bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparison of Tests for QTL Mapping with Introgression Libraries Containing Overlapping and Nonoverlapping Donor Segments
Authors: Mahone Gregory S. , Borchardt Dietrich , Presterl Thomas , Frisch Matthias 
Published: August 2012

ABSTRACTNear‐isogenic line (NIL) libraries can be used to detect beneficial trait variation in germplasm that is unadapted or has poor agronomic performance. The objectives of our study were to compare the t test, Dunnett test, and linear model test with regard to the power and false positive rate of quantitative trait loci (QTL) detection in NIL libraries of different design. We employed computer simulations with maize genome models to investigate nonoverlapping NIL libraries, overlapping NIL libraries, and stepped aligned inbred recombinant strains (STAIRS) libraries for traits with oligogenic inheritance. Quantitative trait loci detection power of the linear model and Dunnett tests were similar for nonoverlapping and STAIRS libraries; for overlapping NIL libraries the Dunnett test was slightly superior. False positives were greatest for the t test and lowest for the linear model test. False positive sums with the Dunnett test were generally higher than for the linear model test if the heritability was 0.9 or lower. We conclude that the linear model test is superior to the Dunnett test for nonoverlapping NIL libraries and for overlapping NIL libraries with heritabilities below 0.9, as usually occur. Analysis of a rapeseed (Brassica napus L.) library revealed two other major advantages of the linear model test. First, detection of positive and negative QTL effects present in the same line is possible. Second, for NILs with multiple donor segments, observed phenotypic differences can be assigned to individual chromosome segments.
Geographical Patterns of Sesame Accessions Grown Under Mediterranean Environmental Conditions, and Establishment of a Core Collection
Authors: Yol Engin , Uzun Bülent 
Published: August 2012

ABSTRACTThe exploitation of exotic germplasm resources in breeding programs is necessary to enhance the diversity of cultivars. The diversity and relationships in a worldwide collection of sesame (Sesamum indicum L.) germplasm were determined in this study. A total of 345 accessions were assessed in relation to 12 qualitative and nine quantitative traits during two growing seasons. The accessions were grouped on the basis of their geographical patterns and morphological and agronomic characteristics. Specific accessions having high seed yield and number of branches and capsules, early maturity, yellow and brown seed color, purple stem and capsule color, hairiness, nonshattering capsules, and determinate growth habit were identified. Multivariate analysis revealed that genetic variation in the entire collection was mainly evident in days to maturity, stem length to the first capsule, plant height, and number of branches. Cluster analysis showed that the germplasm collection was representative of the geographical distribution of sesame. A core collection was developed, providing an indispensable resource for DNA and fatty acid composition studies based on analyses of fewer accessions than the entire collection. Comparison of the core and entire collections based on the qualitative and quantitative descriptors indicated that the core collection was optimal and appropriately represented the entire collection.
Inheritance of Yield‐Related Traits in Climbing Beans (Phaseolus vulgaris L.)
Authors: Checa Oscar E. , Blair Matthew W. 
Published: August 2012

ABSTRACTClimbing beans (Phaseolus vulgaris L.) are a traditional crop that has high productivity compared to bush beans. Very little research has been done on climbing beans in comparison to bush beans, and the genetics of its high yield potential are not well understood. The objectives of this work were (i) to evaluate genetic correlations between growth cycle and yield, (ii) to determine the quantitative trait loci (QTL) controlling these phenological and productivity traits, (iii) to compare QTL for seed yield and yield components with QTL for climbing ability in a recombinant inbred line population derived from crossing the climbing bean G2333 by the bush bean G19839, and (iv) to determine heritability for each variable. The experiment was grown on trellises and repeated across four environments, two of which were contrasting for phosphorus fertilization. The results show that inheritance of yield components is simpler and of higher heritability than seed yield itself. Some yield‐related QTL were overlapping across environments while others were independent. A total of four QTL were found for yield, while a total of 12 QTL were found for yield component traits. The higher heritability of seed weight allowed the detection of nine QTL for this trait. Meanwhile, a total of six QTL were found for phenological traits, with the majority being for time to maturity rather than time to flowering since the former trait had higher heritability. We discuss the implications of these results for breeding of climbing beans.
Pollen‐Mediated Gene Flow in Triticale
Authors: Kavanagh Vanessa B. , Hills Melissa J. , Eudes Francois , Topinka Keith , Yang Rong‐Cai , Hall Linda M. 
Published: August 2012

ABSTRACTTriticale (×Triticosecale Wittm. ex A. Camus) is primarily an animal feed crop with promising qualities for a bioindustrial crop. Development of genetically modified (GM) triticale is in progress and before release of GM cultivars, the potential for pollen‐mediated gene flow (PMGF) needs to be assessed to determine if it can coexist with conventional cultivars without causing market harm. Small and large plot experiments were conducted to quantify PMGF using an experimental blue aleurone triticale line as pollen donor and ‘AC Alta’ as pollen receptor. Small plot experiments were conducted at two locations in both 2007 and 2009 in Alberta, Canada. There were no site or year differences. Average PMGF from 0.2 to 1.4 m was 0.76%. Large plot experiments were conducted at two locations in both 2008 and 2009 using a concentric donor (20 by 20 m) and receptor (120 by 120 m) design. Over 17 million seeds were screened. There were no significant differences between sites or years. Pollen‐mediated gene flow best fit an exponential decay model in which the highest average PMGF (3.4%) occurred adjacent to the donor crop and rapidly declined to 0.09% by 50 m. Directional differences were detected with highest PMGF corresponding to prevailing wind directions at flowering. The estimated adventitious presence of GM triticale after harvest blending within a 50‐m conventional field was 0.22%. Pollen‐mediated gene flow in triticale is similar to spring wheat (Triticum aestivum L.) and should not prevent the coexistence of GM and conventional triticale using the 0.9% threshold established by the European Union.
Using Variability within Digital Images to Improve Tall Fescue Color Characterization
Authors: Ghali Ihab E. , Miller Grady L. , Grabow Garry L. , Huffman Rodney L. 
Published: August 2012

ABSTRACTDigital image analysis (DIA) provides an accurate, nondestructive, and objective assessment of turf color. Previous research developed an index known as the dark green color index (DGCI) via DIA as an indicator of turf color. The objective of this study was to use DGCI variability to better predict a visual rating (VR) index used to evaluate tall fescue (Festuca arundinacea Schreb.) color under different irrigation treatments. To develop DGCI statistics, two freeware software packages (Image J and R) were used to extract and process information from digital images. The model to predict VR from DIA was developed and calibrated using candidate DGCI statistical moments from 120 images in a calibration data set using a multiple linear regression procedure. Fitness of calibration and validation models were verified using the adjusted coefficient of determination, root mean square error, and the Mallow's Cp statistic. The two‐variable model produced more precise estimates (adjusted R2 = 0.926 and 0.899) than the model that only used one term in predicting the VR values (adjusted R2 = 0.879 and 0.843) for calibration and validation sets, respectively. These data suggest incorporating a measure of color uniformity improves the use of DGCI in predicting VR values compared to using only the mean of DGCI values to predict VR values. Model refinements may be needed for other turf species, but current work suggests using additional statistical moments such as SD improves VR estimate precision and accuracy.
Genetic Diversity and Differentiation of Aquilaria sinensis (Lour.) Gilg Revealed by ISSR and SRAP Markers
Authors: Zou Meiling , Xia Zhiqiang , Lu Cheng , Wang Haiyan , Ji Jiamin , Wang Wenquan 
Published: August 2012

ABSTRACTAquilaria sinensis (Lour.) Gilg, one of the most valuable medicinal plants endemic to China, has been largely destroyed and is presently listed as an endangered species in the China Plant Red Data Book: Rare and Endangered Plants. The number of individuals and population genetic diversity of this species have rarely been reported. A total of 567 polymorphic bands were found in 112 accessions of A. sinensis using inter‐simple sequence repeats and sequence‐related amplified polymorphism markers. All accessions from 11 locations were allocated into five geographical natural populations by cluster analysis. The genetic classification of accessions coincided with their geographic distribution, with some overlapping between neighboring regions. Principal coordinate analysis further showed three large‐scale geographic genetic zones of A. sinensis. Nei's genetic diversity had low values in the range 0.2014 to 0.1671 at the species level for A. sinensis. There were significant differences (P < 0.001) among (19.64% of the variance) and within populations (80.36% of the variance). Restricted gene flow (Nm = 1.8292) among populations may result from several factors, such as low seed dispersal and isolation of populations.
Leaf and Plant Water Use Efficiency in Cocksfoot and Tall Fescue Accessions under Differing Soil Water Availability
Authors: Gulías J. , Seddaiu G. , Cifre J. , Salis M. , Ledda L. 
Published: August 2012

ABSTRACTWater availability is one of the most important limiting factors in plant production worldwide. Such limitation is expected to increase in regions with a Mediterranean climate type during the next few decades. The objectives of this study were to evaluate plant water use efficiency (WUE) in contrasting accessions of two perennial grasses, Dactylis glomerata L. (cocksfoot) and Festuca arundinacea Schreb. [syn. Lolium arundinaceum (Schreb.) Darbysh.] (tall fescue), under two different water availability regimes and to study the relationship with instantaneous and intrinsic leaf WUE. Six accessions of D. glomerata and five accessions of F. arundinacea were grown under well irrigated and progressive drought conditions. Plant biomass, water consumption, and gas exchange parameters were measured to estimate the plant and leaf WUE. Few differences in biomass accumulation and gas exchange parameters were observed among the accessions within both species. Plant WUE and total plant biomass accumulation were positively correlated in both species and water treatment. The leaf WUE parameters did not show a consistent relationship with the plant WUE in either species. In contrast, the stomatal conductance decreased as the plant WUE increased in water‐limited D. glomerata, suggesting that stomatal conductance may be a good estimator of plant WUE under water deficit conditions.
Impact of Combining the Rag1 and Rag2 Alleles for Aphid Resistance on Agronomic and Seed Traits of Soybean
Authors: Brace Ryan C. , Fehr Walter R. 
Published: August 2012

ABSTRACTDamage to soybean [Glycine max (L.) Merr.] by the soybean aphid (Aphis glycines Matsumura) has been of economic concern in the midwestern United States since 2000. Soybean lines with both the Rag1 and Rag2 alleles have had substantially reduced aphid development compared to lines with either of the two alleles individually. The objective of our study was to evaluate the impact of the two alleles on agronomic and seed traits of soybean by comparing 22 BC3F2:4 lines with the two alleles to their susceptible recurrent parent ‘IA3027’. The replicated experiment was grown under aphid‐free conditions at three Iowa environments during 2011. Although the mean yield of the backcross (BC) lines was significantly less than IA3027 by 147 g kg−1 (4.5%), 15 of the 22 BC lines (68%) were not significantly different than the recurrent parent. The mean of the BC lines was significantly different than the recurrent parent for maturity, plant height, lodging, oil concentration, and seed weight, but there were individual BC lines that were not significantly different from the recurrent parent for all of the traits. The results indicated that it should be possible to develop resistant cultivars with the Rag1 and Rag2 alleles that have comparable performance for agronomic and seed traits to those of susceptible cultivars.
Resistance to Race TTKSK of Puccinia graminis f. sp. tritici in Emmer Wheat
Authors: Olivera Pablo D. , Badebo Ayele , Xu Steven S. , Klindworth Daryl L. , Jin Yue 
Published: August 2012

ABSTRACTRace TTKSK (Ug99) of Puccinia graminis f. sp. tritici is a serious threat to wheat production worldwide because of its wide virulence on many cultivars and rapid spread. Emmer wheat [Triticum turgidum L. subsp. dicoccon (Schrank) Thell.] is known to be a source of resistance to stem rust but has not been evaluated against race TTKSK. In attempts to identify and characterize stem rust resistance genes effective against race TTKSK at the seedling stage, we evaluated 359 accessions of emmer wheat with race TTKSK and other races with broad virulence. A high frequency (31.8%) of accessions were resistant to TTKSK at the seedling stage with low infection types ranging from 2= to 2+. Thirty‐seven accessions exhibited a resistant to moderately resistant response in Debre Zeit, Ethiopia, and St. Paul, MN, nurseries in 2010 and 2011. Studies were conducted to determine the inheritance of TTKSK resistance in five accessions at the seedling stage. Results from evaluating F2 and F2:3 generations revealed that resistance was conferred by single genes. One additional gene effective against race TTTTF was identified in the resistant parents. Results from this study indicated that emmer wheat is a source of resistance to race TTKSK and may contribute novel resistance genes. Since emmer wheat shares the same genome as durum [Triticum turgidum subsp. durum (Desf.) Husn.] wheat and is in cultivated form, resistance genes should be easily transferred to durum wheat by conventional breeding approaches.
Yield and Yield Components of Winter‐Type Safflower
Authors: Johnson R.C. , Petrie S.E. , Franchini María Clara , Evans Marc 
Published: August 2012

ABSTRACTSafflower (Carthamus tinctorius L.) is a minor yet widely grown oil seed crop adapted to semiarid regions. The development of winter adapted safflower, permitting fall planting, could substantially increase seed production. Our objective was to compare seed production of winter‐type and spring‐type safflower under fall and spring planting regimes. From 2006 to 2009 four winter‐type safflower germplasms and two spring cultivars were compared at Central Ferry, WA, Pullman, WA, and Pendleton, OR, in seven year–location combinations. For all years and locations the minimum average winter temperatures in December and January were always below freezing, with annual extremes ranging from ‐11 to ‐26°C. Extensive winter mortality of fall‐planted, spring‐type cultivars generally resulted in little or no seed production. For each year, seed production of fall‐planted, winter‐type germplasm was always higher than when spring planted (P < 0.05), averaging 310 g m‐2 or 66% more. That advantage was also observed at all locations within years except Pullman and Pendleton in 2009. Anthesis of fall‐planted germplasm averaged 16 d earlier than when spring planted. Increased production of fall‐planted winter‐type germplasm was most closely associated with increased seeds per square meter resulting from more capitula per square meter or seeds per capitulum. The results showed that fall‐planted winter‐type safflower has the potential to substantially increase seed production compared to spring types.
Markers for Quantitative Inheritance of Resistance to Foliar Thrips in Cowpea
Authors: Lucas Mitchell R. , Ehlers Jeffery D. , Roberts Philip A. , Close Timothy J. 
Published: August 2012

ABSTRACTMolecular assisted breeding is currently constrained by the lack of breeder‐friendly trait‐associated markers, especially among lesser studied crops. Recent advances in genomic technology are being applied to many important crop species, promoting the development of robust marker–trait associations. Regions of the cowpea [Vigna unguiculata (L.) Walp.] genome controlling the quantitative resistance to feeding by foliar thrips (Thrips tabaci and Frankliniella schultzei) were tagged by coupling phenotypic observations from two recombinant inbred line populations generated from domesticated parents. Three regions (Thr‐1, Thr‐2, and Thr‐3) explaining approximately 32, 24, and 9%, respectively, of the phenotypic variation were tagged with several expressed sequence tag (EST)‐derived single nucleotide polymorphism (SNP) markers and are presented here as haplotypes composed of multiple SNP markers. Regions within the soybean [Glycine max (L.) Merr.] genome that are syntenic to cowpea Thr‐1, Thr‐2, and Thr‐3 are also reported.
Variation of Responses to Water Stress Between ‘Tifton 85’ and ‘Tifway’ or ‘Coastal’ Bermudagrass
Authors: Husmoen Derek , Vietor D. M. , Rouquette F. M. , Cothren J. T. 
Published: August 2012

ABSTRACTField observations revealed greater retention of green leaf area and growth of ‘Tifton 85’ compared to common and ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] under water stress. Our objective was to compare phenotypic and physiological responses to increased water stress between Tifton 85 and Coastal and between Tifton 85 and ‘Tifway’ bermudagrass under greenhouse conditions. Bermudagrass green leaf area, shoot and root dry weights, leaf CO2 exchange rate (CER), H2O exchange rate (WER), and conductance were measured under well‐watered and reduced watering in two experiments. Tifton 85 retained greater green leaf area than Tifway under water stress in Exp. 1. The CER, WER, and conductance were less for Tifton 85 than Tifway, but water stress over 8 d reduced each variable for Tifway only. In Exp. 2, soil water content and green leaf area declined more for Tifton 85 than for Coastal bermudagrass over 14 d after watering ended. Greater root dry weight below the 13‐cm depth indicated Tifton 85 depleted water content of the finite pot volumes more rapidly than Coastal under reduced watering. After 14 d without watering during Exp. 2, mean CER of green leaves was less than well‐watered pots for Tifton 85 but not for Coastal bermudagrass. Similar to phenotypic traits, leaf CER, WER, and conductance responses of Tifton 85 differed between experiments. These greenhouse experiments documented variation of responses to reduced soil water supply among bermudagrass and revealed the need to evaluate traits affecting water access and use for Tifton 85 and other bermudagrass under field conditions.
Genetic Yield Improvement in Soft Red Winter Wheat in the Eastern United States from 1919 to 2009
Authors: Green Andrew J. , Berger G. , Griffey C. A. , Pitman R. , Thomason W. , Balota M. , Ahmed A. 
Published: August 2012

ABSTRACTPeriodic evaluation of breeding progress is necessary to assess genetic gains over time, and underlying traits responsible for yield gains can direct future breeding. This study was conducted to determine the rate and magnitude of yield progress in eastern soft red winter (SRW) wheat (Triticum aestivum L.) cultivars released from 1950 to 2009 relative to a historical cultivar Red May (1919). The effects of agronomic, morphological, and yield component traits on grain yield were studied in 50 widely grown historic and current cultivars in replicated yield trials at Warsaw, VA, in 2010 and 2011 and at Holland and Blacksburg, VA, in 2011. Genotype × environment interactions were significant (p ﹤ 0.01) for most traits. Linear regression models for yield were constructed for each environment, with r2 values ranging from 0.62 to 0.76 among environments. The traits flag leaf angle, kernel weight, spikes per square meter, lodging, flowering date, harvest index, normalized difference vegetative index (NDVI), and green leaf retention, respectively, explained the most yield variation in multiple environments. The rate of genetic yield improvement ranged from 0.56% yr−1 at Holland in 2011 to 1.4% yr−1 at Blacksburg in 2011. Traits that consistently increased in magnitude over time were spikes per square meter, erect flag leaf angle, harvest index, seeds per spike, seeds per spikelet, and yield. Traits that decreased over the time period studied were flowering date and plant height.
Molecular Characterization of a Spontaneous Waxy Starch Mutation in Cassava
Authors: Aiemnaka Pornsak , Wongkaew Arunee , Chanthaworn Jumnong , Nagashima Sathakupt Ken , Boonma Supawadee , Authapun Jetsada , Jenweerawat Sujin , Kongsila Pasajee , Kittipadakul Piya , Nakasathien Sutkhet , Sreewongchai Tanee , Wannarat Wannasiri , Vichukit Vichan , López‐Lavalle Luís Augusto Becerra , Ceballos Hernán , Rojanaridpiched Chareinsuk , Phumichai Chalermpol 
Published: August 2012

ABSTRACTCassava (Manihot esculenta Crantz) starch is traded in international markets more than starch from any other source. The starch industry requires cassava cultivars with novel starch characteristics for commercial exploitation. A natural source of waxy (amylose‐free) cassava starch, clone AM 206‐5, was identified at the International Center for Tropical Agriculture (CIAT). The granule‐bound starch synthase I (GBSSI) gene is related to the waxy starch trait. The objectives of this study were to introgress the waxy starch mutation into Thailand's cassava breeding populations, to analyze the inheritance of waxy starch in cassava, and to develop molecular markers for this trait. AM 206‐5 (wxwx) was crossed with several elite cultivars (WxWx) to transfer the wx allele. Unrelated “F1” (Wxwx) genotypes were crossed among themselves to produce a “F2” segregating population with negligible levels of inbreeding depression. The waxy starch phenotype was recovered in 25.7% of the 11,192 genotypes tested. This result provides further evidence that cassava is a functional diploid and that only one copy of GBSSI is present in cassava. A full‐length genomic DNA sequence of GBSSI was isolated and characterized from C8, a waxy starch “F2” clone derived from AM 206‐5. We exploited these sequence differences to develop two diagnostic single‐nucleotide‐amplified polymorphism (SNAP) markers to differentiate homozygous waxy (wxwx) from the heterozygous (Wxwx) and homozygous (WxWx) nonwaxy genotypes.