Ultrastructural Characterization of Yellow Shoulder Disorder in a Uniform Ripening Tomato Genotype

Abstract

<jats:p>Yellow shoulder disorder (YSD) is characterized by sectors of yellow or green tissue under the peel of uniform ripening tomato (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.) fruit. Tissues excised from sectors of fruit expressing YSD, from adjacent red sectors, and from mature green fruit were used to compare the ultrastructural alterations in cells and tissue affected by YSD and to determine whether the disorder is caused by delayed fruit maturation or by aberrant development. Cells from YSD sectors were smaller than those from both adjacent red-ripe tissue and mature green fruit. The smaller cells from the YSD sectors were at a different developmental stage than cells of the adjacent red-ripe tissue. Chromoplasts in red-ripe tissue were more advanced in development than those in YSD sectors or mature green fruit. Using the transition from chloroplast to chromoplast and the degradation of the middle lamella between adjacent cells as developmental markers, the maturity of tissue from YSD sectors appeared to be equal or greater than that of tissue from mature green fruit. However, cell enlargement, which takes place early in fruit development, was retarded in YSD sectors. Therefore, the ultrastructural features of YSD are not compatible with a delayed ripening model for this blotchy ripening disorder. These observations provide a basis for comparing YSD in uniformly ripening tomatoes with other blotchy ripening disorders.</jats:p>

Genetic and Environmental Variation for Tomato Flesh Color in a Population of Modern Breeding Lines

“…Variance components indicated that variation within fruit and among fruit in plots accounted for more than 75% of the environmental variation for the five color traits ( Table 2). Most of the within-fruit variation is due to yellow shoulder disorder (YSD) which is characterized by sectors of yellow or green tissue under the peel (Francis et al, 2000). The occurrence of this disorder resulted in an inflated error variance because of the large difference in CIELAB values between green and red tissue relative to the more subtle differences between red and orange-red fruit associated with genotypes (Table 1).…”

“…Any differences among locations may also contribute to color variation. The fruit samples for this study were drawn form a location with a high incidence of YSD (Francis et al, 2000), and we have probably overestimated the within-fruit and within-plot variation relative to environments that are conducive to uniform fruit color. If, through the addition of further locations, σ 2 gL and related interactions were large and the withinfruit and within-plot variance components were not affected, then more sampling would be required.…”

“…Fruit flesh was exposed for measurement by cutting the proximal end of the tomato transversely with a sharp knife, such that only the pericarp at the top of the fruit was visible (Francis et al, 2000). The color of the gelatinous placental tissue was not measured, but two measurements were made on opposite sides of the exposed fleshy surface.…”

Improved Tomato Fruit Color within an Inbred Backcross Line Derived from Lycopersicon esculentum and L. hirsutum Involves the Interaction of Loci

“…Environmental differences were signifi cant for hue (p = 0.0045) and L (p = 0.0137) while genotype × environment interactions were signifi cant for hue (p = 0.0058), L (p = 0.0001), and chroma (p = 0.0001). The signifi cant environment and genotype × environment interactions may be due to a high incidence of the physiological color disorder, yellow shoulder disorder (YSD), prevalent at the OARDC farm in Fremont, Ohio (Francis et al, 2000). A signifi cant positive linear correlation was observed between hue and L values (r = 0.895, p < 0.0001) but not between hue and chroma (r = 0.075, p = 0.0872) or L and chroma (r = 0.0675, p = 0.165).…”

Tomato Analyzer-color Test: A New Tool for Efficient Digital Phenotyping

“…YSD is a blotchy ripening disorder that is characterized by discolored regions under the epidermis of mature fruit. Cells from YSD tissue are smaller and more randomly organized, and the conversion from chloroplasts to chromoplasts is altered (Francis et al, 2000). Variation for YSD within fruit and among fruit in plots explained more than 75% of the variation for color (Sacks and Francis, 2001).…”