Abstract Recently, the residues of some common and widely used herbicides (acetochlor, bispyribac-sodium, bentazon, bensulfuronmethyl, halosulfuron-methyl, and quinclorac) were detected in the surface water, soil, sediments, and fish tissues as the agricultural drainage problems. In this study, juveniles of Nile tilapia Oreochromis niloticus were exposed to sub-lethal concentrations of these herbicides as 2.625, 0.800, 36.00, 2.50, 1.275, and 11.250 mg/l for acetochlor, bispyribac-sodium, bentazon, bensulfuronmethyl, halosulfuron-methyl, and quinclorac respectively for 96 h. Some hemato-biochemical parameters were evaluated. In comparison with the control group, sub-lethal concentrations of all tested herbicides induced alterations in the shape of erythrocytes. Also, in all tested herbicides, hematological parameters of exposed fish exhibited a significant decrease in red blood cell count except bentazon. However, all tested herbicides showed an insignificant reduction in mean corpuscular hemoglobin concentration and total white blood cells except bensulfuron-methyl. For biochemical parameters, most tested herbicides induced a significant increase in levels of cholesterol, albumin, globulin, albumin/globulin ratio, activity of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total plasma protein (only with acetochlor), urea, and creatinine (except bentazon and halosulfuron-methyl that exhibited non-significant decrease in creatinine level) compared with the control. In conclusion, the fish blood profiles can be used as good biomarkers for laboratory study to assess the toxicity of the tested rice herbicides at a sub-acute level especially acetochlor on O. niloticus.

Abstract Recently, the residues of some common and widely used herbicides (acetochlor, bispyribac-sodium, bentazon, bensulfuronmethyl, halosulfuron-methyl, and quinclorac) were detected in the surface water, soil, sediments, and fish tissues as the agricultural drainage problems. In this study, juveniles of Nile tilapia Oreochromis niloticus were exposed to sub-lethal concentrations of these herbicides as 2.625, 0.800, 36.00, 2.50, 1.275, and 11.250 mg/l for acetochlor, bispyribac-sodium, bentazon, bensulfuronmethyl, halosulfuron-methyl, and quinclorac respectively for 96 h. Some hemato-biochemical parameters were evaluated. In comparison with the control group, sub-lethal concentrations of all tested herbicides induced alterations in the shape of erythrocytes. Also, in all tested herbicides, hematological parameters of exposed fish exhibited a significant decrease in red blood cell count except bentazon. However, all tested herbicides showed an insignificant reduction in mean corpuscular hemoglobin concentration and total white blood cells except bensulfuron-methyl. For biochemical parameters, most tested herbicides induced a significant increase in levels of cholesterol, albumin, globulin, albumin/globulin ratio, activity of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total plasma protein (only with acetochlor), urea, and creatinine (except bentazon and halosulfuron-methyl that exhibited non-significant decrease in creatinine level) compared with the control. In conclusion, the fish blood profiles can be used as good biomarkers for laboratory study to assess the toxicity of the tested rice herbicides at a sub-acute level especially acetochlor on O. niloticus.

Abstract Recently, the residues of some common and widely used herbicides (acetochlor, bispyribac-sodium, bentazon, bensulfuronmethyl, halosulfuron-methyl, and quinclorac) were detected in the surface water, soil, sediments, and fish tissues as the agricultural drainage problems. In this study, juveniles of Nile tilapia Oreochromis niloticus were exposed to sub-lethal concentrations of these herbicides as 2.625, 0.800, 36.00, 2.50, 1.275, and 11.250 mg/l for acetochlor, bispyribac-sodium, bentazon, bensulfuronmethyl, halosulfuron-methyl, and quinclorac respectively for 96 h. Some hemato-biochemical parameters were evaluated. In comparison with the control group, sub-lethal concentrations of all tested herbicides induced alterations in the shape of erythrocytes. Also, in all tested herbicides, hematological parameters of exposed fish exhibited a significant decrease in red blood cell count except bentazon. However, all tested herbicides showed an insignificant reduction in mean corpuscular hemoglobin concentration and total white blood cells except bensulfuron-methyl. For biochemical parameters, most tested herbicides induced a significant increase in levels of cholesterol, albumin, globulin, albumin/globulin ratio, activity of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total plasma protein (only with acetochlor), urea, and creatinine (except bentazon and halosulfuron-methyl that exhibited non-significant decrease in creatinine level) compared with the control. In conclusion, the fish blood profiles can be used as good biomarkers for laboratory study to assess the toxicity of the tested rice herbicides at a sub-acute level especially acetochlor on O. niloticus.

WHEAT (Triticum aestivum L.) is a vulnerable crop to heat stress. A set of 12 wheat genotypes were evaluated under timely and late sowing dates using physiological and yield traits during the two years of 2015/2016 and 2016/2017. Consequently, seven genotypes were used in a half-diallel mating system. The parents and their 21F1 hybrids were evaluated under timely and late sowing dates during 2018/2019. The results indicated that both chlorophyll absorbance at anthesis and flag leaf temperature depression at milk stage were strongly associated (r= 0.6; P0.001) with grain yield under heat stress induced by late sowing date. Therefore, using these traits is highly recommended screening tools for heat stress tolerance in wheat breeding programs. Significant differences were observed between the parental genotypes for their GCA and between their crosses for SCA for all traits under heat stress. The additive constituent of gene action was predominant. Among the seven parents, 1, 4, and 6 were the best general combiners for grain yield, 1000 grain weight, chlorophyll absorbance at anthesis, flag leaf temperature depression and canopy temperature depression at milk stage under heat stress. The best specific crosses for grain yield were 6×9, 6×11 and 1×4, for flag leaf temperature depression at milk stage were 6×11, 6×9 and 10×11 and for canopy temperature depression at milk stage were 4×6, 1×4 and 6×11 under heat stress. Taking advantage of both additive and non-additive components requires using bi-paternal and multi-parental mating approaches in wheat breeding programs targeted to develop heat-tolerant varieties.

Powdery mildew, leaf rust and net blotch are major biotic stresses that affect both the quality and quantity of the yield of barley. The current research was conducted at Sids Research Station during 2016/17 and 2017/18 growing seasons in Egypt. We aimed to identify the quantitative trait loci (QTL) and digenic epistatic interactions controlling the resistance to the aforementioned diseases in a doubled haploid population (S42) of barley derived from the cross between the exotic accession of H. vulgare ssp. spontaneum ‘’ISR42-8’’ and the German spring barley cultivar ‘’Scarlett’’ (H. vulgare ssp. vulgare). Results indicated that the wild parent is more resistant to the investigated diseases than the cultivated barley; in addition, a favorable transgressive segregation was detected for all investigated diseases. The QTL analysis showed that the alleles of the marker bPb-9668 (4H, 145.02 cM) displayed favorable performance of decreasing powdery mildew severity in the S42 population. In addition, three QTL were mapped to 2H, 3H and 5H, which associated with the resistance of leaf rust. The alleles of the three detected QTLs showed favorable performance of decreasing leaf rust severity in the S42 population by values ranging between -33.54 and -17.73 %. The locus QTS.S42.3H that located on chromosome 3H, exhibited both marker main effect and marker × environment interaction. Furthermore, the exotic alleles of this locus exhibited favorable performance of decreasing net blotch severity in the S42 population. Moreover, the epistasis analysis revealed nine desirable pairs of epistatic effects responsible for reducing the severity of the previous mentioned diseases in the S42 population. Our study highlighted that additive × additive epistasis was significant in the inheritance and breeding for the resistance of the investigated barley diseases.

Powdery mildew, leaf rust and net blotch are major biotic stresses that affect both the quality and quantity of the yield of barley. The current research was conducted at Sids Research Station during 2016/17 and 2017/18 growing seasons in Egypt. We aimed to identify the quantitative trait loci (QTL) and digenic epistatic interactions controlling the resistance to the aforementioned diseases in a doubled haploid population (S42) of barley derived from the cross between the exotic accession of H. vulgare ssp. spontaneum ‘’ISR42-8’’ and the German spring barley cultivar ‘’Scarlett’’ (H. vulgare ssp. vulgare). Results indicated that the wild parent is more resistant to the investigated diseases than the cultivated barley; in addition, a favorable transgressive segregation was detected for all investigated diseases. The QTL analysis showed that the alleles of the marker bPb-9668 (4H, 145.02 cM) displayed favorable performance of decreasing powdery mildew severity in the S42 population. In addition, three QTL were mapped to 2H, 3H and 5H, which associated with the resistance of leaf rust. The alleles of the three detected QTLs showed favorable performance of decreasing leaf rust severity in the S42 population by values ranging between -33.54 and -17.73 %. The locus QTS.S42.3H that located on chromosome 3H, exhibited both marker main effect and marker × environment interaction. Furthermore, the exotic alleles of this locus exhibited favorable performance of decreasing net blotch severity in the S42 population. Moreover, the epistasis analysis revealed nine desirable pairs of epistatic effects responsible for reducing the severity of the previous mentioned diseases in the S42 population. Our study highlighted that additive × additive epistasis was significant in the inheritance and breeding for the resistance of the investigated barley diseases.

Assessment of genotype-by-environment interaction (G×E) is a curial step in any breeding program through multi-environmental trials (MET). In the current study, we grow a bi-parental population consists of 297 BC2DH lines along with their parents and a local check cultivar in four locations for two years (2016/2017 and 2017/2018) across Egypt. We employed different statistical analyses including AMMI, Eberhart and Russell and Tai’s analyses to assess the G×E. In addition, we estimated broad-sense heritability for grain yield per plant as well as phenotypic and genotypic coefficient of variation. We found that environment (E), genotype (G) and G×E accounted for 52.52, 10.61 and 36.87% of sums of squares of treatment, respectively. Some DHs, e.g. 19, 65 and 4 were stable and adapted across environments unlike 73, 9 and 95, which were not stable across all environments but specifically adapted to Nubaria location during the two growing seasons. Both similar and dissimilar results found using Eberhart and Russel and Tai’s analyses. However, the AMMI biplot analysis successfully elucidate the which-won-where pattern. For the heritability estimates, we found that grain yield per plant showed moderate heritability estimate (0.50). This indicated that this trait can be improved under investigated environments. We identified some promising stable DHs lines that might be used in barley breeding programs in Egypt. Some of these DHs performed better than both parents and the local check cultivar.

Assessment of genotype-by-environment interaction (G×E) is a curial step in any breeding program through multi-environmental trials (MET). In the current study, we grow a bi-parental population consists of 297 BC2DH lines along with their parents and a local check cultivar in four locations for two years (2016/2017 and 2017/2018) across Egypt. We employed different statistical analyses including AMMI, Eberhart and Russell and Tai’s analyses to assess the G×E. In addition, we estimated broad-sense heritability for grain yield per plant as well as phenotypic and genotypic coefficient of variation. We found that environment (E), genotype (G) and G×E accounted for 52.52, 10.61 and 36.87% of sums of squares of treatment, respectively. Some DHs, e.g. 19, 65 and 4 were stable and adapted across environments unlike 73, 9 and 95, which were not stable across all environments but specifically adapted to Nubaria location during the two growing seasons. Both similar and dissimilar results found using Eberhart and Russel and Tai’s analyses. However, the AMMI biplot analysis successfully elucidate the which-won-where pattern. For the heritability estimates, we found that grain yield per plant showed moderate heritability estimate (0.50). This indicated that this trait can be improved under investigated environments. We identified some promising stable DHs lines that might be used in barley breeding programs in Egypt. Some of these DHs performed better than both parents and the local check cultivar.

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