You can technically use your Breadwallet-Dash seed with Electrum-Dash for whatever reason (maybe Breadwallet stops working?), but it requires just a bit of tinkering. Unfortunately, because Breadwallet uses deeper derivation paths than Electrum, you can't go the other way around (Electrum -> Breadwallet won't work).
You just have to get an "xprv" key from your Breadwallet-Dash seed, at the right depth, which is "m/0p". Then import that into Electrum-Dash.
1. Retrieving the correct Breadwallet-Dash "xprv" key:
This BIP39 page is a useful tool for manipulating/displaying BIP32/39 seed data. It has an "Offline Usage" section that you can follow if you're paranoid. To get started, go there and...
2. Importing that "xprv" key into Electrum-Dash:
The Seed Mnemonic won't be available in Electrum(-Dash) now, but you will have full access to spend your funds. You will just need to re-follow the steps above if you want to restore your Electrum wallet from seed again, -OR- just send your old Breadwallet funds to a NEW Electrum-Dash wallet with the seed.
				
			You just have to get an "xprv" key from your Breadwallet-Dash seed, at the right depth, which is "m/0p". Then import that into Electrum-Dash.
1. Retrieving the correct Breadwallet-Dash "xprv" key:
This BIP39 page is a useful tool for manipulating/displaying BIP32/39 seed data. It has an "Offline Usage" section that you can follow if you're paranoid. To get started, go there and...
- Enter in your 12-word seed.
 - Change "Number of Words" to 12.
 - Leave Passphrase blank.
 - Leave coin set to 'Bitcoin'.
 - Under "Derivation Path", click the "BIP32" tab.
 - Now in the "BIP32 Derivation Path" box, type: m/0' (That's not a typo.)
 - Then copy the value in "BIP32 Extended Key".
 
2. Importing that "xprv" key into Electrum-Dash:
- Open "Electrum-Dash" and go to File->New/Restore.
 - Use "Breadwallet", or whatever name you want for the wallet.
 - In the next box, click "Restore a wallet or import keys".
 - Leave the next option set to "Standard Wallet". Then click "next".
 - Now paste in your value from "BIP32 Extended Key" above.
 
The Seed Mnemonic won't be available in Electrum(-Dash) now, but you will have full access to spend your funds. You will just need to re-follow the steps above if you want to restore your Electrum wallet from seed again, -OR- just send your old Breadwallet funds to a NEW Electrum-Dash wallet with the seed.