Initial phenotyping of stomatal density (SD) across a diverse panel of strawberry germplasm has been completed at Niab. This image shows a typical strawberry leaf epidermis with the stomata false-coloured red by a newly developed machine learning algorithm that detects and counts stomata from microscope images. The tessellated black-white cells adjacent to the red stomata are abaxial epidermal cells. The initial phenotyping screen enabled:

1. identification of genotypes with extreme high or low SD to be further tested in field and growth room conditions for differences in water use efficiency;

2. population scale data on SD that can be paired with genomic SNP data for genome-wide association studies (GWAS) to identify genetic loci that control variation in SD;

3. identification of parental genotypes that can be used to develop bi-parental mapping and breeding populations for further analyses of the genetics underlying SD and the physiological consequences of altering SD.