Under high‑temperature conditions, fruit‑set rate showed no significant correlation between qFS6 and pollen germination or pollen dispersal, indicating that the causal gene underlying qFS6 does not function by improving male reproductive traits. These findings suggest that qFS6 enhances fruit‑set capacity under high temperature via an alternative pathway independent of male reproductive competence.
Furthermore, in the F₃ population carrying different qFS6 genotypes, no significant differences were detected in flower sugar contents (sucrose, glucose and fructose) on the day of anthesis under high‑temperature stress. This implies that sugar metabolism is likely not involved in the qFS6‑mediated improvement of fruit set.
The discovery of this novel QTL locus qFS6 provides valuable genetic resources for high‑temperature‑tolerance breeding programmes in pepper.
