COLORIMETRIC CHARACTERIZATION OF RED PEAR CULTIVARS

Fruit color was characterized in eight red pear cultivars by measureme nt using the Commission Internationale d'Eclairage L a* b* color spac e coordinates. Color was measured on sun-exposed and shaded fruit surf aces at mid-summer and three times during harvestable fruit maturity. All cultivars gained red color (a value) on the sun-exposed surface d uring the growing season, but varied in yellowness (b value). Hue ang les calculated from these values described differences in color change and color at final harvest. Color response on the shaded fruit surfac e varied among cultivars to a greater extent than on the sun-exposed s urface. 'Rosired Bartlett' and 'Rogue Red became darker (decreased in L value) and redder (decreased in hue angle) with maturity on both su n-exposed and shaded fruit surfaces. All other cultivars became lighte r and less red with maturity. 'Rogue Red' and 'Cascade' showed the gre atest difference in hue between sun-exposed and shaded fruit surfaces, indicating a strong degree of bi-color. The least contrast between fr uit surfaces was in 'Starkrimson' and 'Geohard Red Anjou'.