This could mean one of two things. Either that you want to grow Z. 'Picasso' from seed or that you want to collect seed from your existing plant.

'Picasso' is a specific hybrid cultivar, and is propagated by division of the tuber rather than by seed. Any seed that the plants did produce would not grow into 'Picasso' but rather into an array of different colours and forms, none of which will be the same as the parent plant, and none of which could be called by it's name either.

Some Zandedeschia do produce seed quite readily in the UK, but the hybrids tend to be sterile or nearly so.