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The use of true potato seed (TPS) is fundamental to potato breeding and research, but can be hindered by poor germination and seed dormancy. TPS germination studies had focused mainly on seed treatment methods after seed extraction and not in combination with the seed extraction methods used. In potato, TPS extraction using water, using yeast fermentation or using sodium bicarbonate are common, but TPS extraction using dilute aqueous hydrochloric acid (HCl) followed by bleach treatment (3% sodium hypochlorite) had never been tested in potato even though this is standard practice for tomato seeds. Therefore, three seed extraction methods (water, 0.1 M HCl, and 0.8% yeast fermentation) in combination with three seed treatment methods (water, 1500 ppm GA3, and 3% sodium hypochlorite) were tested on diploid TPS at 1 week and 1 month after seed extraction. TPS treated with GA3 improved germination for both 1 week- and 1 month-old seeds, while TPS treated with 3% sodium hypochlorite only improved germination for 1 month-old seeds. This study shows that TPS extraction using water, yeast or HCl had no effect on germination, but supports the use of GA3 or bleach to promote TPS germination. 

Abstract Phytochromes are red light and far-red light sensitive, plant-specific light receptors that allow plants to orient themselves in space and time. Tomato (Solanum lycopersicum) contains a small family of five phytochrome genes, for which to date stable knockout mutants are only available for three of them. Using CRISPR technology, we created multiple alleles of SlPHYTOCHROME F (phyF) mutants to determine the function of this understudied phytochrome. We report that SlphyF acts as a red/far-red light reversible low fluence sensor, likely through the formation of heterodimers with SlphyB1 and SlphyB2. During photomorphogenesis, phyF functions additively with phyB1 and phyB2. Our data further suggest that phyB2 requires the presence of either phyB1 or phyF during seedling de-etiolation in red light, probably via heterodimerization, while phyB1 homodimers are required and sufficient to suppress hypocotyl elongation in red light. During the end-of-day far-red response, phyF works additively with phyB1 and phyB2. In addition, phyF plays a redundant role with phyB1 in photoperiod detection and acts additively with phyA in root patterning. Taken together, our results demonstrate various roles for SlphyF during seedling establishment, sometimes acting additively, other times acting redundantly with the other phytochromes in tomato.