Complex sentence: Physical properties of grain such as wheat play very important role in the quality of grain, and final products such as flour, main physical properties that influence quality of wheat are test weight, hardness, grain size and shape, vitreousness and color.
Split into simpler sentences: Physical properties of grain such as wheat play a very important role in the quality of the grain, and in final products such as flour. Main physical properties that influence quality of wheat are test weight, hardness, grain size and shape, vitreousness and color.