The Collaborative International Dictionary of English v.0.48:

maccaroni wheat \maccaroni wheat\ n.
   A type of wheat (Triticum durum) with hard dark-colored
   kernels high in gluten and used for bread and pasta; grown
   especially in South Russia, North Africa, and North central
   North America.

   Syn: durum, durum wheat, hard wheat, Triticum durum,
        Triticum turgidum.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Triticum turgidum
    n 1: wheat with hard dark-colored kernels high in gluten and
         used for bread and pasta; grown especially in southern
         Russia, North Africa, and northern central North America
         [syn: durum, durum wheat, hard wheat, Triticum
         durum, Triticum turgidum, macaroni wheat]