Assessment of kernel presence in winter wheat ears using Near-Infrared Hyperspectral Imaging

Obtaining varieties with higher yield is one of the aims of crop breeding. For winter wheat (Triticum aestivum L.), yield is the result of three components which are the number of ears per unit area, the number of kernels per ear and the kernel weight.

The occurrence of stresses during crop growth can have a negative impact on the yield components. For example, abiotic stresses such as drought or frost, if they occur at sensitive stages of the crop can cause a decrease in the number of kernels per ear. On the other hand, biotic stresses induced by a disease such as Fusarium Head Blight (FHB) can also cause a decrease in the number and weight of kernels per ear. Assessing the physiology behind the number of kernels and the impact of stresses is a complex process requiring observations at specific critical periods of the crop cycle.

The scope of this study is to propose an innovative method based on Near Infrared Hyperspectral Imaging (NIR-HSI) to evaluate the presence of kernels in winter wheat ears. This preliminary study allowed the evaluation of the potential of the method using winter wheat ears collected in a field trial in Belgium. NIR-HSI combined with chemometric tools identified spectral bands potentially characteristic of the presence of kernels inside the ears. A chemometric model using Partial Least Squares Discriminant Analysis (PLS-DA) enabled the identification of ears with and without kernels. The PLS-DA results allowed tracking the presence of kernels in winter wheat ears at spikelet level. These results indicate that NIR-HSI might be a useful method to provide information assessing the status of kernels inside the ear, which plays an important role in yield assessment.