Rapid domestication of purslane (Portulaca sp.) in a vertical farm environment.

Food security requires nutritious food, consistent supply chain, sustainable production system and reduced food miles. To overcome these challenges, agriculture is shifting focus towards urban farming, specifically vertical farming (VF), where crops are grown indoors to maximize the use of limited city spaces. Research progress has been demonstrated in major arable and horticultural crops like wheat, tomato, salad and herbs. However, commercial crop production in VF faces strong competition with the mainstream farming system. In contrast, novel crops are less affected by competition and offer an opportunity for rapid domestication in VF environment.
Purslane (Portulaca sp.) is a crop with substantial commercial opportunities for cultivation under VF. Here, groups from SRUC and the University of Edinburgh are developing a collaborative project on the genetic, genomic, phenomic and physiological characterisation of diverse purslane accessions. The project objectives are as follows:
1: Genetic and genomic characterisation of purslane accessions. Germplasm will be obtained through seed merchants and potentially by collection trips within Europe. Seed stocks will be maintained in SRUC and genotyped with data used for diversity analysis and discovery of the centre of origin. Cytogenetic analysis will identify variation in ploidy level, which may indicate species barriers in crosses among accessions.
2: Development of a purslane cultivation protocol for VF. Optimal growth conditions including light quality and intensity, temperature, soil type and watering capacity will be investigated. A protocol for manipulating flowering time will be developed to obtain the desired growth stages for crossing and seed production. Clonal propagation using simple cuttings and tissue culture will be explored along with factors including genotype, light parameters, explant length/age and growth medium.
3: Phenomic-guided optimisation of production system. A harvest protocol will be developed to maximise the yield and quality of purslane in VF. The appropriate time for harvest will be fine-tuned, and the possibility of multiple harvest to increase yield will be explored. Harvests from various growth stages will be profiled for taste difference through biochemical assays and a participatory breeding approach with SRUC culinary school.
These objectives are intended to (1) provide a comprehensive PhD training in applying fundamental biology to deliver a direct impact to mainstreaming purslane production, (2) create a breeding platform for purslane, and (3) encourage creativity and innovation in designing crop for the future. In addition, the student will be provided with opportunities to undertake valuable training in career and soft skill development.
Major outputs from this PhD project include: (1) publications on the results, (2) community resources for purslane accessions, (3) development of purslane cultivation protocol in VF, and (4) initiation of purslane breeding program in SRUC. This is a major opportunity to rapidly domesticate novel crops in VF and purslane fits well as a novel crop of choice because it has high nutritious values and has already been consumed traditionally in various parts of the world. As a common goal shared by all partners, we strive to create a collaborative environment for accelerated purslane domestication and breeding in VF in the coming years.