Advance on wheat breeding to leaf rust resistance C. Turra, A. L. Barcellos*, A. A. Baggio, S. B. Rosa OR Melhoramento de Sementes Ltda., Av. Rui Barbosa, 1300, Passo Fundo, RS, Brazil, Introduction The Brazilian climate, humid by the frequent rains principally during the reproductive stages, and the susceptible wheat cultivars result in the occurrence of many diseases reducing the yield. Among these diseases, the leaf rust stands out because of its frequency and damage. It is not rare cultivars with race specific leaf rust resistance to turn susceptible after few years of release, caused by selection in the fungi population. In Brazil, 112 cultivars are indicated to be cultivated in the moment. Among these, 59 cultivars have different levels of susceptibility to leaf rust. The aim of this study was the introduction of leaf rust durable resistance genes in the best Brazilian wheat cultivars. Material and Methods The introduction of durable genes was started in 2002 in the breeding company OR Melhoramento de Sementes Ltda. The study was conducted in Passo Fundo, RS, Brazil at OR Sementes laboratory and in experimental field nurseries in Coxilha, RS, Brazil. Durable resistance genes Lr34, Lr21, Lr13 plus minor genes in Frontana, and unindentified genes in Kukuna, Fundacep 30, Toropi (Trp1, Trp2) and Pampeano were introduced in the cultivars OR1, Ônix and Quartzo through backcrossing. The OR cultivars Ametista, Topázio, Jadeíte 11 and ORS Vintecinco were also evaluated, as well as OR advanced lines. Mixture of MDT-MR 4002 Virulence, MCS-LN, TFT-MT, TFP-HT and TFT-PT races were artificially inoculated in the field in rows (8,92 m 2 ) in To evaluate the efficiency of the durable resistance genes to reduce the rust damage was sprayed fungicide (epoxiconazol and piraclostrobine, 500 mL/ha) to manage the disease. The rows were divided in area with and without fungicide. The yield (Kg/ha) was compared among the susceptible cultivars and the lines of each cultivar with additional resistance genes. The lines Kukuna/2*OR1, Toropi/2*OR1, Toropi/2*Ônix were developed following the One Backcross methodology (Singh, RP et al., CIMMYT). Susceptible cultivar (OR1, Ônix or Quartzo X Amadina  F1F1 Chapio  F1F1 Frontana  F1F1 Kukuna  F1F1 Tukuru  F1F1 Toropi  F1F1 20 F 1 spikes of each cross XSusceptible cultivar  seeds RC RC 2 plants/cross 1000 RC 3 -RC 5 plants/cross RC 1, RC 2 and RC 3 : selection of low to intermediate leaf rust severity RC 4 e RC 5 : low severity RC 6 lines evaluated for rust, agronomy, other diseases, etc. Selected lines were evaluated for yield. Effectiveness of durable genes comparing the yield difference between susceptible cultivar and a line of it with durable resistance genes: OR1 and OR1+GRD: Kg/ha Ônix and Ônix+GRD: Kg/ha Quartzo and Quartzo+GRD: Kg/ha High yield of Jadeíte 11 (5.199 Kg/ha) and ORS Vintecinco (5.509 Kg/ha) without fungicide indicated the efficiency of their genetic resistance. The study showed the progress of the breeding for leaf rust resistance by the introduction of adult durable resistance genes and pyramidization of genes through backcrossing and selection of individually plants in the field. OR Sementes has improved OR1, Ônix e Quartzo to be cultivated by wheat growers. Lines with better and durable leaf rust resistance, higher yield and with economical and environmental advantages. Results and Conclusion Table 1. Yiel.d of cultivars and their lines with the introduction of durable resistance genes (DRG) derived from backcrossing with and without fungicide application.

Advance on wheat breeding to leaf rust resistance C. Turra, A. L. Barcellos*, A. A. Baggio, S. B. Rosa OR Melhoramento de Sementes Ltda., Av. Rui Barbosa, 1300, Passo Fundo, RS, Brazil, Introduction The Brazilian climate, humid by the frequent rains principally during the reproductive stages, and the susceptible wheat cultivars result in the occurrence of many diseases reducing the yield. Among these diseases, the leaf rust stands out because of its frequency and damage. It is not rare cultivars with race specific leaf rust resistance to turn susceptible after few years of release, caused by selection in the fungi population. In Brazil, 112 cultivars are indicated to be cultivated in the moment. Among these, 59 cultivars have different levels of susceptibility to leaf rust. The aim of this study was the introduction of leaf rust durable resistance genes in the best Brazilian wheat cultivars. Material and Methods The introduction of durable genes was started in 2002 in the breeding company OR Melhoramento de Sementes Ltda. The study was conducted in Passo Fundo, RS, Brazil at OR Sementes laboratory and in experimental field nurseries in Coxilha, RS, Brazil. Durable resistance genes Lr34, Lr21, Lr13 plus minor genes in Frontana, and unindentified genes in Kukuna, Fundacep 30, Toropi (Trp1, Trp2) and Pampeano were introduced in the cultivars OR1, Ônix and Quartzo through backcrossing. The OR cultivars Ametista, Topázio, Jadeíte 11 and ORS Vintecinco were also evaluated, as well as OR advanced lines. Mixture of MDT-MR 4002 Virulence, MCS-LN, TFT-MT, TFP-HT and TFT-PT races were artificially inoculated in the field in rows (8,92 m 2 ) in To evaluate the efficiency of the durable resistance genes to reduce the rust damage was sprayed fungicide (epoxiconazol and piraclostrobine, 500 mL/ha) to manage the disease. The rows were divided in area with and without fungicide. The yield (Kg/ha) was compared among the susceptible cultivars and the lines of each cultivar with additional resistance genes. The lines Kukuna/2*OR1, Toropi/2*OR1, Toropi/2*Ônix were developed following the One Backcross methodology (Singh, RP et al., CIMMYT). Susceptible cultivar (OR1, Ônix or Quartzo X Amadina  F1F1 Chapio  F1F1 Frontana  F1F1 Kukuna  F1F1 Tukuru  F1F1 Toropi  F1F1 20 F 1 spikes of each cross XSusceptible cultivar  seeds RC RC 2 plants/cross 1000 RC 3 -RC 5 plants/cross RC 1, RC 2 and RC 3 : selection of low to intermediate leaf rust severity RC 4 e RC 5 : low severity RC 6 lines evaluated for rust, agronomy, other diseases, etc. Selected lines were evaluated for yield. Effectiveness of durable genes comparing the yield difference between susceptible cultivar and a line of it with durable resistance genes: OR1 and OR1+GRD: Kg/ha Ônix and Ônix+GRD: Kg/ha Quartzo and Quartzo+GRD: Kg/ha High yield of Jadeíte 11 (5.199 Kg/ha) and ORS Vintecinco (5.509 Kg/ha) without fungicide indicated the efficiency of their genetic resistance. The study showed the progress of the breeding for leaf rust resistance by the introduction of adult durable resistance genes and pyramidization of genes through backcrossing and selection of individually plants in the field. OR Sementes has improved OR1, Ônix e Quartzo to be cultivated by wheat growers. Lines with better and durable leaf rust resistance, higher yield and with economical and environmental advantages. Results and Conclusion Table 1. Yiel.d of cultivars and their lines with the introduction of durable resistance genes (DRG) derived from backcrossing with and without fungicide application. Cultivar Yield (Kg/ha) No fungicide OR1 Ônix Advanced line One Backcross Methodology Kukuna/2*OR1 Toropi/2*OR1 Toropi/2*Ônix