Differential Seed Germination Responses of Tomato Landraces to Temperature under Climate Change Scenarios

This study aims to quantify the seed germination response of six tomato landraces to temperature; predict future climate changes relative to the baseline period (1980–2009) for studied locations in the courses of near-term (2010–2039) and mid-term (2040–2069) under two representative concentration pathways (RCP 4.5 and 8.5); assess the impact of future climate change on the final germination percentage (FGP) and time to reach 50% germination (D50) in the studied landraces. The results show that FGP is zero at 10 °C, reaches the highest value at 15–35 °C, and ceases at 36–40 °C for all landraces. The results also demonstrate that the temperature increment is 0.8–1.3 °C and 1.5–2.7 °C in the near- and mid-term, respectively, under RCP 4.5; further, this increment is 0.9–1.9 °C for the near-term and 2.3–3.4 °C for the mid-term under RCP 8.5. It estimates that the D50 takes 2.5 to 3.8 days among the locations in the baseline course. In the near term, the D50 would be 2.2 to 3.4 days under RCP 4.5 and 2.1 to 3.3 days under RCP 8.5. For the mid-term, the D50 would be projected between 1.9 and 2.9 days under RCP 4.5 and 1.8 to 2.7 days under RCP 8.5. The FGP increases up to 19.5% for Gorgan and 21.3% for Varamin under climatic scenarios relative to baseline, and it will not change in the future climate for other landraces. In conclusion, global warming can result in rapid, uniform, and complete germination in different tomato landraces.