While DuPont may not be the first company name that comes to mind when you think of farming, the company???s agriculture unit has grown into its biggest business by sales. And that???s been the plan now for a while. You see, the nation???s largest chemical company has been concentrating on growing its highest-margin units, which include agriculture, food, specialty materials and alternative energy — for more than the past year. This strategy has been warmly welcomed by investors as the company???s share price has risen 25 percent in that time, closing Monday at $60.24. So successful, in fact, that the company???s management is considering a spin-off of its signature, yet more-volatile, performance chemicals unit. Next up, investors can expect to see another uptick in stock price, as DuPont???s planned a $5-billion stock buyback from investors, with $2 billion of that to be purchased in 2014. So while it may seem odd that DuPont???s divesting itself from the chemicals??? side of the business, its ability to drive profits from innovation is maintaining the company???s status quo. But is that enough reason for you to plunk down your hard-earned shekels for shares?