Leaf rust monogenic lines i.e. Lr27, Lr29 were crossed with four Egyptian wheat cultivars (Triticum aestivum L.,) also, Lr46 was crossed with 3 wheat cultivars and Lr2a was crossed with one cultivar (Sakha 93). These parents, F1's and F2's were tested at adult plant stage under field conditions against race mixtures of the pathogen (Puccinia triticina Eriks.) under the stress of artificial infection. The parents of monogenic lines Lr2a, Lr46, Lr29 and Lr27 showed low disease severity. While, Gemmeiza 7, Sakha 61, Sakha 93 and Sids 1, showed high disease severity against leaf rust disease. The F1's tested plants showed low disease severity with most of crosses except three crosses i.e. Lr27 + Sakha 61, Lr27 + Sakha 93 and Lr27 + Sids 1, which showed high disease severity. The F2 plants populations were segregated into two gene pairs. The dominance tend to the direction of low disease severity (partial leaf rust resistance) with eight crosses. However, the dominance tend to the side of high disease severity with three crosses that were previously mentioned with F1's. But no segregates was recorded with the cross Lr2a + Sakha 93 and dominance tend to the aside of low disease severity (partial leaf rust resistance). The cultivar Sakha 93 exhibited the adult plant resistance to the gene Lr2a under field conditions. These findings may prove that this gene is an effective under the Egyptian environmental conditions. The partial leaf rust resistance in the tested wheat cultivars was thought to be controlled by digenic pairs in adult plant stage. The selection for partial leaf rust resistant materials in the early generations was possible but delaying it to late ones is more effective, due to the important role of dominance effect in the expression of the character.

Leaf rust caused by the biotrophic fungus Puccinia triticina, is one of the most important diseases of worldwide countries and Egypt. The use of resistance genes is of a great interest in numerous breeding programs. Our objectives were to determine the number of resistance gene pairs to wheat leaf rust present in eleven crosses derived from two low rust severity wheat cultivars i.e. Gemmeiza 9 and Sakha 94 with six and five high rust severity wheat cultivars, respectively, at both seedling in greenhouse and at adult plant stages under field conditions. The obtained results showed a high effective response against artificial and natural infection of wheat leaf rust at adult plant than these recorded at seedling stage. The study of combination between traditional wheat cultivars of Egyptian origin showing durable resistance proved to have a great value since they can provide new sources of resistance to such a disease.

The annual survey of 2006/2007 wheat growing season revealed the presence of thrity two physiologic races of wheat leaf rust fungus (Puccinia triticina Eriks.). The more frequent race was PTTS (23.07%) followed by race PTTT (12.30%), race TTTS (9.23%), race TTTT (6.15%), race PTTP (4.61%) and the two races PSTN and PTKS which were represented by (3.07%) each. The rest of races were represented by (1.53%) each. However, the more effective leaf rust resistance genes were i.e. Lr2a (73.84%), Lr2b (61.53%) and Lr36 (50.76%). On the other hand , the highest virulence were observed with Lr's i.e., 10; 11, 14b, 17; 16, 21, 30; and 2c, 3, 24 which were represented by 100% susceptibility; 98.46%; 96.92% and 95.38%, respectively. Leaf rust resistance gene(s) probably present in four Egyptian commercial wheat cultivars in comparison with nineteen leaf rust near-isogenic lines against 65 isolates, the cultivars Gemmiza 10, Giza 168 and Sakha 94 probably have Lr's i.e. 9, 16, 24, 11, 17, 30 and 14b. On the other hand, the tested Egyptian wheat cultivars were postulated to the lack of Lr2a, Lr2b and Lr36 which were proved to be the more effective genes in the present study. These results will remain an integral part of resistance breeding program and studies relevant to the epidemology and evaluation of virulence to leaf rust pathogen populations.

Seven Ras cheese treatments were made to study the effect of replacing milk fat with Novagel® RCN15 (a carbohydrate-based fat replacer) on the quality of low fat Ras cheese. Control cheeses were made from cow's milk containing 3.0% fat, another three Ras cheese treatments were made from the same milk but were standardized to 2.0% fat with adding Novagel® at the rate of 0.0, 0.25% and 0.50% respectively. The other three Ras cheese treatments were made from cow's milk standardized to 1.0% fat with adding Novagel® at the rate of 0.0%, 0.50% and 1.0% respectively. Reducing the fat content of cheese milk caused a significant decrease in moisture, fat, titratable acidity, soluble nitrogen (SN), Shilovitch ripening index (S1) total volatile fatty acid content and scores of organoleptic properties of Ras cheese, meanwhile increased total nitrogen, salt, ash content and hardness of cheese was detected. Adding Novagel® increased the ripening indices, scores of organoleptic properties, acidity and moisture content, while decreased the hardness of cheese. Cheese treatment that made from 2.0% fat milk was the most acceptable one, and was not significantly different from control cheese. Ripening indices, titratable acidity scores of cheese, total nitrogen, fat and ash content of Ras cheese increased as ripening period proceeded, while cheese hardness and moisture decreased.

Leaf rust caused by Puccinia triticina Eriks.is a common and widespread disease of wheat in Egypt and worldwide. Durable genetic resistance to leaf rust in wheat has been difficult to achieve, since the virulence of leaf rust pathogen to specific leaf rust resistance genes form high variability in wheat cultivars aiming to make a genetic prediction of leaf rust resistance, six crosses i.e. Lr25/Gemmeiza 7 , Lr25/Giza163 , Lr25/sids1; Lr35/Gemmeiza7 , Lr35/sakha 61 and Lr35/Sakha93 were carried out. These Egyptian Wheat varieties showed high infection type at both seedling and adult while Lr25 showed resistance and Lr35 was susceptible at seedling stage , but at adult plant stage they showed low rust severity under greenhouse and field conditions subsequently. The segregation in the F2 plant populations at both seedling and adult plants stage tending to the side of partial resistance and dominance with digenic pairs. Lr25 or Lr35 have low rust severity because of the rarity of leaf rust isolates with virulence to Lr25 or Lr35. Wheat cultivars with the combination of Lr25 or Lr35 displayed high levels of partial leaf rust resistance. From this stand point, these cultivars don"t contain Lr25 or Lr35. The dominant nature of some of the slow rusting resistance genes in crosses are of a great interest in breeding for rust durable resistance. This type of resistance will be easier in segregating generations as smaller population sizes would be required than when used lesser effects.