TABLE 1 . Number of viable seeds per fruit in crosses of 4 potential bridging lines with L . esculentum and 3 accessions of L . peruvianum . L . peruvianum Bridging line L . esculentum PI - 126944 PI - 126935 PI - 143679 L . peruvianum   2172 0 . 28/UI * AS/AS AS/AS AS/AS L . peruvianum 1708 0 . 2/UI AS/AS AS/AS AS/AS BC1´ - peruvianum AE/UI UI/33 UI/29 UI/21 . 6 BC1´ - chilense 0 . 4/UI UI/5 UI/3 . 5 UI/28 * First and second data refers to crosses in which the bridge line has been employed as male or female parent in the cross respectively . IU: Unilateral Incompatibility: incompatibility mechanisms only act in one cross - direction . AS: Fruit set occurred, but aborted seeds were found in mature fruits . AE: Fruit set occurred, and aborted seeds were found in mature fruits . However, plants could be obtained by in vitro embryo - rescue from immature fruits .