ISHS Acta Horticulturae 367: VI International Symposium on Pear Growing
DIFFERENCES IN FRUIT COLOR CHANGE WITH MATURITY AND GROWING LOCATION IN RED PEARS |
| Authors: | C. Dussi, D. Sugar, K. Powers, S. Basile |
| Abstract:
A fruit color descriptive study was conducted on ‘Max’ and ‘Sensation’ Red Bartlett, ‘Columbia’ and ‘Gebhard’ Red Anjou, ‘Rogue Red’, ‘Rosired’, ‘Red Clapp’ and ‘Cascade’ red pear varieties in Medford, Oregon in 1991 and 1992. A parallel comparative study was done in the same years to test differences between related red strains. ‘Max’ was compared with ‘Sensation’ in three different growing regions: Medford, Hood River high elevation and Hood River low elevation. ‘Columbia’ was compared with ‘Gebhard’ in two locations: Medford and Hood River. Fruit color was measured on the shaded and exposed fruit surfaces with a Minolta CR-200b portable tristimulus colorimeter using the Commission Internationale de l'Éclairage color space (L*,a* and b*) in the same spot at mid-season and three times during fruit maturity. Visual percentage of blush was also evaluated in some cultivars. In the descriptive study, every strain presented different color development. All varieties increased hue, chroma and L* with maturity except for ‘Rogue Red’ and ‘Rosired’. ‘Rosired’ had the biggest change in hue during maturity and ‘Cascade’ the smallest. ‘Columbia’ and ‘Gebhard’ had the smallest change in chroma and ‘Rogue Red’ had the highest gain in L* value. There were high differences in color between exposed and shaded fruit surfaces and at each stage of maturity for every variety. Hue angle correlated with the percentage of blush, r = -0.64 for ‘Rosired’ and ‘Cascade’. In the variety comparison study various interactions were found among the main factors: growing location, variety, surface of the fruit and stages of maturity. Gain in chroma, hue and L* was higher in ‘Max’ than in ‘Sensation’, higher in Medford than in the other growing regions, and higher on the shaded side of the fruit than on the exposed one. Increase in chroma, hue and L* value with maturity was higher in Hood River for ‘Columbia’ than for ‘Gebhard’, while the opposite was observed in Medford. Shaded fruit surfaces had higher chromaticity values. | |
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