I have been trying to do regeneration of rockmelon plant using cotyledonary explant.

After a few years of trying, I'm not getting the shoots. I'm able to get up to the callus stage but the callus does not undergo differentiation to shoots. Besides that, when i transform the cotyledon, the callus that grows become unhealthy and looks brownish. Is that normal?

Here is what I do,

1. Soak the seeds overnight/24 hrs

2. Sterilize the seeds with ddH20 and few drops of tween-20, then 70% alcohol

3. Grow the seeds in MS Media for 8 days.

4. Excise the cotyledons from the plants and infect it with Agrobacterium for 10mins in liquid MS media, then co-cultivate in dark with solid MS media supplemented with (1mg/L BAP and 0.01mg/L IAA) with Acetosyringone

5. Then wash the explant with ddH20 with cefotaxime and culture the explant in dark with solid MS media supplemented with (1mg/L BAP and 0.01mg/L IAA) .

After that it turns brownish, more over, after that it doesn't produce shoots at all.