Influence of environmental factors on Cucumis melo L. var. agrestis Naud. seed germination and seedling emergence

Cucumis melo L. var. agrestis Naud. (field muskmelon) is an annual invasive weed in many parts of Asia. However, there is very little available information about the germination and emergence of this species. Therefore, laboratory experiments were conducted to evaluate the effects of light, temperature, salt stress, osmotic stress, pH, and depth of planting on field muskmelon germination and seedling emergence. Light had no effect on seed germination, and the seeds germinated at a wide range of temperatures. More than 90% of the seeds germinated at constant temperatures between 20 degrees C and 35 degrees C, and fluctuating day/night temperatures between 15/25 and 30/40 degrees C. The seeds were tolerant to salinity as germination occurred up to the 200 mM NaCl treatment. However, the seeds were sensitive to osmotic stress as seed germination was completely inhibited at -0.6 MPa. The seeds germinated over a pH range of 4 to 10, which suggested that pH was not a limiting factor for germination. Seedling emergence was greatest (97.86%) when the seeds were planted on the soil surface, but emergence declined as the burial depth increased. Information from this study can be used to predict future infestations in China and help develop strategies to manage this species.