No abstract

Cotton is widely acknowledged as a major cash crop across the world, and its socioeconomic relevance, particularly in emerging nations, is well understood. Cotton seedling infections are among the most significant of the diseases that limit cotton lint and seed production. The goal of this study was to determine the pathogenicity of Rhizoctonia solani, Fusarium moniliforme, and Machrophomina phaseolina isolates taken from cotton roots to cotton seedlings in the Giza governorate. Seven fungus isolates were recovered from two cotton cultivars, including Rhizoctonia solani, F. moniliforme, and M. phaseolina (Giza 90 and Giza 94). It was discovered that the differences in pathogenicity between the isolates and controls vary by cultivar, indicating that the cultivars reacted differently to the isolates. All of the fungal isolates were harmful and reduced the survival rate on both cultivars. Pathogenic isolates had a negative impact on seed germination, root shoot length, and increased Cotton seedlings have a significant mortality rate. These problems might be overcome by growing cotton cultivars that are resistant to damping-off. In order to improve resistance, resistance genes must be introduced into cotton cultivars. Future cotton improvement techniques should incorporate damping-off management; however, the inclusion of numerous pathogenic fungi from various genera may confound efforts to create such approaches.

Efficacies of three abiotic inducers (systemic resistance agents) i.e., bion, humic acid (HA), salicylic acid (SA), compared to Rizolex-T50 as seed treatments were tested against damping-off and root rot diseases of cluster bean (Cyamopsis tetragonoloba L.) in pot and field experiments. In green house, pathogenicity test indicated that the three tested fungi were pathogenic and caused emergence damping-off. R. solani caused the highest percentage of pre-emergence damping-off. Moreover, the lowest percentage of survived plants was occurred under F. oxysporum and R. solani (26.7% for each). Rizolex-T50 presented the highest reduction in disease parameters in infested soil with the three fungi, Bion came next to the fungicide followed by humic acid then salicylic acid. All the investigated treatments significantly increased the activity of chitinase, β-1, 3-gluctronase, peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL) enzymes. As well as total content of phenolic compounds and total content of lignin were increased in cluster bean plants grown in artificially infested soil with the three tested fungi (Fusarium oxysporum, Rhizoctonia solani, and Macrophomina phaseolina) each alone compared with untreated control. In field, pre sowing seed treatments with the desired inducer of resistance inducer caused considerable increase in the photosynthesis pigments (chlorophyll-a, chlorophyll-b and total chlorophyll) and seed quality (total nitrogen and total protein). In general, the highest figured data of the increase in the cluster bean tissue were associated with the inducer resistance agents i.e., Bion, salicylic acid and humic acid, respectively, followed by seed treatment with the fungicide Rizolex-T50. Whereas the lowest increase was shown in control treatment. It could be concluded that any of bion, HA or SA can act as inducer of systemic resistance in cluster bean plant against infection by each of Fusarium oxysporum, Rhizoctonia solani, and Macrophomina phaseolina infections. Consequently, these agents could be recommended for management damping-off and root rot diseases in cluster bean plants and improving photosynthetic pigments and seed quality.

A pot experiment was conducted at the Experimental Research Farm, Faculty of Agriculture, Suez Canal University, Ismailia in Fall 2013 till Spring 2014. The experiment included two broccoli genotypes ("Sultan" and "Marathon"), two levels of salinity treatments (0, 100 mM NaCl), two levels of sulfur (0, 3 g/L soil) and two different soil volume containers (2, 4 L), in split-split plot design. The objective was to investigate the impact of genotype, salinity, sulfur treatments and container size on plant growth, yield and incidence of gray mold in broccoli. In addition, the effect of propolis extract as a natural mean of disease control was also explored. The results of the experiment revealed that broccoli genotypes differed in their growth and yield response. Also, salinity treatment adversely affected the growth and yield of broccoli in both genotypes and sulfur treatments were not able to mitigate the unfavorable effects of salinity on broccoli plants. As a result of this experiment, gray mold in broccoli was reported for the first time in Egypt and the fungus w a s identified as Botrytis cinerea based on mycological characteristics. Broccoli genotypes showed different disease severity as "Marathon" cv. was highly susceptible, while "Sultan" cv. showed higher degree of resistance. RAPD analysis identified some specific DNA fragments discriminating between the two genotypes which can explain the different response of both genotypes for yield and disease incidence. Salinity treatment significantly increased the disease severity by an average of 15.6% and 21.2% when compared to the control for plants grown in large and in small culture container, respectively, which demonstrate the effect of container size on the disease response as the larger size promoted the disease severity. Sulfur application was the most effective treatment in decreasing disease severity by 100% in both genotypes and in both container sizes. In presence of salinity, the inhibitory effect of sulfur sustained in "Sultan" cv., while sulfur decreased the disease severity in "Marathon" cv. only by 52.5%. In addition, propolis extract displayed inhibitory effect on Botrytis cinerea growth in both genotypes. Overall, genotypic differences observed for yield and salinity tolerance suggest that breeding programs to enhance such important traits are feasible. Soil-supplied sulfur enhanced broccoli defense to disease and can be suggested as mean of managing nutrition to control plant diseases. Finally, propolis extract can be suggested as a natural mean of gray mold disease control in broccoli.

Two field experiments were conducted during 2012 and 2013 seasons at the Agricultural Experimental Farm of Suez Canal University at Ismailia in the first season and El-Manayf district in the second season in Ismailia Governorate to study the effect of four nitrogen fertilization treatments namely 25, 45, 65 and 25 Kg N/fad plus biofertilizer (Cerealin) as well as three plant densities namely 46666, 35000 and 28000 plants/fad resulted by sowing sunflower in ridges 60 cm in width and hill spacings 15, 20 and 25 cm on sunflower Sakha 53 variety in sandy soils. Increasing nitrogen fertilization up to 65 Kg N/fad significantly increased all growth characters, yield attributes as well as seed, biological and oil yields/fad. Applying biofertilizer (Cerealin) plus 25 Kg N/fad significantly surpassed 25 Kg N/fad alone in the above characters. Decreasing hill spacing up to 15 cm significantly increased seed, biological and oil yields/fad. There was significant interaction between nitrogen fertilization and plant density on seed, biological and oil yields/fad. The highest seed, biological and oil yields/fad were obtained by adding 65 Kg N/fad under dense planting of 46666 plants/fad.