Sequoia Capital is a giant of the Silicon Valley venture scene, known for backing such American IT icons as Apple, Google and PayPal. But the firm’s next IPO candidate has little to do with bytes, and everything to do with broccoli.

The company is Le Gaga Holdings Ltd., one of the largest greenhouse vegetable producers in China. Last Friday it filed for a $100 million IPO, with plans to trade on the Nasdaq under ticker symbol GAGA (sorry Lady).

It was founded in 2004 by Shing Yung Ma, a veteran Chinese agriculture executive interested in growing broccoli inside of giant greenhouses. He soon expanded into other vegetables, and by 2006 had attracted Sequoia’s interest.

The venture capital firm, via its Chinese affiliate, became Le Gaga’s first outside investor via a $4 million Series A infusion. It later expanded the round by $2 million, before investing $5.5 million in March 2008 as part of a $24 million deal that also included SIG China Investments (a regular Sequoia co-investor) and Walden International.

Since that final investment, Le Gaga’s revenue is up more than 82% and its profits have grown by a whopping 186%. We’re still not talking Google numbers here — revenue was around $41 million for the year ending March 31, 2010 — but Le Gaga has a proven ability to grow in a market that keeps wanting to consume more of just about everything.

What Sequoia really has to hope here is that Le Gaga does not become another American Dairy, a Chinese milk producer in which Sequoia plugged $63 million last August. As of market open today, the investment was worth just $25 million (including 525,000 new shares issued to Sequoia as compensation for fiscal underperformance).

Comparing Le Gaga and American Dairy is a bit like comparing butter to beets, particularly considering that the latter was public when Sequoia first invested. But the similarities are hard to ignore: These are the first two agricultural deals done by Sequoia in its 38-year history — it recently added a third, also in China — and both were led by partner Neil Shen.

If Le Gaga bombs like American Dairy, then maybe Sequoia will consider dropping agriculture as a vertical. But if it succeeds, then Sequoia will be one of the very few U.S. venture firms with domain expertise in the largest country’s most vital market.