Genome-wide association mapping in winter barley for grain yield and culm cell wall polymer content using the high-throughput CoMPP technique

<div><p>A collection of 112 winter barley varieties (<i>Hordeum vulgare</i> L.) was grown in the field for two years (2008/09 and 2009/10) in northern Italy and grain and straw yields recorded. In the first year of the trial, a severe attack of barley yellow mosaic virus (BaYMV) strongly influenced final performances with an average reduction of ~ 50% for grain and straw harvested in comparison to the second year. The genetic determination (GD) for grain yield was 0.49 and 0.70, for the two years respectively, and for straw yield GD was low in 2009 (0.09) and higher in 2010 (0.29). Cell wall polymers in culms were quantified by means of the monoclonal antibodies LM6, LM11, JIM13 and BS-400-3 and the carbohydrate-binding module CBM3a using the high-throughput CoMPP technique. Of these, LM6, which detects arabinan components, showed a relatively high GD in both years and a significantly negative correlation with grain yield (GYLD). Overall, heritability (<i>H</i>^<i>2</i>) was calculated for GYLD, LM6 and JIM and resulted to be 0.42, 0.32 and 0.20, respectively. A total of 4,976 SNPs from the 9K iSelect array were used in the study for the analysis of population structure, linkage disequilibrium (LD) and genome-wide association study (GWAS). Marker-trait associations (MTA) were analyzed for grain yield and cell wall determination by LM6 and JIM13 as these were the traits showing significant correlations between the years. A single QTL for GYLD containing three MTAs was found on chromosome 3H located close to the Hv-eIF4E gene, which is known to regulate resistance to BaYMV. Subsequently the QTL was shown to be tightly linked to rym4, a locus for resistance to the virus. GWAs on arabinans quantified by LM6 resulted in the identification of major QTLs closely located on 3H and hypotheses regarding putative candidate genes were formulated through the study of gene expression levels based on bioinformatics tools.</p></div

Effect of Deficit Irrigation on Yield and Water Use Efficiency of Maize at Selekleka District, Ethiopia

Irrigation water availability is diminishing in many areas of the Ethiopian regions, which require many irrigators to consider deficit-irrigation strategy. This study investigated the response of maize (Zea mays L.) to moisture deficit under conventional, alternate and fixed furrow irrigation systems combined with three irrigation amounts over a two years period. The field experiment was conducted at Selekleka Agricultural Research Farm of Shire-Maitsebri Agricultural Research Center. A randomized complete block design (RCBD) with three replications was used. Irrigation depth was monitored using a calibrated 2-inch throat Parshall flume. The effects of the treatments were evaluated in terms of grain yield, dry above-ground biomass, plant height, cob length and water use efficiency. The two years combined result indicated that &nbsp;net irrigation water applied in alternate furrow irrigation with full amount irrigation depth (100% ETc AFI) treatments was half (3773.5 m3/ha) than that of applied to the conventional furrow with full irrigation amount (CFI with 100% ETc) treatments (7546.9 m3/ha). Despite the very significant reduction in irrigation water used with alternate furrow irrigation (AFI), there was insignificant grain yield reduction in maize(8.31%) as compared to control treatment (CFI with100% ETc). In addition, we also obtained significantly (p&lt;0.001) higher crop water use efficiency of 1.889 kg/m3 in alternate furrow irrigation (AFI), than that was obtained as 0.988 kg/m3 in conventional furrow irrigation (CFI). In view of the results, alternate furrow irrigation method (AFI) is taken as promising for conservation of water (3773.5 m3/ha), time (23:22\u2750" hours/ha), labor (217.36 USD/ha) and fuel (303.79 USD/ha) for users diverting water from the source to their fields using pump without significant trade-off in yield

Comparison of screening techniques for traits relating to drought tolerance in grain sorghum

Call number: LD2668 .T4 AGRN 1987 M34Master of ScienceAgronom

Recovery of spinning satellites

The behavior of a space tug and a spinning satellite in a coupled configuration was simulated and analyzed. A docking concept was developed to investigate the requirements pertaining to the design of a docking interface. Sensing techniques and control requirements for the chase vehicle were studied to assess the feasibility of an automatic docking. The effects of nutation dampers and liquid propellant slosh motion upon the docking transient were investigated

An approach to Mel'nikov theory in celestial mechanics

Using a completely analytic procedure - based on a suitable extension of a classical method - we discuss an approach to the Poincar\'e-Mel'nikov theory, which can be conveniently applied also to the case of non-hyperbolic critical points, and even if the critical point is located at the infinity. In this paper, we concentrate our attention on the latter case, and precisely on problems described by Kepler-like potentials in one or two degrees of freedom, in the presence of general time-dependent perturbations. We show that the appearance of chaos (possibly including Arnol'd diffusion) can be proved quite easily and in a direct way, without resorting to singular coordinate transformations, such as the McGehee or blowing-up transformations. Natural examples are provided by the classical Gyld\'en problem, originally proposed in celestial mechanics, but also of interest in different fields, and by the general 3-body problem in classical mechanics.Comment: LaTeX, no figure

Final Report for the Period 1 July 1952 to 15 September 1953

Wright Air Force Development Center. United States Air Force.Contract AF 33(616)-170Expenditure Order No. R 449-37 AW-

Evaluating Traits Influencing Hybrid Wheat Seed Production Using a Double Haploid Population Derived from Freeman x Camelot

Hybrid wheat (Triticum aestivum L.) cultivars are preferred for their advanced agronomic traits such as a yield improvement increase up to 20%. However, hybrid cultivars remain difficult to produce on a commercial scale due to inadequate pollen dispersal, the closed nature of the wheat floret and the high cost of inducing sterility or restoring fertility in cleistogamous wheat. Redesigning parent-specific traits and understanding their potential interactions with related agronomic traits are needed to breed improved male lines in hybrid seed production fields. To better understand the genetic control of anther extrusion (AE), 174 double haploid lines derived from Freeman (excellent AE) x Camelot (poor AE) were visually assessed in three different environments in 2020 and 2021. Genotypic differences within the DH population were found in 2021. The best linear unbiased estimators found approximately normal distributions with low (AD, PH), moderate (GYLD), and high (AE, LODG) coefficient of variations. Pearson’s correlation coefficient results revealed a significant negative correlation (r=-0.39**) between AE and lodging (LOGD). Moderately high broad sense repeatability was calculated (0.66) for AE and other traits in DH population. The contribution of PC1 and PC2 to the total variance were 45.6% and 27.3% respectively and combined explained approximately 70% of the total variance observed in PCA analysis. Advisors: P. Stephen Baenziger and Katherine Frel