The storability of litchi fruits with different maturity is correlated to seed vigor

Litchi (Litchi chinensis Sonn.) fruit, consisting of pericarp, aril (pulp) and a recalcitrant seed, has exceptionally short storage/shelf life. However, research on the intrinsic factors affecting postharvest storability remains limited. To explore how different harvest maturity affects storability, fruits of three cultivars (HY, HZ, and JZ) were harvested at 75, 85, and 95 days after flowering (DAF), representing early harvesting (EH), commercial harvesting (CH) and late harvesting (LH) stages respectively, and stored at 25°C for 12 days. Compared to CH/LH fruits, EH fruit exhibited better storability, as represented by lower pericarp browning and disease index, higher marketability, slower degradation rates of anthocyanins, higher water content, lower relative electrolyte leakage (REL) and malondialdehyde (MDA) levels in the pericarp, slower total soluble solids (TSS) degradation in the aril. Furthermore, the seeds of EH fruit exhibited superior germination capacity and vigor than CH/LH seeds. Using HZ as a representative, we found that EH fruit had higher contents of ABA, CK, GA and IAA phytohormones, and lower expression of eight senescence-related genes (LcPOD, LcPER4, LcAPF2, LcBSP, LcDPD1, LcRNase3, LcLOX1.5-1, and LcLOX1.5-2) than CH/LH fruits. These results provide a new insight that the storability of litchi fruits at different maturity is positively correlated with seed vigor.