geographic distributions. Trifolium nigrescens is a nonstoloniferous annual with widespread distribution in the Mediterranean countries of Europe and northern Africa, Turkey, the Middle East, and the Caucasus region. By contrast, T. occidentale is a stoloniferous perennial and is strictly coastal, occurring on the Gulf Stream coasts of Portugal, Spain, France, Ireland, and the United Kingdom. Here we report for the first time that both 2x T. nigrescens ssp. nigrescens and ssp. petrisavii can be hybridized with 2x T. occidentale. No special techniques are required, and advanced generation hybrid populations can be produced. Furthermore, backcrosses to T. nigrescens are easily obtained, and introgression of genes from T. occidentale occurs. The chromosomes of the two species show perfect pairing and regular disjunction at meiosis. The biological separation (reproductive isolation) of these species is incomplete. This incomplete isolation is paralleled by a partial breakdown of the genetic mechanism that would normally prevent endosperm development in these crosses. Observations on the life history of one hybrid and its progeny showed that two traits involved in perenniality were inherited in opposite ways. These species are close relatives of white clover and are potentially important sources of traits for plant breeding. This work raises the likelihood of simultaneous introgression of traits from both diploid species into white clover.
Diallel Analysis of Aflatoxin Accumulation in Maize
Authors: Williams W. Paul , Windham Gary L. , Buckley Paul M.
Published: January 2008

Aflatoxin, a toxin produced by the fungus Aspergillus flavus Link:Fries, occurs naturally in maize (Zea mays L.). It is a potent carcinogen, and its presence markedly reduces the value of grain. Host‐plant resistance to A. flavus infection and subsequent aflatoxin accumulation is generally considered a desirable means of reducing losses to aflatoxin. Maize germplasm lines with resistance to aflatoxin contamination have been developed in Mississippi. Four of the aflatoxin‐resistant lines and six other lines were used as parents to produce a diallel cross. The diallel cross was evaluated for resistance to aflatoxin contamination in field trials conducted in Mississippi in 2005 and 2006. General combining ability (GCA) and specific combining ability (SCA) were highly significant sources of variation each year. Reciprocal effects were not significant in 2005 or in the combined analysis over years. In the analysis over years, GCA effects for reduced aflatoxin were highly significant for the four lines developed as sources of resistance: Mp313E, Mp494, Mp715, and Mp717. The GCA effect for reduced aflatoxin was also highly significant for Mo18W and NC408. These lines should be useful in developing maize lines and hybrids with resistance to aflatoxin contamination. Breeding methods that maximize the use of GCA should be effective in enhancing resistance to aflatoxin accumulation when using these germplasm lines.
Development of Near‐Isogenic Peanut Lines with and without Resistance to the Peanut Root‐Knot Nematode
Authors: Holbrook C. Corley , Timper Patricia , Dong Weibo , Kvien Craig K. , Culbreath Albert K.
Published: January 2008

Peanut (Arachis hypogaea L.) cultivars are available that have high resistance to the peanut root‐knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] or tomato spotted wilt, caused by tomato spotted wilt Tospovirus (TSWV); however, no cultivars exist that have resistance to both pathogens. The objective of this research was to combine resistance to both pathogens in a single genotype. During the course of this research, we also had the opportunity to develop near‐isogenic lines with and without nematode resistance. Such near‐isogenic lines can be valuable research tools to obtain a better understanding of the interaction of nematodes with other pathogens of peanut. Breeding populations were developed by hybridizing the TSWV‐resistant cultivar C‐99R with the nematode‐resistant cultivar COAN. Selection for nematode resistance was conducted using standard greenhouse screening techniques. Selection for TSWV resistance was conducted in the field with natural virus infection. A breeding line (C724‐19‐15) was selected that had high resistance to both pathogens. A near‐isogenic line (C724‐19‐25) susceptible to the peanut root‐knot nematode was also developed. Both breeding lines exhibited higher resistance to TSWV and higher yield than standard check cultivars when grown in fields with little or no nematode pressure.
Performance of Vernonia as an Alternative Industrial Oil Crop in Limpopo Province of South Africa
Authors: Shimelis Hussein , Mashela Phatu W. , Hugo Arno
Published: January 2008

Vernonia (Vernonia galamensis) is an industrial oil seed crop with potential as a source of natural epoxy fatty acids. Diverse accessions of V. galamensis var. ethiopica were studied at the Limpopo Province in South Africa to determine agronomic performance and to identify suitable germplasm with quantity and quality seed oil content. Thirty‐six accessions were subjected to field evaluations using a partially balanced lattice design in 2005 and 2006. Significant differences were observed for days to flowering (88–143 d), plant height (131.6–167.85 cm), number of productive primary head (23–72 head plant−1), number of productive secondary head (12–35 head plant−1), thousand seed weight (1.68–3.63 g), and seed yield (1594.89– 3126.09 kg ha−1) between different accessions. Results from oil analysis show significant differences in the contents of seed oil (20.36–35.86%), vernolic acid (70.15–77.92%), linoleic acid (12.05–14.73%), oleic acid (3.72–5.52%), palmitic acid (2.49–3.24%), and stearic acid (1.73–3.28%). Of the five accessions identified as potentially useful, three (Vge‐17, Vge‐18, and Vge‐19) had better seed yield and agronomic performances and two (Vge‐4 and Vge‐31) increased contents of seed oil and vernolic acid. Accessions Vge‐4 and Vge‐18 also displayed relatively high oil yield, 966.58 and 801.28 kg ha−1, respectively. The accessions will be used in the stra tegic improvement of vernonia to maximize seed yield and oil content as an alternative crop in the province and similar environments.
Variable Production of Tetraploid and Hexaploid Progeny Lines from Spring Wheat by Durum Wheat Crosses
Authors: Lanning S. P. , Blake N. K. , Sherman J. D. , Talbert L. E.
Published: January 2008

Hexaploid spring wheat (Triticum aestivum ssp. aestivum) and tetraploid durum wheat (Triticum turgidum ssp. durum) are both widely grown in the Great Plains of North America. Transfer of genes between classes may be beneficial to improvement efforts. However, ploidy level differences lead to variable degrees of sterility in crosses between the two classes. Our aim was to quantify variation among a set of spring wheat genotypes for production of viable euploid progeny after crosses with durum wheat. Hexaploid spring wheat parents varied for their ability to produce viable F5 progeny, with attrition occurring at all stages of the inbreeding process. Polymerase chain reaction primers specific for the seven D chromosomes indicated that most lines derived from spring wheat by durum wheat crosses were euploid, with a preponderance of tetraploid progeny lines for most parents. Our results showed variability among hexaploid genotypes for their ability to produce viable progeny and suggested that ‘Choteau’ hard red spring wheat may be a good bridge variety for interploidy crosses.
Seed Performance of Maize in Response to Phosphorus Application and Growth Temperature Is Related to Phytate‐Phosphorus Occurrence
Authors: Modi A. T. , Asanzi N. M.
Published: January 2008

Phytate is associated with antinutrient character in seeds; however, it has potential to contribute significantly to seed performance. The objective of this study was to determine the effect of P (10, 26, and 70 mg kg−1) and growth temperature (22/16, 27/21, and 33/27°C [day/night]) on seed performance in normal and quality protein maize (Zea mays L.). Seeds of normal and quality protein maize were harvested at three stages (15, 25, and 65 days after silking) of development. At each stage, germination capacity and vigor, Phytate‐P concentration, and myo‐inositol were determined. Normal maize displayed a significantly higher (P < 0.001) phytate‐P and inorganic P concentrations compared with quality protein maize, which was associated with significantly better (P < 0.01) seed performance. Myo‐inositol was significantly (P < 0.05) higher in quality protein maize compared with normal maize. Phosphorus nutrition enhanced (P < 0.01) seed performance of both genotypes. Increasing growth temperature caused greater accumulation of inorganic P, but it decreased myo‐inositol. Seed germination and vigor increased when growth temperature was increased from 22/16 to 27/21°C, but they decreased in response to high temperatures (33/27°C). The results of this study indicate that P fertilizer enhances maize seed germination and vigor. High myo‐inositol concentrations may be used to indicate poor phytate synthesis associated with poor seed performance.
Sustaining Plant Breeding–National Workshop
Authors: Stuber Charles W. , Hancock Jim
Published: January 2008

Sustaining plant breeding was the central theme of a national workshop held in Raleigh, NC, February 8–9, 2007. The workshop was spearheaded by Ann Marie Thro, National Program Staff of USDA‐CSREES, and was co‐hosted by the Departments of Crop Science and Horticultural Science of North Carolina State University. The major catalyst for the meeting was the growing imbalance between the importance of plant breeding to the nation's future versus the steady decline in the national plant breeding investment over the past 20 years. This has led to a significant reduction in the number of public plant breeders in the U.S. and an associated substantial weakening of university education programs in this area (Frey, 1996; Guner and Wehner, 2003; Morris et al., 2006; Price, 1999). Several previous efforts have drawn attention to our nation's declining plant breeding capacity (National Plant Breeding Study, 1994). More recently, a plant breeding workshop held in 2005 at Michigan State University also focused on the decline in numbers of plant breeders in the public arena (Hancock, 2006). However, the message from these efforts was not nationally audible or sustained through the establishment of a dedicated group interested in maintaining plant breeding as a science and profession.
Frogeye Leaf Spot of Soybean: A Review and Proposed Race Designations for Isolates of Cercospora sojina Hara
Authors: Mian M. A. R. , Missaoui A. M. , Walker D. R. , Phillips D. V. , Boerma H. R.
Published: January 2008

Frogeye leaf spot (FLS), caused by Cercospora sojina K. Hara, is a common disease of soybean [Glycine max (L.) Merr.] in most soybean‐growing countries of the world. Significant yield losses of soybean (10–60%) have been attributed to FLS under hot and humid growing conditions. The FLS in the southern United States has been kept under control by planting resistant cultivars. Cercospora sojina is a dynamic pathogen with extensive virulence or race diversity. The current number of C. sojina isolates at the University of Georgia collection is 93. Assigning race designations to this large number of isolates has been difficult because of the lack of a well‐defined set of differentials. To facilitate future studies of the genetics of soybean resistance to FLS and the identification and comparison of existing and future races of C. sojina, we have reassessed both the soybean differentials and the C. sojina races. Based on the reactions of 93 isolates of C. sojina on 38 putative soybean differentials, we propose a core set of 12 differentials and 11 races that represent the major diversity among the 93 C. sojina isolates. The definition of these 12 differentials and 11 races should provide the foundation for the identification and comparison of additional soybean resistance genes and new races of C. sojina
A Century of Clover Breeding Developments in the United States
Authors: Taylor Norman L.
Published: January 2008

The perennial clovers, red (Trifolium pratense L.) and white clover (T. repens L.), have been important legumes for livestock feeding in the United States during the past century, particularly in the eastern United States. Recently, sustainable agriculture, organic farming, integrated crop–livestock systems, and high nitrogen prices have stimulated interest in forage legumes. This paper describes the present status of clover improvement programs—their objectives, successes, short falls, and challenges for the future. One goal of most clover breeding programs is increased persistence (longevity of individual plants) because of its association with general adaptability and yield. Persistence, which limits life of clovers to about three to four years, is largely governed by programmed senescence but can be influenced somewhat by breeding for general adaptation to the area of use. New, more‐adapted red clover cultivars have been bred in Wisconsin for use in the northern states, in Kentucky for the middle states, and in Florida for the southern states. For white clover, researchers in several states in the southeast have cooperated in the development of improved cultivars. The unique qualities of these improved species along with high seedling vigor, ease of establishment, and general competitiveness ensure that red and white clover will continue to be the major forage legumes of the United States and justify continued breeding efforts.
Indirect determination of lutetium by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode
Authors: Kumrić Ksenija , Trtić-Petrović Tatjana , Ignjatović Ljubiša , Čomor Jožef
Published: January 2008

Lutetium has been determined by differential pulse anodic stripping voltammetry in an acidic solution containing Zn-EDTA. Lutetium (III) ions liberated zinc (II), which was preconcentrated on a hanging mercury drop electrode and stripped anodically, resulting in peak current linearly dependent on lutetium (III) concentration. Less than 0.4 ng mL−1 lutetium could be detected after a 2 min deposition.
Synthesis, characterization and spectroscopic properties of some new phenylazo-6-aminouracil
Authors: Seferoğlu Zeynel , Ertan Nermin
Published: January 2008

In this study, a series of new 5-phenylazo-6-aminouracil dyes were prepared by linking m-,p-nitroaniline, m-,p-chloroaniline, m-,p-anisidine, m-,p-toluidine, m-,p-cyanoaniline, p-ethoxyaniline, p-phenoxyaniline, p-ethylaniline, p-acetamidoaniline, p-acetylaniline, p-carboxyaniline and aniline to 6-aminouracil. The prepared dyes were characterized by UV-vis, FT-IR, 1H NMR spectroscopic techniques and elemental analysis. The effect of acid and base upon the UV-vis spectra of these dyes were investigated. In addition, the solvatochromic behaviors and substituent effects in various solvents were evaluated.
Synthesis and characterization of thermoresponsive hydrogels cross-linked with chitosan
Authors: Yu Yueqin , Chang Xianzhi , Ning Hansheng , Zhang Shusheng
Published: January 2008

Hydrogels composed of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) were prepared by redox polymerization with degradable chitosan cross-linkers. Chitosan degradable cross-linkers were synthesized by the acrylation of the amine groups of glucosamine units within chitosan and characterized with 1H NMR. With the chitosan cross-linkers, loosely cross-linked poly(N-isopropylacryamideco-acrylic acid) [P(NIPAAm-co-AAc)] hydrogels were prepared, and their phase transition behavior, lower critical solution temperature (LCST), water content and degradation properties were investigated. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels were pliable and transparent at room temperature. The LCST could be adjusted at 32∼39°C by alternating the feed ratio. Swelling was influenced by NIPAAm/AAc monomer ratio, cross-linking density, swelling media, and temperature. All hydrogels with different feeding ratios contained more than 95% water at 25°C in the ultra pure water and phosphate-buffered saline (PBS, pH = 7.4 ± 0.1), and had a prospective swelling in the simulated gastric fluids (SGF, pH = 1.2) > 72.54%. In degradation studies, breakdown of the chitosan cross-linked P(NIPAAm-co-AAc) hydrogels was dependent on the cross-linking density. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels which can be tailored to create environmentally-responsive artificial extracellular materials have great potential for future use.
Watson-crick base pairs with thiocarbonyl groups: How sulfur changes the hydrogen bonds in DNA
Authors: Guerra Célia , Baerends Evert , Bickelhaupt F.
Published: January 2008

We have theoretically analyzed mimics of Watson-Crick AT and GC base pairs in which N-H···O hydrogen bonds are replaced by N-H···S, using the generalized gradient approximation (GGA) of density functional theory at BP86/TZ2P level. The general effect of the above substitutions is an elongation and a slight weakening of the hydrogen bonds that hold together the base pairs. However, the precise effects depend on how many, and in particular, on which hydrogen bonds AT and GC are substituted.. Another purpose of this work is to clarify the relative importance of electrostatic attraction versus orbital interaction in the hydrogen bonds involved in the mimics, using a quantitative bond energy decomposition scheme. At variance with widespread believe, the orbital interaction component in these hydrogen bonds is found to contribute more than 40% of the attractive interactions and is thus of the same order of magnitude as the electrostatic component, which provides the remaining attraction.
Investigation on the catalytic activity of doped low-percentage oxide catalysts Mn/ZnO obtained from oxalate precursor
Authors: Donkova Borjana , Milenova Katja , Mehandjiev Dimitar
Published: January 2008

The precursors with a low manganese content ≤ 0.07% Mn were synthesized by spontaneous crystallization from Zn2+, Mn2+ and C2O42−-containing solutions. The initial ratio Zn2+:C2O42− = 1:1 and 1:2 influences the morphology and prevailing orientations of the crystallites in the oxalate samples. The presence of such small Mn content in the samples does not change the morphology or size of the crystals. The ZnO and Mn/ZnO oxides with manganese content from 0.51×10−2 to 15.1×10−2 Wt % are obtained after thermal decomposition of the oxalates. The oxides preserved the morphology of the precursors. The catalytic tests show that the pure ZnO has a poor activity for CO oxidation reaction. Its doping with Mn promotes the catalytic activity (up from twice to five times) in spite of the very low contents of the dopants. The observed increase of the activity depends on both dopant concentration and Zn2+:C2O42− ratio, probably due to the different mechanism of the manganese inclusion and different morphology of the oxides. The catalysts of the 1:2 series are more active in CO oxidation reaction.
Was that a man? Sex identification as a function of menstrual cycle and masculinity
Authors: Johnston Lucy , Miles Lynden , Macrae C. Neil
Published: January 2008

The accuracy of female perceivers on a face sex‐categorization task was investigated as a function of perceivers' menstrual cycle and target facial qualities. Regularly ovulating female participants completed a sex‐categorization task twice, once during ovulation (high fertility) and once during menstruation (low fertility). Perceivers made more errors in identifying male than female faces at both testing sessions. Fewer errors were made in identifying male targets rated high on masculinity, but only during periods of high fertility. For female targets accuracy was negatively associated with masculinity and positively associated with attractiveness ratings, at both high and low fertility testing sessions. Results are discussed in terms of adaptive person construal. Copyright © 2008 John Wiley & Sons, Ltd.
Anatomy of branches of the musculocutaneous nerve to the biceps and brachialis in human fetuses
Authors: Kwolczak‐McGrath A. , Kolesnik A. , Ciszek B.
Published: January 2008

Forty upper limbs (20 right and 20 left) of spontaneously aborted human fetuses were examined to determine the branching patterns of the musculocutaneous nerve. The mean age of the fetuses was 21.3 weeks. We identified three branching patterns of the musculocutaneous nerve to the biceps muscle. Type I with a single primary branch occurred in 47.5% of cases. Type II with two primary branches each to a separate head of the biceps muscle was observed in 42.5% of cases. Type III consisted of two primary branches, the proximal dividing into two branches, each to a different head of the biceps, and the distal branch supplying the common belly. Type III was present in 10% of cases. We found only one branching pattern for the brachialis muscle, a single primary branch. In our material communicating branches between the median and musculocutaneous nerves were found in 20% of specimens. We measured the distances between the acromion and the exit points of the first and second branch to the biceps, which averaged 36.3% for the first branch regardless of the type of branching pattern, 54.2% for the second branch in Type II, 60.7% for the second branch in Type III and 60.9% for the branch to brachialis, expressed as a percentage of the distance between the acromion and the lateral epicondyle. Clin. Anat. 21:142–146, 2008. © 2008 Wiley‐Liss, Inc.