ADAPTABILITY AND STABILITY OF OAT CULTIVARS TO REDUCE FUNGICIDE USE WITH SATISFACTORY PRODUCTIVITY

Purpose: The objective of the study is to identify oat cultivars with satisfactory productivity and adaptability to reduced use of fungicide concomitant with the longest interval between the last application and grain harvest, in the recommendation of biotype more adjusted to agroecological management. Method/design/approach: The study was developed in 2018, 2019, in Augusto Pestana, RS, Brazil. The experimental design was a randomized block with three replications in a 23 x 5 factorial, for 23 Brazilian oat cultivars and 5 fungicide use conditions, applied on the time scale every 15 days cumulatively: control (no application); one application 60 days after emergence (DAE); two applications at 60, 75 DAE; three applications at 60, 75, 90 DAE and four applications at 60, 75, 90, 105 DAE. Results and conclusion: Experimental strategies with the analysis of adaptability and stability help to identify oat cultivars that are more resilient to the absence or reduction of fungicide use, promoting more sustainable management. The cultivars URS Brava and URS Altiva present satisfactory productivity with adaptability to the absence or reduced use of fungicide, providing a safe interval from the last application to the grain harvest, with the indication for agroecological management. It is necessary to promote food security based on new scenarios, including the environment, technology, economy and society. Originality/value: Unprecedented study seeking to reduce the use of fungicidal pesticides to control oat diseases using adaptability and stability models, providing opportunities for the analysis of different scenarios to identify cultivars more suited to agroecological management.


INTRODUCTION
The growing demand for healthy foods that provide health benefits has favored the greater consumption of white oats (Avena sativa L.), a cereal that stands out for its nutritional quality and multifunctional characteristics in both human and animal feed. Due to the increase in oat consumption, there is a greater expansion of cereal cultivation areas in Brazil, which demands more productive cultivars of industrial grain quality, adjusted to meteorological conditions that guarantee adequate development (Howarth et al,. 2021;Henrichsen et al., 2023).
The performance of an agronomic species and the possibility of large-scale production is conditioned by the presence of a favorable environment for cultivation, however, a situation that often also favors the incidence and pressure of diseases that directly interfere with the productivity and quality of oat grains (Carvalho 2012;Dornelles et al., 2021). In the case of oats, the incidence of fungal diseases such as leaf rust (Puccinia coronata C da. f. sp. avenae) and helminthosporiose [Drechslera avenae (Eidam) El Scharif], is common, causing great damage to productivity, with greater severity in conditions of high relative humidity and air temperature, a characteristic condition during the paniculation and grain filling phases Dornelles et al., 2023). This fact generates the need to use fungicide pesticides, the most efficient technological resource for disease control (Sánchez-Martín & Keller 2019; Alessi et al., 2018), due to the reduced ability to control via genetic resistance (Dornelles et al., 2021;Savicki et al., 2023).
In oat crops, fungicide applications end up being potentiated during the grain filling phase, a condition that can lead to the translocation of photoassimilates with pesticide molecules to the grains during the reserve deposition phase, with a strong impact on the food security, in addition to significant damage to human health and the environment (Lopes-Ferreira et al., 2022;Screminn et al., 2023).
There is increasing pressure from society in the face of the impacts of pesticide use on food contamination, and due to the toxicity present in the various environmental compartments, soil, air and water. This fact is confirmed in studies that show a strong association between cases of cancer, lymphomas, Parkinson's disease, Alzheimer's disease, reproductive and respiratory disorders, among other problems related to exposure to pesticides (Lopes-Ferreira et al., 2022;Basso et al., 2022;Baiotto et al., 2023). The current scenario of oat production shows the need for more sustainable agricultural practices, associating the identification of more resilient genotypes with reduced fungicide use and with a longer interval between the last application and grain harvest (Dornelles et al., 2021;Pradebon et al, 2023).
The adaptability and stability analysis can help in the identification of cultivars that are more resilient to the use of fungicide as well as in the identification of managements that promote a reduction in the use of pesticides, seeking more sustainable managements Moura et al., 2022). In this perspective, the model of Eberhart & Russell (1966) can help identifying oat cultivars with predictable behavior and that evidence the stimulus of positive responses in the absence and reduced condition of fungicide use (Franceschi et al., 2010;Silva et al., 2015). The model is based on a simple linear regression of the genotype as a function of environmental indices, which are obtained from different scenarios of interest (Kruger et al., 2016;Alessi et al., 2021). It is noteworthy that in the proposed scenario, seeking cultivars that are more resilient to fungicide use, the ideal genotype is the one with higher grain yield and less necrotic leaf area, with a regression coefficient equal to one (wide adaptability to favorable and unfavorable environments) or less than one (specific adaptability to an unfavorable environment) and with the smallest regression deviation, configuring genetic stability for this condition (Mohammadi & Amri, 2008;Loro et al., 2022).
The identification of oat cultivars with satisfactory productivity, and adaptability and stability to the reduction of fungicide use, can help in the positioning of potential genotypes and their incorporation into crossing blocks for the development of adjusted cultivars aimed at more sustainable management. Therefore, the objective of the study is to identify oat cultivars with satisfactory productivity and adaptability to the reduction of fungicide use concomitant with the longest interval between the last application and grain harvest, in the recommendation of biotype more adjusted to agroecological management.

MATERIALS AND METHODS
The work was carried out in the municipality of Augusto Pestana, RS, Brazil (28° 26' 30'' latitude S and 54° 00' 58'' longitude W) from 2018 to 2019. The soil of the experimental unit is characterized as a Typical Dystroferric Red Latosol (Oxisol), with a deep, well-drained profile, dark red color and high clay contents. According to the Köppen climate classification, the climate in the region is Cfa (humid subtropical), with well-distributed rainfall throughout the year, with an average annual volume close to 1600 mm and an average air temperature in the cold season of the year to around -3°C and in the hot season around 22°C.
Ten days before sowing, soil analysis was performed showing the following chemical characteristics (pH= 6.0; P=33.3 mg dm -3 K= 205 mg dm -3 ; MO= 3.1 %; Al= 0 cmolc dm -3 ; Ca= 6.7 cmolc dm -3 e Mg=2.8 cmolc dm -3 ). Sowing was carried out with a seeder-fertilizer in a soybean/oat cropping system between the second and third week of June in the different years, using a population density of 400 viable seeds m -2 , as recommended. The experimental plot ___________________________________________________________________________ Rev. Gest. Soc. Ambient. | Miami | v.17.n.3 | p.1-18 | e03417 | 2023. 4 consisted of 5 lines of 5 meters in length and 0.20 meters spacing for the composition of the experimental unit of 5 m². In order to meet the expected yield of 4000 kg ha -1 , a total of 60 kg ha -1 of nitrogen was applied, with 10 and 50 kg ha -1 directed at sowing and coverage, respectively. The top-dressing application was carried out at the expanded fourth leaf phenological stage. Based on soil P and K contents, 45 and 30 kg ha -1 of P2O5 and K2O were applied at sowing, respectively.
The experimental design was randomized blocks with three replications following a 23 x 5 factorial scheme, for 23 white oat cultivars and 5 fungicide application conditions, respectively. The oat genotypes used for the research represent cultivars recommended and no longer indicated for cultivation by the current Brazilian recommendation, namely: Barbarasul,Brisasul,FAEM 006,FAEM 007,FAEM 4 Carlasul,FAEM 5 Chiarasul, IPR Afrodite, IPR Artemis, UPFA Gaudéria, UPFA Ouro, UPFPS Farroupilha, URS 21, URS Altiva, URS Brava, URS Charrua, URS Corona, URS Estampa, URS Fapa Slava, URS Guará, URS Guria, URS Tarimba, URS Taura and URS Torena. The conditions of use of fungicides were defined in the time scale and applied in a cumulative sequential way, as follows: [control (no application); one application 60 days after emergence (DAE); two applications at 60 and 75 DAE; three applications at 60, 75 and 90 DAE and four applications at 60, 75, 90 and 105 DAE]. The conditions for using fungicides were proposed based on the possibility of increasing the interval between harvest and the last application of the pesticide (fungicide) by reducing the number of applications in a sequential and cumulative manner. In the dynamics of the application intervals, the residual time of action of the product was considered, which according to the recommendation has action for approximately 15 days. The fungicide used was tebuconazole, commercial name FOLLICUR® CE at a dose of 0.75 L ha -1 . In crop management, weed control was carried out by using the herbicide metsulfuron-methyl, trade name ALLY®, at a dose of 2.4 g ha -1 of the commercial product and weeding whenever necessary.
The variables analyzed were necrotic leaf area (AFN, %) and grain yield (PG, kg ha -1 ). In determining the necrotic leaf area, at 105 days after emergence, three plants were randomly collected from each plot for all cultivars and fungicide use conditions. From each plant, the three upper leaves were removed to evaluate the leaf area. The leaves were scanned using the Leaf Area Reader and WinDIAS Software (Copyright 2012, Delta-T Devices Limited) to determine the area of disease necrosis over the total leaf area. To estimate grain yield, the three central lines of each plot were considered, harvested manually when the grains had moisture around 15%. The plants were threshed with a stationary harvester and the grains were sent to the laboratory to correct the humidity to 13% and to determine the productivity in kg ha -1 .
The data were submitted to analysis of variance to detect the main and interaction effects between cultivars and fungicide use conditions. After a comparison test was carried out by Scott & Knott to analyze the performance of the cultivars in each condition of fungicide use. Under these conditions, the cultivars were classified as superior (S) and inferior (I) considering the mean plus or minus one standard deviation. Using the Eberhart & Russell (1966) model, adaptability and stability parameters were determined for an experiment with c cultivars, to different environments (fungicide use conditions) and r repetitions, with the following conceptual structure: Where is the average of cultivars in environments with different conditions of use of fungicide ; 0 is the general average of cultivars ; 1 is a linear regression coefficient that measures the response of the i-th cultivar to the variation of fungicide use conditions; is the standardized environmental index formed by the conditions of sequential cumulative application of fungicide, defined by: with = 1, … , and = 1, … , , where represents the number of environments (fungicide use conditions) and is the number of cultivars; 2 are the deviations from the linear regression and; ̅ average experimental error. The adaptability parameter estimator is given by: and the hypothesis is evaluated by the t test: H0i: = 1, whose statistic is given by: In which: The stability parameter is estimated from the mean square of the regression deviation of each fungicide use condition ( ) and the mean square of the residue ( ), given by the equation: in which is obtained by the equation: Where is the number of repetitions.
The adaptability and stability parameters by the regression method of Eberhart and Russell (1966), have as 0 representative of the general average of the genotype in the different environments. The adaptability parameter is estimated by the linear regression coefficient ( ), the genotype being adapted to favorable environments with > 1, adapted to unfavorable environments of < 1 and to those of broad adaptation, with = 1 (Crus & Carneiro, 2003). For stability analysis, genotypes with regression deviations ( 2 ) equal to zero (not significant) are considered stable, and unstable when 2 ≠ 0 (significant). The analyzes were performed using the GENES software (Quantitative Genetics and Experimental Statistics, version 2015.5.0).

RESULTS AND DISCUSSIONS
In figure 1, in the year 2018 there is an adequate distribution of precipitation throughout the cycle, with minimum and maximum temperatures around 0 and 30ºC, respectively. At the time of nitrogen application, there was adequate soil moisture for nutrient use. In 2019, adequate soil moisture was also observed at the time of nitrogen application, however, with rainfall with values above 40 mm soon after the nutrient application, a condition that tends to promote nitrogen losses through leaching and surface runoff. In addition, in 2019, a greater amplitude of variation of minimum and maximum temperatures was observed, ranging from -4 to 36ºC, configuring a greater stress in the biology of this species. In table 1, in 2018, the necrotic leaf area analyzed at 105 days after emergence in the absence of fungicide (SF) and with one application (CF1) at 60 days after emergence shows practically total leaf necrosis, with no statistical differences by the average test. However, with one application (CF1), the cultivar URS Estampa was below the distribution average, representing the genotype that shows greater statistical superiority. The highest averages of grain yield were obtained with cultivars URS Altiva, URS Brava, URS Guará and IPR Artemis, without pesticide application, and with cultivars Brava and Tarimba by performing an application at 60 days after emergence. It is noteworthy that the differentiation between cultivars became more evident after the second application of fungicide, although more than 50% of the leaf area was necrotic, even with four applications of the agrochemical. Therefore, the performance of two fungicide applications (CF2), at 60 and 75 days after emergence, show that half of the evaluated cultivars represented the "b" group with the smallest necrotic leaf area, however, within this group, the superiority of the average minus one standard deviation was obtained only in the cultivars URS Altiva, URS Brava, Faem 4 Carlasul, URS Fapa Slava and IPR Afrodite. In this condition of fungicide use, the cultivars URS Altiva, URS Brava, also showed superior productivity, along with URS Torena, URS Tarimba, URS Taura and IPR Artemis. The performance of three fungicide applications (CF3), at 60, 75 and 90 days after emergence, highlights the superiority of the cultivars URS Brava, URS Estampa, Faem 5 Chiarasul and IPR Artemis. In the analysis of grain yield, considering the use of three fungicide applications, although the vast majority of cultivars show more expressive average values "a", superiority was only obtained for cultivars URS Taura, IPR Aphrodite and IPR Artemis. The use of four applications of the fungicide (CF4) at 60, 75, 90 and 105 days after emergence leads to a short interval from the last application to the harvest of the grains, which can compromise the safety of the product due to the residual level present, in addition to the results being similar to the management of three fungicide applications. In table 2, in the year 2019 in the condition of absence of fungicide (SF), the cultivars Brisasul, UPFPS Farroupilha and UPFA Ouro stood out for their superiority with the smallest necrotic leaf area. With one application (CF1) at 60 days after emergence, differences by the average test were observed, highlighting the cultivars URS Estampa, Faem 5 Chiarasul, Brisasul, IPR Afrodite and UPFA Ouro, representing group "b". Within this group, the superiority in the average minus one standard deviation was observed in the cultivars URS Estampa, Brisasul, IPR Afrodite and UPFA Ouro. The fungicide application at 60 and 75 days after emergence (CF2), a condition in which the oat does not yet have an exposed panicle, shows in almost half of the analyzed cultivars, more expressive values of reduction of necrotic leaf area "b", within of this group the superiority obtained only for URS Estampa, URS Taura and IPR Artemis. The cultivar Estampa stands out for the expressive reduction of the necrotic leaf area with the accomplishment of one or two applications, before the paniculation.
The performance of three applications (CF3) at 60, 75, and 90 days after emergence (Table 2) showed a strong reduction in necrotic leaf area in cultivars URS Taura and Faem 4 Carlasul, representing the "c" group, but the superiority in mean minus one standard deviation also qualify the cultivar URS Brava. Applications at 60, 75, 90 and 105 after emergence (CF4) also show superiority of lower necrotic leaf area for cultivars URS Taura and URS Carlasul, effectively showing the strong dependence of these genetic constitutions on the use of pesticides. Also, in table 2 in 2019, the absence of fungicide use (SF), shows expressive means of productivity "a" for the cultivars URS Altiva, URS Charrua, FAEM 006, UPFA Ouro, UPFA Gaudéria and IPR Artemis. Of these, only the cultivar FAEM 006 did not represent the superiority group of the mean plus one standard deviation. A single application (CF1) at 60 days after emergence showed greater expression of grain yield only in the UPFA Gaudéria cultivar, however, with superiority of the average plus one standard deviation also for Estampa. Fungicide application at 60 and 75 days after emergence (prior to paniculation) show a large number of cultivars with superior performance "a". However, within this group, superiority was obtained for the cultivars FAEM 5 Chiarasul, IPR Afrodite, UPFA Ouro and UPFA Gaudéria.
The use of three fungicide applications (CF3) at 60, 75 and 90 days after emergence showed more expressive values of averages in the cultivars URS Tarimba, IPR Afrodite, UPFA Ouro and UPFA Gaudéria (Table 2). These were also the ones that represented the superiority group of the mean plus one standard deviation. It is noteworthy that these same cultivars were the ones that showed superiority of the mean plus one standard deviation with four fungicide applications, except IPR Artemis, which did not follow the superiority pattern. In general, the cultivar URS Estampa showed superior performance by the average test for grain yield and superiority for necrotic leaf area, demonstrating a genetic potential for cultivation with reduced use of fungicide. In table 3 of the adaptability and stability parameters of grain yield and necrotic leaf area by the number of fungicide applications in 2018, the superiority of yield and specific adaptability to more unfavorable environments (less fungicide use) for cultivars URS Altiva and URS Brava, configuring genotypes with a potential direct relationship to resilience to fungicide reduction, with greater genetic control in withstanding pathogen pressure. Also the cultivars URS Tarimba, URS Taura and IPR Artemis showed superiority in productivity with general adaptability, adjusted to favorable and unfavorable environments, but a greater tendency to dependence on fungicide. In addition, IPR Aphrodite showed superiority with specific adaptability to a favorable environment, with greater dependence on the use of agrochemicals. Of all the cultivars mentioned, the cultivar URS Altiva stands out, which also shows productivity stability due to the conditions of fungicide use in a specific adaptability condition to withstand the pressure of the inoculum, unlike URS Brava, which did not show stability.
Still in table 3, the superiority of the necrotic leaf area by the mean minus one standard deviation highlighted only the cultivars URS Brava, URS Estampa and IPR Artemis. URS Brava and IPR Artemis were also superior in terms of grain yield, with the exception of URS Estampa. It was observed that for the necrotic leaf area, all showed specific adaptability to favorable environments, but with stable expression of URS Brava and IPR Artemis. There is a good coincidence between the superiority of smaller necrotic leaf area and superiority of greater grain yield. 1989 85 * = Significant at 5% probability by the F test; ns = Not Significant; 0 = general average of the cultivar; 1 = linear regression coefficient; R 2 = Determination Coefficient. 2 = Eberhart and Russell model; SD = standard deviation; S = superior genotype, for GY S= mean plus one SD, for NLA S= means minus one SD. Source: Prepared by the authors (2023).
In table 4 of the adaptability and stability parameters of grain yield and necrotic leaf area by the number of fungicide applications in 2019, superiority was obtained only for the cultivars IPR Afrodite, UPFA Ouro and UPFA Gaudéria in grain yield. Among these, IPR Afordite and UPFA Ouro showed specific adaptability to favorable environments, justifying a greater dependence on the use of fungicide, with stability in the face of the number of applications. On the other hand, the UPFA Gaudéria showed general adaptability, indicating that it is more adjusted to favorable and unfavorable environments, but with productivity instability due to the number of applications. In fact, of all the cultivars evaluated, it was the only one that showed instability. In the analysis of the necrotic leaf area, evaluated at 105 days after the emergence of the plants (Table 4), only the cultivars URS Estampa, URS Taura, FAEM 4 Carlasul and UPFA Ouro were superior in the mean minus one standard deviation. Among these, general adaptability with stability was confirmed for URS Estampa and UPFA Ouro, but with specific adaptability to favorable environment. In this condition, a reduced coincidence between superiority of expression of necrotic leaf area and superiority of grain yield stands out. This condition raises the hypothesis that the year 2019 was more restrictive to cultivation, with a reduction in productivity to the greater detriment of abiotic conditions than the effect by the pathogen. However, the cultivars that showed superior productivity and necrotic leaf area in 2018, whether with broad or specific adaptability and stability, did not show this same trend for 2019, with the exception of a single cultivar, IPR Aphrodite. Table 4 -Average values and parameters of adaptability and stability in oat cultivars of grain yield and necrotic leaf area at 105 days after emergence in 2019.
The meteorological conditions observed during oat cultivation in 2018 are adequate for the development of the cereal, with adequate use of nitrogen and obtaining a grain yield of 2228 kg ha -1 . This year, there is a favorable environment for the development of oats with good distribution of rainfall and milder temperatures compared to 2019. In 2019, the weather conditions were unfavorable, reflecting low grain productivity, around 1752 kg ha -1 . This year was characterized by well-distributed rains, however, with a high volume close to the completion of fertilization, together with a strong fluctuation in temperature. It is noteworthy the occurrence of severe frost at 20 days after emergence and temperatures around 35°C from the grain formation phase until harvest. This condition reinforces the presence of an unfavorable environment for the development of oats and favorable to the emergence and progression of fungal diseases.
The productive performance of oats is strongly influenced by meteorological conditions that change the availability of nitrogen and the efficiency of use by the plant, with reflections on productivity and grain quality Reginatto et al., 2022). In cereals such as oats, the crop year condition is defined from the volume of rainfall and its distribution throughout the cycle, a condition that influences the relative humidity of the air along with the variation in temperature (Reginatto et al., 2021;Henrichsen et al., 2022). Well-distributed and smaller amounts of rainfall favor adequate soil moisture, characterizing an ideal condition for management and better use of nitrogen for greater expression of grain yield, reducing fertilizer losses (Marolli et al., 2018;Trautmann et al., 2022). In addition, favorable years for oat cultivation are characterized by minimum air temperatures of 4 to 5°C and maximum of 30°C, with an optimum temperature of 25°C. In oat cultivation, nitrogen absorption efficiency is maximized by the presence of a favorable environment for plant development (Spasova et al., 2013;. Under conditions of high temperature and relative humidity, they characterize a favorable environment for the emergence of foliar diseases, especially those caused by fungi of the Puccinia spp. and Drechslera spp. (Dornelles et al., 2021;Marolli et al., 2021). These diseases are potentiated by temperatures above 18°C with leaf wetness periods of 8 hours or more (Deuner et al., 2021). In this configuration, it is verified that in both years of oat cultivation, the cultivation period was characterized by high thermal amplitude, with maximum temperature above 20°C, mainly from 70 days after emergence. Although the high temperature is essential for the development of fungal diseases, the occurrence of precipitation is a key element for the onset of infection, in addition to favoring the spread of fungi in the area (Byamukama et al., 2019). The combination of these meteorological characteristics reflects the higher prevalence of foliar diseases, especially in the formation and grain filling phases, a condition that requires a greater number of fungicide applications for control (May et al., 2020).
The use of fungicidal pesticides is necessary when seeking greater economic return from the crop . However, reducing dependence on these chemicals is one of the goals to achieve more sustainable agriculture in the environmental, economic and social spheres, with food security guaranteed (Lykogianni et al., 2021;Rosa et al., 2022). For this, it must be considered that the efficiency and profitability of fungicide application is influenced by cultivar susceptibility, disease pressure, weather conditions and grain price at the time of marketing (Byamukama et al., 2019;Dornelles et al., 2021). In this sense, the identification of oat cultivars with genetic resistance or more responsive to fungicide management is a way to ensure the cultivation of genotypes that add greater economic return to the farmer due to higher grain productivity and less dependence on the use of pesticides. On the other hand, the results presented in table 1 demonstrate that not always the cultivars that have superiority due to the reduction of necrotic leaf area are necessarily the ones with the highest grain yield. This fact can be observed in the cultivar Estampa with superiority in the different conditions of fungicide use, but at no time was it superior in the expression of grain yield (Table 1). In addition, the cultivars with superiority in a greater number of applications represented genotypes strongly dependent on the use of fungicide, a condition that generates dependence among farmers on the use of agrochemicals, increasing production costs, environmental pollution and the possibility of residues in food.
According to Dornelles et al. (2020) cultivars with high grain yield are not necessarily those with less necrotic leaf area, thus, leaf necrosis does not demonstrate a direct relationship in grain yield by the hypothesis of increased photosynthetic efficiency of non-necrotic tissue. This fact can be seen in Table 1 with the cultivars URS Torena and URS Tarimba in the year 2018 and in Table 2 with the cultivar Chiarasul in the year 2019. These cultivars stand out for their inferiority in the analysis of the necrotic leaf area with two applications of fungicide (CF2) showing superiority in grain yield in the same condition of pesticide use. On the other hand, the cultivar URS Brava showed great potential to reduce the use of fungicide with satisfactory grain yield (Table 1). It is noteworthy that this cultivar is the only one to show superiority of lower necrotic leaf area corresponding to the superiority of expression of grain yield in the year 2018. In 2019 (Table 2) the cultivars UPFA Ouro and URS Estampa were the ones that showed superiority in both variables analyzed for the conditions of absence of fungicide and one application of the pesticide, respectively.
The analysis of the cumulative application of fungicide in oats is important to define more assertive management in the search for satisfactory productivity combined with greater economic efficiency with environmental quality. In this sense, cultivars with genetic resistance and/or responsive to less use of fungicide pesticides are required to qualify crop indications and promote the use of more adapted genotypes in genetic improvement programs. In this perspective, studies were also developed by Alessi et al. (2018) in oats and Sacon et al. (2018) in soybean. It is noteworthy that two applications of fungicide at 60 and 75 days after emergence shows a large interval from the last application of the pesticide to harvest. In addition, the application is directed at the stage prior to grain filling, raising the hypothesis of the impossibility of mobilizing agrochemicals to the grains.
The results indicate the need for a sequence of studies, providing opportunities for different environmental conditions to strengthen the patterns of behavior to reduce the use of fungicides depending on the application conditions, analyzing separately the conditions of each agricultural year. This scenario can show that the genotype expression depends on the condition of the environment resulting in changes in behavior . Studies carried out by Alessi et al. (2018), working on the relationship between genetic resistance to diseases with the time of application of the fungicide, had already been warning of the need for studies within this line of action. The same genotype can express different behaviors, due to numerous environmental effects, conditions also observed by Franceschi et al. (2010). In some cases, due to the inconsistency of the superiority of the genotypes in the environments, the use of specific cultivars for each environment or with high adaptability and stability has been recommended (Cruz et al., 2020). Adaptability is understood as the ability of the genotype to benefit from environmental variations, while stability reflects the ability of genotypes to show highly predictable behavior in given environmental stimuli Loro et al., 2021).
The adaptability and stability analyzes make it possible to identify the cultivars that present the most stable behavior and predictable responses to environmental variations, making it possible to evaluate the best genotypes and recommend the best specific cultivars for the region. Thus helping to optimize management techniques, ensuring productivity and grain quality and especially food and environmental safety. For Krüger et al. (2016) it was possible to indicate the most suitable arrangement of two canola hybrids considering meteorological conditions of the different seasons through the Eberhart & Russell method, contributing to a better crop management. Franceschi et al. (2010) analyzed the adaptability and stability in wheat cultivars in the state of Paraná, noticed cultivars with high stability, evaluated by the Eberhart & Russell method, indicating adjusted grain yield with stability to environmental conditions. Rother et al. (2019) using Eberhart & Russel noted that the method is efficient to accurately estimate adaptability and stability of white oat cultivars, analyzing the hectoliter mass, thousand-grain mass and grain yields and characters of interest to the industry.
Phenotypic characteristics, such as productivity, generate great economic impact due to the strong dependence on genotype, environment and the genotype versus environment interaction. In this way, the same cultivar can present different behaviors during years and places of cultivation. Favorable climatic conditions increase the possibilities of achieving higher yield potential with reduced use of inputs (Crestani et al., 2010;. In addition to the edaphoclimatic factors directly linked to grain yield and quality, leaf rust is a disease with great severity, causing enormous economic and environmental damage due to the need to use fungicides. One of the main sustainable control measures is genetic resistance (Capistrano et al., 2020). However, in this species, it is difficult to fully resist the main diseases. Caierão et al. (2001) verified the influence of the severity levels of the foliar disease on the yield of white oat, which indicates that the increase in the incidence of leaf rust negatively influences the yield and quality of oat grains, making commercialization unfeasible. The desired white oat pattern requires cultivars of high grain yield with the technological standard recommended by the cereal industry. Therefore, the high percentage of caryopsis, high hectoliter mass and grain size have been increasingly demanded (Crestani et al., 2010;. These characteristics are not always obtained as a result of climatic factors and the prevalence of fungal diseases (Nerbass Junior et al., 2008;Kraisig et al., 2020). In modern agriculture, it is crucial to recommend cultivars with high grain yield and sensitive response to variations, taking advantage of improved environments or that produce reasonably in adverse conditions (Crestani et al., 2010;Alessi et al., 2021). Thus, it is essential to identify oat genotypes with high performance in characters of agronomic and industrial interest. As the cultivars are less demanding on the use of fungicide and with adaptability and stability, which can favor a more sustainable production of oat cultivation.

FINAL CONSIDERATIONS
Experimental strategies with the analysis of adaptability and stability help to identify oat cultivars that are more resilient to the absence or reduction of fungicide use, promoting more sustainable management.
The cultivars URS Brava and URS Altiva present satisfactory productivity with adaptability to the absence or reduced use of fungicide, providing a safe interval from the last application to the grain harvest, with a suggestion for the indication for agroecological management.
The results obtained show the possibility of advances in the production of oats with a reduction in the use of fungicidal pesticides, bringing environmental benefits and food security. In this context, it is necessary to promote food security based on new scenarios, which requires a much broader and systems-based approach, including the environment, technology, economy and society, at all levels of the organization.