With the vast quantity of side missions you received earlier finally complete, it is now time to host the peace summit and win over the Krogan. Head to the peace summit, which will be marked by a series of ships on your Galactic Map. When you arrive, a representative of the salarians and the krogans will each board your ship to join you and Victus in the council room. When you arrive, you will find the salarian politician, Dalatrass, bickering with the krogan. Who the krogan diplomat is will depend on your past actions in the series. If you spared Wrex in the first game, he will take the position. Otherwise, a krogan named Wreav will be there. Either way, he will be none too happy with Dalatrass, who will be in the midst of insulting him as you walk in.
After you calm the situation, the different races will make their cases. The krogan will find it humorous that the turians have come crawling back for their aid after years of unrest between the races. The only way that the krogan can help the turians, the diplomat will reason, is if you are able to stop the genophage from making the krogan infertile beforehand. This Dalatrass opposes fervently. The salarian will remind you of why, exactly, the krogan became infertile in the first place. The salarians used the race for help during a war, and when the war was over, the krogan proved more trouble than they were worth. Dalatrass will beg you not to let history repeat itself. You can earn Paragon or Renegade points here, but either way you will have to cure the genophage before taking action.
This feat will be easier if you saved Maelon’s work in Mass Effect 2. This will provide a base for the salarians to begin developing a stable cure. After some pressuring, Dalatrass will admit the location of a salarian research facility where work is being done on the genophage, as well as a number of other scientific oddities. The group will agree to head there right away. As you leave the conference, a Renegade interrupt opportunity will present itself when Dalatrass begins to chide you for your support of the krogan. Take it, and the salarian will warn you that bullies have few friends when they are needed. Clearly, the salarians will not take kindly to these actions.
In the shuttle on the way to the lab, the krogan diplomat will confront you about whichever decision you made regarding Maelon’s research. From here, the next phase of the story will begin.