The use of productive cultivars with adaptability and stability and less demanding to fungicide use are critical to the sustainability of production factors. The objective of this work was to determine the per se performance of white oat cultivars and parameters of adaptability and stability on yield and grain quality in the proposition of cultivars more responsive in reducing the use fungicide. The study was conducted in Augusto Pestana, RS, Brazil, between the years 2010 and 2013. The experimental design was randomized blocks with six replicates, three with and three without fungicide. The study evaluated 14 white oat cultivars for yield and industrial capability. The white oat cultivars FAEM 4 Carlasul and URS Corona indicate high grain yield with stability and general adaptability, independent of chemical control. The cultivar URS Corona shows together high yield and thousand grain weight and hectoliter with general adaptability and stability in the absence of fungicide. Although no stability has been detected in industrial yield without the use of fungicides, cultivars of URS Charrua, URS Corona and URS Taura show high means with general adaptability.

The onset of flowering is decisive to the reproductive success of plants. The objectives of this study were to characterize the phenotypic variation in heading date and estimate its heritability in segregating populations of oat (Avena sativa L.). F 2 and F 3 generations of two large populations, derived from crosses 'URS Taura × Leggett' and 'FL0206B-S-B-S1 × UFRGS 078030-1', were evaluated. A wide phenotypic variation in the number of days to heading was observed in both populations. Heritability coefficients of 0.68 and 0.46 were estimated for the 'URS Taura × Leggett' and 'FL0206B-S-B-S1 × UFRGS 078030-1' populations. Our results demonstrate that genetic differences derived from parents in response to photoperiod and temperature explain most of the phenotypic variation in heading date of oat populations. Understanding genetic and environmental effects on flowering expression is essential to increase the response to selection for well-adapted and high-yielding oat cultivars.

The biomass productivity and wheat grains efficiency is determined by nitrogen dose adjustment (full or fractioned), environmental conditions, and cropping system. The aim of this study was to improve the efficiency of N-fertilizer usage on wheat to maximize the biomass productivity and grain yield by adjusting the full or fractioned nitrogen dose in favorable and unfavorable year conditions, in succession systems with high and reduced N-residual release. In this study, two experiments were conducted between 2012 and 2014. One was to quantify the biomass productivity rate and another to determine grain yield. The experimental design was a complete randomized block, with four replications, in a 4 × 3 factorial scheme to N fertilizer rates (0, 30, 60 and 120 kg ha-1) and supply forms of the nutrient [full dose (100%) in the V 3 phenological stage (third expanded leaf); fractioned (70 and 30%) at the V 3 and V 6 phenological stages (third and sixth expanded leaf, respectively) and; fractionated (70 and 30%) at the V 3 and E phenological stages (third expanded leaf and early grain filling), ] respectively, in soybean/wheat and maize/wheat cultivation systems. The nitrogen supply in wheat through single dose or fraction indicates linear tendency over the productivity biomass daily rate-1 with the increase of N-fertilizer, regardless of a favorable and unfavorable year and system of a succession of the high and reduced N-residual release. However, in favorable years, the use of full dose on V 3 stage is indicated. In the maize/wheat system, the full dose at V 3 stage is more efficient, especially with higher doses of the nutrient. For grain yield, the N-fertilizer fractioning was adjusted in intermediate cropping years, while the full dose became suitable at the V 3 stage in favorable years. However, in unfavorable years, nitrogen investments should be minimized, regardless of the supply form and succession system.

RESUMO O objetivo do trabalho foi analisar a adaptabilidade e estabilidade de genótipos apomíticos do gênero