Abstract
Polar and equatorial diameters, thicknesses, arithmetic mean diameters, frontal surface, cross sectional and total surface
areas, sphericities, shape indexes, roundnesses, true and bulk densities, porosities and rolling angles on two surfaces of five
varieties of popularly cultivated onions in Nigeria were determined. Analysis of variance (ANOVA) at 1 and 5% level of
significance and least significant difference at 5% level probability were used to compare the data. The equatorial diameter,
polar diameter and thickness for Light Red onion were the largest among the varieties evaluated and gotten as 6.53 ± 0.94,
5.12 ± 0.59 and 2.53 ±0.24 cm respectively. The ari thmetic and geometric mean diameters of White onion were 4.36 ± 0.42
and 4.0 ± 0.34 cm respectively; those of Red Creole were 4.42 ± 0.40 and 4.11 ± 0.33 cm and those o f Dark Red onions are
4.48 ± 0.48 and 4.18 ± 0.38 cm accordingly. Brow n onion had the least frontal, cross-sectional and total surface areas of
17.74 ± 3.43, 12.52 ±2.28 and 27.60 ± 3.99 cm 2respectively. All the varieties evaluated were oval with shape index range of
1.65 ± 0.21 to 1.87 ± 0.21. The solid densities wer e obtained as 0.94 ± 0.04, 0.91 ± 0.0, 1.07 ± 0.08, 0.95 ± 0.04 and 0.95 ±
0.06 for Red Creole, Brown, Dark Red, White and Light Red varieties of Nigerian onions respectively. Rolling angles of the
varieties ranged from 25 ± 2˚ to 29 ± 1˚ and 30.7 ± 1.5˚ to 33.7 ± 2.1˚ on galvanized steel and plywoo d surfaces respectively.
The ANOVA showed that the thicknesses, total surface areas, solid densities, and rolling angles on galvanized sheet and
plywood were not significant for the varieties while all other evaluated parameters were highly significant.

Key words: Polar diameter, equatorial diameter, frontal surface area, shape index, rolling angle, onions