Wheat leaf rust race specific resistance controlling genes (Lr) caused 0.01-0.03 decrease of SAGR = divided first two internodes with stem length. In addition, nitrogen transport in upper parts by those genes was 3-19% higher in comparison to near isogenic lines with nonspecific Lr 22a and Lr 22b genes. RAR (divided root nitrogen content with sum of up ground and root ones) values of Lr16, Lr29 and Lr37 between Lr1, Lr15 or Lr19 and nonspecific genes were explained by hydrolytic stability of endo-proteases responsible for cleaving of glutens disulphide bridges. According to RAR, Lr 34 seemed to be specific Lr gene but increased SAGR as was by nonspecific Lr genes focused SUTs as adequate for its conformity. Two different drought and heat stress respond systems were linked to Lr genes; one based on gluten degradation consequential through photosynthesis decrease and another on accelerated transfer of starch products and water in stem.

The individual use of single race-specific resistance genes with major phenotypic effects has rarely provided lasting resistance. However, breeding and combining or pyramiding of resistance genes into individual cultivars has had considerable success, particularly in situation where the pathogen does not reproduce sexually, as in the case of wheat leaf rust pathogen. Within international leaf rust of wheat investigations it was necessary, to create by breeding new resistant wheat lines to Puccinia recondita tritici for differentiation of pathogen population, as well as for sources of resistance in European-Mediterranean regions. In the beginning 18 donors of resistance had been selected after an extensive screening test of several International Rust Nurseries, to be crosses with recur- rent parents varieties Princ and Starke. These tests proved that in those lines were present new resistant genes. Eighth genetically different hybrids of the first back-cross had been selected and tested in the seedling stage with three international pathogen cultures (YU-13-19-1; H-13-9-1 and C2-13-Ar-3). Considerable influence of recurrent parent to the number of resistant genes in donors used was demonstrated. On the other side, it was established considerable influence of the pathogen culture to the number of resistant genes in donors used. The same crossing combinations tested with one pathogen culture results in presence of two resistance genes, but with another culture three or one resistant gene. In order to enhancement resistance and pyramiding genes in these hybrids, eight selected the most interesting lines have been crossed with only effective isogenic containing the strong genes Lr9, Lr19 and Lr24.The genetic analysis of twenty two crossing combinations have been realized by testing with three pathotypes of Puccinia recondita tritici ( Bg.s. 12/89; Is.w 8/89 and Chl.w. 14/89). On the base of different segregation ratios of all crossing combinations it was proved that no one of the resistant donors contained the strong resistant genes used. It means that our hybrid lines contained resistant genes from the donors and in addition three strong resistant genes Lr9, Lr19 and Lr24

The durable resistant varieties were developed more than 15 years ago. The basis of the resistance was investigated at seedling stage according to reaction type (RT) at air temperatures 20-25°C. The F2 generations of varieties Anastasia or Selekta x Lr 1, Lr 2a, Lr 3, Lr 13, Lr 14a, Lr 16 or Lr 26 were tested with isolates producing low RT on first two mentioned Lr lines. The presence of these single resistant genes in the varieties was excluded by presence of susceptible plants in F2 progenies of adequate crosses. The resistant combinations were Lr 3+B as Lr3+C in Selekta and Lr26+E, Lr26+C as EC in Anastasia. According to lower infection efficiency and yellowing of the above tip top part the C was similar or Lr 34. The Lr 13 and 14a were near the same effective at seedlings when were added to proposed combinations in parents. According to F1 results in field the most effective over season combination was achieved by crossing the investigated varieties because of two LP prolong able complementary genes and accumulation of three infection severity responsible ones

The main objective within new approach in international pathogenicity surveys of Puccinia recondita tritici was to provide genetically diverse sources of resistance (wheat lines with pyramiding resistant genes) to be used in a survey of wheat leaf rust pathogen in European-Mediterranean regions and to search for and document pathogenicity of P. recondita tritici cultures useful in differentiating sources of resistance. Emphasis is placed on sources of resistance and their usefulness rather than on description of fungus populations. In this international survey new methods have been applied containing Central Field Nursery, Central Seedling Tests, Cooperative Seedling Tests and Regional Field Nurseries (ELRWN-European Leaf Rust of Wheat Nursery). The results have been reported from one year of investigations. ELRWN contained 20 winter wheat hybrid lines with pyramiding resistant genes including strong ones Lr9, Lr19 and Lr24. In addition, 16 spring wheat lines were included, as control lines were Lr9, Lr18, Lr19, Lr24 and Lr14. In that year ELRWN have been realized in 13 countries and cooperative seedling test in 8 countries using 22 pathotypes of P. recondita tritici. The best results obtained by the winter wheat lines NS-66/5'Lr24, NS-77/2'Lr19, NS- 37/2'Lr19 and spring wheat lines 647-CMA-14793 and 26TH-ESWYT-10. The results have shown loosing almost complete resistance of Lr9 and Lr24, but much less Lr19

Eighteen wheat lines and varieties were classified in four groups according to different reactions to Puccinia triticina isolate of the race 77 at seedlings. Nitrogen distribution from seed, dependent of stored proteins bridge cleaving was presented across RAR (divided root with sum of up ground and root nitrogen content). Varieties expressed highest RT had RAR 0.35 or 0.37 indicating nonspecific genes like were LrTc, Lr 34 or Lr 13 presence or accumulations. The lowest RT of 0;, never present when Lr near isogenic lines were tested at seedlings, characterized three lines with RAR=0.33 fitting combinations of Lr 24 (RAR=0.34), Lr 29 (RAR= 0.34) and Lr 37 RAR=0.33. Lr 1 and 19 were excluded also by previous estimated higher influence on RAR (0.30). Lr 1 or Lr 19 were most probable ingredient in investigated genotypes for ;N RT and RAR of 0.31 as well Lr 24 was for ;N2 (0.34). RAR was decreased for only 0.01 when genes influential on RT decrease were accumulated. According to presented results the S-S linkage was not rejectable for specific resistance to parasite responsible enzymes discovering and differentiation by hydrolytic stability as well as was lower frequented in used parasite isolate.