bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Diversity of Chinese Cultivated Soybean Revealed by SSR Markers
Authors: Wang Lixia , Guan Rongxia , Zhangxiong Liu , Chang Ruzhen , Qiu Lijuan
Published: March 2006

China is the center of origin of soybean [Glycine max (L.) Merr.] and is therefore expected to represent a primary source of germplasm for this crop. Genetic diversity assessments among Chinese soybean accessions should provide useful information for local and international soybean researchers to more effectively utilize this material. A sample of 129 accessions were selected to represent phenotypic variability for 14 agronomic and morphological traits in the Chinese soybean collection. These accessions were analyzed with 60 mapped simple sequence repeats (SSRs) to determine the genetic diversity represented. In total, 732 alleles were detected (12.2 alleles per locus) and the polymorphic information content (PIC) among accessions varied from 0.5 to 0.92 with a mean of 0.78. Pairwise coefficients of genetic distance among all accessions ranged from 0.05 to 0.91 (mean 0.23). Unweighted pair‐group method arithmetic average (UPGMA) analysis showed that the accessions formed five major clusters; two contained primarily Northern ecotypes, one contained primarily Yellow River Valley ecotypes, and one contained Southern ecotypes. The fifth cluster contained a mixture of Northern and Yellow River Valley ecotypes. Accessions from the lower regions of the Yellow River Valley possessed the greatest allelic richness, had the lowest pair‐wise genetic diversity estimates, and were dispersed throughout the five clusters, suggesting that the Yellow River Valley may be center of diversity for Chinese cultivated soybean. The results indicated that stratified sampling based on seven primary ecotypes may represent an optimal strategy for assembling a representative core collection of Chinese soybean.
Demand for Genetic Resources and the U.S. National Plant Germplasm System
Authors: Rubenstein Kelly Day , Smale Melinda , Widrlechner Mark P.
Published: March 2006

Although genetic resources have strong public‐goods characteristics, public genebanks often have struggled for adequate funding. A review of economic literature on the value of plant genetic resources indicated that more information is needed about germplasm use. The data compiled in this paper examine patterns of germplasm use for one of the world's largest national genebank networks, the U.S. National Plant Germplasm System (NPGS). Data on 10 major crops, gathered directly from within the NPGS and from end‐users, revealed patterns of usage for germplasm during the period from 1995 to 1999. Data were collected describing the characteristics of NPGS users, the types of germplasm requested, the purpose of requests, and, when applicable, the specific traits sought. From these findings, we estimated the utility of distributed materials, their secondary use, and projected future demand for NPGS resources. To explore relationships between the usefulness of germplasm samples and accompanying data in a more systematic fashion, we estimated a linear regression. The regression model suggests that accompanying data make germplasm more useful. We conclude that demand for NPGS resources was substantial and came from broad range of users. Utilization rates were higher than suggested by past studies. Countries with developing economies made greater use of NPGS resources, relatively speaking, than did countries with high‐income economies. Finally, demand for NPGS resources is likely to increase, especially among users in countries with developing economies.
Quantitative Trait Loci for Resistance to Banded Leaf and Sheath Blight in Maize
Authors: Zhao Maojun , Zhang Zhiming , Zhang Shihuang , Li Wanchen , Jeffers Daniel P. , Rong Tingzhao , Pan Guangtang
Published: March 2006

Banded leaf and sheath blight (BLSB) caused by Rhizoctonia solani Kühn in maize (Zea mays L.) is an important disease in China as well as South and Southeast Asia. The identification of quantitative trait loci (QTL) for resistance to this disease would facilitate the development of disease resistant maize hybrids. A mapping population consisting of 229 F2 individuals derived from the cross of inbreds R15 (resistant) and 478 (susceptible) was used in this study. A genetic linkage map was constructed containing 146 single sequence repeat (SSR) markers, which covered 1666 cM of the maize genome, with an average distance of 11.4 cM. All F2:4 population individual plants were artificially inoculated by anastomosis groups AG1‐IA of R. solani at two locations for disease evaluations. Composite interval mapping (CIM) identified 11 QTL for resistance to BLSB located on chromosomes 1, 2, 3, 4, 5, 6, and 10, but only four QTL located on chromosomes 2, 6, and 10, were identified across both locations. The range of phenotypic variation explained by the QTL was 3.72 to 10.35%. The information gained from mapping resistance can be used in a marker‐assisted selection (MAS) program for the development of BLSB resistant germplasm.
Spectral Reflectance to Estimate Genetic Variation for In‐Season Biomass, Leaf Chlorophyll, and Canopy Temperature in Wheat
Authors: Babar M. A. , Reynolds M. P. , van Ginkel M. , Klatt A. R. , Raun W. R. , Stone M. L.
Published: March 2006

Spectral indices as a selection tool in plant breeding could improve genetic gains for different important traits. The objectives of this study were to assess the potential of using spectral reflectance indices (SRI) to estimate genetic variation for in‐season biomass production, leaf chlorophyll, and canopy temperature (CT) in wheat (Triticum aestivum L.) under irrigated conditions. Three field experiments, GHIST (15 CIMMYT globally adapted historic genotypes), RILs1 (25 recombinant inbred lines [RILs]), and RILs2 (36 RILs) were conducted under irrigated conditions at the CIMMYT research station in northwest Mexico in three different years. Five SRI were evaluated to differentiate genotypes for biomass production. In general, genotypic variation for all the indices was significant. Near infrared radiation (NIR)–based indices gave the highest levels of association with biomass production and the higher associations were observed at heading and grainfilling, rather than at booting. Overall, NIR‐based indices were more consistent and differentiated biomass more effectively compared to the other indices. Indices based on ratio of reflection spectra correlated with SPAD chlorophyll values, and the association was stronger at the generative growth stages. These SRI also successfully differentiated the SPAD values at the genotypic level. The NIR‐based indices showed a strong and significant association with CT at the heading and grainfilling stages. These results demonstrate the potential of using SRI as a breeding tool to select for increased genetic gains in biomass and chlorophyll content, plus for cooler canopies.
Persistence and Yield Stability of Intersubspecific Alfalfa Hybrids
Authors: Riday Heathcliffe , Brummer E. Charles
Published: March 2006

Long‐term persistence and sustained biomass yields of alfalfa (Medicago sativa L.) stands are important to producers. Yield performance and persistence of intrasubspecific crosses between alfalfa subspecies sativa and falcata after the first post‐establishment year are unknown. The objectives of this study were to measure biomass yields, persistence, and biomass yield stability in inter‐ and intrasubspecific alfalfa crosses derived by mating nine elite sativa clones and five falcata clones in a half‐diallel. Progeny were space planted in 1998 at Ames and Nashua, IA, and evaluated for persistence, biomass yield, and biomass yield stability from 1998 through 2002. Medicago sativa subsp. sativa (sativa) × M. sativa subsp. falcata (falcata) hybrids produced substantial biomass yield and exhibited heterosis through the first post‐establishment year, but declined in subsequent years. From 1998 through 2002 the intersubspecific hybrids had persistence equivalent to the more persistent parental subspecies, with the effect becoming more apparent as time progressed. Intrasubspecific hybrids had less biomass yield stability than the more stable intrasubspecific sativa crosses. The results indicate that selection of improved falcata germplasm for long term persistence and higher yield is needed.
Structure and Genetic Diversity of Wild Populations of Lima Bean (Phaseolus lunatus L.) from the Yucatan Peninsula, Mexico
Authors: Martínez‐Castillo Jaime , Zizumbo‐Villarreal Daniel , Gepts Paul , Delgado‐Valerio Patricia , Colunga‐GarcíaMarín Patricia
Published: March 2006

This study was conducted to determine the genetic diversity, structure and gene flow of 11 wild populations of Phaseolus lunatus L. in four regions of traditional agriculture in the Yucatan Peninsula, Mexico, part of the putative domestication area of its Mesoamerican gene pool. Analyzing eight microsatellite loci, the populations showed high values of diversity: observed heterozygosity (Ho) 0.46 to 0.9; Nei's index of diversity (H) 0.35 to 0.59 and average number of alleles per locus (A) 2.37 to 3.38. Both Nei's index of populations differentiation (Gst) and analysis of molecular variance (AMOVA) indicated strong differentiation. The Bayesian analysis of grouping and the Mantel test suggested isolation among agricultural regions as a major factor for population differentiation. Even though a low long‐term gene flow (Nm = 0.66) and low rates of recent migration among populations were observed, there were some cases where the accidental transport of seeds could be favoring a gene flow at a long distance. Data found in this study suggest a positive correlation between agricultural intensification and increase in diversity, suggesting that wild populations are favored by the intensification of disturbance in situations involving at least 3 yr of fallow. However, the opposite could be true at higher levels of intensification as has been reported in the Central Valley of Costa Rica, where the diversity is diminishing.
Response from Selection for Pectin Concentration and Indirect Response in Digestibility of Alfalfa
Authors: Tecle Isaak Y. , Viands Donald R. , Hansen Julie L. , Pell Alice N.
Published: March 2006

Genetic improvement of alfalfa (Medicago sativa L.) for increased pectin concentration, estimated by neutral detergent soluble fiber (NDSF), would improve the efficiency of utilization of its high protein and digestibility by ruminants. The objectives of this study were to: (i) estimate the realized direct response from one cycle of phenotypic selection for NDSF concentration; (ii) evaluate association of NDSF concentration with other forage quality traits, and; (iii) determine the impact of selection for NDSF concentration on in vitro dry matter digestibility (IVDMD) of alfalfa. Selection for NDSF was applied to five alfalfa populations from 1996 to 2000 and synthetic generation two seed was produced. Progress from selection for NDSF concentration was evaluated in plot trials for 2 or 3 yr at two locations near Ithaca, NY. Populations divergently selected for NDSF were 1.62 to 5.15 g kg−1 of dry matter (DM) higher and 2.26 to 4.20 g kg−1 DM lower, respectively, than their respective base populations. Neutral detergent soluble fiber concentration was negatively correlated with total cell wall concentration (CW), and proportions of neutral detergent fiber (NDF), cellulose, and lignin in the CW. A positive correlation existed between NDSF concentration and crude protein (CP) concentration and IVDMD. Populations bred for higher or lower NDSF concentration had 0.20 to 8.82 g kg−1 DM higher IVDMD and 0.63 to 15.06 g kg−1 DM lower IVDMD than their respective base populations. Selection for NDSF concentration and indirectly for CP, total CW concentration and composition, and IVDMD of alfalfa forage was successful.
Fine Mapping of a Major Insect Resistance QTL in Soybean and its Interaction with Minor Resistance QTLs
Authors: Zhu S. , Walker D. R. , Boerma H. R. , All J. N. , Parrott W. A.
Published: March 2006

Utilization of native insect resistance genes can be an important component for managing insects in soybean [Glycine max (L.) Merr.]. A major quantitative trait locus (QTL‐M) for insect resistance from PI 229358, controlling antibiosis and antixenosis, was previously identified on linkage group (LG) M and was found to increase the effectiveness of a Bacillus thuringiensis (Bt) transgene in soybean. The objectives of this study were to fine‐map QTL‐M using recombinant substitution lines (RSLs) identified from a ‘Benning’ backcross population, and to evaluate the main effects and the epistatic interactions between QTL‐M and other resistance QTLs on LGs G and H using near‐isogenic lines (NILs) in a Benning genetic background. The effect of QTL‐M was still detectable in the Benning NILs when they were evaluated for resistance to corn earworm [CEW, Helicoverpa zea (Boddie)]. The two minor resistance QTLs only provided insect resistance when QTL‐M was also present in the Benning NILs. The QTL‐M was fine‐mapped to an approximately 0.52‐cM region after the first round of phenotyping the RSLs for resistance to CEW and soybean looper [SBL, Pseudoplusia includens (Walker)]. These results should increase the feasibility of cloning QTL‐M and help guide the development of insect resistant soybean cultivars.
Nonparametric Methods for Interpreting Genotype × Environment Interaction of Lentil Genotypes
Authors: Sabaghnia Naser , Dehghani Hamid , Sabaghpour Syyed Hossain
Published: March 2006

Analysis of multienvironment trials (METs) of crops for cultivar evaluation and recommendation is an important issue in plant breeding research. Evaluating both stability of performance and high yield is essential in MET analyses. The objective of this investigation was to compare 10 nonparametric stability methods and apply nonparametric tests (which do not require distributional assumptions) for genotype‐by‐environment (G × E) interaction to 11 lentil (Lens culinaris Medik) genotypes. Nine improved lentil genotypes and two local cultivars were grown in 20 semiarid environments in Iran from 2002 to 2004. Results of nonparametric tests of G × E interaction and a combined ANOVA across environments showed there were both crossover and noncrossover G × E interactions and genotypes varied significantly for yield. In this study, high values of TOP (proportion of environments in which a genotype ranked in the top third) and low values of rank‐sum (sum of ranks of mean yield and Shukla's stability variance) were associated with high mean yield, but the other nonparametric methods were not positively correlated with mean yield and instead characterized a static concept of stability. The results of principal component (PC) analysis and correlation analysis of nonparametric stability statistics and yield indicated that only rank‐sum and TOP methods would be useful for simultaneously selecting for high yield and stability. These methods recommended FLIP 92–12L as stable and FLIP96–6L as unstable genotypes. A biplot of the first two PCs also revealed that the nonparametric methods grouped as three distinct classes that corresponded to different agronomic and biological concepts of stability.
Planting Date Effects on Winter Triticale Grain Yield and Yield Components
Authors: Schwarte Aaron J. , Gibson Lance R. , Karlen Douglas L. , Dixon Philip M. , Liebman Matt , Jannink Jean‐Luc
Published: March 2006

Winter triticale (×Triticosecale Wittmack) has the potential to introduce valuable economic and environmental benefits to U.S. grain production systems. To maximize triticale's value, research was conducted to identify planting dates that allow maximum productivity after soybean [Glycine max (L.) Merr.]. Winter triticale was planted at 10‐d intervals from 15 September to 15 October at three Iowa locations: central, NE, and SW, during three growing seasons: 2001–2002, 2002–2003, and 2003–2004. Grain yield decreased with planting dates after late September at the NE and SW locations in 2002–2003, and the central, NE, and SW locations in 2003–2004. Yield reductions from planting in mid October rather than late September ranged from 13 to 29%. At the NE location in 2001–2002 and the central location in 2002–2003, grain yield was 15% less for mid September than late September planting, similar for late September and early October plantings, and 13 to 15% less for mid October. Grain yield did not change with planting date at central Iowa in 2001–2002. The greatest yields occurred for planting dates where between 533 and 955 growing degree days (GDD, 0°C base temperature) accumulated between planting and 31 December. Winter triticale would most likely be placed after soybean in Iowa, suggesting that a 2‐wk period would be available for planting winter triticale without diminished yield caused by late planting.
Can Spring Wheat‐Growing Megaenvironments in the Northern Great Plains Be Dissected for Representative Locations or Niche‐Adapted Genotypes?
Authors: Navabi Alireza , Yang Rong‐Cai , Helm James , Spaner Dean M.
Published: March 2006

Characterizing variety testing sites and identification of sites with negligible genotype × environment crossover interaction is important for plant breeders wishing to identify superior germplasm and (or) cultivars for a wide range of environments. Long‐term multilocation grain yield data from the regional hard red spring wheat (Triticum aestivum L.) variety trials from 1981 to 2002 (472 location years assessing 64 wheat genotypes) in Alberta, Canada, were employed for this study. The shifted multiplicative model (SHMM) and the site regression model (SREG) were used to group testing sites into subsets with reduced crossover interaction. Both models identified yearly subsets of testing sites with negligible crossover interaction. However, the yearly site groupings did not generally follow a repeatable pattern over years. Clustering did not correspond with provincial agroclimatic classification, nor did it correspond with site‐specific yield potential. Genotype × environment patterns were therefore inconsistent over the years, mainly because of complex, highly variable, and unpredictable year × location effects. We identified sites appearing to be more discriminative and predictive of average genotype performance. This suggests that regional variety trials may be conducted at a fewer more representative locations predictive of average varietal performance. We conclude that the spring wheat growing areas in Alberta (and in the northern Great Plains in general) belong to a single megaenvironment with unpredictable crossover interaction patterns. Because of the highly variable and unpredictable genotype × environment interaction patterns in Alberta, genotypic selection targeting wide adaptation is recommended. Although genotype × environment patterns were not repeatable, the yearly high yielding and stable varieties were repeatedly selected over years. These varieties were the most popular varieties grown by farmers during the testing time period.
Kernel Size Variation in Naked Oat
Authors: Doehlert Douglas C. , Jannink Jean‐Luc , McMullen Michael S.
Published: March 2006

Kernel size in naked oat (Avena sativa L.) is of interest because of the importance of groat size in determining flake size in “old fashioned” style oat flakes. Here we compared naked oat kernel size distributions with those of hulled oat (Avena sativa L.). Most hulled oat spikelets have two kernels, where the primary kernel is distinctly larger than the secondary kernel. Although naked oat panicle architecture was similar to that of hulled oat, naked oat had a distinctive multiflorous spikelet architecture that contained from one to six kernels. Because single and double‐kernel spikelets were most abundant in naked oat, the mean kernel number per spikelet did not differ between hulled oat and most naked genotypes. Like hulled oat, naked oat kernel size decreased with increasing kernel order. All hulled oat and most naked genotypes had size distributions departing from normality, but some naked genotypes had normal kernel size distributions. Variances of naked oat kernel size were much smaller than those of hulled genotypes, indicating a greater degree of kernel sizes uniformity in naked genotypes. However, the increased variation in the hulled oat kernel size appeared to be due to the presence of the hull and hulled oat groats had about the same size variation as did naked oat groats.
Blending Hard White Wheat to Improve Grain Yield and End‐Use Performances
Authors: Lee Kyung‐Min , Shroyer James P. , Herrman Timothy J. , Lingenfelser Jane
Published: March 2006

Two hard white wheats (Triticum aestivum L.), ‘Betty’ with high protein and good processing quality and ‘Trego’ with good yield potential, were blended at percentages of 0, 10, 30, 50, 70, 90, and 100% Betty and planted at three locations in western Kansas during 2001 to 2003. Grain yield and wheat end‐use quality were evaluated to assess the impact of blending two cultivars in an attempt to optimize yield and processing quality. A significant two‐way interaction between blend and location was observed for grain yield, test weight, grain protein, single kernel properties, flour extraction, mixograph tolerance, and bread loaf volume per gram of protein. The different yield and quality response of the Betty–Trego blends among locations resulted, in part, from the presence of stripe rust (caused by Puccinia striiformis Westend.) during 2 of the 3 yr (2001 and 2003). Test weight, single kernel weight and size, grain yield, and flour extraction decreased in response to increasing Betty in the blend, whereas grain protein, kernel hardness index, mixograph water absorption, mixograph tolerance, and bread loaf volume increased with the blending level of Betty. Some variables did not exhibit a statistical linear response to the percentage of Betty, indicating that blending Betty and Trego was a good strategy to stabilize agronomic performance and end‐use quality.
Genetic Gain Equation with Correlated Genotype × Environment Effects
Authors: Helms T. C. , Hammond J. J.
Published: March 2006

The genetic gain formula has been used to determine the best allocation of resources. The assumptions of this formula are that genotypes are selected based on the mean of data averaged across several locations within years. When plant breeders select genotypes after the first year of replicated yield tests, the assumptions of the genetic gain formula are violated. For this reason, information provided by the genetic gain formula is not useful for determining the optimum allocation of replicates and environments. Our objectives were to (i) develop a heritability formula that included covariances between genotype‐by‐environment (G × E) interaction effects for the same genotype evaluated in different environments; and (ii) show how these G × E covariances influence resource allocation strategies to maximize genetic gain. Our operational genetic gain formula considers genetic gain to be a correlated response between the test and target environments and allows for G × E covariances between the same genotype evaluated at two selection sites. When selection was conducted at two sites that had a small G × E component of variance and also conducted at two sites with a large G × E component of variance, the realized gain was equal in the target environments. Optimal resource allocation cannot be decided, based on the genetic gain formula.
Inheritance of Resistance to Gray Leaf Spot Disease in Perennial Ryegrass
Authors: Han Yuanhong , Bonos Stacy A. , Clarke Bruce B. , Meyer William A.
Published: March 2006

Gray leaf spot disease, caused by Pyricularia oryzae Cavara, is an important disease in perennial ryegrass (Lolium perenne L.) turf. Host resistance is an ideal and promising approach to disease control. In this study, two diallel crosses involving six parents and eight parents, respectively, of perennial ryegrass were established to investigate the inheritance of gray leaf spot resistance. Parents and progenies were evaluated for gray leaf spot resistance in growth chamber experiments where they were inoculated with a mixture of five pathogen isolates. A field experiment was conducted on the progenies of one diallel cross. Effects of both general combining ability (GCA) and specific combining ability (SCA) were significant in both growth chamber and field tests. However, the GCA variance accounted for the major portion of the total genotypic variance. Narrow‐sense heritability calculated by midparent–offspring regression ranged from 0.57 to 0.76, indicating additive gene effects were the major genetic component in control of gray leaf spot. Estimates of minimum number of genes ranged from 2.1 to 4.4, suggesting resistance to gray leaf spot was controlled by a small number of genes. All the results suggested that a breeding program basing on recurrent selection should be effective to improve the resistance to gray leaf spot in perennial ryegrass.
Nitrogen Effects on Herbage Nitrogen Use and Nutritive Value in a Meadow and Loblolly Pine Alley
Authors: Burner David M. , MacKown Charles T.
Published: March 2006

Herbage response to N is poorly understood in alley cropping systems. Our objective was to determine site specific effects of N on herbage N use and nutritive value in separate experiments conducted in a meadow and a loblolly pine (Pinus taeda L.) alley (995 trees ha−1) near Booneville, AR. Tall fescue (Festuca arundinacea Schreb.) was the predominant herbage species. Fertilizer N was broadcast as split‐applications at six rates (100 kg ha−1 increments from 0 to 500 kg ha−1 yr−1). The proportion of total herbage as tall fescue was favored at rates ≥ 200 kg N ha−1, but these rates increased concentrations of herbage NO3−–N in the pine alley to potentially harmful levels for grazing ruminants (>2300 μg NO3−–N g−1). Cumulative herbage N use efficiency (CNUE) was 23 and 10 kg dry weight per kilogram supplied N for the meadow and pine alley, respectively. Cumulative N acquisition efficiency (CNAE), not cumulative N conversion efficiency (CNCE), appeared to be the primary driver of low CNUE in the pine alley. The apparent increase in crude protein (CP) in pine alley vs. meadow herbage appeared to be a mechanistic response to decreased specific leaf weight. Only maintenance levels (≤100 kg ha−1) of N fertilization should be applied to pine alley herbage given the low CNUE, and risk of NO3−–N toxicity to ruminant livestock at higher N rates.
Genetic Effects of Thirteen Gossypium barbadense L. Chromosome Substitution Lines in Topcrosses with Upland Cotton Cultivars: I. Yield and Yield Components
Authors: Jenkins Johnie N. , Wu Jixiang , McCarty Jack C. , Saha Sukumar , Gutiérrez Osman , Hayes Russell , Stelly David M.
Published: March 2006

Gossypium barbadense L. line 3–79 is lower in yield, has smaller bolls and longer, finer, and stronger fibers than upland cotton G. hirsutum L. Thirteen chromosome substitution (CS‐B) lines with individual 3–79 chromosomes or arms substituted into TM‐1, G. hirsutum, were top crossed with five elite cultivars and additive and dominance effects for the yield components, lint percentage, boll weight, seed cotton yield, and lint yield, were measured over four environments. Additive effects were greater than dominance effects for all traits. CS‐B lines had smaller additive and homozygous dominance effects than the cultivars for most traits. Many CS‐B lines had negative additive effects; however, chromosome substituted arms 22sh and 22Lo showed additive effects for lint yield that were significantly greater than homologous chromosome arms in TM‐1. Hybrids of DP90 × CS‐B15sh, ST 474 × CS‐B17, and FM 966 × CS‐B02 had positive dominance effects for lint yield significantly greater than the homologous chromosomes in TM‐1. Several chromosomes or arms were associated with significant negative additive or dominance effects. These data provide a valuable baseline on yield components for the utility of these CS‐B lines in commercial breeding programs. When individual chromosomes or chromosome arms, via CS‐B lines, are used in crosses with cultivars, alleles for yield components on specific G. barbadense chromosomes were uncovered that showed positive interactions with alleles in elite germplasm.
Validation of Quantitative Trait Loci for Multiple Disease Resistance in Barley Using Advanced Backcross Lines Developed with a Wild Barley
Authors: Yun S. J. , Gyenis L. , Bossolini E. , Hayes P. M. , Matus I. , Smith K. P. , Steffenson B. J. , Tuberosa R. , Muehlbauer G. J.
Published: March 2006

Quantitative trait loci (QTLs) for resistance to spot blotch {Cochliobolus sativus (Ito & Kurib.) Drechs. ex Dastur [anamorph: Bipolaris sorokiniana (Sacc. in Sorok.) Shoem.]}, net type net blotch (NTNB, Pyrenophora teres f. teres), Septoria speckled leaf blotch (SSLB, primarily Septoria passerinii Sacc.), and leaf scald [caused by Rhynchosporium secalis (Oudem.) Davis] were previously detected in a recombinant inbred line (RIL) population derived from a cross between the wild barley [Hordeum vulgare subsp. spontaneum (K. Koch) Thell.] accession OUH602 and the two‐rowed malting barley (H vulgare L.) cultivar Harrington. Our objectives in this study were to develop and genetically characterize an advanced backcross (AB) population with OUH602 as the donor parent and Harrington as the recurrent parent, to validate seedling disease resistance QTLs detected in the OUH602/Harrington RIL population, and to identify adult plant spot blotch resistance QTLs. We developed an AB population (BC2F6:8) and genotyped the population with a set of 111 simple sequence repeat (SSR) markers. The estimated donor‐parent genome introgression averaged 11.25%. A QTL analysis of the AB population validated all major QTLs previously identified in the OUH602/Harrington RIL population. No new QTLs for seedling resistance were identified in the AB population, indicating that AB populations do not provide an advantage compared with RIL populations for detecting seedling disease resistance QTLs. A previously unidentified QTL conferring adult plant spot blotch resistance was identified on chromosome 4(4H). The resistance alleles for each of the QTLs were contributed by OUH602. The AB population is a valuable resource for further genetic studies and breeding applications.
Tillage Effects on Wheat Emergence and Yield at Varying Seeding Rates, and on Labor and Fuel Consumption
Authors: Lithourgidis A. S. , Dhima K. V. , Damalas C. A. , Vasilakoglou I. B. , Eleftherohorinos I. G.
Published: March 2006

Conservation tillage systems can play an important role in reducing soil erosion and improving soil quality with the extra benefit of being equal to or more economical than conventional tillage; however, yield variability still remains a major concern among farmers. Field experiments were conducted in 2003 through 2004 and 2004 through 2005 in northern Greece to determine the effect of seeding rate (100, 150, 200, and 250 kg ha−1) on wheat establishment and grain yield under three tillage systems (minimum, reduced, and conventional tillage). In addition, labor time and fuel consumption for wheat production under these tillage systems were compared. For all tillage systems, the greatest number of wheat plants was recorded at the two highest seeding rates (P < 0.05). However, wheat plant numbers, averaged over seeding rates, were reduced by 11 to 17% in minimum tillage compared with conventional and reduced tillage systems in both growing seasons. Ear numbers were unaffected by tillage systems but generally increased with the increased seed rate. However, differences were not found in grain yield either among tillage systems or seeding rates. Regarding labor time and fuel consumption, 50 and 53% savings was achieved with minimum tillage, respectively, and 43 and 48% with reduced tillage in comparison with conventional tillage. These findings indicate that wheat can be grown successfully under conservation tillage systems with yields equal to those of conventional tillage and lower labor and fuel inputs. Increasing of seeding rate favored crop establishment in all tillage systems, but it did not provide any grain yield advantage.
Evolution of North American Dent Corn from Public to Proprietary Germplasm
Authors: Mikel Mark A. , Dudley John W.
Published: March 2006

Current corn (Zea mays L.) hybrids are produced using proprietary inbred lines as parents. These proprietary lines are protected by U.S. Patent and/or the U.S. Plant Variety Protection Act (PVPA) and their use is restricted, but as protection expires these lines become available to the entire corn breeding industry. Our objectives were to gain understanding of this protected germplasm by utilizing pedigree information available in the U.S. Patent and PVPA records to enhance the use of this germplasm in new line development as the lines become publicly available. Ownership, derivation, and lineage of corn inbred lines protected by U.S. Patent or PVPA from 1980 to 2004 were surveyed. Thirty‐three companies have protected 908 corn inbred lines and four of these companies: Dekalb Genetics (DK), Holden's Foundation Seeds (LH), Pioneer Hi‐Bred (PH), and Syngenta (SG) originated 685 of them. We identified the most significant lines by their cumulative use as parents in the development of new lines. Much of today's germplasm originates from seven progenitor lines: B73, LH82, LH123, PH207, PH595, PHG39, and Mo17. The germplasm surveyed is grouped by pedigree lineage into Oh43, Lancaster, Oh07‐Midland, Iodent, Stiff Stalk, Commercial hybrid derived, and Argentine Maiz Amargo backgrounds, with new diversity emerging from the two latter groups. Recycling elite inbred lines using two‐parent crosses followed by pedigree breeding was the most prevalent method of new line development.
Identification and Monosomic Analysis of Tan Spot Resistance Genes in Synthetic Wheat Lines (Triticum turgidum L. × Aegilops tauschii Coss.)
Authors: Tadesse Wuletaw , Hsam Sai L.K. , Wenzel Gerhard , Zeller Friedrich J.
Published: March 2006

Tan spot, caused by the fungus Pyrenophora tritici‐repentis (Died.) Drechs. (Ptr), anamorph Drechslera tritici‐repentis (Died.) Shoem., is becoming a major yield limiting leaf disease of both durum (Triticum turgidum L. var durum) and common wheat (Triticum aestivum L.) worldwide. In this study, differential isolates and varieties were developed, and using the most virulent isolate, ASC1b, we screened about 100 synthetic wheat genotypes against the disease. Two (2%) and 20 (20.4%) of the genotypes were found to be immune and highly resistant, respectively. Monosomic analyses of the F2 hybrids (crosses of the highly resistant accessions (XX41, XX45) and the moderately resistant accession XX110 with the monosomic lines (D‐genome) of the wheat cultivar Chinese Spring have revealed that the resistance genes are located on chromosome 3D. The gene in lines XX41 and XX110 showed a recessive monogenic inheritance, whereas the gene in line XX45 exhibited a dominant mode of inheritance. The recessive genes from XX41 and XX110 are tentatively named tsn3 and tsn‐syn1, respectively, and the dominant gene from XX45 is named as Tsn‐syn2.
Modeling and inferential control of the batch acetylation of cellulose
Authors: Dubey Anshul , Realff Matthew J. , Lee Jay H. , Schork F. Joseph , Butté Alessandro , Ollé Bernat , Kizer Lawton E.
Published: March 2006

The batch acetylation of cellulose involves two main stages, acetylation followed by hydrolysis. Mathematical models were constructed for these processes using reaction parameters obtained from earlier publications. The two models were then combined, along with a model predicting the cellulose feedstock moisture content. The overall temperature profiles as well as the final degree of acetylation and polymerization were shown to match the data obtained from a commercial process. From the results of the model and the observations made in a typical process, it has been established that this process is highly sensitive to disturbances in the input streams that can result in unacceptable final properties of the batch. Because the exact disturbance occurring in a batch cannot be identified and measured, inferential control is used to formulate an intrabatch control strategy. Support vector regression is used to make predictions on the final properties of the batch. These predictions, along with the model of the hydrolysis stage, are used to estimate the inputs that, when applied during hydrolysis, can counter the disturbances caused during the acetylation stage. Simulations show that this hydrolysis control strategy can improve the average batch properties of cellulose acetate required for subsequent processing. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Prenatal diagnosis of hypochondroplasia: Report of two cases
Authors: Karadimas C. , Sifakis S. , Valsamopoulos P. , Makatsoris C. , Velissariou V. , Nasioulas G. , Petersen M. B. , Koumantakis E. , Hatzaki A.
Published: March 2006

Hypochondroplasia (HCH) is an autosomal dominant skeletal dysplasia characterized by short extremities, short stature and lumbar lordosis, usually exhibiting a phenotype similar to but milder than achondroplasia (ACH). Mutations in the fibroblast growth factor receptor 3 (FGFR3) gene are present in a significant proportion of HCH patients. Reports of prenatal diagnosis of HCH are very rare and the phenotype/genotype correlation in these patients is poor. Here we present two sporadic cases with second trimester ultrasound findings consistent with a diagnosis of a non‐lethal skeletal dysplasia. Ultrasound evaluation after 23 weeks of gestation showed a decreased rate of development of the femora (femur length <fifth centile), while biparietal diameter, abdominal circumference, and foot length were within normal limits. Femur length/foot and femur length/abdominal circumference ratios were <0.87 and <0.18, respectively. Prenatal cytogenetic and molecular genetic analysis was performed. Karyotype was normal and FGFR3 G380R mutation characteristic of ACH was excluded in both fetuses. Molecular genetic analysis carried out retrospectively revealed that both fetuses were heterozygous for the C1620A mutation resulting in N540K substitution in FGFR3, the most common mutation in HCH. We conclude that the combination of ultrasound and molecular genetic approach is helpful for establishing an accurate diagnosis of HCH in utero and subsequently for appropriate genetic counseling and perinatal management. © 2006 Wiley‐Liss, Inc.
Frizzled‐related protein variants are risk factors for hip osteoarthritis
Authors: Lane N. E. , Lian K. , Nevitt M. C. , Zmuda J. M. , Lui L. , Li J. , Wang J. , Fontecha M. , Umblas N. , Rosenbach M. , de Leon P. , Corr M.
Published: March 2006

Objective

To examine the association of the Arg200Trp and Arg324Gly variants of FRZB with the risk and phenotype of radiographic osteoarthritis (OA) of the hip and serum levels of Frizzled‐related protein (FRP) in a prospective cohort of elderly Caucasian women.

Methods

Radiographic hip OA status of patients was defined by the presence of severe joint space narrowing (JSN) (feature grade ≥3), a summary grade ≥3, or definite osteophytes (grade ≥2) and JSN (grade ≥2) in the same hip. Genotypes were obtained in 569 patients with radiographic OA of the hip and in 1,317 and 4,136 controls for the Arg200Trp and Arg324Gly variants, respectively. Serum FRP levels were measured by enzyme‐linked immunosorbent assay. Multivariate logistic regression was performed.

Results

The minor allele frequency for the Arg200Trp polymorphism was 0.12 in the control group compared with 0.14 in the group with radiographic OA of the hip (P = 0.12), and the minor allele frequency for the Arg324Gly variant was 0.083 in the control group compared with 0.088 in the group with radiographic OA of the hip (P = 0.63). The multilocus genotypes available in 1,886 subjects suggested that inheritance of both minor alleles was a risk factor for developing OA characterized by JSN (P < 0.01). Patients with radiographic OA of the hip who were homozygous for the Arg200Trp minor allele had higher serum FRP levels than controls who were homozygous for the major allele.

Conclusion

Our data confirm findings of another study, that a rare haplotype with both Arg200Trp and Arg324Gly FRZB variants contributes to the genetic susceptibility to hip OA among Caucasian women, and that these polymorphisms may contribute to increased serum levels of proteins as biomarkers of OA.
Contribution of activin receptor–like kinase 5 (transforming growth factor β receptor type I) signaling to the fibrotic phenotype of scleroderma fibroblasts
Authors: Chen Yunliang , Shi‐Wen Xu , Eastwood Mark , Black Carol M. , Denton Christopher P. , Leask Andrew , Abraham David J.
Published: March 2006

Objective

To use a specific transforming growth factor β receptor type I (TGFβRI; activin receptor–like kinase 5 [ALK‐5]) kinase inhibitor (SD208) to determine the role of activation of the TGFβRI kinase (ALK‐5) in maintaining the profibrotic phenotype of dermal fibroblasts in systemic sclerosis (SSc).

Methods

The effect of SD208 on the expression of key biochemical markers of the fibrotic phenotype was compared in fibroblasts cultured from clinically involved (lesional) and clinically uninvolved skin of patients with diffuse cutaneous SSc (dcSSc) and in fibroblasts from healthy controls matched for age, sex, and anatomic site. Protein expression was compared together with the ability of fibroblasts to adhere to the extracellular matrix and to remodel and contract a free‐floating fibroblast–populated type I collagen lattice.

Results

Inhibiting TGFβRI kinase reduced the expression of a cohort of fibrotic markers by dermal fibroblasts from patients with dcSSc, including type I collagen and β1 integrin. Moreover, inhibition also attenuated the elevated adhesive and contractile abilities of dcSSc fibroblasts.

Conclusion

Our data suggest that some of the key profibrotic features of lesional SSc fibroblasts are dependent upon ALK‐5 activity. Thus, TGFβRI kinase–mediated signaling may contribute to dermal fibrosis in dcSSc.
Low vitamin K status is associated with osteoarthritis in the hand and knee
Authors: Neogi Tuhina , Booth Sarah L. , Zhang Yu Qing , Jacques Paul F. , Terkeltaub Robert , Aliabadi Piran , Felson David T.
Published: March 2006

Objective

Poor intake of vitamin K is common. Insufficient vitamin K can result in abnormal cartilage and bone mineralization. Furthermore, osteophyte growth, seen in osteoarthritis (OA), may be a vitamin K–dependent process. We undertook this study to determine whether vitamin K deficiency is associated with radiographic features of OA.

Methods

We conducted an analysis among 672 participants (mean age 65.6 years, 358 women) in the Framingham Offspring Study, a population‐based prospective observational cohort. Levels of plasma phylloquinone (the primary form of vitamin K) had previously been measured in these participants, for whom we also had bilateral hand and knee radiographs. The main outcomes were 1) prevalence ratios (PRs) of OA, osteophytes, and joint space narrowing (JSN) per quartile of plasma phylloquinone level for each joint, adjusting for correlated joints using generalized estimating equations, and 2) adjusted mean number of joints with each feature per quartile of plasma phylloquinone level. Analyses were conducted in hands and knees separately and adjusted for age, sex, body mass index, total energy intake, plasma vitamin D, and femoral neck bone mineral density.

Results

The PRs for OA, osteophytes, and JSN and adjusted mean number of joints with all 3 features in the hand decreased significantly with increasing plasma phylloquinone levels (P ≤ 0.03 for all). For example, as plasma phylloquinone levels rose, the PR for hand OA decreased from 1.0 to 0.7 (P = 0.005). For the knee, only the PR for osteophytes and the adjusted mean number of knee joints with osteophytes decreased significantly with increasing plasma phylloquinone levels (PR decreased from 1.0 to 0.6, P = 0.01).

Conclusion

These observational data support the hypothesis of an association between low plasma levels of vitamin K and increased prevalence of OA manifestations in the hand and knee.
A high‐resolution magnetic resonance imaging study of distal interphalangeal joint arthropathy in psoriatic arthritis and osteoarthritis: Are they the same?
Authors: Tan Ai Lyn , Grainger Andrew J. , Tanner Steven F. , Emery Paul , McGonagle Dennis
Published: March 2006

Objective

Distal interphalangeal (DIP) joint arthropathy is characteristic of both psoriatic arthritis (PsA) and osteoarthritis (OA), but the microanatomic basis for DIP joint localization is poorly understood. This study used high‐resolution magnetic resonance imaging (MRI) to investigate the basis for hand disease localization in both conditions.

Methods

Twenty patients matched for disease duration (10 with DIP joint PsA and 10 with DIP joint OA) and 10 normal control subjects were scanned with a 1.5T MRI scanner utilizing a high‐resolution 23‐mm diameter surface coil with displayed pixel dimensions of 80–100 μm. Images were obtained precontrast and postcontrast, and all joint structures, including ligaments, tendons, and entheses, were evaluated by 2 independent assessors.

Results

PsA could be distinguished from OA on the basis of more severe inflammation in the collateral ligaments and the extensor tendons and more severe changes at the corresponding DIP joint entheseal insertions. A much greater degree of extracapsular enhancement, with diffuse involvement of the nailbed and diffuse bone edema without cartilage damage, was also typical of PsA. Compared with the normal controls, the OA cohort exhibited prominent ligament and entheseal changes, but with much less contrast enhancement than in PsA and less bone involvement at the insertions.

Conclusion

These findings suggest prominent inflammatory changes in ligament, tendon, enthesis, and adjacent bone in the DIP joint disease of PsA patients. Involvement of the same structures is common in the DIP joints of OA patients, but inflammatory changes are much less marked. These findings are potentially important for a better understanding of arthritis in humans.