Correlation studies with strains of flax with particular reference to the quantity and quality of the oil

To study the percentage and iodine number of the oil and their relation to plant and seed characters, 46 strains of flax were grown in 1929 and 1930 in replicated rod-row plats. The strains used included domestic and foreign types with crosses and selections in each, and gave a wide range in the characters studied. During both years the percentage of oil and in 1930 the iodine number were correlated with each of the other characters studied by means of simple, partial, and multiple correlations. Significant positive simple correlations were found between the oil content and weight of 1,000 seeds, date ripe, and number of days from full bloom to maturity. Negative simple correlations were secured between iodine number and percentage of oil, weight of 1,000 seeds, date ripe, and number of days from full bloom to maturity. The simple negative correlation between iodine number and weight of 1,000 seeds was statistically significant by Fisher's method of interpretation. Other simple negative correlations with iodine number were not significant. A further study of these relationships made in partial correlations gave a high positive correlation between the percentage of oil and weight of 1,000 seeds when either date ripe or number of days from full bloom to maturity was held constant. Partial correlations between the percentage of oil and date ripe and between the percentage of oil and number of days from full bloom to maturity were not significant when seed size was held constant. A significant partial negative correlation was obtained between iodine number and weight of 1,000 seeds when oil content and either date ripe or number of days from full bloom to maturity was held constant. Other partial correlations with iodine number were not significant. The high multiple correlation between the percentage of oil and the variables studied indicates that the oil content of the seed is dependent to a considerable extent on the same factors that condition seed size, date ripe, and number of days from full bloom to maturity. The low multiple correlation of iodine number with these variables suggests that the iodine number is inherited independently of the plant and seed characters studied. Inter-annual correlations of oil content, seed weight, date ripe, and number of days from full bloom to maturity indicate that these characters are relatively constant in their inheritance.