soluble solids (°Brix), number of black seed (count), and hollow heart incidence (length × width, cm 2 ). Cotton yield. After defoliation, the center four rows of each cotton plot were harvested with a two-row mechanical picker. Watermelons were ended with
Gilbert Miller and Jeremy Greene
Ockert P.J. Stander, Jade North, Jan M. Van Niekerk, Tertia Van Wyk, Claire Love, and Martin J. Gilbert
(Brix°) of the juice, titratable acidity (TA) of the juice, and fruit juice content (%), a sample of 12 randomly selected fruit was collected from the two individual trees within each treatment replicate row that were used to determine fruit yield. Fruit
L.A. Gills, A.V.A. Resurreccion, W.C. Hurst, A.E. Reynolds, and S.C. Phatak
Descriptive analysis was used to compare sensory color, flavor, and textural attributes of Georgia-grown carrots. The relation between °Brix, total sugar, and intensity perception of sweetness was also studied. Significant differences existed in the perception of sweet taste and of color, and in levels of °Brix and percentage of sugar among all cultivars, but perceived intensity of sweetness was not related to the levels of °Brix or percentage of sugar. No significant differences were found among cultivars in harsh carroty, green, astringent, and earthy flavors, and in the perception of sour taste. Intensity ratings for perceived hardness were nonsignificant in either study. Differences in sensory profiles existed among all cultivars, but no trend was evident in the relation of sweetness to harsh flavor.
Larry Parsons and Ed Etxeberria
Moderate water stress applied to citrus trees can increase fruit °Brix. Florida citrus growers have been required to use less irrigation as competition for water increases. The goal of this study was to see if irrigation could be eliminated in the fall and winter with few negative consequences. Water stress was imposed over a 3-year period on `Hamlin' and `Valencia' oranges (an early and late variety, respectively) by stopping irrigation in late October and restarting it in March. `Hamlin' fruit was harvested after 2 months of stress and `Valencia' fruit was harvested after 4 to 5 months of stress. In most years, °Brix was increased by water stress. Over a 3-year period, `Hamlin' yield was not affected by the water stress, but `Valencia' yield decreased slightly in the 3rd year. The increase in °Brix is beneficial economically, and, over 3 cm of irrigation water per year can be saved.
J.C. Beaulieu, J.M. Lea, G. Eggleston, and Z. Peralta-Inga
Markedly higher average sucrose (58.1%) was recovered from mesocarp tissue of six orange-flesh cantaloupe (Cucumis melo L.) genotypes over three seasons compared to glucose (17.5%) and fructose (25.6%). A significant decrease in sucrose concentration was observed in the fall for all six genotypes, and the glucose (21.2%) and fructose (33.5%) ratios were also higher in the fall; markedly different than the spring fruit averages. The female inbreds had significantly (P = 0.05) lower glucose, fructose, sucrose, and total sugars than the commercial hybrids. Compared to the male and female inbreds, commercial hybrids had significantly (P = 0.05) higher concentrations of fructose, sucrose and total sugars, but not glucose. Two refractometric digital measures of °Brix (°Brix-At and °Brix-II) in homogenized slurries were positively correlated (r = 0.914; P ≤ 0.001), and were also correlated with total sugars (r ≥ 0.839) and sucrose (r ≥ 0.752). °Brix of cubes (°Brix-cube) was significantly correlated with sucrose and total sugars (r ≥ 0.627). Total sugar was positively correlated with sucrose (r = 0.843; P ≤ 0.001). Eastern-type U.S. melons had significantly (P = 0.05) higher °Brix-cube and °Brix-At compared to U.S. western shipper-types. Female inbreds were significantly (P = 0.05) lower in mean °Brix (all three measures) compared to the hybrids and male inbreds, and female inbreds had higher pH than the male inbreds. Western shippers had significantly (P = 0.05) higher pH compared to eastern genotypes. The predominant organic acid in all six genotypes was succinic acid, generally followed by oxalic, citric/isocitric, then malic acid. Succinic acid recovery was significantly higher in all six genotypes harvested in the fall, compared to spring. Eastern genotypes had significantly (P = 0.05) lower organic acids compared to western genotypes. Results indicate that maternal inheritance appears to confer lower sugar accumulating capacity and higher pH, which, is associated with vacuolar acid invertase (AI) and hexose balance. Breeding programs should focus on hybrid vigor derived through accentuating homozygous female inbreds with lower pH and higher capacity for sucrose accumulation, as well as morphological and agronomic traits often carried in the female line.
O. Smith-Kayode, S.A.O. Adeyemi, Remi Aribisala, Funke Bogunjoko, and G.N. Elemo
Conventional procedure for producing concentrated orange juice through evaporation often causes thermally induce gelation with difficulties in raising brix to optimum level. The objective of this study was to determine the effects of mixed pectinase treatment on solids extraction, recovery and pulp wash from selected sweet orange fruit cultivars. Enzyme use level, depectinization time were varied and pertinent rheological parameters determined on concentrate samples towards standardising quality control protocols. The enzyme treatment improved juice circulation in the climbing film evaporator and solids content raised to ≥ 60 Brix.
Rongcai Yuan, Fernando Alferez, Igor Kostenyuk, Shila Singh, James P. Syvertsen, and Jacqueline K. Burns
The effects of 2 consecutive years of annual defoliation during the harvest season on fruit size, yield, juice quality, leaf size and number were examined in trees of the midseason cultivar `Hamlin' and the late-season cultivar `Valencia' orange [Citrus sinensis (L.) Osb.]. In `Hamlin', removal of up to 50% of the leaves in late November had no effect on fruit yield, fruit number, fruit size, soluble solids yield, juice °Brix, and °Brix to acid ratio of juice the following year. In `Valencia', removal of 50% of the leaves in late March decreased fruit yield and soluble solids yield but did not affect Brix or the Brix to acid ratio of the juice. Leaf size of new flush was reduced by removal of 50% of the leaves in both cultivars but there was little effect on total canopy size. There were no measured effects of removing 25% of leaves from tree canopies. Thus, canopy growth, fruit yield, fruit quality, and leaf size were not negatively impacted when annual defoliations did not exceed 25% of the total canopy leaf area in `Valencia' and `Hamlin' orange trees for two consecutive years. Overall, fruit weight increased linearly with increasing ratio of leaf area to fruit number, suggesting that fruit enlargement can be limited by leaf area.
T.K. Hartz*, P.R. Johnstone, M. LeStrange, J.J. Nunez, and E.M. Miyao
Soluble solids concentration (SSC) is a major quality factor for tomatoes (Lycopersicon esculentum Mill.) grown for processing. The effects of early irrigation cutback were investigated in a series of drip-irrigated field trials in California from 2000-03. Irrigation cutback was initiated from 4-7 weeks preharvest, with irrigation volume reduced to 30% to 70% of reference evapotranspiration. Early irrigation cutback was compared to full irrigation until cutoff 2-3 weeks preharvest. SSC was monitored from the initiation of deficit irrigation until harvest, with breaker-stage fruit sampled at approximately 10-day intervals; additionally, early-maturing fruits were tagged on the plant at breaker stage and retrieved at harvest for SSC analysis. Fruit yield, overall SSC, and brix yield (Mg·ha-1 fruit solids) were evaluated at commercial maturity. Fruit SSC increased in response to soil moisture stress, with late-maturing fruit as much as 2.0 °Brix higher than fruit maturing before significant moisture stress. However, once a fruit reached the breaker stage of maturity, its SSC did not increase regardless of subsequent soil moisture stress. Across field trials, yield decline resulting from early irrigation cutback was matched by a corresponding increase in overall SSC, resulting in equivalent brix yield in all test fields. We conclude that the early irrigation cutback provides a flexible tool for SSC management and that °Brix monitoring of breaker-stage fruit can augment soil moisture monitoring to tune irrigation management to field-specific conditions.
Rongcai Yuan, Francisco Garcia-Sanchez, Fernando Alferez, Igor Kostenyuk, Shila Singh, Guangyan Zhong, James Syvertsen, and Jacqueline Burns
The effect of annual defoliation over two consecutive years on fruit yield, juice quality, leaf size, and number was examined in 11-year-old `Hamlin' and 13-year-old `Valencia' orange [Citrus sinensis (L.) Osb.] trees. Removal of up to 50% of the leaves in late November had no effect on fruit number, fruit weight, fruit yield, soluble solids yield, juice °Brix, and °Brix: acid ratio of juice in `Hamlin' oranges. In `Valencia' oranges, removal of up to 50% of the leaves in late March also did not affect °Brix or the °Brix: acid ratio of the juice, but decreased fruit yield and soluble solids yield. Leaf size was reduced by removal of 50% of the leaves in both cultivars. Removal of up to 50% leaves in late November had no significant influence on net CO2 assimilation (aCO2) of the subsequent spring flush leaves in early May in `Hamlin' oranges, whereas aCO2 of `Valencia' spring flush leaves in early May increased linearly with increasing levels of defoliation in late March. The results indicate that fruit yield, fruit quality, leaf size, and number were not negatively impacted when annual defoliations did not exceed 25% of the total canopy leaf area for `Valencia' and `Hamlin' oranges for two consecutive years. Overall, in whole `Hamlin' or `Valencia' orange trees, fruit weight increased linearly with increasing ratio of leaf area to fruit, suggesting that fruit enlargement depends on available photosynthate and can be limited by leaf area.
Ming-Wei S. Kao, Floyd Woods, William A. Dozier, Robert C. Ebel, Chang Y. Lee, and Jun Bae Jee
The health status of Alabama's population ranks above the national average with respect to the prevalence of poor overall health indicators. Consumer knowledge of the health benefits of consumption of fresh fruit is lacking. The compositional and nutritional qualities of fruit are highly variable among states with different climate, soil, and other environmental conditions. Compositional and nutritional data of fresh fruit that reflect Alabama growing conditions is limited. Commercially fully ripened kiwi fruit (Actinidia deliciosa cvs. Fitzgerald and Hayward) were compared for fruit quality (pH, TA, °Brix, °Brix/TA, and soluble sugars), and antioxidant properties; Vitamin C (reduced, oxidized, and total), Vitamin C Equivalent Antioxidant Capacity (VCEAC), ferric reducing antioxidant power (FRAP), DPPH radical scavenging activity, total phenolics, and flavonoids. In general, `Fitzgerald' ranked higher in overall fruit quality and antioxidant properties when compared to `Hayward'.