الفهرس 
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Abstract
The present study focused on two major diseases, wheat leaf rust and powdery mildew which threat wheat during growing seasons around the world. Upon the presented literature losses in wheat yield in Egypt due to powdery mildew may reach up to 20% and due to leaf rust may reach 50-70%. The study implemented in Egypt and USA under joint-supervision program between both universities.
The obtained results could be summarized as follow:
- The results revealed that early sowing date at 15 November, applying sulfur, and using induced resistance compound (200 ppm salicylic acid, 200 ppm ascorbic acid, 200 ppm BTH, and 20 ppm citric acid) separately or combined with bio-control agent (plant guard) significantly reduced leaf rust severity and suppressed the development of rust during 2013/2014 and 2014/2015 growing season, while compost treatment showed non-significant effect on reducing rust severity, it may affected other non-tested parameters such as yield quality and quantity.
- The Egyptian wheats were evaluated against the natural North Carolina P. triticina population in 2015-16 and 2016-17. Some bread wheats and all durum wheat genotypes displayed low disease severity and infection type in both seasons.
- Leaf rust severely affecting the yield of Egyptian wheat, which according to previous studies leaf rust may cause yield loss reach up to 50%. Getting more information about virulence of Puccinia triticina population in Egypt was urgent. Thus, the USA part was implemented in North Carolina State University, focused on analyzing the virulence of Puccinia triticina population from Egypt. Also, from the pathogen various leaf rust resistance genes were postulated and detected using simple sequence repeats (SSR) and single nucleotide polymorphism (SNP) markers.
- The present study revealed that in Egyptian P. triticina population collected during 2016/2017 growing season, the most frequent phenotype was TCTTQ (16%), followed by MBBTB (12%), the remaining virulence phenotypes ranged from 8 to 2% in frequency. There is no virulent was observed against Lr19 and Lr42.
- The results showed that Lr46 was detected in most old and new genotypes, and Lr9 was found in two old lines (L1360-3838 and V-3) and one recent cultivars (Sakha-94), while Lr21, Lr24, Lr34, and Lr67 were mainly found in old genotypes.
- The virulence frequencies of a representative sample of the Egyptian B. graminis f. sp. tritici population were studied. Seven provinces were chosen to represent the country: two in Upper Egypt (Qena and Sohag), one in Middle Egypt, (El Minia) and four in the north (Alexandria, Kafr Elsheikh, Dakahlia and Sharqia). Ten isolates from each province, were derived from single ascospores and used for this study.
- Among all tested Pm genes, only seven (Pm1b, Pm2, Pm21, Pm34, Pm36, Pm37, and Pm53) were effective against B. graminis f. sp. tritici isolates from all provinces. Several other genes were effective against most or all isolates from a majority of provinces.
- Also 20 Egyptian wheat cultivars were tested included 14 bread and 6 durum wheat against 70 Pm isolates. All tested bread wheat cultivars showed full susceptibility to all isolates, while two durum wheat cultivars, Beni-Suef-5 and Beni-Suef-6, had intermediate responses to a large percentage of the isolates, likely indicating partial resistance.