Fruit Red Color Research Articles

Effects of nitrogen fertilization on fruit yield and quality of processing tomatoes

Four processing tomato (Lycopersicon esculentum Mill.) cultivars (CC337, H9230, H9492 and H9553) were field-grown in southwestern Ontario using five N fertilization rates in each of 4 yr (0, 50, 100, 150 and 200 kg N ha-1 in 1999 and 0, 100, 150, 200 and 250 kg N ha-1 in 2000, 2001 and 2002). Total fruit yield increased linearly as N rate was increased except in 2001, which was a dry year. Responses of marketable yield to fertilizer N rate were dependent on cultivar and the year. In years when sufficient soil water was available, N fertilizer rates of 200 kg ha-1 or higher were required to produce the maximum marketable yield for the four cultivars. In the dryer years, the response to fertilizer N rate was cultivar dependent, and the application of 150 to 200 kg N ha-1 was sufficient to maximize marketable yield. Fertilizer N above the rate required for maximum marketable yield increased green fruit yield at harvest. Nitrogen rate did not affect the soluble solids (SS) content, firmness, size or colour of marketable fruit. Differences in yield and fruit quality were noted among cultivars. H9553 was the highest-yielding cultivar. H9230 had the largest fruit size. CC337 generally had the best red fruit colour and the lowest percent SS. H9492 generally had the highest percent SS. To attain maximum marketable yields, it appears that N rates should be adjusted based on cultivars, anticipated rainfall levels and availability of irrigation. Key words: Lycopersicon esculentum, processing tomato, nitrogen fertilization, yield, quality

EFFECT OF PARTICLE FILM ON FRUIT SUNBURN, MATURITY AND QUALITY OF 'FUJI' AND 'HONEYCRISP' APPLES

Studies were initiated in Idaho and New York to determine the effects of Surround, a kaolin clay particle film product recently labeled as a crop protectant for agricultural crops, on fruit maturity and quality of ‘Fuji’ and ‘Honeycrisp’ apples (Malus ×domestica) and fruit mineral concentration of ‘Fuji’ apples. Surround reduced fruit weight, red color, and the incidence of sunburn of ‘Fuji’ apples in Idaho. Sunburn did not occur on ‘Honeycrisp’ in the New York study. In that study, Surround had no effect on fruit weight or red fruit color when applied in May and June but reduced fruit weight and red color when applied later. The reduction in red color development observed in both ‘Fuji’ and ‘Honeycrisp’ was not related to mineral nutrients or to a delay in fruit maturity. Surround applications resulted in undesirable residues in the basin and in the cavity of harvested fruit that were not satisfactorily removed by brushing on a commercial packing line. While effective for reducing sunburn, Surround was ineffective for increasing red fruit color of apples.

Efeito da tela antigranizo em algumas características dos frutos de macieira

A cobertura do pomar com telas de náilon é uma opção de combate ao granizo, principalmente em pequenas áreas. Durante cinco anos, avaliou-se o efeito do sombreamento provocado pela tela antigranizo, com níveis de sombreamento de 12%, 18% e 30%, sobre os fatores de produção na macieira, cvs. Gala e Fuji. A coloração vermelha dos frutos foi a variável mais afetada pelo sombreamento, reduzindo-se até 14,2% da coloração na cv. Gala e 7,2% na cv. Fuji. O sombreamento reduziu a incidência de "russeting" nos frutos, mas aumentou a incidência da mancha de glomerela. No último ano de avaliação, as plantas com cobertura de tela apresentaram uma redução de 19% no número de gemas com flor, quando comparadas com as plantas sem cobertura.

Effect of Particle Film on Fruit Sunburn, Maturity and Quality of `Fuji' and `Honeycrisp' Apples

Studies were initiated in Idaho and New York to determine the effects of Surround, a kaolin clay particle film product recently labeled as a crop protectant for agricultural crops, on fruit maturity and quality of `Fuji' and `Honeycrisp' apples (Malus×domestica) and fruit mineral concentration of `Fuji' apples. Surround reduced fruit weight, red color, and the incidence of sunburn of `Fuji' apples in Idaho. Sunburn did not occur on `Honeycrisp' in the New York study. In that study, Surround had no effect on fruit weight or red fruit color when applied in May and June but reduced fruit weight and red color when applied later. The reduction in red color development observed in both `Fuji' and `Honeycrisp' was not related to mineral nutrients or to a delay in fruit maturity. Surround applications resulted in undesirable residues in the basin and in the cavity of harvested fruit that were not satisfactorily removed by brushing on a commercial packing line. While effective for reducing sunburn, Surround was ineffective for increasing red fruit color of apples.

Pomological and physiological characteristics of Slender Pyramid central leader apple (Malus domestica) planting systems grown on intermediate vigour, semi‐dwarfing, and dwarfing rootstocks

Three apple (Malus domestica Borkh.) planting systems utilising medium vigour (MM. 106, 5.0 × 3.0 m), semi‐dwarf (M.26, 4.0 × 2.0 m), or dwarf (Mark, 4.0 × 2.0 m) rootstocks were compared using pomological and physiological attributes affecting productivity and fruit quality of the cultivar ‘Fuji’. All planting systems were grown using Slender Pyramid tree management. Individual tree size increased with rootstock vigour, but canopy development per unit land area was similar for planting systems on MM. 106 and M.26. Light interception was up to 50% less in the Mark dwarf tree system which corresponded to small tree size and limited canopy growth once cropping began. Leaf area index of the dwarf tree system on Mark was 1.9, half that of systems on MM. 106 and M.26, whereas leaf area density of 3.7, was more than 50% higher than for the other systems. Irradiance reaching the lower inner canopy region of trees was most affected by canopy aspect with highest irradiance in the eastern sector and lowest in the southern sector for all planting systems. Floral precocity of trees on all rootstocks was not limiting to production but was proportionally higher on trees grown on Mark root‐stock. Yield in the first cropping year (third season) was greatest for planting systems with highest tree density although the Mark dwarf tree system had the highest initial production. Continued canopy growth in the systems on MM.106 and M.26 resulted in higher yields than from the Mark planting system from the fourth year onwards. Peak yields within 6 or 7 years reached 110 t/ha. Highest cumulative yields occurred with the M.26 semi‐dwarf planting system. The proportion of fruit achieving export quality standard was lowest from the intermediate vigour MM. 106 planting system. Inadequate fruit red colour was the most common quality defect. Performance of these alternative planting systems is discussed in relation to the physiological requirements for optimising the efficiency of apple planting systems.

Molecular identification of the yellow fruit color (c) locus in diploid strawberry: a candidate gene approach

A candidate gene approach was used to determine the likely molecular identity of the c locus (yellow fruit color) in Fragaria vesca, a diploid (2n=2x=14) strawberry. Using PCR with degenerate primer pairs, intron-containing segments of structural genes coding for chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS) and one Del-like regulatory gene in the anthocyanin biosynthetic pathway, were amplified, cloned and sequenced. Intron length polymorphisms for each of these genes were detected among three diploid varieties: F. vesca Alpine variety ’Yellow Wonder’ (YW) (Europe); DN1C, a F. vesca clone collected from Northern California; and Fragaria nubicola FRA520, a U.S.D.A. accession collected in Pakistan. Using F2 generations of the crosses DN1C×YW and YW×FRA520 as mapping populations, the six candidate genes were mapped in relation to previously mapped randomly amplified polymorphic DNA (RAPD) markers and morphological markers. The F3H gene was linked without recombination to the c locus in linkage group I, while the other five candidate genes mapped to different linkage groups. These results suggest that the wild-type allele (C) of the c (yellow fruit color) locus encodes an F3H necessary for red fruit color in F. vesca.

Tree Fruit Reflective Film Improves Red Skin Coloration and Advances Maturity in Peach

Replicated trials were conducted during the summers of 1998 and 1999 at commercial orchards in South Carolina to determine the influence of ground application of a metalized, high density polyethylene reflective film on fruit red skin color and maturity of peach (Prunus persica) cultivars that historically have poor red coloration. At each site there were two experimental treatments: 1) control and 2) reflective film (film). Film was applied 2 to 4 weeks before anticipated first harvest date by laying a 150-cm (5-ft) wide strip of plastic on either side of the tree row in the middles. Treatment areas at a given farm ranged from 0.25 to 0.5 ha (0.5 to 1.0 acre) in size and each treatment was replicated four times at each site. At harvest, two 50-fruit samples were picked from each plot per treatment. All fruit were sized and visually sorted for color (1 = 0% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = 76% to 100% red surface, respectively). A 10-fruit subsample was selected following color sorting and evaluated for firmness and soluble solids concentration (SSC). All cultivars tested (`CVN1', `Loring', `Bounty', `Summer Gold', `Sunprince', `Cresthaven' and `Encore') experienced significant increases in percent red surface when film was used in 1998 and 1999. This color improvement ranged from 16% to 44% (mean = 28%). On average, fruit from film were 4.2 N (0.9 lb force) softer and had 0.3% higher SSC than control fruit. Growers harvested more fruit earlier and in fewer harvests for film. Fruit size was not affected by film. Reflected solar radiation from film was not different in quality than incident sunlight. Film resulted in an increase in canopy air temperature and a reduction in canopy relative humidity during daylight hours.

503 Effect of Source and Timing of Potassium Fertilizer on `Empire' Apple Tree Growth, Yield, and Fruit Quality

A field experiment was established in 1993 in a 3-year-old `Empire'/M.9 apple orchard. An incomplete factorial treatment design compared nitrogen only fertilization with nitrogen plus potassium fertilizer applied either on the ground with and without trickle irrigation or through the trickle irrigation system. Timing of potassium fertigation treatments compared season-long K fertigation to early season or late-season K fertigation. Results of main effects showed that K fertilization reduced trunk cross-sectional area increase, but increased yield, fruit size, and fruit red color. There was no benefit of fertigation compared to ground application of fertilizers plus trickle irrigation. There was no effect of source of K fertilizer (KCl vs KNO3) on tree growth, yield, fruit size, or color. Time of K fertigation showed that late-season K fertigation resulted in greater trunk cross-sectional area increase compared to early season fertigation or season-long fertigation. Fruit size was greatest when K fertigation was done in the early season. There was no effect of time of fertigation on yield or fruit red color. Potassium fertilization increased leaf K levels and reduced leaf Mg levels. Time of fertigation did not affect leaf K levels, but early season fertigation resulted in higher leaf N levels.

578 The Influence of Reflective Film on Red Skin Color and Maturity of Peaches in South Carolina

Replicated trials were conducted in summers of 1998 and 1999 at several commercial orchards to determine the influence of a metalized, high-density polyethylene reflective film (SonocoRF, Sonoco Products Co., Hartsville, S.C.) on fruit red skin color and maturity of peach cultivars that historically have poor red coloration in South Carolina. At each site there were two experimental treatments: i) Control; and ii) Reflective Film (RF). RF was laid 2 to 4 weeks before anticipated first pick date by laying a 5-ft-wide strip of plastic on either side of the tree row in the middles. Treatment blocks at a given farm ranged from 0.5 to 1 acre in size and each treatment was replicated four times at each site. At harvest, two 50-fruit samples were picked from each block per treatment. All fruit were sized and visually sorted for color (1 = 0% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = 76% to 100% red surface, respectively). A 10-fruit subsample was selected following color sorting and evaluated for puncture pressure and soluble solids concentration (SSC). All cultivars tested (CVN1, Loring, Bounty, Summer Gold, Sun Prince, Cresthaven, and Encore) experienced significant increases in percent red surface when RF was used in 1998 and 1999. This color improvement ranged from 16 to 44% (mean = 28%). On average, fruits from RF were 0.8 lb softer and had 0.3% higher SSC than control fruits. Growers harvested more fruit earlier and in fewer picks for RF. Fruit size was not affected by RF. The influence of RF on orchard microclimate and quality and quantity of reflected light will be discussed.

577 The Influence of Reflective Film and ReTain on Red Skin Color and Maturity of `Gala' Apples in South Carolina

Replicated trials were conducted in summers of 1998 and 1999 at two commercial orchards (A and B) to determine the influence of a metalized, high-density polyethylene reflective film (SonocoRF, Sonoco Products Co., Hartsville, S.C.) and ReTain (Abbott Laboratories, Inc., N. Chicago, Ill.), on fruit red skin color and maturity of `Gala' apples. There were four experimental treatments: i) Control; ii) Reflective Film (RF); iii) ReTain; and iv) RF + ReTain. RF was laid 4 weeks before anticipated first pick date by laying a 5-ft-wide strip of plastic on either side of the tree row in the middle. ReTain was applied 4 weeks before harvest at the commercial rate in one orchard (A) and at 60% the commercial rate in the other orchard (B). At harvest, two 50-fruit samples were picked from each of four replicate blocks per treatment. All fruit were sized and visually sorted for color (1 = 0% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = 76% to 100% red surface, respectively). A 10-fruit subsample was selected following color sorting and evaluated for puncture pressure, soluble solids concentration (SSC) and starch hydrolysis. ReTain delayed maturity and reduced preharvest drop of `Gala'. Fruit from RF trees had a significantly greater percent red surface than fruit from trees not treated with RF. Fruit from RF + ReTain were significantly redder and had higher SSC than fruits from trees treated with ReTain alone. There were no differences in size, puncture pressure or starch hydrolysis between RF and RF + ReTain. RF appears to be a means to ensure greater redness in `Gala' treated with ReTain in South Carolina.

267 Improving Red Color on Apples with a Reflective Groundcover

In many years, apples grown in the mid-Atlantic region fail to exhibit a high percentage of the dark red color that buyers and consumers desire. In 1996, we initiated studies to examine the use of a metalized silver low-density polyethylene reflective groundcover (RGC) to improve red color on several apple cultivars under several training systems. A RGC placed in the orchard drive middle of 8-year-old `Delicious' apple trees trained to a “Y” trellis increased the percent surface red color and resulted in darker, more red-colored apples at harvest. A RGC increased surface red color on `Empire' apples on a “Y” trellis, but on central leader-trained semi-dwarf and standard size `Empire' showed no effects on color. Central leader-trained `Fuji'/EMLA.7 apples with a RGC had more red color than untreated fruit at harvest. In 1997, RGC placed under the canopy of 3-year-old `Fuji' trees trained to a “Y” trellis increased the full sunlight on the underside of the canopy by 28%. Ambient air temperatures within the RGC illuminated canopy averaged 2.1 °C higher than the non-RGC canopy. The level of percent full sunlight was increased within the canopy of well-pruned 32-year-old `Miller Spur Delicious' apple trees 4- to 8-fold with RGC placed in the row middle or under the canopy in a commercial orchard in 1998. Position of the RGC to the canopy affected fruit red color response differently between the lower and upper part of the canopy. Bins of fruit graded with a commercial color sorter showed no difference in fruit color; however, there was a strong trend toward increased red color where the RGC material was applied.

Midsummer copper sprays have no effect on ‘delicious’ apple fruit color grade or typiness

Recent reports suggested that multiple midsummer copper (Cu) sprays could improve the proportion of apple fruit (Malus × domestica Borkh.) being packed in the reddest market color grades. We conducted a three‐year field experiment in a low‐Cu orchard with a history of poor fruit coloring. We applied multiple mid‐summer sprays of Cu sulfate and basic Cu sulfate in 1994 and 1995 to ‘Bisbee Delicious’ and ‘Oregon Spur II Delicious’ apple trees. Plant tissue nutrient levels, fruit color grade, and fruit typiness were evaluated in the years of application and the following year. The Cu sprays increased leaf Cu in the years of application; however, leaf Cu in the Cu‐sprayed plots returned to or very near to background concentrations in the year after sprays were terminated. The Cu treatments did not increase the proportion of fruit in the reddest market color grades or influence five fruit typiness indices of either apple cultivar. Although midsummer Cu sprays may not enhance apple fruit red color or typiness, they may be useful for increasing overall tree Cu status, particularly for long‐season cultivars which are harvested too late for postharvest sprays to be effective.

Effects of covering the orchard floor with reflecting films on pigment accumulation and fruit coloration in `Fuji' apples

Effects of covering the orchard floor with reflecting films (crinkled aluminum foil bonded onto cloth (foil film), aluminum metalized polypropylene film (metalized film), and polypropylene film (Poly film) on anthocyanin, flavonoid, chlorophyll, and carotenoid accumulation and fruit coloration in `Fuji' apple were studied. After film application, light intensity inside the tree canopy increased from 30% of daylight to 68% and 50% of daylight, respectively, for foil film and metalized film. Poly film did not significantly increase light intensity in the tree canopy. Both foil film and metalized film increased anthocyanin concentration and reduced chlorophyll concentration in fruit peel, and improved percent red color of fruit. Carotenoid and flavonoid concentrations were not affected by use of reflecting films. Poly film did not affect anthocyanin synthesis and chlorophyll degradation, or carotenoid and flavonoid accumulation. Both foil and metalized film application stimulated internal ethylene synthesis and elevated UFGalT activity. The relationships among light intensity, UFGalT activity, and pigment concentrations in fruit peel are discussed.

Response of apple and pear trees to nitrogen, phosphorus, and potassium fertilizers

Apple (Malus domestica, Borkh) and pear (Pyrus communis, L.) trees responded to nitrogen (N), phosphorus (P), and potassium (K) fertilizers. In low P soils, leaf, and fruit P concentrations were increased and yield was improved with moderate rates of mono‐ammonium phosphate (MAP) fertilizers. Improved fruit quality including fruit firmness, red fruit color of ‘Delicious’ apples, and a lower incidence of fruit disorders of apples (bitter pit) and pears (alfalfa greening and cork spot) was frequently associated with trees that were fertilized with calcium nitrate [Ca(NO3)2] (CN). Although yield was often improved in experiments containing N‐P‐K or MAP fertilizers, long‐term use of N‐P‐K or MAP could be associated with a higher incidence of fruit disorders and a lower soil pH than with CN fertilizer at equivalent rates of N.

Advanced backcross QTL analysis of tomato. II. Evaluation of near-isogenic lines carrying single-donor introgressions for desirable wild QTL-alleles derived from Lycopersicon hirsutum and L. pimpinellifolium

Improved-processing tomato lines were produced by the molecular breeding strategy of advanced backcross QTL (AB-QTL) analysis. These near-isogenic lines (NILs) contained unique introgressions of wild alleles originating from two donor wild species, Lycopersicon hirsutum (LA1777) and L. pimpinellifolium (LA1589). Wild alleles targeted for trait improvement were selected on the basis of previously published replicated QTL data obtained from advanced backcross populations for a battery of important agronomic traits. Twenty three NILs were developed for 15 genomic regions which were predicted to contain 25 quantitative trait factors for the improvement of seven agronomic traits: total yield, red yield, soluble solids, brix×red yield, viscosity, fruit color, and fruit firmness. An evaluation of the agronomic performance of the NILs in five locations worldwide revealed that 22 out of the 25 (88%) quantitative factors showed the phenotypic improvement predicted by QTL analysis of the BC3 populations, as NILs in at least one location. Per-location gains over the elite control ranged from 9% to 59% for brix×red yield; 14% to 33% for fruit color; 17% to 34% for fruit firmness; 6% to 22% for soluble-solids content; 7% to 22% for viscosity; 15% to 48% for red yield, and 20% to 28% for total yield. The inheritance of QTLs, the implementation of the AB-QTL methodology for characterizing unadapted germplasm and the applicability of this method to other crops are discussed.

Development and Correction of K-deficiency in Drip-irrigated Apple

Various schedules of 40 g N and 17.5 g P/tree per year were applied with irrigation water (fertigation) to `Summerland McIntosh' apple (Malus ×domestica Borkh.) trees on M.9 rootstock commencing the year of planting. Leaf K concentrations averaged 0.82% dry mass, indicating deficiency, by the third growing season. This coincided with extractable soil K concentrations of 50-60 μg·g-1 soil in a narrow volume of the coarse-textured soil located within 0.3 m of the emitters. The decline in leaf K concentration was reversed and fruit K concentration increased by additions of K at 15-30 g/tree applied either as granular KCl directly beneath the emitters in spring or as KCl applied as a fertigant in the irrigation water. K-fertilization increased fruit red color, size, and titratable acidity only when leaf K concentration was <1%. Fruit Ca concentration and incidence of bitter pit or coreflush were unaffected by K application. NPK-fertigation commencing upon tree establishment is recommended for high-density apple orchards planted on similar coarse-textured soils.

Development and Correction of K-deficiency in Drip-irrigated Apple

Various schedules of 40 g N and 17.5 g P/tree per year were applied with irrigation water (fertigation) to `Summerland McIntosh' apple (Malus ×domestica Borkh.) trees on M.9 rootstock commencing the year of planting. Leaf K concentrations averaged 0.82% dry mass, indicating deficiency, by the third growing season. This coincided with extractable soil K concentrations of 50-60 μg·g-1 soil in a narrow volume of the coarse-textured soil located within 0.3 m of the emitters. The decline in leaf K concentration was reversed and fruit K concentration increased by additions of K at 15-30 g/tree applied either as granular KCl directly beneath the emitters in spring or as KCl applied as a fertigant in the irrigation water. K-fertilization increased fruit red color, size, and titratable acidity only when leaf K concentration was <1%. Fruit Ca concentration and incidence of bitter pit or coreflush were unaffected by K application. NPK-fertigation commencing upon tree establishment is recommended for high-density apple orchards planted on similar coarse-textured soils.

The capsanthin-capsorubin synthase gene: a candidate gene for the y locus controlling the red fruit colour in pepper.

The red colour of pepper fruits is determined by the y+ dominant allele and the yellow colour by the y recessive allele. The capsanthin-capsorubin synthase (CCS) gene is activated specifically during the final stages of pepper fruit ripening. RFLP and specific-PCR polymorphisms derived from the CCS gene were analysed in a F2 progeny of a red by yellow-fruited cross. They cosegregated completely with fruit colour. Our results support the hypothesis that the yellow phenotype might result from a deletion of the CCS gene. These specific markers were integrated into the genetic map and will be useful for marker assisted plant breeding.

Effect of Spacing and Rectangularity on Tree Growth, Yield, Light Interception, and Fruit Quality of Y-trellis-trained Apple Trees

In 1986, an orchard systems trial was planted with `Empire' and `Jonagold' on M.26 rootstock to compare the performance of the Y-trellis training system at a range of spacings and rectangularities. There were four in-row spacings ranging from 90 cm to 3.66 m and four between-row spacings ranging from 3 to 6 m, giving tree densities from 472 trees/ha up to 3588 trees/acre. Rectangularities ranged from 0.83 to 6.67. In several cases, different spacings gave the same tree density, but with different rectangularity. Trees were trained to a Y-shaped trellis with a 60° angle. Scaffold branches were trained to the wires on each side of the Y in a fan-shaped arrangement. At the closest in-row spacing only two scaffolds were allowed per tree, while at the widest in-row spacing up to 12 scaffolds were allowed per tree. At the end of 11 years, tree weight and cumulative yield per tree were negatively correlated to tree density, while light interception and cumulative yield per hectare were positively correlated to tree density. However, the relationship was weakened by differing results with different rectangularities at the same spacing. As rectangularity increased at a given density, tree size, yield, and light interception were reduced. However, at the lower densities, trees failed to completely fill the trellis when rectangularity was low, thus limiting yield per hectare. Fruit red color was reduced at the highest densities and increased with increasing rectangularity.

Effect of Sun Exposure on the Red Color of Salted Ume Fruit After Coloring.

Ume fruit brined with 2.5 kg of brine solution mixed with calcium hydroxide (3 g Ca(OH)2/1 kg of fruit) was either non-exposed or sun-exposed and subsequently colored with new coccine (0.004-0.1%), acid red (0.0008-0.04%), red cabbage color (0.1-10%) or perilla color (0.1-10%) colorant. A comparison was made between the sun-exposed and non-exposed samples using Hunter L-, a- and b-values as optical measurements and by sensory evaluation as an organoleptic measurement. It was confirmed that the color change with each colorant had almost reached equilibrium after 7 days. It was also noticed that the dye effect of red cabbage color and perilla color was weaker than that of new coccine and acid red. The L- and a-values of the sun-exposed samples were higher than those of the non-exposed samples, although the b-values indicated no clear difference between the sun-exposed and non-exposed samples with any colorant. The sun-exposed samples were evaluated as being lighter, redder and more preferred than the non-exposed samples with all colorants by the visual-sensory test. The degree of difference in ‘redness’ was numerically evaluated, and the ‘redness’ effect ratio on the sun-exposed samples to the non-exposed samples with the same colorant concentration was 1.1 for new coccine, 1.7 for acid red, 2.1 for red cabbage color and 1.5 for perilla color. This study clarifies that even if the colorant concentration is reduced, the same level of redness for ume fruit could be obtained with sun exposure before coloring. It is proposed that sun exposure will contribute to the coloring of salted ume fruit.