Drought tolerance variability in S<Subscript>1</Subscript> pollinator lines developed from a sugar beet open population

Drought tolerance is one of the most important objectives of sugar beet breeding programs in semi-arid regions, particularly during the last decade. Due to global climate changes and limitations of agricultural irrigation water, varieties with drought tolerance are taken into consideration in order to avoid yield losses due to drought. In this study, drought tolerance of 76 S₁ lines (full-sib families) that had been extracted from a genetically broad base multigerm sugar beet open pollinated population, were examined. Test crosses were made between the lines as pollinators and a cytoplasmic male sterile (CMS) single cross. The consequent hybrids along with checks were evaluated during 2007 and 23 more tolerant hybrids during 2008, in two adjacent experiments under drought stress and non-stress conditions. Drought tolerance indices calculated based on sugar yield, such as mean productivity (MP), geometric mean productivity (GMP) and stress tolerance index (STI) were used to assess hybrids responses to drought. The results showed significant genetic differences for root yield and sugar yield under both conditions. Drought tolerance indices displayed significant genetic variability for sugar yield among the hybrids. Many hybrids were drought tolerant as compared with the original base population as indicated by their high STI. The estimates of heritability for sugar yield in stress and non-stress conditions were much close to each other (0.31 and 0.34, respectively). Whereas, for root yield the heritability estimate in stress condition (0.46) was relatively higher than that in non-stress condition (0.34). Significant differences were observed among the selected hybrids for root yield and sugar yield, indicating genotypic variability for pollinator lines derived from the population. There were no significant differences for sugar content. For increasing the drought tolerance potential in a breeding population and developing drought-tolerant varieties by male parent, the drought-tolerant lines could be used.     

Predicting performance of broiler chickens from dietary nutrients using group method of data handling-type neural networks

1. Successful artificial neural network (ANN) applications have been found for many areas. One sub-model of ANNs is the group method of data handling-type neural networks (GMDH-type NNs). The use of self-organising networks leads to successful application in a broad range of areas. However, the use of such methods is not common in poultry science. 2. Broiler chicken nutrition is recognised as a biological system consisting of a complex set of interconnected variables. The adequate information on nutrients (variables), such as metabolisable energy (ME) and amino acid requirements, can help to establish specific feeding programmes, defining optimal performance and reducing production costs. 3. This study addressed the question of whether GMDH-type NNs can be used to estimate the performance of broiler chickens (output) based on specified variables-inputs (dietary crude protein (CP), ME, ME/CP, methionine (Met), lysine (Lys), ME/Met and ME/Lys)-for a commercial broiler chicken farm. The recorded data from 10 broiler chicken flocks were obtained, from March 2003 to April 2005, corresponding to 52 data lines. 4. The results suggested that the GMDH-type NNs may provide an effective means of recognising the patterns in data and accurately predicting the performance of broiler chickens based on investigating inputs. In addition the polynomial equations obtained can be used to optimise the performance of broilers.     

Evaluating two multistrain probiotics on growth performance,intestinal morphology,lipid oxidation and ileal microflora in chickens

An experiment was conducted to investigate the supplementation of two commercially available multistrain probiotics as an alternative to antibiotics on growth performance, intestinal morphology, lipid oxidation and ileal microflora in broiler chickens. A total of 280‐day‐old ROSS 308 mixed‐sex broiler chickens with an average initial body weight of 42 ± 0.5 g were randomly divided into four treatments with five replicate cages of 14 birds each cage in a completely randomized design and fed with the following diets for 42 day: (a) control (CON) (antibiotic‐free diet), (b) antibiotic (ANT) (CON + Avilamycin 150 g/ton feed), (c) probiotic A (CON + Protexin^® 150 g/ton feed) and (d) probiotic B (CON + Bio‐Poul^® 200 g/ton feed). The results showed the broilers fed the ANT diet had greater average daily gain than broilers fed the CON diet during day 1–14 (p < 0.05). At day 42, two birds were randomly selected per replicate for evaluation intestinal morphology, lipid oxidation and ileal microflora. birds fed diet supplemented with probiotic A and probiotic B increased villus height and goblet cells numbers in the jejunum and villus height to crypt depth ratio and villus height in the ileum as compared to birds fed CON diet (p < 0.05). The malondialdehyde value was reduced (p < 0.05) in the ANT, probiotic B and probiotic A groups compared with the CON group. The Lactobacillus population was increased and Clostridium spp. population decreased in the ileum of broilers fed diets containing the probiotic B and probiotic A compared with those fed CON diet (p < 0.05). The results from this study indicate that the probiotic A (Protexin^®) and probiotic B (Bio‐Poul^®) used in this trial may serve as alternatives to ANT.     

Evaluation of kernel yield and agronomic traits of European maize hybrids in the temperate region of Iran

The production of locally adapted maize hybrids requires parental material with adequate genetic variation in the relevant traits. The objective of the present study was to evaluate 20 European maize hybrids under temperate region for their potential use in direct cultivation or as parent material in local breeding programs. Results showed that European hybrids except BC 566 had higher kernel yield (11.4–14.3 t ha^?1) than local cultivars (KSC705 and KSC704). Korimbos, Krebs, BC 566, and BC 532 had lower kernel moisture (14–15%) compared to KSC705 (21.7%) and KSC704 (22.7%). Cluster analysis categorized these hybrids in three groups. Cluster 2 comprised of Korimbos, BC 612, DKC 6589, and 89May70. These hybrids had high plant height, thousand kernel weight, and kernel yield. Due to high kernel moisture, the hybrid 89May70 could not be proposed for direct cultivation but it can be involved in transferring high grain yield to local hybrids. Genotype × environment analysis showed that Korimbos and Krebs had low S²_i and low genotypic coefficient of variation, high and stable performance and low kernel moisture. Therefore, Korimbos and Krebs can possibly be used for direct cultivation in temperate regions of the Fars Province.     

Schwannoma of the External Auditory Canal in a Filly: A Case Report

Schwannomas of the external auditory canal (EAC) are exceedingly rare in human beings and domestic animals. Herein we describe the clinicopathological and immunohistochemical features of a benign schwannoma arising in the EAC of a 2.5-year-old filly. Microscopically, the mass showed a spindle cell tumor composed of hypocellular Antoni type B areas as a myxomatous arrangement of mesenchymal cells and hypercellular Antoni type A areas displaying short fascicles of densely packed neoplastic cells in the collagenous stroma. Immunohistochemically, the tumor cells were diffusely positive for S100 protein and vimentin but negative for Ki67. It was concluded that schwannomas should be included in the differential diagnosis of EAC masses, and immunohistochemical markers such as S100 protein can strongly help in differentiating this tumor from other spindle cell tumors.     

Geostatistical analysis of sorptivity for a soil under tilled and no-tilled conditions

The properties of soils, even in short distances differ from point to point. These spatial variabilities may be described by geostatistics. This method determines the spatial structure of a specified variable. In this study, we measured the sorptivity of soil in field under tilled and no-tilled conditions with different sampling distances by using a simple method and performed the geostatistical analysis on the obtained data. The measurements were done on the corners of a regular network having dimensions of 5 m × 5 m in a tilled and no-tilled soil, and 0.5 m × 0.5 m in the same tilled soil. The results revealed that sorptivity had spatial structure in a tilled soil with 0.5 m × 0.5 m grid distances and no spatial structure occured in 5 m × 5 m distances, so it was believed that sorptivity is a structural variable only for short distance. The range of variogram was between 3.09 and 3.42 m for the sorptivity with 0.5 m × 0.5 m grids. The spherical model was the best-fitted theoretical variogram. In addition to the simple method for sorptivity measurement, we measured the sorptivity using double rings, which is known as Talsma method. Statistical tests showed a significant and non-significant difference between the two methods in 5 m × 5 m and 0.5 m × 0.5 m grids, respectively. In the simple method for sorptivity measurement, a ring with 10 cm height, 10 cm diameter, and about 2 cm depth of water was applied, but the rings used in the Talsma method were about three to four times larger. Therefore, it is concluded that for short distances, the sorptivity of simple method is in accordance with that obtained in Talsma method. The kriging method was used to estimate the presumed unknown values of sorptivity in some locations in the 0.5 m × 0.5 m grid distances. Results revealed that kriging method is capable enough to estimate the sorptivity if the variable has a spatial structure.     

Root Nitrogen Remobilization and Ion Status of Two Alfalfa (Medicago sativa L.) Cultivars in Response to Salinity Stress

In a pot experiment the responses of two alfalfa cultivars differing in salt tolerance were evaluated in terms of root nitrogen remobilization rates (RNRR) and their relationship with the ionic status of the plants. A split‐plot design with factorial treatments in three replications was used. Three levels of salinity stress with electrical conductivities (EC_s) of 1.2, 7 and 12 ds m^?1 were established in irrigation water by using tap water with and without NaCl. The average data taken from plant materials at three defoliations were used for statistical analysis. Each time, plant materials were harvested at the 10 % flowering stage and then 10 days later. From the results observed, it was found that alfalfa shoot growth is highly dependent on RNRR under salinity stress. However, the total N reserves within the roots do not appear to be a limiting factor. The high positive correlation coefficient between shoot K⁺/Na⁺ and RNRR (r = 0.77; P = 0.01) indicates that lower demands for N because of diminished metabolic activities within the shoot sink may have reduced the rates of root N utilization. Unlike in some other species, the shoot K⁺ concentration and contents of alfalfa plants were significantly reduced by increasing salt stress. However, a relatively suitable K⁺/Na⁺ ratio of 7.1 is maintained in the shoots at the second level of salinity, as lowering the rates of salt induced an increase in Na⁺ uptake (Na exclusion). The salt tolerance recognized in the Bami cultivar may be attributed to the 339 % increase in its selectivity rates of K⁺ over Na⁺ in ion transport from the soil to the shoots, as the shoot Na⁺ content did not increase with increasing salt levels.     

A major quantitative trait locus for rice yellow mottle virus resistance maps to a cluster of blast resistance genes on chromosome 12

ABSTRACT Two doubled-haploid rice populations, IR64/Azucena and IRAT177/ Apura, were used to identify markers linked to rice yellow mottle virus (RYMV) resistance using core restriction fragment length polymorphism (RFLP) maps. Resistance was measured by mechanical inoculation of 19-day-old seedlings followed by assessment of virus content by enzyme-linked immunosorbent assay tests 15 days after inoculation. IR64/Azucena and IRAT177/Apura populations, 72 and 43 lines, respectively, were evaluated, and resistance was found to be polygenic. Resistance was expressed as a slower virus multiplication, low symptom expression, and limited yield loss when assessed at the field level. Bulked segregant analysis using the IR64/Azucena population identified a single random amplified polymorphic DNA marker that mapped on chromosome 12 and corresponded to a major quantitative trait locus (QTL) evidenced by interval mapping. When pooling RFLP data, integrated mapping of this chromosome revealed that the QTL was common to the two populations and corresponded to a small chromosomal segment known to contain a cluster of major blast resistance genes. This region of the genome also reflected the differentiation observed at the RFLP level between the subspecies indica and japonica of Oryza sativa. This is consistent with the observation that most sources of RYMV resistance used in rice breeding are found in upland rice varieties that typically belong to the japonica subspecies.