F1's are the first generation hybrid... Could be a LMB, BG, whatever. When two F1's reproduce, their offspring are F2's. When two F2's reproduce, their offspring are F3's, etc.

Normally the 1st generation, or F1's, reap the greatest benefit from the hybridization process.

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.