​Germination test in corn crops

Corn culture is of great importance on the national scene, being cultivated to feed pigs and poultry, where approximately 70% of production is consumed, being one of the most planted crops in the country.

In 2011, according to the Brazilian Institute of Geography and Statistics (IBGE), corn was the second crop with the largest planted area in the country, having been planted at 13.585.807/ha, behind only soybeans cultivated at 24.082.345 .9.139.834/ha and was even ahead of sugar cane, which was planted at XNUMX/ha.

The corn, zea mays, is a quick emergence plant. Under ideal conditions of light, temperature and humidity in the environment in which the seed was sown, emergence occurs four to five days after sowing, making corn a great plant to carry out and demonstrate how to carry out a germination test.

Much is said about seed germination, the productivity of the batch to which it belongs, that the greater the germination of a batch of seeds, the greater the profit and the lower the loss for a producer. However, few know how to discover the germination of a batch of seeds, what a standard test is and which germination tests are used.

Seed germination is the emergence of the seedling and its essential structures from the embryo (root system, coleoptile and aerial part). In the laboratory it is the emergence of the seedling and structures, so that the plant can have good development in the field under favorable conditions.

The standard germination test serves to identify the quality of a batch of seeds, with a simulation of how it would behave in the field and how it differs from other seeds. The test is carried out in the laboratory, with the aim of obtaining all favorable conditions for seed development: temperature, lighting and water. Germination percentage corresponds to the number of seeds that produced seedlings considered normal.

Four types of substrates can be used in the standard germination test: paper, sand and water. However, in the laboratory, the usual practice is paper and water. The choice will depend on some factors of the seed and its requirements such as size, water requirement and light.

Germination test in sand must use material with relatively uniform grains, neither very large nor very small particles. It is interesting that the particle size is between 0,8mm and 0,05mm. The sand must be free from any contamination to prevent the contaminant from hindering seed germination. If testing sand in the laboratory, it is recommended that it be autoclaved at 120ºC for one hour and maintain a pH between 6 and 7,5.

To carry out the test, it is important to place the seed buried 1cm, exerting a small pressure with water and a controlled photoperiod. Soil can also be used as a substrate, however, to obtain more accurate results, it should not be used, especially in the laboratory.

In the laboratory, the most commonly used standard test is paper, which can be a towel, blotter or filter. These papers have the capacity to retain water to meet the needs of the seeds. It must also be porous, with plastic bags to protect it from impurities and possible damage.

The main purpose of this work is to familiarize the reader with the analysis method for checking the germination of a batch that does not have an arrival date and/or has not been packaged correctly, with the aim of knowing whether it still maintains its vigor.

This practice was carried out in a laboratory, at the Federal University of Ceará, by the Agricultural Machinery Accident Investigation Laboratory (Lima) and the Research Group on Energy and Machinery for Semiarid Agriculture (Gemasa) with seeds already existing at the university, without batch and defined date.

The standard germination test was carried out on germ test paper, a substrate that is simple to work with and safer, with a good percentage of germination. Storage carried out in a B.O.D. ensures ideal temperature conditions between 25ºC and 30ºC, an ideal photoperiod for germination and good humidity maintenance.

The materials used were 15 sheets of germ test paper, six alloys, a precision scale, B.O.D chamber, seed counter. 300 seeds were analyzed.

First, the corn seeds were cleaned with a 10% sodium hypochlorite solution for one minute and then with commercial alcohol for five minutes. Soon after, the materials used were aseptically cleaned: alloys, the table where the assembly was carried out and the hands of the roller handler.

15 sheets of germ test paper were used and they were all weighed together on a precision scale. The measured weight was multiplied by two and the result obtained was the amount of distilled water placed on the leaves.

The sheets were separated into six groups, with two sheets each and three more to be placed on the outside, one for each group of two rolls. Handling the two leaves, the top leaf was removed and 50 seeds were placed in a seed counter and distributed on the leaf. Afterwards, the second sheet was placed on top, closing it to make a roll. This procedure was repeated with the second group of leaves. With the remaining foil, the two rolls were wrapped to form a straw, placing the garters one at the top and the other at the bottom. The procedure was repeated for the remaining leaves.

The straws were taken to a B.O.D. chamber. and left for six days. At the end of this time, the seeds that did not germinate and the normal seedlings were counted. This analysis is known as test interpretation. After counting, the calculation was made.

Table 1 - Germination of corn seeds

Rollers	Seeds that did not germinate	Normal seedlings	Abnormal seedlings	Germination percentage (%)
1	4	42	4		83
2	2	41	7
3	5	39	6		82
4	4	43	3
5	2	40	8		84
6	4	44	4

Rollers

Seeds that did not germinate

Normal seedlings

Abnormal seedlings

Germination percentage (%)

1

4

42

4

83

2

2

41

7

3

5

39

6

82

4

4

43

3

5

2

40

8

84

6

4

44

4

The germination percentage of straw 1 was 83%, the second reached 82% and the third reached 84%, with an average germination of 83%, below that recommended for the species and verified by Embrapa (2010) which is 90 %. There was also a loss of vigor with the passage of time and packaging conditions.

This practice highlights the need for correct packaging and marking of seed batch data, such as arrival time and germination efficiency, so that standard germination tests can be carried out to find out if seed vigor remains the same and if planting will provide a quality stand.

Click here to read the article in Revista Cultivar Grandes Culturas, issue 177.