Fruit Total Soluble Solids Research Articles

Plant and fruit responses of lysimeter-grown ‘Braeburn’ apple to deficit irrigation

SummaryDeficit irrigation (DI) at different times during the growing season was investigated for its effects on plant water relations, growth, and fruit quality of ‘Braeburn’ apple trees grown in lysimeters. Five year old trees on MM.106 rootstock were subjected to three irrigation treatments: well-watered control (C), early deficit-irrigated (ED) from 40 d after full bloom (DAFB) until harvest, and late-deficit irrigated (LD) from 102 DAFB to harvest in a completely randomized design. Both ED and LD trees developed lower soil water content and lower predawn and midday leaf water potential (ψ) than C trees. Reduction occurred in trunk diameter growth, return bloom and mean fruit mass for ED fruit. The LD treatment increased the concentration of fruit total soluble solids (TSS), aroma volatiles, and resulted in more mature fruit based on higher ethylene production at harvest and on TSS concentration. Firmness and aroma volatile concentration were greater in LD and ED fruit than in C fruit after 12 weeks of storage at 0°C. Deficit irrigation may be used in apple production to save water while improving fruit quality in terms of increased TSS, firmness in storage, and volatile concentrations without adversely affecting fruit mass. The ED fruit were still in the highest export grade despite 12% reduction in fruit mass.

Effect of polyethylene mulch colour on aphid populations, soil temperature, fruit quality, and yield of watermelon under tropical conditions

Field studies were conducted in southwestern Mexico to determine the effect of three plastic mulch colours (black, white, and clear) on aphid populations, soil temperature, and on fruit yield of watermelon (Citrullus vulgaris Schard.). Aphids were counted on alternate days in traps placed on the mulched beds. Aphids were least numerous on the clear mulch and most numerous on the bare soil. Maximum soil temperatures under clear polyethylene reached 38.5°C and were 1.0, 4.5, and 4.2°C greater than those under white, black, and 10 cm deep unmulched soil, respectively. Total soluble solids of fruits were not modified by different coloured polyethylene. Fruit length was increased with clear and white plastic. Plants grown on clear plastic mulch produced higher marketable yields than those grown on bare soil. Other colours (black and white mulches) were intermediate in their effects on aphid populations, soil temperature, fruit weight, and yield response. Marketable yields of 48.3, 43.2, 38.3, and 22.8 t/ha were achieved under clear, black, white, and unmulched soil treatments respectively. Clear plastic mulch increased fruit weight by 2.94 kg and watermelon yield by 25.5 t/ha in comparison with unmulched soil. All plastic mulches increased fruit weight and total yield as compared with production on bare soil. By delaying aphid population increases, use of mulches may reduce the need for insecticides targeted for aphid control. In conclusion, coloured polyethylene mulch has an important effect, and clear plastic could be a practical management tool for the increase of watermelon production and enhancement of fruit quality under tropical conditions.

Sugar Metabolism and Relative Enzyme Activities during Fruit Development and Ripening of Papaya

This study examined the relationship between the activity of fruit enzymes involved in metabolizing sucrose and sugar accumulation during fruit development, to clarify the role of these key enzymes in sugar accumulation in papaya fruit. Papaya fruit (Carica papaya L. cv. Sunset) were harvested from 14 to 140 days after anthesis (DAA). Fruit dry matter persent, total soluble solids (TSS), and sugar composition and the activity of enzymes: sucrose phosphate synthetase (SPS), sucrose synthetase (SS), and acid invertase were measured. `Sunset' papaya matured 140 days after anthesis during the Hawaii summer season and in about 180 days in cool season on the same plant. Fruit flesh dry matter persent, TSS, and total sugar did not significantly increase until 30 days before harvest. Sucrose synthetase was very high 2 weeks post-anthesis, then decreased to less than one-third in 42 to 56 DAA, then remained relatively low during the rest of fruit development. Seven to 14 days before fruit maturation, SS increased about 30% at the same time as sucrose accumulation in the fruit. Acid invertase activity was very low in the young fruit and increased more than 10-fold 42 to 14 days before maturation. SPS activity remained very low throughout the fruit development and was about 40% higher in mature-green fruit. The potential roles of invertase and sucrose synthetase in sugar accumulation will be discussed.

Chemical Characterization of 24 Strawberry Cultivars and Selections

Abstract Fruit quality of 24 selected strawberry cultivars and selections was evaluated. Early season genotypes were: ‘Earliglow,’ NJUS 8219-2, ‘Delmarvel,’ ‘Northeaster,’ MDUS4987, ‘Mohawk;’ mid-season genotypes: ‘Lester,’ ‘Chambly,’ MEUS 16, MEUS 12, MEUS 9, MEUS 8, MDUS 5016, ‘St. Williams,’ ‘Settler,’ ‘Prime-time’ (MDUS 5069), ‘Allstar’; and late season genotypes: ‘Scotland,’ ‘Governor Simcoe,’ ‘Selkirk,’ MDUS 5036, ‘Lateglow,’ ‘Jewel,’ and ‘Latestar’ (MDUS 5084). Soluble solids concentration (SSC), titratable acidity (TA), sugars, organic acids, and ascorbic acid varied greatly among the cultivars and selections, reflecting primarily genetic differences. Fructose, glucose, and sucrose were the three primary sugars, comprising > 65% of fruit total soluble solids. Fruit contained lower amounts of sucrose compared to fructose and glucose, whereas leaves contained similar amounts of fructose, glucose, and sucrose. Citric acid was the major organic acid in fruit and leaves, and showed high correlation to ...

Qualidade da maçã "Fuji" sob condições de atmosfera controlada

O experimento foi conduzido no NPP/UFSM durante o ano de 1993. Maçãs da cv. Fuji foram armazenadas durante oito meses em atmosfera controlada com o objetivo de avaliar concentrações de CO2 e O2 para o armazenamento. O delineamento experimental foi inteiramente casualizado com três repetições. Os tratamentos foram combinações de concentrações de CO2 e O2, em alta e baixa umidade relativa do ar (UR) e baixa concentração de etileno. A UR do ar foi mantida em tomo de 97% para tratamentos com alta UR e, em tomo de 75% para aqueles com baixa UR. O tratamento com baixo etileno foi mantido sob constante absorção deste gás com um filtro de permanganato de potássio. Após o armazenamento avaliou-se firmeza de polpa, sólidos solúveis totais (SST), acidez titulável, podridões e degenerescência interna da polpa. Constatou-se que, concentrações de CO2 acima de 1% causaram degenerescência interna dos frutos. Com a redução de 2,0% para 1,0% de O2, em combinação com 0% de CO2, houve maior retenção de firmeza da polpa, acidez titulável e SST, no entanto, não influenciou na manifestação da degenerescência da polpa. A redução da UR para 75% diminuiu a incidência de degenerescência e pelo efeito da desidratação aumentou a firmeza da polpa e os SST. A eliminação do etileno manteve a firmeza da polpa e acidez titulável em valores mais elevados, porém não diminuiu ocorrência da degenerescência. Não houve diferença significativa entre os tratamentos em relação às podridões.

EFFECTS OF FERTILIZER PLACEMENTS AND IRRIGATION FREQUENCIES ON GROWTH, MINERAL NUTRITION AND YIELD OF TOMATOES GROWN IN SOILESS CULTURE

ISHS International Symposium on Horticultural Substrates other than Soil in situ EFFECTS OF FERTILIZER PLACEMENTS AND IRRIGATION FREQUENCIES ON GROWTH, MINERAL NUTRITION AND YIELD OF TOMATOES GROWN IN SOILESS CULTURE

Reclaimed Wastewater for Irrigation of Citrus in Florida

Reclaimed municipal wastewater has been used to irrigate young and mature sweet orange and grapefruit trees in Florida. In the central ridge area of Florida, trees receiving reclaimed wastewater had greater yields and improved tree vigor compared to trees receiving wellwater. The high level of reclaimed wastewater applied (2.54 cm/week), however, decreased fruit total soluble solids, acids, and their ratio. In contrast, tree vigor and fruit quality were not different for mature grapefruit trees growing in the coastal, flatwoods area of Florida, which received reclaimed wastewater or canal water. Yields, however, were higher for the reclaimed wastewater treatments in one season, but the effect was variable. No adverse effects of applying high levels of reclaimed wastewater were noted at either site. The use of reclaimed wastewater for citrus irrigation has potential benefits for Florida citrus growers in the future.

Effect of gypsum, deep ripping, and irrigation on determinate tomatoes

Treatments of gypsum, deep ripping, and level of irrigation were applied to alluvial soils at Carnarvon, Western Australia, to assess the effect on yield of determinate tomatoes. Yield was increased (P<0.05) from 3 1.9 to 41.5 t/ha when gypsum (5 t/ha) was applied and increased (P<0.05) with level of irrigation (65.6 t/ha at 699 mm v. 14.9 t/ha at 270 mm). Blossom end rot and total soluble solids in fruit were significantly (P<0.05) higher at low and medium irrigation (355 mm) levels than at the high level. Total soluble solids increased significantly (P<0.05) when gypsum was applied to deep-ripped treatments. Dispersion of soil colloids was significantly (P<0.05) reduced by gypsum. Deep ripping to 0.6 m removed the soil hardpan but had no effect on tomato yield or dispersion.

Use of high soil solution electrical conductivity to improve the quality of fresh market tomatoes from coastal New South Wales

High electrical conductivity (EC) in the soil solution or hydroponic medium is thought to increase the concentration of total soluble solids (TSS) and thereby improve the flavour of tomato fruit. We used trickle irrigation in 2 field experiments (1988, 1989) to apply KC1 at rates up to 4.4 t/ha to tomatoes to raise soil solution EC and examine the effects on TSS and other components of fruit quality, as well as yield. The KCl was subject to leaching in both years and EC varied widely despite regular additions of KCl. Where a high EC was achieved in 1988 (3.9 mS/cm) there was no effect on fruit firmness or TSS, but titratable acids (TA) increased from 7.25 to 8.0 m.e./100 mL. In 1989, high EC (>7mS/cm) resulted in a small increase in TSS (0.3%) in 1 of 6 harvests but significant (P<0.05) increases in TA in 4 harvests. Yield was unaffected (P>0.05). We conclude that irrigation with salinised water is unlikely to be an effective means of raising the TSS of tomatoes grown on freely draining soils in the high rainfall environment of coastal New South Wales.

Effect of root volume and nitrate solution concentration on growth, fruit yield, and temporal N and water uptake rates by apple trees

Meager information is available on the specific effects of root volume (V) and N concentration in the water (CN) on uptake rates of water and N by apple trees, as related to fruit yield and tree growth. To investigate this relationship, Golden Delicious/Hashabi trees were grown for 5 years in containers of 200, 50 and 101. Trees in the 200–1 containers were irrigated with a nutrient solution containing 10.7±1.3, 7.1±1.5 or 2.5±1.0 mM NO3. Trees in the remaining two container-volume treatments were uniformly supplied with a solution of 7.1±1.5 mM NO3. Elevated CN had no effect on the rate of water uptake, but increased the rate of N absorption by the trees from 2.4 to 4.8 g N tree−1 day−1 during July. The stimulated N uptake rate stemmed from enhanced fluxes of N uptake by the roots. CN had a negligible effect on root weight and root permeability to NO3 and water. The elevated N uptake rate did not result in greater fruit yield and growth, or greater N content in tree organs, indicating considerable release of N from living and decaying roots to the growth medium. Reducing the container volume decreased yield, total dry matter production and N and water uptake rates, but increased root permeability to NO3 and water, and total soluble solids in fruits. The all-season average CN in the irrigation solution above which N concentration in the transpiration stream was lower than the inflowing CN was 4.2 mM NO3.

Response of ‘Valencia’ Orange Trees to Four Soil Water Schedules During 20 Years1

Abstract ‘Valencia’ orange scions on sour orange rootstock, planted in 1935 at Tempe, Arizona, in calcareous sandy loam, were grown from 1949 through 1968 under 4 irrigation programs: high—15 irrigations a year, 1.72 m water applied; moderate—10 irrigations a year, 1.35 m water applied; low—5 irrigations a year, 0.95 m water applied; high-low—high, March to July, and low, August to February, 9 irrigations a year, 1.18 m water applied. Yields were similar in high, moderate and high-low trees; reduced in low trees. Trunk growth was proportionately reduced as less water was applied. High soil water produced larger tree canopies than moderate, low and high-low, which were similar. Summer shoot growth was stimulated in high trees, limited by fruiting and soil water deficits in moderate and high-low regimes, and promoted by reduced yields in low trees. Low soil water reduced total feeder roots and increased the proportion below 60 cm. Fruit sizes were similar in high and moderate, markedly reduced in high-low and variable in low schedules. Total soluble solids in fruit increased as less water was applied after mid-July. Peel thickness was similar in high and moderate and thinner than in low and high-low. High yields from the high-low regime show there is no advantage in maintaining high soil water during the entire year. Moderate stresses after July induced highest soluble solids in fruit, maintained smaller trees which facilitated picking, and prevented iron chlorosis.