The study was conducted at the University of Baghdad (Aljadiria) by taking samples from three sites (water environments) per week, which are the stagnant water environment (Site A), the water table (Site B) and the water basin (Site C) for the purpose of studying the population density of mosquitoes and their accompanying predators. The results showed that the population density of mosquito larvae was the highest in the stagnant water environment (Site A), followed by the water table (Site B), and then the water basin (Site C). As for predators, the results indicated that small water bugs were more present in site A and in large numbers, followed by small tremors, then Gambusia fish, while large tremors and large water bugs were relatively few. It was found that using clove extract (Syzygium aromaticum) reduced mosquito larvae by 100%, at highest concentrations 10 and15% , the mortality was 100% after 2 hours. Plus, it was found that apple of sodom extract (Calotrpis procera) affected the second and fourth instars less than cloves extract. The lantana extract (Lantana camara) was the least effective extract against mosquito larvae.

The impact of increasing resistance of mosquitoes to conventional pesticides has led to investigate various unique tools and pest control strategies. Herein, we assessed the potency of flupyradifurone, a novel pesticide, on fourth instar larvae of Culex quinquefasciatus Say. Further, we evaluated the synergistic action of piperonyl butoxide (PBO) and the octopamine receptor agonists (OR agonists) chlordimeform (CDM) and amitraz (AMZ) on the toxicity of flupyradifurone in comparison with sulfoxaflor and nitenpyram to increase their toxicity on Cx. quinquefasciatus. Results demonstrated that flupyradifurone was the most potent pesticide followed by sulfoxaflor and nitenpyram. Further, the synergetic effect of PBO, CDM, and AMZ was significant for all selected pesticides especially flupyradifurone. However, AMZ had the most significant effect in combination with the selected pesticides followed by CDM and PBO. The toxicity of the pesticides was time-dependent and increased over time from 24, 48, to 72 h of exposure in all experiments. The results indicate that flupyradifurone is a promising component in future mosquito control programs.

Flowering time is an important agronomic trait that determines the distribution and adaptation of plants. The accurate prediction of flowering time in elite germplasm is very critical for maize breeding. However, the molecular mechanisms underlying photoperiod response remain elusive in maize. Here we cloned the flowering time controlling gene, ZmNF-YC2, by map-based cloning and confirmed that ZmNF-YC2 is the protein of nuclear transcription factor Y subunit C-2 and a positive regulator of flowering time in maize under long-day conditions. Our results show that ZmNF-YC2 promotes the expression of ZmNF-YA3. ZmNF-YA3 negatively regulates the transcription of ZmAP2. ZmAP2 suppresses the expression of ZMM4 to delay flowering time. Then we developed a gene regulatory model of flowering time in maize using ZmNF-YC2, ZmNF-YA3, ZmAP2, ZMM4 and other key genes. The cascading regulation of …

Soil flooding severely impairs agricultural crop production. Plants can cope with flooding conditions by embracing an orchestrated set of morphological adaptations and physiological adjustments that are regulated by the elaborated hormonal signaling network. The most prominent of these hormones is ethylene, which has been firmly established as a critical signal in flooding tolerance. ABA (abscisic acid) is also known as a “stress hormone” that modulates various responses to abiotic stresses; however, its role in flooding tolerance remains much less established. Here, we discuss the progress made in the elucidation of morphological adaptations regulated by ABA and its crosstalk with other phytohormones under flooding conditions in model plants and agriculturally important crops.

Fertilization with high levels of phosphorus increases the risk of environmental pollution. Identification of critical values of P in soil (SOP) and in plant tissues (PiP) is essential for achieving the maximum wheat yield without P loss. The critical value is the value of P which gives the optimum yield; the response of crop yield to P fertilization above this value is not predictable or nil. Here, a 4-year field experiment was conducted to identify the SOP and PiP for achieving maximum yield of bread wheat using 11 rates of P fertilization (0, 15, 30, 45, 60, 75, 90, 105, 120, 135, and 150 kg P2O5 ha-1). The linear–linear and Mitscherlich exponential models were employed to estimate the PiP and SOP. The degree of phosphorus saturation (DPS) was used to assess the potential environmental risk; furthermore, phosphorus use efficiency (PUE)was also calculated under the studied fertilization levels. Phosphorus in soil and wheat plant was affected by the application rates and growing seasons. Increasing P fertilization rates led to gradual increases in soil and plant P. The SOP ranged between 21 and 32 mg kg?1, while the PiP ranged between 6.40 and 7.49 g kg?1. The critical values of P calculated from the Mitscherlich exponential models were 20% higher than those calculated from the linear–linear models. Adding levels of P fertilization 90 kg P2O5 ha?1 leads to higher potentials of P runoff and leaching, in addition, PUE decreased sharply under high P fertilization levels. The response of wheat yield to P fertilization in sandy calcareous soil is predictable below Olsen P values of 21 mg kg?1. Identification of critical P values for wheat production is of great importance to help policy makers improve P use efficiency and attain optimum wheat yield under eco-friendly environmental conditions by eliminating the accumulation of excess P fertilizers in soil and water.

Soil salinity is one of the constraints of crop production in Egypt. The aims of this study were to identify genomic regions associated with grain weight and its related traits along with their salinity tolerance indices and to identify the most salinity tolerant and high-yielding genotypes. Therefore, we evaluated an advanced backcross mapping population of barley in newly reclaimed soil under two salinity levels of groundwater aquifers in South of Sinai, Egypt. We detected significant QTL associated with grain weight related attributes and the salinity tolerance index (STI) distributed throughout the whole genome of barley, which can be used to enhance salinity tolerance. Moreover, the markers bPb-3739 (4H, 96.3 cM), AF043094A (5H, 156 cM), bPb-8161 (7H, 2.22 cM), and bPb-5260 (7H, 115.6 cM), were the most important identified genomic regions corresponding to vernalization, dwarfing and dehydrin genes, which are correlated with salinity tolerance. Additionally, the doubled haploid lines SI001, SI043, SI044, SI028, SI242, SI035, and SI005 had the highest STI values based on yield average. The present study demonstrated that wild and elite barley do harbor novel valuable alleles, which can enrich the genetic basis of cultivated barley and improve quantitative agronomic traits under salinity conditions.

Twenty-one cultivars of bread wheat were evaluated for drought-stress tolerance at seedling ‎and maturity stages under non-drought and drought-stress conditions. Significant differences among ‎genotypes were obtained under non-drought and drought-stress conditions for all seedling and ‎maturity characteristics. Highly positive and significant correlations were found for root length with ‎respect to fresh weight of 0.74 and dry weight seedling of 0.80. However, negative and highly ‎significant correlations were found for both drought susceptible index based on seedling traits ‎‎(DSIST) and maturity traits (DSIST) with all seedling traits except root: shoot ratio, whereas no ‎correlations were obtained for either DSIST or DSIMT with all maturity traits except 1000 kernel ‎weight. Positive and highly significant correlation found between DSIST and DSIMT (0.85). SSR ‎markers analysis showed that three bands produced by Xgwm596-7A (507 bp), Xgwm497-1A (556 ‎bp) and Xgwm174-5D (409 bp), they were presented in all tolerant genotypes based on DSIST. The ‎three bands (507, 556 and 409 bp) were correlated to DSIST, with R2 values of 81.05%, whereas the ‎three bands were correlated to DSIMT with R2 values of 61.96%. Strong association was observed for ‎genotypic distance with phenotypic distance based on seedling characteristics, that amounted to ‎‎0.66, whereas the correlation was less strong between genotypic distance and phenotypic distance ‎based on maturity traits by 0.30. The seedling traits at 15% PEG were more association than maturity ‎traits under drought-stress with SSR markers, this gives preference to using seedling traits as an indicator of drought-stress tolerance in breeding programs.