Fruit Soluble Solids Research Articles

The effect of rootstocks on the vigor, yield, and fruit quality of Maciel peach trees

This study was conducted aiming to evaluate the effect of rootstocks in plant vigor, yield, and fruit quality of ‘Maciel’ peach trees growing in a 7-8-year-old orchard in the municipality of Pelotas, Rio Grande do Sul state, Brazil. The experiment was performed with plants of the ‘Maciel’ cultivar grafted on the following eight Prunus persica rootstocks: ‘Capdeboscq’, ‘Aldrighi’, ‘Tsukuba 1’, ‘Okinawa clone 1’, ‘Okinawa ‘clone 12’, ‘Industry’, ‘Nemaguard’, and ‘Rubira’. Trunk diameter, height and yield of plants, fruit mass, soluble solids content, and fruit classification by category were evaluated. The experimental design used randomized blocks with three replicates, with five plants per parcel. In two evaluation cycles (2011/2012 and 2012/2013), ‘Aldrighi’ presented the largest trunk diameter (75.5 and 80.4 mm, respectively) compared with ‘Okinawa clone 1’ (65.80 and 67.7 mm, respectively) and ‘Rubira´ (63.4 mm and 65.8, respectively). Fruit mass was greater for ‘Aldrighi’ (118.6 g), ‘Industry’ (106.5 g) and ‘Capdeboscq’ (103.5 g) in the 2011/2012 cycle. The ‘Maciel’/’Aldrighi’ combination showed the highest yield, with the highest percentage of fruits in class I; however, the fruits showed the lowest soluble solids content among the tested scion/rootstock combinations (12.6 °Brix), differing only from ‘Maciel’/’Okinawa clone 1’ (15.2 °Brix). Under the conditions in which the experiment was conducted, we conclude that characteristics such as vigor, yield, and fruit quality of ‘Maciel’ peach trees are differentially influenced by the rootstocks used. The ‘Okinawa Clone 1’ rootstock induces less vigor and greater total soluble solids in fruits of ‘Maciel’ peach trees compared with the ‘Aldrighi’ rootstock, but it does not significantly influence the productive efficiency and yield of the plants.

Optimum Nutrient Solution Strength for Korean Strawberry Cultivar ‘Daewang’ during Seedling Period

과채류는 육묘의 중요성이 큰 것으로 알려져 있는데, 딸기는 육묘가 80%라고 할 정도로 육묘의 비중이 큰 것으로 인식하고 있다. 그러나 아직 딸기의 수경재배 육묘에 대한 연구는 국내외 모두 많지 않다. 딸기는 품종에 따라 생육 특성의 차이가 확연하게 다르므로 품종마다 적합한 비료 조성, 비료 농도와 pH 관리, 고형배지 종류별 적절한 급액량 구명 등이 필요한데, 딸기 수경재배 육묘에서 우선적으로 구명할 사항은 배양액의 농도관리 기술이라고 할 수 있다. '대왕(大王)' 딸기 모주를 2012년 3월 28일에 코코피트를 충진한 수경재배 육묘 벤치에 정식하였다. 육묘기간 동안의 배양액 처리구는 각각 EC <TEX>$0.6dS{\cdot}m^{-1}$</TEX>의 배양액을 30일간 공급한 후 20일간 물만 공급한 구[0.6(30) + 20], EC <TEX>$1.2dS{\cdot}m^{-1}$</TEX>의 배양액을 30일간 공급한 후 20일간 물만 공급한 구[1.2(30) + 20], 그리고 EC <TEX>$1.2dS{\cdot}m^{-1}$</TEX>의 배양액을 50일간 공급한[1.2(50)] 3가지 처리구로 하였다. 9월 20일에 코코피트를 충진한 수경재배 벤치에 정식하고, 야마자키 조성 딸기배양액을 이용 하여 EC <TEX>$0.6-0.8dS{\cdot}m^{-1}$</TEX>로 관리하였다. 정식 후 지상부 생육, 개화율 그리고 정화방의 과실 품질을 조사하였다. 엽병장, 엽장, 엽폭 그리고 크라운 직경 모두 [1.2(50)], [1.2(30) + 20], [0.6(30) + 20] 처리구 순으로 육묘기의 배양액 농도가 높을수록 생육이 양호하였다. 그러나 생육이 진전됨에 따라 처리구 간의 생육차이는 점차 사라졌고 특히, 크라운의 직경은 처리구 간에 거의 차이가 없을 정도가 되었다. 개화는 [0.6(30) + 20], [1.2(30) + 20], [1.2(50)] 처리구 순으로 빨랐는데, 특히 [0.6(30) + 20] 처리구는 다른 처리구보다 월등하게 빠른 개화율을 나타내어 육묘기의 저농도의 배양액 관리가 '대왕' 딸기의 개화에는 유리한 것으로 생각되었다. 과장, 과경 및 과실의 경도는 처리구간에 통계적으로 유의한 차이를 나타내지 않았다. 과중은 [1.2(50)] 처리구가 다른 처리구보다 유의하게 높았다. 그러나 과실의 고형물 함량은 [1.2(50)] 처리구에서 가장 낮았고 다른 두 처리구에서 높은 수치를 나타내었다. 본 실험의 결과에서, 딸기의 수경재배 육묘기 동안 적정한 배양액의 농도 관리는 EC <TEX>$0.6dS{\cdot}m^{-1}$</TEX>로 30일간 공급한 후에 20일간 수분만 공급하는 것이 좋을 것으로 생각되었다. Raising seedlings is important for fruit crops and is especially significant for strawberries as it accounts for 80% of their cultivation. However, there are few studies on raising seedlings of strawberries by hydroponics. Since strawberries show clear differences in growth characteristics based on cultivar, it is necessary to develop suitable fertilizer formula, concentration and pH for each cultivar, and also to examine the amount of nutrient feeding appropriate for each medium type. A key to raising seedlings of strawberries by hydroponics is the development of strategies to manage the concentration of nutrient solution. The mother plants of 'Daewang' strawberries were planted on hydroponics benches filled with cocopeat on March 28, 2012. Three nutrient solution treatments were employed during the term of raising seedlings: a type that supplied EC <TEX>$0.6dS{\cdot}m^{-1}$</TEX> nutrient solution for 30 days and only water for 20 days [0.6 (30) + 20]; a type that supplied EC <TEX>$1.2dS{\cdot}m^{-1}$</TEX> nutrient solution for 30 days and only water for 20 days [1.2 (30) + 20]; and a type that supplied EC <TEX>$1.2dS{\cdot}m^{-1}$</TEX> nutrient solution for 50 days [1.2 (50)]. The plants were then planted on hydroponics benches filled with cocopeat on September 20, and managed with EC <TEX>$0.6-0.8dS{\cdot}m^{-1}$</TEX> strawberry nutrient solution developed by Yamazaki. After planting, shoot growth, flowering rate and fruit quality of the first cluster were investigated. The petiole length, leaf length, leaf width and crown diameter showed the highest grown in the [1.2 (50)] treatment, followed by [1.2 (30) + 20], and then [0.6 (30) + 20], indicating that the higher concentration of nutrient solution was preferable for raising seedlings. However, the growth differences among treatments gradually disappeared as growth continued, and the crown diameter especially grew to exhibit almost no difference at all among treatments. The point of flowering came first in [0.6 (30) + 20], followed by [1.2 (30) + 20] and then [1.2 (50)]. The [0.6 (30) + 20] treatment showed much earlier flowering than other treatments, which implies that low-concentration nutrient solution may be beneficial to the flowering of 'Daewang' strawberries while raising seedlings. There was no statistically significant difference among treatments in fruit length, fruit diameter and fruit firmness. Fruit weight in [1.2 (50)] treatment was significantly higher than other treatments. However, soluble solids of fruit was the lowest in [1.2 (50)] treatment. Together, the results of this experiment imply that it is better to supply EC <TEX>$0.6dS{\cdot}m^{-1}$</TEX> solution for 30 days and then supply only water for 20 days to adequately manage concentration of nutrient solutions during the period of raising seedlings of strawberries by hydroponics.

Impact of Supplemental Calcium Chloride on Yield, Quality, Nutrient Status, and Postharvest Attributes of Tomato

Little is known regarding the impact of calcium chloride applications during growth and development on tomato postharvest quality. This trial investigated supplemental calcium chloride applications on yield, nutrient content, texture, and postharvest quality of tomato fruit. Calcium (Ca) nutrient solution concentrations were: 60, 180, and 360 mg·L−1 calcium, while foliar applications were (0, 1, and 2% calcium chloride w/v). Plants grown with 60 mg·L−1 Ca had a high incidence of blossom end rot, which was not affected by calcium chloride sprays. Fruit nutrient concentrations were affected by calcium delivered through the nutrient solution. As fruit cluster position increased, fruit nutrient concentrations significantly decreased. Foliar calcium chloride sprays affected fruit soluble solids content and dry weight, but did not affect texture. Pericarp elasticity increased concomitantly with calcium in the nutrient solution. Postharvest disease incidence was not affected by calcium treatment, though weight loss during storage was negatively affected by calcium chloride sprays.

Seasonal growth and characteristics of fruits developed from delayed flowers of ‘Fuyu’ persimmon

Growth and characteristics of the fruits developed from “delayed flowers” (DFs) of ‘Fuyu’ persimmon (Diospyros kaki) were investigated to determine their usefulness to supplement the frost-damaged normal flowers (NFs). In hand-pollinated trees without frost damage, DFs bloomed on June 6 and June 5 in 2012 and 2013, respectively, 13 and 11 days later compared with NFs. DF fruit diameters were 5.8–9.4mm less than the NF fruits on July 16 in both years, but the difference became 1.5–2.4mm on August 27. Such a difference persisted until harvest on November 12. DF fruits at harvest weighed 6.6–7.3% less compared with NF fruits, an insignificant reduction. Skin color, firmness, and soluble solids of fruits were not different between both DF and NF. In trees with insufficient NFs due to spring-frost, DF bloomed 10 days later than NF. DF decreased fruit drop under open pollination but produced more deformed fruits. DF fruits, containing more seeds, were not significantly lower in size, skin color, and soluble solids. It was concluded that DFs could yield marketable fruits with no delay in maturity although their size is slightly smaller.

Bell Pepper (Capsicum annum L.) Crop as Affected by Shade Level: Fruit Yield, Quality, and Postharvest Attributes, and Incidence of Phytophthora Blight (caused by Phytophthora capsici Leon.)

High temperatures can be detrimental to bell pepper, resulting in reduced fruit yield and increased incidences of fruit disorders such as sunscald and blossom-end rot. Shade nets are used to modify the crop microenvironment to improve plant growth and yield. The objectives were to evaluate effects of shade level on fruit yield, quality, and postharvest attributes and the incidence of Phytophthora blight (caused by Phytophthora capsici Leon.) in bell pepper (Capsicum annum L.). Experiments were conducted in Tifton, GA, in 2008 (with cv. Heritage) and 2009 and 2010 (with cvs. Camelot, Lafayette, Sirius, and Stiletto). Bell pepper plants were grown under shade levels of 0% (unshaded, as a control), 30%, 47%, 63%, and 80%. Shade level affected fruit yield, quality, postharvest attributes, and incidence of Phytophthora blight in plants. Total marketable (Fancy and US1) fruit yield increased with increasing shade level to a maximum at 35% shade and then decreased with further increments in shade level. Relative to unshaded plants, marketable yields were improved by 119% (2008) and 43% (2009 and 2010) at 35% shade level. US2 and cull (sunscald) fruit number declined with increasing shade level. ‘Camelot’ produced among the greatest number and yield of marketable fruit; ‘Sirius’ had the heaviest fruit and greatest number of culls. Fruit nitrogen (N), phosphorus (P), and potassium (K) concentrations increased and aluminum (Al), molybdenum (Mo), and nickel (Ni) decreased with increasing shade level. ‘Lafayette’ had the highest fruit concentration of N, calcium (Ca), sulfur (S), manganese (Mn), and zinc (Zn). Fruit soluble solids and percent of fruit dry weight decreased with increasing shade level; fruit water loss rate and bacterial soft rot incidence were unaffected. Fruit skin a* and b* values decreased in yellow fruit cultivars (‘Lafayette’ and ‘Sirius’) with increased shade level. Incidences of Phytophthora blight in plants and fruit sunscald decreased with shade level. Beneficial effects of shading on bell pepper were associated with a reduction in irradiation, air temperature, and soil temperature under shaded conditions resulting in amelioration of heat stress in the plants. Optimal shade level for maximal fruit yield was that which maximized the cooling effect resulting from reduction of infrared (IR) radiation and minimized the decrease in net photosynthesis resulting from reduction in photosynthetically active radiation (PAR).

Densidade de plantio e genótipos de tomateiro cereja em sistema fechado de cultivo em substrato

O cultivo de tomateiro em sistemas fechados (com reutilização da solução drenada) é essencial para reduzir as perdas de água e nutrientes e a contaminação ambiental, mas escassas são as informações na literatura. O objetivo foi avaliar o efeito de densidades de cultivo (2,9; 3,9; 4,7; 5,9 e 7,8 plantas m-2) no crescimento, na produtividade e na qualidade de frutos de dois genótipos de tomateiro cereja ('Cereja Vermelho' e 'Flavor Top') cultivados em casca de arroz com sistema fechado de circulação da solução nutritiva. Foram avaliados a produção e partição da matéria seca de hastes, folhas e frutos; número, massa fresca média e produtividade de frutos; teor de sólidos solúveis e concentração de fitoquímicos (carotenóides, compostos fenólicos totais e capacidade antioxidante). 'Cereja Vermelho' apresentou maior alocação de fotoassimilados nos frutos, crescimento e produtividade e 'Flavor Top' apresentou maior concentração de sólidos solúveis, maior concentração de fenóis e capacidade antioxidante. O aumento da densidade de plantio reduziu o crescimento individual das plantas sem afetar a partição de matéria seca, aumentando a produtividade por unidade de área. As densidades de plantio de 5,9 e 7,8 plantas m-2 são as mais adequadas, respectivamente, para 'Cereja Vermelho' e 'Flavor Top'.

Improving quality of greenhouse tomato (Solanum lycopersicum L.) by pre- and postharvest applications of hexanal-containing formulations

From harvest to consumption, tomato (Solanum lycopersicum L.) fruit are exposed to several exogenous factors that enhance product deterioration. Phospholipase D is a key enzyme involved in membrane deterioration that occurs during fruit ripening and senescence. Hexanal, an inhibitor of phospholipase D has been successfully used for pre- and postharvest treatment of fruit, vegetables and flowers. In this study, effectiveness of pre- and postharvest application of an aqueous hexanal formulation and an enhanced freshness formulation (EFF) containing hexanal and other ingredients were evaluated by monitoring changes in quality parameters during postharvest storage of greenhouse tomatoes. Tomatoes subjected to preharvest spray with EFF containing 1mM hexanal twice a week had better colour, and firmness than untreated fruit and hexanal formulation treated fruit. EFF treated tomatoes also showed low hue angle values indicative of enhanced red colour. Preharvest spray with 1mM hexanal twice a week resulted in higher levels of ascorbic acid and soluble solids in fruit than those subjected to EFF treatment, and the control. Postharvest dip application of harvested tomatoes in 2mM hexanal as EFF resulted in enhanced brightness and hue angle values, reduced red colour, increased fruit firmness and ascorbic acid content after 21 days of storage, indicative of better quality. The results suggest that hexanal has the potential to enhance shelf-life and quality of greenhouse tomatoes.

Antimicrobial and antioxidant properties of pullulan film containing sweet basil extract and an evaluation of coating effectiveness in the prolongation of the shelf life of apples stored in refrigeration conditions

Abstract The antimicrobial and antioxidant activities of pullulan films containing sweet basil extract (SBE) at varying concentrations were examined in the paper. Additionally, the content of bioactives in SBE was determined. A strong correlation was noted between SBE concentrations in the film and the obtained film thickness. Pullulan film containing SBE was characterized by a smooth surface as well as a uniform and compact internal structure. The study involved an examination of the effectiveness of pullulan coatings containing 24 mg SBE/cm 2 on the prolongation of the shelf life of “Jonagored” apples. Pullulan coating with SBE was found to offer low antibacterial activity against mesophilic bacteria and good antifungal protection against Rhizopus arrhizus on apple surfaces. This coating also contributed to a reduction in weight losses and lower changes in the color and soluble solids of fruits during storage. Apples with pullulan enriched SBE coating presented better overall preference parameters. Industrial relevance The consumers express an increasing aversion and objections towards an application of chemical means in order to prolong the durability of food products. This prompts food producers to search for new methods of preventing raw materials against harmful microbial activity. Plant extracts, due to their chemical variability, ensure unlimited possibilities of microorganism growth control. An application of natural plant extracts combined with edible coatings for fruit and vegetable durability prolongation may find an acceptance among the consumers. Incorporation of plant extract to edible coating ensures slow release of bioactives on food surface, i.e. at the site of the highest microbiological food changes. Pullulan is a natural polysaccharide, a carrier of small energy amounts, forming glossy, colorless and flavorless films, resistant to oils and impermeable for oxygen. The authors decided to elaborate the procedure concerning an application of edible pullulan coating combined with sweet basil extract for an elongation of apple durability, which will improve the quality of fresh fruits during their storage and in the trade.

Functionality and yield of pectin extracted from Palmyra palm (Borassus aethiopum Mart) fruit

Large numbers of fruits from Palmyra palm (Borassus aethiopum Mart), a common, native tree of tropical regions, are underutilized and left to spoil. This work was conducted to assess pectin content of Palmyra palm fruit, and to develop a reliable protocol for pectin extraction. Yield and galacturonic acid content of Palmyra palm fruit soluble solids were investigated at various pH (natural pH of 5.2–5.5, 2.5, 7), time (30–120 min) and temperature (70 °C, 80 °C, 90 °C). Yield and galacturonic acid content of extracted soluble solids were strongly dependent (p < 0.0001) on temperature, time and pH of extraction and ranged from 47 to 149 g kg−1 and 682 to 880 g kg−1 dry weight, respectively. High galacturonic acid (808–852 g kg−1) were obtained at 70 °C and 90 °C under natural pH; at 70 °C pH 7 and pH 2.5 at all temperatures studied. Analysis of pectin extracted at natural pH (30 min, 90 °C) revealed highly esterified pectin with good gelling and emulsifying properties. Production of galacturonic acid of more than 650 g kg−1 dry weight indicates that Palmyra palm fruit could serve as an excellent raw material for industrial pectin production.

POMOLOGICAL AND CHEMICAL CHARACTERISTICS OF SWEET CHERRY CULTIVARS GROWN IN DALMATIA, CROATIA

Sweet cherry growing in Mediterranean area of Croatia has a long tradition because of the favourable ecological conditions. Four local cultivars ('Gomilicka', 'Rana Stonska', 'Stonska' and 'Tugarka') and five introduced cultivars ('Bigarreau Burlat', 'Garnet', 'Isabella', 'Summit' and 'Van') were evaluated for ripening time and fruit characteristics. To assess external and internal fruit quality, the following was investigated: fruit weight (g), fruit lenght, width and fruit thickness (mm), weight of pits (g), fruit pedicel length (mm), fruit soluble solids (%), fruit acid content (g/l) and fruit skin colour (L, C, H, CIELAB system). Large differences for particular quality attributes were found between cultivars. Fruit of 'Isabella' and 'Tugarka' had a mean weight >7.5 g, while those of 'Bigarreau Burlat' was less than 5 g. Fruit soluble solid content varied from 13.1% ('Tugarka') to 19.2% ('Van'), and total titrable acidity varied from 4.8 g/l ('Rana Stonska') to 9.3 g/l ('Van'). The 'Garnet' fruits had the highest L values (dark red skin colour). Chroma and hue angle had higher level for fruits of 'Summit', 'Isabella' and 'Garnet', and lover for the other cultivars.

TRAINING SYSTEM AND ROOTSTOCK AFFECT YIELD, FRUIT SIZE, FRUIT QUALITY AND CROP VALUE OF SWEET CHERRY

A 1999 field trial compared ‘Hedelfingen’, ‘Lapins’, and ‘Sweetheart’ cherry cultivars on Gisela 5, (Gi.5), Gisela 6, (Gi.6) and MxM.2 rootstocks each planted in six cherry training systems (Central Leader-336 trees/ha, Spanish Bush-673 trees/ha, Slender Spindle-897 trees/ha, V-997 trees/ha, Marchant-1,035 trees/ha, and Vertical Axis-1,196 trees/ha). A second 2002 trial compared ‘Lapins’ and ‘Regina’ cultivars on Gi.5, Gi.6, Gi.12 and Mazzard seedling rootstocks each planted in four cherry training systems (Quad Axis-598 trees/ha, Spanish Bush-748 trees/ha, Central Leader-748 trees/ha, and Vertical Axis-997 trees/ha). After 11 years tree size in experiment 1 was smallest with Gi.5, intermediate with Gi.6 and largest with MXM.2. In experiment 2 after 8 years, trees on Gi.5 were the smallest, followed by trees on Gi.6, G.12 and Mazzard which were the largest. Trees on all three Gisela stocks were much more precocious than either MXM2 or Mazzard. Cumulative yield after 11 years with experiment 1 or after 8 years with experiment 2 were highest for trees on Gi.5 followed by Gi.12, Gi.6, Mazzard and MXM.2. With the self fertile cultivars, ‘Sweetheart’ and ‘Lapins’, Gi.5 induced excessive production which resulted in small fruit size. However, with the self infertile cultivar, ‘Regina’, Gi.5 was the only rootstock which induced commercially acceptable high yields of large fruit. Although Gi.12 was a vigorous tree, it had much greater precocity and productivity than Mazzard. Average fruit size was largest on Gi.12 and Gi.6, intermediate on MXM.2 or Mazzard and smallest on Gi.5. Among training systems, the Vertical Axis system had the highest cumulative yield per hectare followed by the V, the Slender Spindle, the Spanish Bush, the Quad Axis, the Marchant, and the Central Leader. Cumulative yields largely reflected density. Fruit size was largest with the Central Leader, Quad Axis and Spanish Bush, intermediate with the Slender Spindle and Marchant system and smallest with the V and the Vertical Axis. Fruit soluble solids were highest with the Central Leader and Quad Axis and lowest with the Spanish Bush and the Marchant. Cumulative crop value was highest for the V in experiment 1 and for the Vertical Axis in experiment 2.

Pericarp polypeptides and SRAP markers associated with fruit quality traits in an interspecific tomato backcross

The aim of this study was to detect polypeptides and genomic regions associated with fruit quality traits in a backcross generation using as parent the Argentinean cultivated tomato Caimanta of Solanum lycopersicum and the wild accession LA722 of S. pimpinellifolium. We tested two types of molecular marker: polypeptide profile (at two ripening stages, mature green and red ripe) and SRAP (sequence-related amplified polymorphism). A polypeptide of 45 kDa present in the wild parents at the mature green stage was associated with larger fruit and long shelf life. Some amplification fragments from SRAP markers were associated with more than one quality trait such as fruit color, firmness, titratable acidity, and fruit soluble solids content. This study demonstrated for the first time the usefulness of the polypeptide profiles of pericarp and SRAP markers in finding associations with quality fruit traits in a tomato backcross generation.

Using visible and near infrared diffuse transmittance technique to predict soluble solids content of watermelon in an on-line detection system

Sugar content is one of the most important factors determining the eating quality of watermelon fruit. In order to detect the fruit soluble solids content (SSC) on-line, this work develops a nondestructive on-line detection prototype system using visible and near-infrared (Vis/NIR) technology. For the acquisition of the diffuse transmittance spectrum of watermelon, the conveyor was set at a speed of 0.3m/s and ten 150W tungsten halogen lamps were used as the light source. The crucial model for SSC value prediction was optimized by chemometrics. Partial least squares regression (PLSR), stepwise multiple linear regressions (SMLR), Monte-Carlo uninformative variable elimination (MC-UVE) and genetic algorithms (GA) were applied to the spectra in the range of 687–920nm. The data pre-processing methods were optimized to transmittance spectra with baseline offset correction (BOC), and the BOC-MC-UVE-SMLR calibration model was the best with a correlation coefficient (rpre) of 0.70, root mean square error of prediction (RMSEP) of 0.33°Brix for the prediction set. In on-line testing of 30 samples, the rpre was 0.66 and RMSEP was 0.39°Brix. The results showed that a nondestructive on-line SSC value determination prototype based on Vis/NIR technology was feasible.

The response of processing tomato to deficit irrigation at various phenological stages in a sub-humid environment

Field studies were conducted to determine the response of processing tomato (Lycopersicon esculentum Mill.) to deficit irrigation (DI) to guide programs for the development of improved irrigation management practices for sub-humid zones. Field experiments were conducted in Bursa province, Turkey. Industrial tomato plants (cv. Shasta) were subjected to different levels of irrigation using a drip system in the field on a clay–loam Entisol soil for 2 years. Well-watered plants were irrigated at100% crop evapotranspiration (ETc) with 3-day intervals. In other treatments, irrigation was not applied during the vegetative, flowering, yield formation or ripening stages or during combinations of these stages. Fruit weight, marketable yield (MY) and net income decreased with decreases in the amount of irrigation depending on the irrigation timing, but the effect of soil water deficit on the shape index was minor. The highest MY and fruit weight were obtained with the full irrigation (100% ETc) treatment. Water deficit by non-irrigation during the flowering and/or yield formation stages substantially reduced MY values in both years. The results showed that full irrigation during the whole growing season is preferable for higher yield and net income. However, in regions of water scarcity, irrigation managers should adopt the DI approach to achieve economically sustainable crop production. As an alternative to full irrigation during the entire growing season, the application of full irrigation until the beginning of the fruit ripening stage and the cessation of full irrigation after that time can be recommended as optimal because it achieved irrigation water savings of 33%, an increase of 42% in irrigation water use efficiency (IWUE), a satisfactory fruit soluble solids content (SSC) and an acceptable net income with a yield loss of only approximately 5% compared with full irrigation.

Herencia de la concentración de los sólidos solubles entre líneas parentales de papaya (Carica papaya L.) y sus híbridos

Se estableció un experimento con el objetivo de determinarel patrón de herencia de la concentración de sólidossolubles de frutas (medido como grados brix) entre tres líneasde papaya y sus tres posibles híbridos. Se utilizaron comomateriales parentales tres líneas genéticas con niveles de azúcaressignificativamente diferentes entre ellos. Se determinóque la característica de alto contenido de sólidos solubles secomportó de manera dominante sobre un bajo contenido delos mismos. Se concluyó que existe un gran potencial paraexplotar comercialmente este patrón dominante al posibilitarel uso de germoplasma de buenas características agronómicaspero deficientes en sus contenidos de azúcares en sus frutas.La posible naturaleza de los factores que intervienen en la característicaestudiada se discuten.

Evaluación de Materiales para el Acolchado de la Fresa Cultivada Bajo Invernadero

El objetivo fue comparar el efecto de tres materiales de acolchado (cascarilla de arroz, plástico negro y plástico plateado/negro) sobre el crecimiento y rendimiento de las plantas y la calidad de la fruta cosechada en ‘Camarosa’. El cultivo fue plantado bajo invernadero de cubierta plástica, empleando un diseño de bloques completos al azar. Mediante muestreos destructivos mensuales se evaluó el área foliar y la materia seca por planta y se ajustó para ambas el modelo de Gompertz. Se realizaron cosechas durante 15 semanas para determinar el rendimiento por planta y la calidad de la fruta en cuatro categorías de clasificación (Extra, I, II y Pérdidas). Se midieron sólidos solubles, calibre y longitud de los frutos. Periódicamente se determinó la temperatura y la humedad gravimétrica del suelo bajo cada tipo de acolchado. Las mayores temperaturas del suelo se registraron en los acolchados plásticos, mientras que la humedad gravimétrica fue similar en todos los materiales. Las plantas acolchadas con plásticos tuvieron similar acumulación de materia seca respecto a las de cascarilla de arroz, sin embargo, el plástico plateado/negro favoreció la mayor área foliar (5647 cm2/ planta). El rendimiento acumulado de las plantas bajo el plástico plateado/negro y la cascarilla de arroz fue similar (347.8 y 279.47 g/planta), mientras que con el polietileno negro tuvieron el menor rendimiento (246.43 g/planta), pero con frutos de mayor calibre. El material del acolchado no influyó sobre el contenido de sólidos solubles. Se concluyó que el material más recomendado como acolchado en fresa en las condiciones del estudio fue el plástico plateado/negro.

Vegetative growth, mineral change, and fruit quality of ‘Fuji’ tree as affected by foliar seawater application

Extensive researches have been conducted over the decades to investigate the effects of seawater on many crop plants either by irrigation or foliar spray in an attempt to enhance the yield and quality. The purpose of this study was to quantitatively determine the effects of different foliar seawater sprays on vegetative growth, fruit quality and yield of eight-year-old ‘Fuji’/M.9 apple trees. A field experiment was conducted using two different concentrations of seawater (100 or 50-fold dilution) starting from 130 DAFB (days after full bloom) at 5-day intervals between the treatments. Foliar seawater sprays to ‘Fuji’ tree led to increased levels of fruit soluble solids along with higher activities of sucrose phosphate synthase (SPS) (EC 2.4.1.14), sucrose synthase (SS) (EC 2.4.1.13) and neutral invertase (EC 3.2.1.26). In addition, a significant increase in anthocyanin concentration was observed, especially when ‘Fuji’ trees were sprayed three times with 50-fold diluted seawater. Foliar seawater sprays also resulted in increases in Na+ concentration and K+/Ca2+ ratio in fruit. In contrast to fruit, the levels of N, Na+, K+, Mg2+ in leaves remained unchanged regardless of different seawater treatments. Moreover, foliar seawater sprays did not affect the vegetative growth since leaf area, leaf fresh weight, shoot elongation, and chlorophyll content did not differ significantly from those of control plants. The results suggest that foliar seawater treatments could be useful for improving fruit quality without affecting the yield.

강전정에 의한 저수고 감나무의 시비량 조절에 따른 수체 생장 및 과실 생장 반응

노동력 절감을 위해 감나무의 수고 낮추기가 일반화되고 있지만 수고를 심하게 낮춘 해에는 나무 세력이 강해져 과원 관리가 어려워지는 것이 문제가 되고 있다. 본 시험은 동계전정 때에 강전정을 하여 3 m 이상의 수고를 약 2 m로 낮춘 12년생 '상서조생' 단감나무를 대상으로 수세 안정을 위한 시비량 조절 효과를 검토하였다. 관행 시비량을 기초로 4월 기비 (주당 N 224 g, <TEX>$P_2O_5$</TEX> 172 g, <TEX>$K_2O$</TEX> 172 g), 6월 추비(주당 N 112 g, <TEX>$K_2O$</TEX> 99 g), 10월 추비 (주당 N 112 g, <TEX>$K_2O$</TEX> 99 g)를 시용하는 관행시비구와 각 시기마다 관행시비구의 1/3, 2/3씩 주는 시비구 및 무시비구 등 4처리구를 두었다. 처리 당년에 무시비구는 관행시비구에 비해 신초장이 작고 불필요한 2차생장지 발생이 39% 줄었으나 수량과 과실 크기, 색도, 경도, 당도는 감소하지 않았다. 또한 시비구들간의 신초 및 과실의 반응에도 유의적인 차이가 없었다. 이듬해 3월에 채취한 휴면 가지의 가용성 당, 전분, 질소, 칼륨농도는 전년도 시비량에 따른 차이가 명확하지 않았다. 시비량이 동일했던 이듬해 신초장, 도장지 및 2차 생장지 발생, 수량 및 과실 특성은 전년도 시비량에 따른 차이가 없었다. 그러므로 수세 관리 및 시비 비용 절감 측면에서 강전정에 의한 수고 낮추기 당년에는 시비량을 관행의 1/3 이하로 줄여도 될 것으로 판단되었다. Lowering tree height has been a key practice for efficient management of persimmon orchards. This experiment was conducted to assess whether fertilization rates could be reduced after lowering the tree height by heavy pruning. Twelve-year-old 'Uenishiwase' persimmon trees were lowered to 2 m from over 3 m by severe dormant pruning, and then conventional fertilization rate was applied to some trees in April (N 224 g, <TEX>$P_2O_5$</TEX> 172 g, and <TEX>$K_2O$</TEX> 172 g per tree), June (N 112 g and <TEX>$K_2O$</TEX> 99 g per tree), and October (N 112 g and <TEX>$K_2O$</TEX> 99 g per tree). At the same time, 1/3 or 2/3 of the conventional rate and none were applied to other trees, respectively. Non-application decreased shoot length and reduced number of unnecessary secondary shoots by 39% compared with the conventional rate, not affecting yield and weight, color, firmness, and soluble solids of fruits. No significant difference was also found in the yield and the fruit characteristics among the trees fertilized with different rates. Concentrations of soluble sugars, starch, N, and K of dormant shoots in March of the following year were not significantly changed by the different treatments of the previous year. There was no significant difference of shoot growth and yield among the treatments the following year when the same fertilization rate was supplied to all the trees. Results indicated that fertilization rate could be reduced to less than 1/3 of conventional rate to save the cost and stabilize shoot vigor when tree height is lowered by severe pruning.

Productivity and fruit quality of Vaccinium corymbosum cv. Elliott under photo-selective shading nets

The productivity and development of northern highbush blueberry plants (Vaccinum corymbosum L. cv. Elliott) was examined under photo-selective nets of different colors (black, red and white) and shade intensities (25%, 50% and 75%) in Michigan-USA over two growing seasons. Photoselective nets influenced the photosynthetic active radiation (PAR) transmitted through the canopy, with white nets allowing significantly higher radiation to penetrate than red and black nets at all shade levels. After one year of treatment, the rate of flower bud development decreased linearly as % PAR increased, but the total number of flower buds per cane and terminal shoots increased gradually as light levels increased, reaching an asymptote at 50% PAR. The percentage of mature fruit on a particular date was higher in the control plants and decreased as the % PAR was reduced. The harvest delay was maximum at the lowest light level (20%) and decreased exponentially with increasing % PAR. Fruit soluble solids increased linearly (r2=0.86; P<0.0001) and fruit water content decreased linearly (r2=0.88; P<0.0001) as % PAR increased. Fruit yield showed a positive, curvilinear relationship with % PAR and reached an asymptote at 50% PAR. The interaction between color and shade was not significant. However, fruit quality (fruit weight, soluble solid and firmness) showed significant color×shade and color×harvest time (fruit weight, soluble solids and titratable acidity) interactions. Our results indicate that placing red and white nets over mature plants at intermediate shade levels (40–60% PAR) provide a harvest delay without detrimental effects on return bloom, yield or fruit quality.

Avaliação da diversidade fenotípica em rambuteiras (Nephelium lappaceum) com base na qualidade dos frutos

O rambotã (Nephelium lappaceum L.), fruta originária da Ásia, é cultivado comercialmente no Brasil, nos Estados da Pará e Bahia, mas devido à propagação sexuada, apresenta grande variabilidade para características morfológicas e químicas dos frutos. Visando a identificar potenciais matrizes, foram avaliados, em Ituberá-BA, frutos de 105 genótipos de rambotã com base na coloração da casca, suculência e teor de sólidos solúveis. Nesse grupo de plantas, 80 genótipos (76,2%) apresentaram frutos com teor de sólidos solúveis igual ou superior a 16 ºBrix e tiveram uma amostra coletada para análise em laboratório. Após a pesagem, foram identificados 20 genótipos cujos frutos apresentaram peso médio acima de 30 g e foram submetidos às análises físico-químicas. Os genótipos avaliados apresentaram frutos com peso médio de 33,2 g (30,2 a 39,4 g), rendimento do arilo de 42,3% (35,1 a 50,2%), sólidos solúveis de 17,6 ºBrix (15,8 a 19,7 ºBrix) e acidez titulável 0,44% (0,19 a 0,86%). A amostra de rambuteiras avaliadas apresentou grande variabilidade fenotípica e permitiu a identificação de 20 19 ou 19,05% do total de genótipos avaliados, cujas características dos frutos atendem aos padrões estabelecidos em outros países (peso acima de 30 g e sólidos solúveis acima de 16 ºBrix).