For decades, germplasm characterization has relied on people looking at plants, seeds and fruits and recording what they see; first on paper forms, more recently admittedly on tablets and the like. I’ve done that myself, and let me tell you, recording the colour of taro stems on bits of damp paper in the middle of a forest clearing in Vanuatu is no fun.
Lately, thankfully, the camera has been taking over.
A recent overview of new tools for plant genebanks highlights digital photography as a way of capturing standardized information on the colour, size and morphology of seeds and other plant parts, alongside more sophisticated technologies such as hyperspectral imaging and mobile field sensors. The attraction is obvious: instead of recording a handful of descriptors by eye, images can capture a much richer set of characteristics that can subsequently be measured and analysed at your leisure.
The potential is particularly striking for fruit crops. A new study of heritage apples used controlled multi-view imaging to characterize about 350 accessions over three years and two locations. Fancy maths achieved 95% accuracy in distinguishing 38 cultivars, rising to 99% when images of three fruits were combined.
And the technology does not necessarily require sophisticated equipment. In a recent demonstration with beans with complex colour patters, Miguel Angel Acosta Chinchilla used ordinary photographs, image pre-processing and clustering algorithms to extract dominant palettes and colour distributions.
We’re moving from a limited number of human-defined descriptors to infinitely explorable machine-readable phenotypes. An image can preserve information that nobody thought to score at the time, and algorithms can return to it later to measure traits that were not originally part of the characterization protocol. For genebanks, that could be transformative. A photograph taken today may become a source of data for questions that don’t actually arise until tomorrow.
I wish I had a digital camera with me in that taro patch twenty-odd years ago. Goodness knows what people could be finding in them now.