Seed germination measurements refer to the process of measuring various parameters related to the growth and development of seedlings after they have been planted. These measurements can provide important information about the quality and viability of the seeds, and can be used to optimize plant growth and maximize yield.

Contents

- 1 Introduction
- 2 Sections of the tool
- 3 Getting the output
- 4 Methodology for calculations
- 4.1 Germination percentage
- 4.2 Relativized percentage
- 4.3 Mean germination time
- 4.4 Mean germination rate
- 4.5 Uncertainty of germination process
- 4.6 Synchrony of germination process
- 4.7 Coefficient of variation of germination time
- 4.8 Germination index
- 4.9 Coefficient of velocity of germination
- 4.10 Time to 50% germination
- 4.11 Mean daily germination percent
- 4.12 Peak value
- 4.13 Germination value

- 5 How to download excel tool
- 6 References

### Introduction

Seed *germination* refers to the physiological process culminating in the emergence of the embryo from its enclosing coverings, which can include the endosperm , perisperm, testa, or pericarp. The visible indication that germination has been completed is when the radicle (or other embryonic tissue) emerges from the tissues enclosing it. This point marks a clear end to germination and the start of seedling growth. There are many ways to measure the attributes related to seed germination.

This effort was made to develop an excel tool for making ease in calculations related to some important seed germination measurements. By using this tool a researcher can enter data up to 200 counts. First I shall discuss how to enter data and get the output and then will describe the methodology used for parameters or germination attributes.

### Sections of the tool

The first sheet of the tool is a data entry sheet which is comprised of 44 different sections. The detail of each section representing how to enter values is given below.

#### Section-I

First section (section-I) specifies the treatment labels. The labels `Rep`

, `Factor A`

, `Factor B`

and `Factor C`

are just to represent the treatment combinations. There is no hard and fast rule to enter exactly the same variable levels in its respective column. However, you can enter any sequence of treatment combinations in this section but *make sure* the combination entered in this section are in accordance with the germination count values entered in the n_{i} section.

#### Section-II

This section represents the number of seeds used in each experimental unit. According to the section-I treatment level, enter the number of seeds used in that specific experimental unit.

#### Section-III

Third section of the tool represent the time interval (t_{i}) used for each count. The values for time taken for each count will be entered in this section. If time interval is 2424 hours or 11day and germination completed on 66^{th} day then enter values from 1 to 6 in t_{1} to t_{6} in this section.

If time interval for each count is 88 hours then enter values in the sequence of 88, 1616, 2424, 3232, 4040 and 4848 in t_{1} to t_{6} in this section. Similarly, count interval can be in minutes, weeks or months so use the values for t_{i} accordingly.

#### Section-IV

This section is labeled as the n_{i} section and it specifies the number of seeds germinated in each count. In accordance with the treatment label in section-I and t_{i} section, enter the number of seeds germinated in this n_{i} section.

`paste special`

: Make sure if you are pasting values in each section then right click on the starting cell, choose paste special, check *values and number formats* and then click OK.

### Getting the output

The second sheet of the tool `Analysis result`

represent the output of the data entry sheet. To get the results from this sheet do the following:

- Select the output including the treatment labels and variable names.
- Press
`Ctrl + N`

to open a new worksheet - Go to the first cell, right click and choose
`paste special`

- Check the box
`values and number formats`

and click`OK`

. - Delete empty column if any

Now the results can be used to further fit analysis of variance model to see the significance of treatment factors followed by suitable mean comparison test if necessary.

### Methodology for calculations

The output will show more than 13 attributes related to seed germination measurements. Here, I shall briefly describe how these measurements were computed.

#### Germination percentage

Germination percentage is an estimate of the germinability of the population of seeds. The equation to calculate germination percentage is:

$$G\: (\%) = \frac{\sum_{i=1}^k\:n_i}{N}\:\times\:100$$

Where;

\(n_i =\) number of seeds germinated in the \(i^{th}\) time

\(N =\) Total number of seeds used

#### Relativized percentage

The germination percentage can be relativized by the following equation (Fitch et al. 2007):

$$R\:(\%) = \frac{AP}{HP}\:\times\:100$$

\(AP =\) actual percentage

\(HP =\) highest percentage amongst group of data

This standardization allow comparisons among treatments equivalent when amount of dormancy broken varied

#### Mean germination time

Mean germination time is a measure of the rate and time spread of the germination. It indicates time spent to germinate or emerge. Following formula was used to calculate the mean germination time (Ellis and Roberts 1981):

$$\bar{t} = \frac{\sum_{i=1}^k\:n_it_i}{\sum_{i=1}^k\:n_i}$$

Where;

\(n_it_i=\) The product of seeds germinated at interval \(i^{th}\) with the corresponding time interval

\(n_i=\) number of seeds germinated in the \(i^{th}\) time

#### Mean germination rate

Mean germination rate is the reciprocal of the mean germination time as shown below (Ranal et al. 2009).

$$\bar{v} = \frac{1}{\bar{t}}$$

Where;

\(\bar{t} =\) Mean germination time

#### Uncertainty of germination process

The uncertainty of germination process indicates the degree of uncertainty associated with the distribution of relative frequency of germination. Uncertainty is calculated using the following equation (Labouriau and Valadares 1976):

$$U = \sum_{i=1}^k\:fi\:log_2\:fi$$

Where;

\(f_i = \frac{n_i}{\sum_{i=1}^k\:n_i}\)

\(f_i=\) Relative frequency of germination

Low values of uncertainity indicate frequencies with few peaks (i.e. germination more concentrated in time). Low value (towards zero) indicates more synchronized germination

#### Synchrony of germination process

Evaluate the degree of overlapping among individuals of one population. Synchronization index produces a number if and only if there are two seeds finishing the germination process at the same time. It is calculated using the following formula (Labouriau 1978):

$$Z = \frac{\sum_{i=1}^k\:C_{n_i,2}}{C_{\sum n_i,2}}$$

Where;

\(C_{n_i,2} = n_i(n_i-1)/2\)

\(C_{ni,2}=\) combination of seeds germinated in the \(i^{th}\) time, two by two.

\(n_i=\) number of seeds germinated in the \(i^{th}\) time

Z = 1: when germination of all seeds occur at the same time

Z = 0: when at least two seeds could germinate, one at each time

#### Coefficient of variation of germination time

Coefficient of variation of the germination time is calculated by the following expression (Ranal et al. 2009)

$$CV_t=\frac{S_t}{\bar{t}}\times100$$

Where;

\(S_t=\sqrt{\frac{\sum_{i=1}^k\:n_i(t_i-\bar{t})^2}{\sum_{i=1}^k\:n_i-1}}\)

\(S_t=\) standard deviation of germination time

\(\bar{t}=\) mean germination time

Samples with only one seed germinated do not have the value of this measurement because the divisor of variance of germination time is zero.

#### Germination index

Germination index is an estimate of the time (in days) it takes a certain germination percentage to occur. Germination index can be calculated by using following expression (AOSA and SCST 1993):

$$GI=\sum_{i=1}^k\:{n_i}/{t_i}$$

Where;

\(n_i=\) number of seeds germinated in the \(i^{th}\) time

\(t_i=\) time taken for seeds to germinate at \(i^{th}\) count

#### Coefficient of velocity of germination

Coefficient of velocity of germination can be calculated using the following expression (Jones and Sanders 1987):

$$CVG=\frac{\sum_{i=1}^k\:n_it_i}{\sum_{i=1}^k\:n_i}\times100$$

#### Time to 50% germination

Time to 50% germination (\(T_{50}\)) indicates that how much time was taken for half of the seeds to germinate. \(T_{50}\) can be calculated using the following expression (Coolbear, Francis, and Grierson 1984):

$$T_{50}=\frac{t_i\:+\:(\frac{\sum_{i=1}^k\:n_i}{2}-n_i)(t_j-t_i)}{n_j-n_i}$$

In the above equation to find out the value of nini and njnj there is need to look in the cumulative number of seeds germinated for which the condition is given below.

\(n_i<\frac{\sum_{i=1}^k\:n_i}{2}<n_j\)

Where;

\(n_i =\) nearest cumulative number of seeds germinated (\(Cn_i\)) \(<\frac{\sum_{i=1}^k\:n_i}{2}\)

\(n_j=\) nearest cumulative number of seeds germinated (\(Cn_j\)) \(>\frac{\sum_{i=1}^k\:n_i}{2}\)

\(t_i=\) the time interval corresponding to \(n_i\)

\(t_j=\) the time interval corresponding to \(n_j\)

Other time related germination parameters like \(T_{10}\), \(T_{25}\), \(T_{75}\) and \(T_{90}\) were calculated using the same above formula by replacing \(\frac{\sum_{i=1}^k\:n_i}{2}\) with \(\frac{\sum_{i=1}^k\:n_i}{10}\), \(\frac{\sum_{i=1}^k\:n_i}{4}\), \(\frac{3\sum_{i=1}^k\:n_i}{4}\) and \(\frac{9\sum_{i=1}^k\:n_i}{10}\), respectively.

#### Mean daily germination percent

It represents the mean number of seeds germinated per day. This can also be defined as the number of seeds germinating daily relative to the maximum number of germinated seeds. It is calculated using the following expression (Adams and Farrish 1992):

$$\bar{G}=\frac{GP}{T_n}$$

Where;

\(GP=\) final cumulative germination percentage

\(T_n=\) total number of intervals required for final germination

#### Peak value

It is the accumulated number of seeds germinated at the point on the germination curve at which the rate of germination starts to decrease. It is computed as the maximum quotient obtained by dividing successive cumulative germination values by the relevant incubation time (Adams and Farrish 1992).

#### Germination value

Germination value is obtained by combining both speed and completeness of germination into a composite score as described by Czabator (1962).

$$GV=MDG\:\times\:PV$$

Where;

\(MDG=\) mean daily germination

\(PV=\) peak value or largest quotient obtained when all of the cumulative germination percentages were divided by the respective time interval.

Khalid, Farhan. “An Easy Way to Compute Seed Germination Measurements With an Excel Tool – AGRON INFO TECH.”

Cite this tool:AGRON INFO TECH – One Place for Data Analysis and Product Marketing, 27 Feb. 2023, www.agroninfo.com/seed-germination-measurements.

### How to download excel tool

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### References

Adams, JC, and KW Farrish. 1992. “Seedcoat Removal Increases Speed and Completeness of Germination of Water Oak.” *Tree Planters’ Notes-US Department of Agriculture, Forest Service (USA)*.

AOSA, and SCST. 1993. “Rules for Testing Seeds.” *Journal of Seed Technology* 16: 1–113.

Coolbear, P, A Francis, and D Grierson. 1984. “The Effect of Low Temperature Pre-Sowing Treatment on the Germination Performance and Membrane Integrity of Artificially Aged Tomato Seeds.” *Journal of Experimental Botany* 35 (11): 1609–17.

Czabator, FJ. 1962. “Germination Value: An Index Combining Speed and Completeness of Pine Seed Germination.” *Forest Science* 8 (4): 386–96.

Ellis, RH, and EH Roberts. 1981. “The Quantification of Ageing and Survival in Orthodox Seeds.” *Seed Science and Technology* 9: 373–409.

Fitch, EA, JL Walck, SN Hidayati, et al. 2007. “Temporal Fulfilment of the Light Requirement for Seed Germination: An Example of Its Use in Management of Rare Species.” *Seeds: Biology, Development and Ecology*, 365.

Jones, KW, and DC Sanders. 1987. “The Influence of Soaking Pepper Seed in Water or Potassium Salt Solutions on Germination at Three Temperatures.” *Journal of Seed Technology*, 97–102.

Labouriau, LG. 1978. “On the Frequency of Isothermal Germination in Seeds of Dolichos Biflorus l.” *Plant and Cell Physiology* 19 (3): 507–12.

Labouriau, LG, and MEB Valadares. 1976. “On the Germination of Seeds of Calotropis Procera (Ait.) Ait. f.” *Anais Da Academia Brasileira de Ciencias* 48: 263–84.

Ranal, MA, Santana DG, WR Ferreira, and Mendes RC. 2009. “Calculating Germination Measurements and Organizing Spreadsheets.” *Brazilian Journal of Botany* 32: 849–55.