Wheat is one of the most important cereals globally, playing a vital role in human nutrition and the agricultural economy. To guarantee high productivity and a quick and uniform plant stand, it is necessary to make the right choice of seed, taking into account the quality of the seed and the cultivar that is best adapted to your region.
- Seed quality
Influenced by four fundamental attributes: genetic, physical, health and physiological. Genetic quality encompasses characteristics such as varietal purity, homogeneity, resistance to diseases and insects, precocity, height, among others. Physical quality is expressed by purity (separation, quantification and identification of all materials that make up the batch) and the physical condition of the seed (moisture content, size, color, density, mechanical damage and damage caused by insects). Sanitary quality comprises the presence and degree of occurrence of fungi, bacteria, viruses, nematodes and insects that cause damage to seeds. The physiological quality of the seed is related to its ability to perform vital functions and is analyzed through vigor and germination tests carried out in laboratories.
- Germination
Germination is the main test carried out in the laboratory to determine the physiological quality of seeds and expresses the seed's ability to form a normal seedling under normal conditions. The seeds have reserve material, which is used during the first few days to germinate and emerge. Furthermore, for a seed to germinate and form a plant, it is also essential that the environmental conditions are adequate. This relationship between environmental conditions and seed germination is crucial, especially when it comes to germination rate, an essential parameter for seed commercialization.
Each seed species has a marketing standard, for wheat the minimum germination is 80%. Therefore, the germination test evaluates the percentage of seeds in the batch that germinate under favorable conditions of water, light and temperature. However, in the field, environmental conditions are not always favorable. Therefore, under favorable conditions, seed vigor is a fundamental attribute for germination.
- Vigor
Vigor is the seed's potential to germinate and emerge quickly, producing normal seedlings in a wide range of environmental conditions. Seeds with high vigor have the ability to tolerate stress, such as lack of water, light and non-ideal temperatures, and still germinate and emerge, forming normal seedlings.
- Certified seeds
The preference for certified seeds is a very important aspect to evaluate when choosing the seed, after all, they are the most important input in agriculture, which carry the plant's full productive potential, in addition to investment in genetic improvement and biotechnology.
Characteristics to take into consideration when choosing a wheat cultivar
Once you choose a certified seed with high germination and vigor, you need to take some care to ensure that the chosen cultivar performs well in your crop. Selecting the right cultivar is one of the most critical factors for the success of a crop. Although some varieties have high productivity rates, they are not always equally effective in all growing conditions.
The type of cultivar selected is what determines the variations in wheat planting in different regions of Brazil, since each cultivar is developed to adapt to the specific microclimate of its respective region, so that losses are minimized and the desired productivity is achieved. achieved. Therefore, we must pay attention to some decisive factors, such as:
- Resistance to lodging
When there is excess rainfall for long periods during the tillering phase, some of these cultivars may present exaggerated vegetative growth. There are some managements to minimize wheat lodging:
use of recommended sowing densities;
use of nitrogen fertilizer applied shortly after the plants emerge, when they have two to three unfolded leaves. If nitrogen is applied at the end of tillering, there is a tendency to increase the length of the plants' stem internodes, favoring lodging;
use a growth reducer (trinexapac-ethyl) to manage lodging in cultivars, however, as it is a hormonal inducer, the product must be used with great care to avoid toxic effects on the crop.
- Disease resistance
Diseases can negatively affect wheat plant development.
In order to reduce the incidence of diseases, the producer must analyze and know the history of his area and the region in which wheat will be sown, in order to know the main recurring diseases in recent harvests and choose cultivars resistant to them.
In periods of recurrent rain, the main pathologies that affect wheat are Fusarium head blight (Gibberella zeae) and Blast (Pyricularia grosso). Other common diseases are: Leaf spots, Leaf rust (Puccinia triticina) and Powdery mildew (Blumeria graminis f. sp. tritici).
For effective disease control, it is essential to adopt some measures. This includes the use of certified and high-quality seeds, the preference for resistant cultivars, adequate seed treatment, the practice of crop rotation - as many pathogens can persist in crop residues, as in the case of yellow spot. Additionally, it is important to consider implementing chemical control measures when necessary.
- Resistance to germination on the cob
Germination on the cob is a problem that occurs in regions where rainfall occurs for a relatively long period (three to four days) close to the grain's maturation. This condition occurs very frequently during the wheat harvest period in the South and Center-South regions of Brazil. Germination in the cob causes losses in yield, due to increased threshing of the cob and the elimination of germinated grains by the harvester, in addition to drastically reducing the hectoliter weight of the grain, since the weight/volume relationship is greatly affected in germinated grains. In some situations it is necessary to harvest with 18% to 20% humidity to avoid germination on the cob. Therefore, depending on your region, it is very important to invest in cultivars that have some level of resistance to ear germination, as this will reduce losses, however, increase productivity.
