Complex sex determination and a large genome hinder conventional spinach breeding. To address this challenge, a biotechnological approach could be used to establish a reliable protocol for somatic embryogenesis and apply genetic tools such as CRISPR. However, spinach is recalcitrant to somatic embryogenesis, with substantial inter- and intrapopulation variability in embryogenic capacity. In this study, we assessed the impact of environmental conditions during donor plant growth on the embryogenic capacity of the resulting seedlings. Seed populations, selected for differing embryogenic capacities, were sown in greenhouses at two distinct locations, and cross-pollination was only permitted between plants of the same origin. The resulting seeds were aseptically sown, and the embryogenic capacity of the seedlings’ root apices was determined. Root explants from seedlings originating from Ukraine and Poland showed low regenerative capacity regardless of cultivation locality, with a maximum of 22.71% regenerating explants and 1.3 somatic embryos per explant. Conversely, seedlings originating from Slovenia exhibited high regeneration potential, with significant differences between cultivation localities: 89.36% vs. 59.72% regenerating explants and 12.04 vs. 3.77 somatic embryos per explant. Therefore, the embryogenic capacity in spinach is strongly influenced by environmental conditions during donor plant growth and could be further increased by manipulating these factors.
Milojević et al. (Sun,) studied this question.