たね
seed
tane
JMdict 1328820
たね種seedをまこう蒔こうlet's plant
A short two-part sentence. を (object) marks 種たね (seed) as what gets planted, and the verb 蒔くまく (sow, plant) shifts to the volitional 蒔こうまこう (let’s plant) — an invitation to do it together.