measure word of 香蕉 (个，根，条，只)

[coykiesaol]

I was surprised when my textbook introduced the measure word for 香蕉. It says 个 is the correct one. A good friend from Shanghai said 根 is the only correct one and I used that when shopping for bananas. If I had to guess freely, I thought 条 should be correct. Google says:

"一只香蕉" 594,000 (edit: thanks to xiaocai)
"一根香蕉" 195,000
"一个香蕉" 110,000
"一条香蕉" 66,100

Wikipedia uses 根 and 条 in one single article:
但是一根淨重約100克的香蕉的卡路里僅約87千卡
一條中等大小的香蕉含有451mg的鉀

So I'm a little bit confused which one is correct. Maybe one of those is meant for bananas after removing the peel? Or is it a regional thing? Formal vs. informal? Any insight would be nice.