test
node1
TO:0000053
pollen sterility
node2
CO_320:0000158
rice pollen sterility
trait
node1->node2
node3
TO:0000387
plant trait
node4
TO:0000392
sterility or
fertility trait
node3->node4
node5
TO:0000485
sterility related
trait
node4->node5
node6
TO:0000437
male sterility
node5->node6
node6->node1