How to test alfalfa seed vigor in a non-destructive way?
Why is seed vigor an important index of seed health?
Seed vigor directly correlates to its quality, it not only measures the percentage of viable seeds in a sample, but also allows to discover in what conditions they were stored. It can be influenced by maturation, development, storage, or genetic factors.
The seed vigor percentage usually increases during the development stage, until it reaches its peak maturity, following a significant decrease due to aging. The most common way to measure seed quality is to check for some deterioration factors or weaknesses. Some of those tests include electrical conductivity or artificial accelerated aging and can be perceived as destructive and not as efficient.
Spectral imaging and seed analysis
Some of the tests provided above are officially recognized by the International Seed Testing Association (ISTA) and used as a standard in measuring e.g., chickpeas, radish, or soybean seeds. However, only a few seeds that have officially-approved testing methods, all other seeds’ methods are in the experimental stage – one of them being alfalfa seeds (Medicago sativa).
Seed vigor of alfalfa seeds
A recent publication in the Smart Agriculture of Sensors journal illustrates the non-destructive assessment of alfalfa seed vigor using the state-of-the-art instrument VideometerLab. Spectral imaging can be used for various applications in seed testing in terms of health, purity, treatment, or germination.
This research used numerous alfalfa seeds, from different harvest periods and levels of maturity, as samples to ensure their reproducibility and validity. Scientists from China Agricultural University together with Ningxia Academy of Agricultural and Forestry Sciences used 19 wavelengths to analyze, distinguish, and predict seed vigor levels. The experiment finished with an average accuracy of assessing dead seeds with no vigor of 93.3% and the identification of seeds with high levels of vigor resulted in 95.7%.
The peer-reviewed paper concluded that the use of Multispectral Imaging and multivariate analysis in this experiment can accurately evaluate and predict the seed vigor, seed viability, and seed germination percentages of alfalfa. The positive results of the study demonstrate the effectiveness of using spectral imaging in seed testing.