Genome-wide QTL analysis for pre-harvest sprouting tolerance in bread wheat

A framework linkage map comprising 214 molecular marker (SSR, AFLP, SAMPL) loci was prepared using an intervarietal recombinant inbred line (RIL) mapping population of bread wheat. The RIL population that was developed from the cross SPR8198 (red-grained and PHS tolerant genotype) × HD2329 (white-grained and PHS susceptible genotype) following single seed descent segregated for pre-harvest sprouting (PHS). The RIL population and parental genotypes were evaluated in six different environments and the data on PHS were collected. Using the linkage map and PHS data, genome-wide single-locus and two-locus QTL analyses were conducted for PHS tolerance (PHST). Single-locus analysis following composite interval mapping (CIM) detected a total of seven QTL, located on specific arms of five different chromosome (1AS, 2AL, 2DL, 3AL and 3BL). These seven QTL included two major QTL one each on 2AL and 3AL. Two of these seven QTL were also detected following two-locus analysis, which resolved a total of four main-effect QTL (M-QTL), and 12 epistatic QTL (E-QTL), the latter involved in 7 QTL × QTL interactions. Interestingly, none of these M-QTL and E-QTL detected by two-locus analysis was involved in Q × E and Q × Q × E interactions, supporting the results of ANOVA, where genotype × environment interaction were non-significant. The QTL for PHS detected in the present study may be efficiently utilized for marker-aided selection for enhancing PHST in bread wheat.     

Application of biocementation technique using Bacillus sphaericus for stabilization of soil surface and dust storm control

Dust emission and wind erosion are widespread phenomena in arid and semi-arid regions, which have far-reaching harmful effects to the environment. This study aimed to use microbial induced carbonate precipitation (MICP) method with Bacillus sphaericus to reduce soil losses that occur in a dust-producing area due to wind erosion in the Ilam Province, Iran. Soil samples at the 0-30 cm depth were used and sterilized in an autoclave for 2 h at 121°C and 103 kPa. Approximately 3 kg soils were weighed and poured in the 35 cm×35 cm×3 cm trays. Different treatments included two levels of B. sphaericus (0.0 and 0.5 OD), three levels of suspension volume (123, 264, and 369 mL), two levels of urea-chloride cementation solution (0.0 and 0.5 M), and two levels of bacterial spray (once and twice spray). After 28 d, soil properties such as soil mass loss, penetration resistance, and aggregate stability were measured. The results showed a low soil mass loss (1 g) in F₁₄ formulation (twice bacterial spray+264 mL suspension volume+without cementation solution) and a high soil mass loss (246 g) in F₅ formulation (without bacteria+264 mL suspension volume+0.5 M cementation solution). The highest (42.55%) and the lowest (19.47%) aggregate stabilities were observed in F₁₆ and F₇ formulations, respectively, and the highest penetration resistance (3.328 kg/cm²) was observed in F₁₈ formulation. According to the final results, we recommended the formulation with twice bacterial spray, 0.5 M cementation solution, and 269 mL suspension volume as the best combination for soil surface stabilization. Furthermore, this method is environmentally friendly because it has no adverse effects on soil, water, and plants, thus, it would be an efficient approach to stabilize soil surface.     

Oxidative damage in forage rape (Brassica napus L.) seeds following heat stress during seed development

A short period (240°C hr; Tb = 25°C) of heat stress (30°C day/25°C night) during forage rape (Brassica napus L.) seed development or at seed physiological maturity can reduce seed vigour, but the extent of oxidative damage associated with this short heat stress was not known. Heat-stressed seeds were assessed for malondialdehyde (MDA) content, hydrogen peroxide (H₂O₂) accumulation, antioxidant enzyme activity, adenylate energy charge and seed ultrastructural integrity, and compared with that of non-heat-stressed seeds. Heat stress increased both MDA content and H₂O₂ accumulation by 35%–50%, reduced antioxidant enzyme activity by between 12% and 67%, and significantly reduced adenosine energy charge. Transmission electron microscope images showed clear evidence of seed deterioration in heat-stressed seeds, including ruptures in cell wall and plasma membranes, fused lipid bodies and damaged mitochondria. Heat stress at physiological maturity caused more oxidative damage than the same heat stress during seed development. Seed vigour decreased as H₂O₂ accumulation increased and antioxidant enzyme activity decreased, but no direct relationship between lipid peroxidation and seed vigour was established. The extent of damage resulting from even shorter periods of heat stress (<240°C hr) before or at seed physiological maturity requires investigation.     

Nursery performance of Pacific white shrimp (Litopenaeus vannamei Boone, 1931) cultivated in a biofloc system: the effect of adding different carbon sources

Effect of different carbon sources on nursery performance of Pacific white shrimp (Litopenaeus vannamei) cultivated in biofloc system was investigated. Shrimp postlarvae (98.47 ± 8.6 mg) were fed for 32 days in tanks with water volume of 130 L and density of 1 individual L^?1. One control treatment and four biofloc treatments (BFT1, BFT2, BFT3 and BFT4) with adding different carbon sources including molasses, starch, wheat flour and mixture of them, respectively, were considered at equal weight ratios. According to the results, salinity, dissolved oxygen and pH were not significantly different among the biofloc treatments (P > 0.05). Maximum pH (8.27) and maximum dissolved oxygen (6.35 mg L^?1) were recorded in the control. Maximum (0.43 mg L^?1) and minimum (0.09 mg L^?1) ammonia were recorded in the control and BFT2, respectively (P < 0.05). Using simple carbohydrates (molasses and starch) lowered the ammonia concentration significantly. The highest increase in body weight (1640.43 ± 231.28 mg), growth rate, specific growth rate (8.97 ± 0.42% per day) and biomass (190.29 ± 26.83 mg) were found in BFT1 and the highest survival (90 ± 0.77%) was found in BFT4. The highest feed conversion (1.52 ± 0.23) and the lowest feed efficiency (66.81 ± 7.95) were observed in the control (P < 0.05). The proximate composition analysis revealed an increase in lipid and ash in biofloc treatments. Results indicated that using biofloc technology with zero‐water exchange system and adding carbon sources could help to recycle waste and improve the water quality. Moreover, the type of carbonaceous organic matter as a substrate for heterotrophic bacteria would be effective in degradation and metabolization of ammonia and nitrite.     

Effects of salt and nitrogen on physiological indices and carbon isotope discrimination of wheat cultivars in the northeast of Iran

In order to study the effects of different levels of salt stress and nitrogen(N) on physiological mechanisms,carbon isotope discrimination(△~(13)C),and yield of two wheat cultivars(cv.),a two-year field experiment was carried out during 2013-2015.The treatments included three levels of salt stress(1.3,5.2,and 10.5 dS m~(-1)),three levels of N(50,100,and 150 kg N ha~(-1)),and two wheat cultivars,Bam and Toos.Under salt stress,N application(100 and 150 kg N ha~(-1)) produced a significant effect on both cultivars with respect to physiological traits,i.e.,net photosynthetic rate(P_n),stomatal conductance(g_s),chlorophyll index(Cl),Na~+/K~+ratio as well as the grain yield(GY).The salt-tolerant and-sensitive cultivars exhibited the maximum values of physio-biochemical and yield attributes at 100 and 150 kg N ha~(-1),respectively.The results of △~(13)C showed a significant difference(P0.001) between wheat cultivars under the control and salt stress.According to our result,salt-tolerant cultivar Bam seems to be more efficient in terms of higher GY,P_n,g_s,Cl,and lower Na~+/K~+ratio as well as higher △~(13)C as compared with salt-sensitive cultivar Toos,under salt stress.Therefore,a significant positive correlation that observed between △~(13)C and GY,indicated that △~(13)C may be an effective index for indirect selection of yield potential in wheat under irrigation regimes with saline water.     

Influence of Humic Substances and Nitrogen on Yield,Fruit Quality,and Leaf Mineral Elements of ‘Early Spur Rome’ Apple

The effects of humic substances (AgriPlus, Humi-Zyme, and Humic Acid 6%) and nitrogen (N) on growth, yield, quality, and leaf minerals in apple (Malus domestica Borkh.) were studied during 1997–2000. Trees receiving medium or high N tended to be larger than trees with other treatments in 2000. Trees receiving AgriPlus with high N had higher yield than untreated control trees in 1998. Trees receiving medium N had larger fruits than control trees. Fruits of trees receiving high N (alone) had less red color than the control. Soluble solids concentrations (SSC) in fruits of all treatments were higher than those of the control at harvest in 1999. Fruit from the untreated control and low Humi-Zyme tended to be firmer than that from other treatments. The untreated control and low Humi-Zyme trees had lower leaf N and manganese (Mn), but higher leaf potassium (K) than trees under most other treatments. Leaf iron (Fe) in trees receiving medium Humi-Zyme was higher than that in the untreated control in two years. AgriPlus-treated trees showed higher water retention in the root zone.     

Comparison of In Vivo and In Vitro assays for nitrate reductase activity determination in soybean tissues

Nitrate reductase (NR) activities of soybeans (Glycine max L. Merr. Cv. Altona), grown in sand with nutrient solution containing only nitrate as a nitrogen (N) source, were compared, using one in vivo and two in vitro assays. The in vivo assay was the most sensitive of the three, particularly in measuring root NR activity. NR activity was highest in the upper most expanded leaf and declined with leaf position lower in the canopy. NR activity in the lower 6 em sections of roots was more than double that of the upper 6 cm sections. Differences in NR activity at different stem positions were not detected by the three techniques.     

Multiorgan engraftment of human somatic cells in swine foetuses after intra-blastocyst transplantation

Adult human stem cells, mainly from hematopoietic lineage, have been injected into developing pre-immune animal foetuses, and xenogenic engraftment of liver and other organs has been reported. We isolated a rare cell population from adult human liver, fat and skin. Colonies with few cells became visible as early as 2-3 days, and a fully formed colony took 10-14 days to form. These colonies were named as liver-derived cell lines (LDCs), fat-derived cell lines (FDCs) and skin-derived cell lines (SDCs). All these cells express few pluripotency markers like Klf4, c-myc and Sox2. Pig blastocysts were injected with LDCs, FDCs and SDCs and transferred to recipient pigs. We achieved an overall pregnancy rate of 71.4% at day 35. The foetuses were analysed for human cell chimerism in liver, kidney and heart both by RT-PCR and real-time PCR using primers specific to human and pig mitochondrial DNA. The percentage of foetuses showing chimerism was 17.4% (4/23), 12.5% (2/16) and 11.1% (1/9) for LDCs, FDCs and SDCs, respectively. Of these, 42.9% (three out of seven) showed chimerism in liver and 71.4% (five out of seven) showed kidney chimerism. However, we did not detect any chimerism in the heart. The level of chimerism varied and was in the range of one human cell per one hundred thousand to one million pig cells.