What issues should be noted when selecting the latest corn seed varieties?

Excellent varieties and seeds are the foundation of a good harvest, and variety selection is the first step in corn production. Varieties differ greatly in growth period, yield level, disease resistance, drought tolerance, disease resistance, lodging resistance, and suitable regions. A variety that performs well in one region may perform poorly in another. In production, there are often cases where improper variety selection or poor-quality seeds lead to reduced yields or even total crop failure. How to choose the excellent varieties and seeds that suit your needs is an important issue that corn producers must face. It is generally believed that the following points should be noted:

1. Choose varieties that have been tested and demonstrated locally for at least 3 years

After 3 years or longer of local testing and demonstration, the local adaptability of a variety can basically be known. Choosing varieties that have performed well over many years and at many sites makes the possibility of various catastrophic losses in production relatively small.

2. Choose varieties that can mature normally in the local area

Choose early-maturing and medium-late-maturing varieties that can mature normally in the local area, and use late-maturing varieties less. Before the first heavy frost in autumn, grain corn must reach physiological maturity or develop a black layer; otherwise, grain moisture content is higher, test weight is lower, and commercial quality declines. With climate change, in some years the autumn frost comes later, and two or three consecutive years of late frost often cause people to lower their vigilance and plant some varieties with longer growth periods, resulting in relatively large losses. This often occurs in the spring corn region of Northeast China and the summer corn region of northern North China.

3. Choose varieties with high production potential and wide adaptability

Varieties with similar growth periods can differ greatly in yield potential. The production potential of a variety cannot be determined by special traits such as ear size, number of rows per ear, number of kernels per row, kernel depth, double-ear rate, and upright (compact) versus spreading leaves. The production potential of a variety is reflected in its yield level. Therefore, varieties should be selected based on the yield results of variety comparison trials, not merely because of traits such as ear size and double-ear rate. Because climate is unpredictable and variable, choose varieties that have a high yield level across multiple sites, multiple regions, and multiple environments.

4. Choose varieties with high lodging resistance

Choosing lodging-resistant varieties is very important, especially in windy areas. Although lodging is closely related to the environment and cultivation measures, genetic differences among varieties are also an important cause of lodging. Lodging generally includes lodging during the growth period and lodging after maturity. Lodging during the growth period is more harmful and can lead to total crop failure in severe cases; while lodging in the late growth period or after physiological maturity has a relatively small impact on yield, it often causes quality decline, grain rot, increased rodent losses, and greater harvest difficulty and harvest cost.

5. Choose disease-resistant or disease-tolerant varieties

Disease is an important disaster in corn production. In recent years, the main feature of variety improvement and renewal has been the continuous improvement of disease resistance. The main disease types and severity differ among regions. For example, head smut is a major disease in corn production in the spring corn region of Northeast China, while its damage is relatively light in the Huang-Huai corn region. In addition to referring to variety characteristic descriptions, comparison trials by local seed companies or agricultural technology extension departments, disease resistance of varieties should also be based on the planting experience of other farmers.

6. Plant multiple maturity periods and multiple varieties in combination

Planting multiple maturity periods and multiple varieties in combination is one of the most effective measures to reduce pests and diseases and resist adverse environmental conditions such as drought and low temperature. Strip-intercropping combinations of multiple maturity periods and multiple varieties, such as early-maturing, medium-maturing, and late-maturing varieties in a 25%-50%-25% combination, can reduce yield loss caused by failure to meet flowering time and poor pollination in early and medium-early maturing varieties due to drought. At the same time, it can allow varieties with long growth periods to make full use of light and heat resources and reduce the degree of damage from early autumn frost. In addition, combined planting of varieties with multiple maturity periods can increase the genetic diversity of corn and reduce losses caused by the loss of varietal resistance.

7. Choose special-purpose varieties for special needs

For special needs, such as feeding or processing, choose special corn varieties, such as high-starch varieties, high-oil varieties, quality protein corn varieties, waxy corn, sweet corn, etc.

8. Choose practical varieties

At present, most farmers are interested in new varieties. This reflects the improvement of farmers' own scientific and technological production level and their desire for new technologies. However, it should be pointed out that new varieties are not necessarily suitable for the needs; choose varieties that match production management level, soil fertility status, and so on.

In addition, under current management conditions, some new varieties have not undergone many years and many sites of local testing, and whether they can adapt to the local environment is not yet clear, so the planting risk is relatively greater. Therefore, variety selection should start from practicality, and do not seek only what is new. Choose high-quality seeds. Seed quality has a great impact on yield, and its impact sometimes exceeds the yield differences among varieties. Therefore, in production, it is necessary not only to choose good varieties but also to choose high-quality seeds.

At the current stage, the indicators used in China to measure seed quality mainly include four items: varietal purity, seed cleanliness, germination rate, and moisture. The state has made clear provisions for the four indicators of corn seed purity, cleanliness, germination rate, and moisture. For grade-one seeds, varietal purity is not less than 98%, cleanliness is not less than 98%, germination rate is not less than 85%, and moisture content is not higher than 13%; for grade-two seeds, varietal purity is not less than 96%, cleanliness is not less than 98%, germination rate is not less than 85%, and moisture content is not higher than 13%. China's inspection and supervision of corn hybrid seeds adopts the method of “setting a lower quality limit”, that is, seeds that do not meet the stipulated grade-two seed indicators cannot, in principle, be sold as seeds.

That is all for the issues to note when choosing corn seed varieties. For more knowledge about corn seeds, please continue to follow us!