Treatments for improving seed germination in eggplant and related species

Abstract

Orthodox seeds may present differences in germination due to several reasons. In this work, we tested treatments for improving germination in two cultivars of common eggplant (Solanum melongena) and in six accessions of the related species S. macrocarpon, S. aethiopicum, and S. incanum. With the exception of S. incanum MM-557, which did not germinate, seeds of the other accessions directly had lower final germination percentages when sown in Petri dishes with deep filter paper than those that were pretreated by surface sterilization and sown in nutrient medium; a further increase in the final germination percentages was achieved by addition of 1 mg L-1 GA(3) to the medium. The GA(3)-pretreatment not only increased the final germination percentages but promoted germination also by reducing germination time. Other treatments included stratification of S. macrocarpon and S. aethiopicum seeds at 4 degrees C for 15 or 30 days, as well as addition of 1 mg L-1 of TDZ and BAP for the BBS-168 accession, but this did not improve germination. The addition of 0.3 mg L-1 fluridone, an inhibitor of carotenoid biosynthesis, that is known to prevent ABA biosynthesis, increased the final germination percentages of S. melongena, S. aethiopicum and S. macrocarpon to a similar degree as GA(3). Seeds of S. incanum MM-557 did not respond to this treatment but the hybrid derived from this S. incanum accession with eggplant accession ANS-26 showed high germination percentages (70%, 13 days after sowing) in NM medium with GA(3), fluridone or both components. These results show that seed treatments can contribute to improving germination of Solanum accessions with low germination.