The Single and Interactive Effect of Salinity and Temperature on Germination Characteristics of Italian Ryegrass (Lolium multiflorum Lam.) Seeds

Italian ryegrass (Lolium multiflorum) is a grass species within the Lolium genus of the Poaceae family. In recent years, annual ryegrass has shown excellent adaptability to the climatic and soil conditions of Türkiye. It serves as a good alternative forage source to bridge the forage deficit and is widely used as a low-growing native turf mixture in local landscaping. Abiotic stress factors are among the primary elements that hinder plant growth and development. Temperature and salinity significantly affect seed germination and development. This study aimed to investigate the germination and growth parameters of three different Italian ryegrass varieties (İlkadım, Kocayaşar, Zeybek) under different salt concentrations (Sodium chloride-NaCl) and temperatures. Three different salt doses (control, 5 EC, and 10 EC) and three different temperatures (15 °C, 20 °C, and 30 °C) were used in the study. Germination percentage, shoot and root lengths, fresh and dry weights of shoots, and ion leakage parameters were examined. The results showed that the highest germination rate, shoot and root lengths, and fresh and dry weights in all varieties were recorded at 20 °C with 0 EC and 20 °C with 5 EC salt treatments, while the lowest were observed at 15 °C with 10 EC salt treatments. The lowest ion leakage was determined in the control treatment at 15 °C, while the highest ion leakage was observed in the 10 EC treatment at 30 °C. Increasing temperature positively influenced growth parameters. It was determined that salt stress could be tolerated up to a certain level at higher temperatures. This study on different Italian ryegrass varieties highlights the importance of developing ryegrass varieties resistant to temperature and salt stress, which are significant issues in sustainable agriculture.