Field-based crop phenotyping: Multispectral aerial imaging for evaluation of winter wheat emergence and spring stand

• High-resolution multispectral aerial imaging was used to estimate winter wheat growth parameters.
• Visual ratings of emergence and spring stand were compared with data extracted from aerial images.
• A high correlation (r = 0.86) between the ground-truth and aerial image data was observed.
• UAV-based sensing can be an alternative to standard methods for rapid field-based crop phenotyping.

The physical growing environment of winter wheat can critically be affected by micro-climatic and seasonal changes in a given agroclimatic zone. Therefore, winter wheat breeding efforts across the globe focus heavily on emergence and winter survival, as these traits must first be accomplished before yield potential can be evaluated. In this study, multispectral imaging using unmanned aerial vehicle was investigated for evaluation of seedling emergence and spring stand (an estimate of winter survival) of three winter wheat market classes in Washington State. The studied market classes were soft white club, hard red, and soft white winter wheat varieties. Strong correlation between the ground-truth and aerial image-based emergence (Pearson correlation coefficient, r = 0.87) and spring stand (r = 0.86) estimates was established. Overall, aerial sensing technique can be a useful tool to evaluate emergence and spring stand phenotypic traits. Also, the image database can serve as a virtual record during winter wheat variety development and may be used to evaluate the variety performance over the study years.