seed potato
A potato tuber used for planting, not for eating. Common in agricultural and gardening contexts.
I will plant seed potatoes when spring comes.
種芋はホームセンターで買えます。
You can buy seed potatoes at home improvement stores.
Standard kanji spelling for seed potato.
Kana spelling is common in everyday writing, especially in gardening contexts.
Compound of 種 (たね, 'seed') and 芋 (いも, 'tuber'). The reading たねいも is a straightforward combination of the two components.