Reevaluation of common wheats from the USDA world wheat collection for protein and lysine content

MUCH OF THE VARIATION FOR PROTEIN AND LYSINE WAS NON-GENETIC IN ORIGIN, SINCE THE WHEATS ANALYZED WERE NOT ALL GROWN DURING THE SAME YEAR. TO TEST THE VALIDITY OF THOSE ANALYSES. 600 WHEATS WHICH REPRESENTED THE RANGE OF PROTEIN AND LYSINE AMONG THE COMMON WHEATS WERE GROWN AT YUMA, ARIZONA, IN 1972 AND 1973. MOST OF THE VARIATION IN PERCENT PROTEIN WAS FOUND TO BE DUE TO GENETIC DIFFERENCES AMONG THE WHEATS TESTED. WHEATS WITH THE HIGHEST MEAN PROTEIN PERCENTAGES WERE FIVE PERCENTAGE POINTS HIGHER THAN THE LOWEST-PROTEIN WHEATS. WHEATS THAT SHOULD BE USEFUL TO WHEAT BREEDERS AS GENETIC SOURCES FOR HIGH PROTEIN ARE IDENTIFIED. LYSINE EXPRESSED AS A PERCENT OF SAMPLE WAS POSITIVELY CORRELATED WITH PERCENT PROTEIN, BUT LYSINE EXPRESSED AS A PERCENT OF PROTEIN WAS NEGATIVELY CORRELATED WITH PERCENT PROTEIN. SELECTION FOR LYSINE USING BOTH CRITERIA WOULD PRODUCE CONFLICTING RESULTS. RESULTS OF OTHER RESEARCHERS INDICATE THAT THE COMPLEX RELATIONSHIP BETWEEN LYSINE AND PROTEIN IS DUE TO HIGH-PROTEIN WHEATS HAVING MORE GLUTEN PROTEINS WHICH ARE LOW IN LYSINE THAN LOW-PROTEIN WHEATS.