Caracterização de genótipos brasileiros de trigo para eficiência de uso do nitrogênio e qualidade industrial em multi-ambientes

Abstract

To characterize the genetic variability as the nitrogen use efficiency (NUE) and identify environments that maximize grain yield and baking quality is of essential importance for the competitiveness and sustainability of crop wheat in Brazil. The first experiment was objective to evaluate the levels of deoxynivalenol (DON) and to characterize Brazilian wheat cultivars recently release and available for cultivation, as the efficiency of use of N (EUN) in two growing locations (Pato Branco, Paraná and Coxilha-RS), in 2011 crop season. The experimental design was a randomized block with three replications and analyzed jointly. The mycotoxin DON was detected in 97.23% of samples ranging from 200 to 4140 μg kg-1, with mean values of 1058 μg kg-1 in Pato Branco and 1357 μg kg-1 in Coxilha. From a total of 108 samples, 17% represented by cultivars IPR Catuara TM, IPR 144, BRS 220 and BRS Tangará, had DON levels above the limit tolerated by ANVISA for 2012 crop season. Additionally, was identified genetic variability for nitrogen use efficiency by grains (NUEg – 47,6 to 81,1 kg/kg) and nitrogen harvest index (NHI – 71,3 to 84,6%), highlighting the cultivars Mirante, Quartzo, F. Cristalino, F. Raízes and CD 150. Grain yield of current brasilian wheat cultivars was positively associated with total biomass production (0,85 ** and 0,82 **) at both locations. The objective of the second experiment was to evaluate the general ability combination (GCA) and specific ability (SCA) of NUE components and investigate possible associations with agronomic traits in diallel crosses. Six parents and 15 F2 segregating populations were evaluated in the field in a randomized block design with three replications. Additive and non-additive genetic effects influenced the expression of the components of NUE. The parents Mirante, Valente and BRS Tangará showed the highest CGC values for components of NUE. The relative relative chlorophyll B was significantly associated with the RG (0,49*), thousand kernel weight (0,44*) and NUEg (0,50*), indicating that this traits can be used for indirect selection of superior genotypes in early generations. Lastly, 29 wheat lines and 10 cultivars were tested in 11 cultivation sites in Paraná in the 2010 and 2011 growing seasons, with the objective of this study was to select wheat lines and identify ideal test environments for maximizing yield and baking quality. AMMI and GGE Biplot graphic methodologies were used for data analysis. In 2010 crop season, Nova Fatima e Ventania locals classified themselves as discriminating and representative for grain yield (GY). In 2011 crop season, Apucarana and Astorga showed out as ideal environments to selection of genotypes with high baking quality. The ideal-genotype analysis indicated the BIO-08528 BIO-08228 lines to GY and protein concentration, respectively. In the 2011 crop season, BIO-10161 and BIO-10141 lines and were higher for GY and baking quality and should be selected. Grain protein concentration SDS-sedimentation test correlated with each other (r = 0,61**) and were positively associated with gluten strength (r = 0,49** and 0,74**), indicating that they can be used as indirect selection criteria for bread-making quality in wheat breeding programs.