Hybrid Sunflower Oil May Keep Arteries Clean By BETSY BLANEY    LUBBOCK, Texas (AP) -- Some farmers are placing their hope in a hybrid sunflower seed that could help keep arteries clear and hearts pumping in a nation smitten with snacks and processed food.    "It's a healthier oil," said Willie Wieck, 62, who started growing sunflowers on his 450 acres in the Texas Panhandle in the early 1970s...