THE USE OF X-RAYS FOR SEED VIGOR ASSESSMENT
OF COTTON
R. R. Otoni1, M. B. McDonald2 and D. Tay3
1 Department of Agriculture, University Federal of Lavras, 37200-000, Lavras, MG, Brazil (e-mail ribasotoni@yahoo.com.br)
2 Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, 43210, USA
3 Ornamental Plant Germplasm Center, The Ohio State University, Columbus, Ohio, 43210, USA
X-rays have been studied for a long time. In particular, x-ray machines have been very useful in
seed assessment, such as for maize (Zea mays L.) (Carvalho, 1999), cotton (Ferguson and Turner,
1971), forest tree species (Machado, 2002) since it is a faster and non-destructive method to
assess seed quality. By using x-rays, it is possible to evaluate both the internal and external
anatomy of the seed and still use the same seeds in other seed quality tests, such as standard
germination and vigor tests. Another potential use of x-rays, and the objective of this study, was
to classify seeds according to the fill size of embryo in the embryo cavity. Ferguson and Turner
(1971) showed a significant difference in emergence and survival of cotton seedlings among half
filled (50%), 75% filled and filled cotton seeds. The first objective of this study was to show how
useful x-rays can be as a seed quality test, being used alone or in combination with other vigor
tests, such as the Seed Vigor Imaging System (SVIS) where human errors are avoided and
standardization of seed vigor tests can be achieved. The second objective of this study was to
show how important the use of high quality seeds is compared to mechanically damaged seeds.
Acid delinted cotton seeds were
classified into four categories: High,
Medium and Low quality seeds based
on the size of embryos in the embryo
cavities, and Mechanically Damaged
seeds based on the presence of any
damage on the seed coat (figure 1). A
Faxitron MX-20 x-ray machine was
used to classify the seeds (figure 1).
The seeds were exposed to 20 Kv for
20 sec.; the i