Abstract: In order to study the feasibility of transferring exogenous DNA into watermelon by
pollen-tube pathway，the antimicrobial peptide gene Gnk2-1 was introduced into watermelon accession
‘04-1-2’by pollen-tube pathway with different concentration（100，200，300 and 400 ng · μL-1）at different
time（24 h，27 h，30 h，33 h）after self-pollination. Seeds from treated fruits were harvested and tested by
PCR. The results were as follows：The fruit setting rate and average number of seeds of T0 generation
increased with the increment of treatment time after self-pollination，though the two figures both showed a
significant decrease under all treatments compared with control. The germination rate of T1 seeds treated
27 h after self-pollination and the seedling emergence rate of T1 seeds treated 24 h after self-pollination
decreased significantly. Compared with control，there was no distinct difference illustrated in the rate of
germination and seedling emergence of T1 seeds between different concentration treatments. The PCR
results of 1 280 tested T1 seedlings showed 32 positive plants and the total transformation rate was 2.5%.
The optimum transformation time was 24–27 h after self-pollination and the optimum transformation concentration were 100–200 ng · μL-1. The positive plants were inoculated with Fusarium and showed a
stronger resistance compared with non transgenic plants.

Key words: watermelon, pollen-tube pathway, molecular detection, antimicrobial peptide