bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Water Repellency Development in Amended Sand Rootzones
Authors: Moody David R. , Schlossberg Maxim J. , Archibald Douglas D. , McNitt Andrew S. , Fidanza Michael A. 
Published: August 2009

ABSTRACTParticulate organic matter (OM) and surface area–limited sands are associated with soil water repellency (SWR) in turfgrass systems. The increasing ubiquity of amended sand rootzones warrants investigation of factors contributing to SWR. Our objective was to identify how amendment type and/or inclusion rate affect rootzone SWR over a range of irrigation regimes. A U.S. Golf Association–specified sand was amended with dried turfgrass roots and either sphagnum peat moss (SPM), reed sedge peat (RSP), biosolid compost (BSC), or calcined clay (CC) at 0, 0.1, or 0.2 m3 m−3 Mixes were saturated, gravitationally drained, incubated under isothermal ventilation having mean vapor pressures of 1.78, 2.19, or 2.45 kPa, and reirrigated when matric tension exceeded 300 kPa. After 138 d, rootzone subsamples were eluted of particulate OM before measuring mineral‐adsorbed hydrocarbon content (MAHC) by infrared spectroscopy. The repellency index was used to quantify SWR of intact (Rintact) and eluted (Reluted) samples. Amendment rate (0.2 > 0.1 > 0 m3 m−3) and type (BSC > RSP = SPM > CC) significantly affected Rintact Only CC‐amended rootzones were more wettable than the control. Severely elevated Reluted and MAHC were observed in all sands amended by BSC. Inclusion of SPM or RSP at 0.1 m3 m−3 resulted in Reluted and MAHC values statistically equivalent to the control rootzone. At 0.2 m3 m−3 inclusion, all organic amendments significantly increased Reluted and MAHC relative to the control (BSC > RSP = SPM).
Impact of Biosolids on Hormone Metabolism in Drought‐Stressed Tall Fescue
Authors: Zhang Xunzhong , Ervin E.H. , Evanylo G.K. , Haering K.C. 
Published: August 2009

ABSTRACTThe presence of biologically active substances (BAS) in biosolids may enhance plant stress tolerance and growth, but the underlying mechanisms are not well understood. This greenhouse study investigated the effects of untreated biosolids, containing 2.1 μg indole‐3‐acetic acid (IAA) g−1, and tryptophan‐treated biosolids, containing 15.4 μg IAA g−1, on tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] drought resistance. Treatments included a fertilizer control, indole‐3‐butyric acid (IBA) at 2 μM (hormone control), treated biosolids (2.95 g kg−1 soil), and untreated biosolids (2.97 g kg−1 soil). Nitrogen availability was equalized among treatments, and tall fescue physiological responses were measured under well‐watered or moisture stress conditions. Treated biosolids improved turfgrass quality and root mass under both soil moisture regimes and delayed leaf wilting under moisture stress. At the end of the second drought cycle (2 February), treated biosolids improved quality and photochemical efficiency by 18 and 26% relative to the control. Treated biosolids increased leaf IAA by 122 and 52%, respectively, and trans‐zeatin riboside by 100 and 189%, respectively, during each of two maximum drought periods. Leaf tissue increases of IAA and cytokinin were associated with greater content of these hormones in the soil. The data suggest that biosolids application may alter growth hormone (IAA and cytokinin) content and improve plant drought resistance.
Imazamox Tolerance in Mutation‐Derived Lines of Upland Cotton
Authors: Bechere Efrem , Auld Dick L. , Dotray Peter A. , Gilbert Lyndell V. , Kebede Hirut 
Published: August 2009

ABSTRACTInduction of genes conferring herbicide resistance by mutagenesis could facilitate use of imidazolinone herbicides in upland cotton (Gossypium hirsutum L.). In 1997 and 1998, seeds of eight High Plains cotton cultivars were treated with 2.45% v/v ethyl methanesulfonate. The resulting M3 and M4 generations were sprayed with imazethapyr, and the M5 and M6 generations were sprayed with imazamox. Four stable M6 to M7 lines with tolerance to imazamox were identified in 2004. During 2005 and 2006, tolerant mutants and their nonmutated parents were treated at the four‐leaf stage with topical applications of imazamox applied at five rates (0, 88, 175, 350, and 700 g a.i. ha−1). Elevated levels of tolerance to imazamox were observed in all mutants. Imazamox did not impact fiber length. Preliminary investigation indicated that tolerance to imazamox was controlled by a partially dominant single gene. An allelism test revealed that the tolerance genes in the four mutants are either alleles in the same locus or are very tightly linked.
A Target Region Amplified Polymorphism Marker for Fertility Restorer Gene Rf1 and Chromosomal Localization of Rf1 and Rf2 in Cotton
Authors: Wang Fei , Yue Bing , Hu Jinguo , Stewart J. McD. , Zhang Jinfa 
Published: August 2009

ABSTRACTCytoplasmic male sterility (CMS), a maternally inherited trait characterized as an inability to produce functional pollen, is an important biological system for economically producing hybrid seed to enhance crop yield and studying cytoplasmic and nuclear gene interactions. In cultivated tetraploid cotton (Gossypium hirsutum L.), male fertility in two systems CMS‐D2 and CMS‐D8 is restored by two restorer genes Rf1 and Rf2, respectively. The objectives of the present study were to identify additional molecular markers for the two restorer genes and to determine their chromosomal location in the cotton genome. Two backcross (BC1F1) populations were developed with D2 and D8 restorers containing their respective cytoplasms as female in crosses with the same Upland cotton maintainer as male and recurrent parent. One pentatricopeptide repeat (PPR)–based target region amplified polymorphism (TRAP) marker was developed to be tightly linked to the Rf1 gene with a genetic distance of 0.8 cM, while three more simple sequence repeat (SSR) markers (NAU2232‐550/650, NAU2232‐750/850, and NAU 2801‐250) were identified to be closely linked to Rf2 Using two common SSR markers, a consensus linkage group was constructed to include both Rf1 and Rf2 loci that were anchored in a 14.0‐cM region by the two PPR gene‐based markers. Based on four chromosome‐anchored SSR markers, Rf1 and Rf2 were localized on chromosome D5 within a genetic distance of 1.4 cM, providing an incentive for further investigations of this Rf1/Rf2–containing region.
Associations among Lint Yield, Yield Components, and Fiber Properties in an Introgressed Population of Cotton
Authors: Zeng Linghe , Meredith William R. 
Published: August 2009

ABSTRACTBroadening the genetic base is essential for genetic improvement of lint yield and fiber quality in upland cotton (Gossypium hirsutum L.). An exotic germplasm population derived from multiple crosses between G. barbadense L. and G. hirsutum was obtained from USDA‐ARS at Las Cruces, NM. Experiments were designed to evaluate this germplasm for genotypic variation in lint yield and fiber quality. Two hundred germplasm lines and five cultivars were planted at two locations in 2006 and one location in 2007. Significant (P ≤ 0.001) genotypic variation for yield and fiber quality was identified. In path coefficient analysis, bolls per square meter had the largest direct effect on lint yield, while boll weight and lint percentage had secondary direct effects on yield. Lint yield was negatively associated with fiber quality. Lint per seed was favorably correlated with lint percentage, elongation, span lengths, and fineness. Based on stepwise analysis, 50% length, short fiber content, fineness, maturity ratio, and 2.5% length contributed to strength, in decreasing order of significance. Short fiber content was negatively correlated with fineness (r = −0.41). These results indicate that this germplasm is a useful genetic resource for genetic improvement of lint yield, fiber quality, and analysis of interrelationships between lint yield and fiber quality.
Development of Drought‐Tolerant Canola (Brassica napus L.) through Genetic Modulation of ABA‐mediated Stomatal Responses
Authors: Wan Jiangxin , Griffiths Rebecca , Ying Jifeng , McCourt Peter , Huang Yafan 
Published: August 2009

ABSTRACTCanola is one of the most important oilseed crops, and its seed yield and quality are significantly affected by environmental stresses such as drought. The phytohormone abscisic acid (ABA) is induced by drought and triggers stomatal closure to reduce transpiration, which accounts for >90% of water loss in plants. The ABA‐mediated stomatal response is a dosage‐dependent process that can be achieved by either increasing the endogenous ABA concentration or by sensitizing the responsiveness of guard cells to the hormone. We summarize the recent breakthroughs in the understanding of key molecular components that regulate the homeostasis and sensing of ABA, and their potential applications in genetic engineering for drought tolerant canola. In particular, the α and β subunits of protein farnesyltransferase have been identified as negative regulators of ABA‐mediated stomatal responses, and their effectiveness as the targets for engineering drought tolerance and yield protection has been confirmed in canola in the field. Further development of the drought stress tolerance property in the crop will likely have a fundamental impact on its productivity in many regions of the world.
Enhanced Tolerance to Multiple Abiotic Stresses in Transgenic Alfalfa Accumulating Trehalose
Authors: Suárez Ramón , Calderón Cecilia , Iturriaga Gabriel 
Published: August 2009

ABSTRACTAlfalfa (Medicago sativaL.) is an important forage crop in many countries with high biomass production and the third‐most‐cultivated crop in the United States, with high protein content and potential use as biofuel. Here we describe the use of a chimeric translational fusion of yeast trehalose‐6‐phosphate synthase (EC 2.4.1.15) and trehalose‐6‐phosphate phosphatase (EC 3.1.3.12) genes to engineer stress tolerance in alfalfa. The gene fusion was overexpressed using either the constitutive35Spromoter or the stress‐regulatedrd29Apromoter. Transgene insertion in the genome was checked by polymerase chain reaction and transcript expression by reverse transcription polymerase chain reaction. Several independent transgenic plants were selected in the presence of kanamycin and further analyzed. Yeast gene encoding trehalose‐6‐phosphate synthase (TPS1)–yeast gene encoding trehalose‐6‐phosphate phosphatase (TPS2) gene expression under the35Spromoter led to plants with stunted growth and less biomass, whereasTPS1‐TPS2expression driven by therd29Apromoter improved growth and provoked a significant increase in plant biomass at the foliage level in the different transgenic lines. Trehalose accumulated in all the different lines at similar levels under stress conditions. Transgenic plants displayed a significant increase in drought, freezing, salt, and heat tolerance. This is the first time that genetic engineering of trehalose metabolism is reported in alfalfa and demonstrates that it can improve multiple stress protection in this crop. Thus, the yeast TPS‐TPP fusion protein represents a great potential for generating stress‐tolerant crop plants for agriculture.
A Comparison of Mixed‐Model Analyses of the Iowa Crop Performance Test for Corn
Authors: So Yoon‐Sup , Edwards Jode 
Published: August 2009

ABSTRACTMultienvironment trials generally have highly unbalanced data structures in which a particular cultivar is only observed in a subset of all environments for which data are available. A very common approach to reporting data from such unbalanced data is to subset the data into balanced subsets and restrict comparisons within balanced subsets. Such an approach results in much information being ignored. We undertook an empirical study of 65 individual data sets from the Iowa Crop Performance Test for corn (Zea mays L.) to compare eight different mixed linear models to determine which features in the data need to be considered in developing approaches to make use of all available information. We used a model selection approach to identify the best model based on the presence or absence of heterogeneity of error variances among environments, heterogeneity of genotypic variances among environments, and heterogeneity of genotypic correlations between pairs of environments. The trait analyzed was grain yield. We found evidence of heterogeneity of error variances among locations in 58 of 65 data sets for two model selection criteria. Heterogeneity of genotypic variances and correlations between pairs of environments was found in about half of the sets we analyzed. A general recommendation for model selection cannot be made from this analysis. In general, we found that heterogeneity of variances and correlations was prominent in many data sets. Identification of the best statistical model for a particular data set may be dependent on application of a model selection approach.
Phosphorus Fertility Effects on the Expression of the Low Phytic Acid Barley Phenotype
Authors: Jackson Chad A. , Windes Juliet M. , Bregitzer Phil , Obert Don , Price William , Brown Bradford 
Published: August 2009

ABSTRACTLow phytic acid (LPA) barley (Hordeum vulgare L.) cultivars partition phosphorus (P) in seed tissue differently than conventional wild‐type (WT) barley cultivars. A reduction in seed phytic acid (myo‐inositol‐1,2,3,4,5,6‐hexkisphosphate) is coupled with an increase in inorganic phosphorus (Pi). The response of the LPA characteristic to phosphate fertilization has not been previously investigated; therefore the effect of phosphate fertility on barley seed yield, and concentrations of seed total P, seed Pi, and flag leaf P was investigated at four locations over two years. The LPA cultivars were hypothesized to behave similarly to WT cultivars, therefore two WT cultivars, Baronesse and Colter, were compared to one LPA cultivar, Herald (lpa1–1 mutation), and one LPA advanced breeding line, 01ID451H (mutation 640). At three locations, phosphate fertilizer (P2O5) was applied in the form of triple superphosphate (0–45–0) at rates of 0, 56, 112, and 168 kg ha−1 Increased P fertilization was associated with increased flag leaf P concentration, but no changes were observed for other measured characteristics. At a fourth location, differential soil P fertility was provided via previously established plots varying from very low to adequate P fertility. Inadequate levels of P were associated with delayed maturity, and reductions in yield, test weight, height, and total seed P concentration. The responses of LPA and WT barleys were similar, indicating the LPA traits in barley originating from the lpa1‐1 and 640 mutations are stable under a wide range of soil P fertility.
Effect of Advanced Cycle Breeding on Genetic Gain and Phenotypic Diversity in Barley Breeding Germplasm
Authors: Condón Federico , Rasmusson Donald C. , Schiefelbein Edward , Velasquez Guillermo , Smith Kevin P. 
Published: August 2009

ABSTRACTPlant breeding with elite parents within closed populations has proven to be a successful strategy to achieve genetic gains and conserve favorable gene complexes. To investigate the effects of advanced cycle breeding on genetic gain, phenotypic variation, and germplasm differentiation, 15 agronomic and malting quality traits were evaluated for a set 98 genotypes including ancestors, parental founders, and elite breeding lines developed at the University of Minnesota barley (Hordeum vulgare L.) breeding program between 1958 and 1998. The material was evaluated in five trials at three locations in 2002 and 2003. Significant gains were observed for 11 traits during the 40‐yr period of advanced cycle breeding, including yield, lodging, malt extract, and wort beta‐glucan content. In parallel, we observed a change in phenotypic variance for seven traits while eight traits, including yield, showed no change. Of the seven traits that showed a change in variance, five showed a reduction, one increased, and one was variable. There were significant correlations among most of the traits, most likely due to simultaneous selection. A principal component analysis explaining 58.1% of the variation showed differentiation of the most recent breeding lines from the breeding program founders. Retrospective analysis of changes in genetic gain and phenotypic variance can be useful in designing strategies to manage genetic variation for target traits in breeding programs.
Genomewide Selection and Marker‐Assisted Recurrent Selection in Doubled Haploid versus F2 Populations
Authors: Mayor Patricio J. , Bernardo Rex 
Published: August 2009

ABSTRACTMolecular markers have been previously found useful for increasing genetic gain in maize (Zea mays L.). The use of doubled haploids (DHs) instead of F2 plants (or, equivalently, F3 families) may permit a better estimation of marker–trait associations. Our objective was to determine the usefulness of DH versus F2 populations in marker‐assisted recurrent selection (MARS) and genomewide selection. We simulated testcrosses from a DH population and an F2 population from the same cross between two inbreds and studied genetic models defined by the number of quantitative trait loci (QTL) and trait heritability (H). Equal‐time comparisons of selection response were between Cycle 3 with an F2 population and Cycle 2 with a DH population. For the genetic model of 100 QTL, H = 0.20 and a population size of N = 100, the ratio of response to selection in DH versus F2 populations was RDH:F2 = 109% for genomewide selection and 128% for MARS. For the genetic model of 20 QTL, H = 0.80 and N = 100 these values decreased to 99% for genomewide selection and 109% for MARS. Although genomewide selection was superior to MARS for a given type of population, the advantage of using DH instead of F2 populations was greater in MARS than in genomewide selection. We concluded that DH populations are most useful in genomewide selection and MARS when many QTL control the trait, H is low, and N is small.
Chilling Effects during Maize Tassel Development and the Lack of Compensational Plasticity
Authors: Tranel Dean , Knapp Allen , Perdomo Antonio 
Published: August 2009

ABSTRACTStress during tassel formation can reduce tassel size and cause insufficient pollen production in seed production. When stresses affect plant development, component compensation for grain yield is known to occur in some crops. Tassel component compensation for pollen production has not been previously reported. Chilling was imposed on two dent maize (Zea mays L.) inbreds (103 and 113 relative maturity [RM]) at the initiation of tassel formation, a critical period for maximizing pollen production. The 103 RM inbred showed limited response to chilling stress. The 113 RM inbred produced 60% fewer branches resulting in 45% fewer spikelets and 43% fewer pollen grains per tassel when chilling was applied during branch meristem initiation. For the same inbred, 42% fewer spikelets and 29% fewer pollen grains per tassel were produced when chilling was applied during spikelet meristem initiation. Chilling stress during meiosis of microsporogenesis did not decrease pollen production per anther. A decrease in the percentage of starch‐filled pollen grains was found only in the lower florets on the lowest branch. The effect of decreased branch or spikelet production on total pollen production was not compensated by subsequent production of spikelets, florets, anthers, or pollen grains per anther. Susceptibility of pollen production to chilling stress during tassel formation varies among modern dent inbreds, although plasticity in the tassel for pollen yield was not observed.
Development and Characterization of Large‐Scale Simple Sequence Repeats in Jute
Authors: Mir Reyazul R. , Banerjee Sumana , Das Moumita , Gupta Vikrant , Tyagi Akhilesh K. , Sinha Mohit K. , Balyan Harindra S. , Gupta Pushpendra K. 
Published: August 2009

ABSTRACTJute is an important crop of the Indian subcontinent and comprises tossa jute (Corchorus olitorius) and white jute (C. capsularis). The yield and fiber quality of this crop remained stagnant for many years and could not be improved through conventional plant breeding. Also, no effort has been made to develop molecular markers on a scale required for marker‐assisted selection (MAS) to supplement conventional plant breeding. As a first step toward deploying MAS for jute improvement, 2469 simple sequence repeats (SSRs) were developed in tossa jute (JRO 524) using four SSR‐enriched genomic libraries. A random subset of 100 SSRs (25 SSRs from each library) was used to detect polymorphism between the parental genotypes of each of the two recombinant inbred line (RIL) mapping populations. The RILs are being developed from JRO 524 × PPO4 (for fiber fineness) and JRC 321 × CMU 010 (for lignin content) crosses to prepare molecular maps and conduct quantitative trait loci (QTL) analyses. Both SSR length polymorphism and ± polymorphism (null alleles, i.e., presence and absence of specific SSR) were detected; 50 SSRs detected polymorphism between the two genotypes of tossa jute, whereas 45 SSRs detected polymorphism between the two genotypes of white jute. This SSR allelic polymorphism in jute is higher than that reported in other crops and is adequate for construction of genetic maps for QTL analysis. The large‐scale SSRs will also prove useful in studying genetic diversity, population structure, and association mapping.
Investigation on Cross‐Compatibility Barriers in the Biofuel Crop Jatropha curcas L. with Wild Jatropha Species
Authors: Kumar R. Senthil , Parthiban K. T. , Hemalatha P. , Kalaiselvi T. , Rao M. Govinda 
Published: August 2009

ABSTRACTInterspecific hybridization in Jatropha species plays a significant role in crop improvement by transferring useful traits such as yield, high oil content, maximum number of seeds, more femaleness, and hard stems for promoting Jatropha as a biofuel crop. The wide crosses among the species resulted in limited success due to pollen incompatability. Hence, the objective of the study was to assess pre‐ and postzygotic barriers through pollen–pistil interaction between cultivated Jatropha curcas and other three wild Jatropha species. In this study, the cross J. curcas × J. gossypifolia, even though the pollen tubes reached ovaries after pollination, failed to produce seeds, and the cross between J. curcas × J. podagrica indicated incompatibility signs of bulged pollen tubes coupled with reverse direction of pollen tube growth. The interspecific cross of J. curcas with J. villosa showed crossability barriers of crinkled and twisted growth pattern of pollen tubes and failed to reach ovary. In the case of selfing (J. curcas × J. curcas), pollen tubes reached ovary within an hour and produced normal seeds. Reciprocal crosses of these species exhibited successful fertilization of pollen tubes, but seed set was very low or no seed set was noticed.