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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SUMMARY This study investigated the impacts of dietary yeast culture (Saccharomyces cerevisiae) supplementation on rumen fermentation, nutrient digestibility and rumen microbial population in sheep. Three digestibility trials were carried out using fifteen Sohagi rams randomly assigned into three groups (5 rams/ each). Each trial lasted for three weeks, the first two weeks were considered as a preliminary period followed by one week collection period.The groups were a control group fed basal diet without yeast supplement and treated groups fed either 0.5 (T1) or 1% (T2) yeast culture (YC) mixed with concentrate diet. All animals were fed 60% of their requirements as concentrate mixture while, chopped corn stover was given as roughages ad libitum. The results referred that, the digestibility of dry matter, organic matter, crude protein, crude fibre, neutral detergent fibre and hemicellulose were significantly (P0.05) improved for yeast treated diets compared with basal diet. Live yeast culture either 0.5 or 1% in concentrate diet increased (P 0.05) the pH, volatile fatty acids (VFAs), acetate and propionate, while rumen ammonia nitrogen concentration was decreased (P0.05). Live yeast supplementation (0.5 or 1%) improved (P0.05) N retention. The rumenal bacterial and protozoal counts increased (P0.05) due to YC supplementation. In conclusion, dietary live yeast culture (S. cerevisiae) particular 1% of concentrate mixture may improve nutrient digestibility, fermentation patterns and rumen microbial population.

SUMMARY This study investigated the impacts of dietary yeast culture (Saccharomyces cerevisiae) supplementation on rumen fermentation, nutrient digestibility and rumen microbial population in sheep. Three digestibility trials were carried out using fifteen Sohagi rams randomly assigned into three groups (5 rams/ each). Each trial lasted for three weeks, the first two weeks were considered as a preliminary period followed by one week collection period.The groups were a control group fed basal diet without yeast supplement and treated groups fed either 0.5 (T1) or 1% (T2) yeast culture (YC) mixed with concentrate diet. All animals were fed 60% of their requirements as concentrate mixture while, chopped corn stover was given as roughages ad libitum. The results referred that, the digestibility of dry matter, organic matter, crude protein, crude fibre, neutral detergent fibre and hemicellulose were significantly (P0.05) improved for yeast treated diets compared with basal diet. Live yeast culture either 0.5 or 1% in concentrate diet increased (P 0.05) the pH, volatile fatty acids (VFAs), acetate and propionate, while rumen ammonia nitrogen concentration was decreased (P0.05). Live yeast supplementation (0.5 or 1%) improved (P0.05) N retention. The rumenal bacterial and protozoal counts increased (P0.05) due to YC supplementation. In conclusion, dietary live yeast culture (S. cerevisiae) particular 1% of concentrate mixture may improve nutrient digestibility, fermentation patterns and rumen microbial population.

Summary This study was conducted to evaluate the effect of supplying two levels of Acacia nilotica (A. nilotica) pods to rations of sheep on nutrient digestibility, nitrogen balance and rumen liquor parameters (pH, total protozoa count, protein concentration and enzymes activity). Twelve mature rams (50 ± 1.25 kg B.W.) were distributed into three groups, each with four rams. Animals in group one were considered as a control which fed a basal diet, consisting of concentrate mixture and Egyptian clover. The second group and the third one received the same basal diet with supplying the concentrate mixture by 1.5% and 3.0% of A. nilotica pods meal respectively. The experiment lasted for 3 weeks. It was found that supplementation of A. nilotica pods to the concentrate mixture at a rate of 1.5% and 3.0% significantly improved the total feed intake compared to the control. The digestibility of dry matter and crude fibre was significantly reduced with A. nilotica supplements, whereas the gestibility of crude protein was significantly improved. All of nitrogen intake and N-retained were significantly increased in rams fed on concentrates with 1.5% and 3.0% A. nilotica pods when compared to the control. The pH of ruminal fluid was not affected by the dietary treatments. Nevertheless, the total rumen protozoa count was significantly decreased in A. nilotica pods supplemented groups. Also, the rumen protein concentration and the ruminal enzymes activity, especially α-amylase, cellulase and protease, were lower in A. nilotica pods supplemented treatments. In conclusions, inclusion of low levels of A. nilotica pods (1.5% and 3.0%) in the concentrates can be used as a natural protein protectant in ruminants by forming tannin protein complexes in the rumen to maximize the amino acids available in the lower digestive tract. Also, these levels can increase the protein digestibility as well as the N-retained in the body .

Summary This study was conducted to evaluate the effect of supplying two levels of Acacia nilotica (A. nilotica) pods to rations of sheep on nutrient digestibility, nitrogen balance and rumen liquor parameters (pH, total protozoa count, protein concentration and enzymes activity). Twelve mature rams (50 ± 1.25 kg B.W.) were distributed into three groups, each with four rams. Animals in group one were considered as a control which fed a basal diet, consisting of concentrate mixture and Egyptian clover. The second group and the third one received the same basal diet with supplying the concentrate mixture by 1.5% and 3.0% of A. nilotica pods meal respectively. The experiment lasted for 3 weeks. It was found that supplementation of A. nilotica pods to the concentrate mixture at a rate of 1.5% and 3.0% significantly improved the total feed intake compared to the control. The digestibility of dry matter and crude fibre was significantly reduced with A. nilotica supplements, whereas the gestibility of crude protein was significantly improved. All of nitrogen intake and N-retained were significantly increased in rams fed on concentrates with 1.5% and 3.0% A. nilotica pods when compared to the control. The pH of ruminal fluid was not affected by the dietary treatments. Nevertheless, the total rumen protozoa count was significantly decreased in A. nilotica pods supplemented groups. Also, the rumen protein concentration and the ruminal enzymes activity, especially α-amylase, cellulase and protease, were lower in A. nilotica pods supplemented treatments. In conclusions, inclusion of low levels of A. nilotica pods (1.5% and 3.0%) in the concentrates can be used as a natural protein protectant in ruminants by forming tannin protein complexes in the rumen to maximize the amino acids available in the lower digestive tract. Also, these levels can increase the protein digestibility as well as the N-retained in the body .