[Relationship between nutritional composition and anatomical parameters in sorghum (Sorghum bicolor L. Moench)]

Nutritional and chemical parameters with significant differences (P = 0.5) among 10 varieties of sorghum and rates observed in them were as follow: lipids (2.76 to 3.75%), raw fiber (60.0 to 64.7%) protein (9.01 to 11.43%), no nitrogen extract 977.65 to 83.07%), starch (60.5 to 64.20%), tannin (2.50 to 10.16 mg/g), and total calories (380 to 4000 Kcal). Ash content with value of 1.17 to 1.91% protein digestibility (23.8 to 38.8%) and "in situ" starch (54.4 to 66.6%) were not statistically different. When correlation indexes were determined between results of chemical analysis, it was obtained follow positive correlation having significance: carbohydrates with total calories and fat with fiber. The main negative correlations were: fat and fiber with carbohydrates, fiber with calories, and digestibility "In vitro" of protein with tannin. In order to obtain equivalent analytical tests to substitute an anatomic determination for a chemical one, or vice versa, and make easy the selection of varieties for different use, and the adequate process for sorghum grain, were obtained correlations between chemical data of this study and compared to anatomic features determined in a previous analysis with same samples (1), it was found 19 significant coefficients from which 8 were positives and 11 negatives. The main correlations with capacity of analytical substitution were: size of starch grain of cornea endosperm-starch amount; size of protein body of flour-like endosperm-digestibility "in vitro" and "in situ" of protein; length of cell of flour like endosperm-starch amount; length and broad of aleurona cells-fiber content. The major negative correlations were: size of starch grain of cornea and flour-like endosperm ash; size of protein body of cornea endosper-starch amount; length and broad of aleurona cells-carbohydrates and total calories.