Storage-root weight, diameter and length relationships in carrot (Daucus carota) and red beet (Beta vulgaris)

SUMMARY The functional relationships between logediameter and logeweight, and between length and diameter of the storage roots in carrot and red beet were described by two linear equations. These equations were fitted to data from three red beet and two carrot experiments. The agreement between the fitted and observed data was close. With increasing plant population density of red beet, the slope of the relationship between length and diameter decreased and the intercept increased. Although these changes in slope and intercept were statistically significant (P< 0·05), their magnitude was of negligible practical importance. The relationship between logediameter and logeweight was little affected by length; the relationship between length and diameter was little affected by logeweight. Using these equations in independent experiments, the diameters of roots of both species were predicted from measured root weights. The roots were then assigned to various commercial diameter grades on the basis of either the measured or the predicted diameter. Except for a few roots of red beet greater than 85 mm in diameter, there was close agreement between the observed and predicted number of roots in each grade. Any model which predicts root weight might be extended to predict yield of marketable size grades, using these equations as a calibration between weight, diameter and length.