Visualization of Leaf and Bracteal Nectaries of Cotton using Digital Microscopy to Improve Scoring Accuracy and Data...

Nectaries are distinct nectar-producing glands, present in many plant species. Nectaries exhibit diverse structures and functions. In cotton, traditional scoring of nectary trait is error-prone, unreliable and has limitations as phenotypes of this trait are often not visible to the naked eye. Nectary trait expressions are controlled by genes, Ne1 and/or Ne2. Additionally, trait expression can be influenced by the environment and growth stages, stressing the need for accurate scoring methods. Particularly, phenotypic scoring by digital images results in a more accurate scoring method of nectaries. This method overcomes the limitations of the traditional scoring by generating high-resolution images. Further, facilitates the identification and differentiation of fine differences of nectary trait expression while preserving these digital images for future reference. This phenotyping scoring method described here can be easily adapted to score other plant traits such as glands, hairs, and color. These scoring methods can be tailored to other plant species. In this article, we explain step-by-step procedure on how to collect samples from the field or greenhouse, dissect to observe them using digital microscopy, and preserve these images for future scoring analysis. For this method, we will use, for example, scoring of leaf and bracteal samples of cotton plants to differentiate the presence of nectaries (fully developed, reduced and vestigial) and the absence of nectaries.