Unmarketable Yield Research Articles

English

Lack of improved varieties and production practices have been the major bottlenecks of onion production and productivity in Tigray, particularly at Aksum area. There have been no recommended intra-row spacing and variety for that area specifically; rather farmers used to practice non-uniform plant spacing. Thus, a field experiment was conducted to investigate the influence of intra-row spacing, variety and their interactions on yield, shelf life and bulb quality of onion, thereby recommend the optimum practices to farmers in the study area. The study was conducted between August 2010 and April 2011 at Aksum area (L/maichew district). Three different intra-row spacings (5, 7.5 and 10 cm) were evaluated using four varieties of onion (‘Adama’ Red, ‘Bombay’ Red, ‘Melkam’ and ‘Nasik’ Red) using RCBD replicated four times. Data on yield and quality parameters were recorded and subjected to ANOVA. Results indicate that intra-row spacing of 10 cm was superior in plant height, leaf number per plant, leaf biomass yield, leaf dry matter content and percentage of bolters. Highest total bulb yield was recorded at the closest intra-row spacing (5 cm) followed by 7.5 cm. ‘Melkam’ variety was the highest yielder, while ‘Adama’ Red was the lowest yielder. Average bulb weight increased with increasing intra row spacing. ‘Melkam’ variety followed by ‘Bombay’ Red variety was superior in average bulb weight. ‘Adama’ Red recorded the highest unmarketable yield. Key words: Intra-row spacing, yield, quality, onion varieties, spacing.

Evaluation of Round and Roma-type Tomato Varieties and Advanced Breeding Lines Resistant to Tomato Yellow Leaf Curl Virus in Florida

Tomato yellow leaf curl virus (TYLCV) is considered to be the most damaging tomato (Solanum lycopersicum) virus worldwide. Management of TYLCV has relied primarily on insecticidal control targeting the vector sweetpotato whitefly [SPW (Bemisia tabaci)]. However, resistance of the SPW to insecticides; increased length of the growing season, due in part to increased plantings of grape tomato; and asymptomatic hosts of TYLCV such as pepper (Capsicum annuum) have increased the need for wider use of TYLCV-resistant (TYLCV-R) varieties. The objective of this study was to evaluate horticultural characteristics of commercially available TYLCV-R varieties/advanced breeding lines of round and Roma-type tomato varieties in Florida. Sweetpotato whitefly populations and incidence of TYLCV were greater in 2007 than 2008. Under high TYLCV pressure, most of the TYLCV-R varieties/advanced breeding lines produced higher yield than susceptible varieties. In contrast, no clear advantage was found by using TYLCV-R varieties under low TYLCV pressure. Additionally, TYLCV-R varieties produced a high percentage of unmarketable fruit due to rough blossom end scars (BES), zippering, catfacing, sunscald, yellow shoulders, off shapes, and radial or concentric cracking compared with susceptible varieties in both years. Visual assessment of TYLCV-R varieties/advanced breeding lines for horticultural traits showed that ‘Security 28’, Sak 5443, and ‘Shanty’ were the best overall varieties/advanced breeding lines based on participants combined score rating, although ‘Tygress’ and Sak 5808 performed best based on empirical evaluation (numerical data) of total marketable yields and low unmarketable yield.

Effect of Alginure® (seaweed extract), Myco-Sin®VIN (sulfuric clay) and Polyversum® (Pythium oligandrum Drechs.) on yield and disease control in organic strawberries

In 2011 and 2012 three commercial products Alginure® (seaweed extract), Myco-Sin® VIN (sulfuric acid clay with yeast and plant extracts) and Polyversum® (spores of Pythium oligandrum) were tested in field experiment with strawberry cv. ‘Induka’ under the conditions of organic growing system. The aim of the study was to determine the effect of the preparations on yield, fruit quality and diseases control. The preparations were applied five times during flowering. We assessed total yield, marketable and unmarketable yields, average fruit weight, grey mould incidence on fruits caused by Botrytis cinerea and leaf spot severity caused by Mycosphaerella fragariae. Efficacy (%) of preparations was calculated. Preparations did not show positive effect on yields parameters. Total and marketable yields were not significantly different to untreated control in both years. Nevertheless considerable increase of yields from 2011 to 2012 was observed in strawberries treated by biofungicide Polyversum®. Preparations did not significantly reduce the incidence of grey mould. Alginure® showed the best results by efficacy 39.6 % and 57.4 %, respectively. All preparations provided very low, less than 10% efficacy to control leaf spot severity.

EFFECT OF SHADING AND GRAFTING TECHNIQUE ON GROWTH AND FRUIT PRODUCTION OF SWEET PEPPER PLANTS

Horticultural cultivation in Mediterranean greenhouses requires the implementation of refrigeration systems to avoid stress situations, particularly under spring-summer conditions. The effect of the temperature and high solar radiation in the greenhouse can be decreased by shade screen. The use of grafting onto adequate rootstocks could be an interesting alternative to maintain commercial fruit yield and quality under stress conditions. The effects of using aluminised screens offering different degrees of shading combined with two transplant types (grafted or ungrafted) were analyzed in sweet pepper plants. Simultaneous comparisons were made among greenhouse that were either non-shaded (control) or covered with reflective aluminized shadecloth that attenuated 40% (T40) and 60% (T60) of direct sunlight. The shadecloth was applied at the start of warm weather in May. The greenhouses were shaded for the rest of the summer, and fruit being picked until August. The use of shadecloth proved to be efficient in improving vegetative growth and reducing the unmarketable yield, compared to non-shaded conditions. The results showed that fruit yield was highest in the T40 treatment, presented significantly different, and the T60 treatment had a lower production. On the other hand the use of the grafting promoted vegetative growth. Grafting increased the marketable yield compared to the ungrafted plants under shade and non-shade conditions.

QUANTIFYING YIELD LOSS OF AUBERGINE (SOLANUM MELONGENA L.) INDUCED BY LEAF AREA REDUCTION

The foliar area loss is a typical damage in crops caused by fungus, insects or hailstorm. A lot of studies have been carried out to describe the effect of defoliation in the main herbaceous and woody crops. The results of two trials carried out in Navarra (Spain) in 2007 to determine the effects of different levels of defoliation in several phenological stages in aubergine plants are described in this work. In a randomly split-plot design with four replications, four levels of defoliation were applied: control, slight, moderate and heavy, at six phenological stages of aubergine plants var Nilo (Rijk Zwaan). Defoliation was made by means of a jet of water under pressure in one trial and, by means of scissors in the other one. Fruits were harvested on three occasions and classified as marketable and unmarketable yield and were weighed. The BBCH stages 71 (the first fruit reaches the typical size) and 86 (60% of fruits reach the typical size, shape and colour) were the most sensitive stages for water defoliation and scissor defoliation respectively. These experimental results were used to obtain regression equations in which the percentage of yield reduction is calculated in relation with the stage and the percentage of defoliation. These equations were plotted and maximum loss of 77% in defoliation by scissor and 64% in defoliation by water were observed for 100% of defoliation. These equations can be used to improve simulation patterns of the aubergine growth in case of foliar damages caused by fungus, insect attacks or hailstorm.

Grafting is an efficient alternative to shading screens to alleviate thermal stress in greenhouse-grown sweet pepper

Sweet pepper crop yield and quality in some Mediterranean regions are negatively affected by the high radiation and temperature during the spring–summer harvesting period. Although the use of shading screens is a common, although expensive, strategy to minimize the impact of thermal stress, the use of grafting onto adequate rootstocks could be an interesting alternative to maintain commercial fruit yield and quality under non-shaded conditions, in addition to providing other advantages such as resistance to soil-borne diseases. In order to test this hypothesis, we studied the behaviour of ‘Herminio’ plants ungrafted and grafted onto three different commercial rootstocks (Atlante, Creonte and Terrano) under non-shaded and shaded conditions. The use of shading screen proved to be efficient in improving vegetative growth, photosynthesis, transpiration and leaf water status, and for reducing the unmarketable yield, especially the incidence of the sunscalded fruits, compared to non-shaded conditions. In general, the grafted plants performed better than the ungrafted ones under both growing conditions, but the differences were more evident under non-shaded conditions. The plants grafted onto Atlante produced up to 40% more leaf area than the other combinations but did not increase yield nor reduce the incidence of the sunscald disorder. However, grafting onto Creonte did not significantly affect leaf biomass but increased the total and marketable fruit yield by 30% and 50% under non-shaded and shaded conditions compared to the ungrafted plants, respectively. Moreover, this rootstock maintained 30–60% higher leaf photosynthetic activity and reduced the amount of sunscalded fruits by 6% during the harvest period in non-shaded conditions. However some fruit nutritional parameters were affected. These results suggest that improved protection of the photosynthetic apparatus is more efficient for increasing yield and for reducing sunscald disorder than more foliage per se under non-shaded conditions, in the absence of any other imposed stress. The use of the rootstock Creonte is an efficient alternative to using shading screens in greenhouse-grown sweet peppers.

Effect of plant population, stem and flower pruning on hydroponically grown sweet pepper in a shadenet structure

A study was conducted in 2009/2010 and 2010/2011 to investigate the effect of plant population, flower and stem pruning of hydroponically grown peppers in a 40% (black and white) shadenet structure at the ARC-Roodeplaat VOPI. The research was done in an open bag hydroponic system with sawdust as growing medium. Pepper plants were subjected to three plant populations (2, 2.5 and 3 plant/m 2 ), three stem pruning treatments (2, 3 and 4 stems) and three flower pruning treatments (removal of first two or first four flowers or zero flower removal). Experimental layout was a randomized block design with two replicates. Sweet pepper fruits were harvested at a mature green stage. Data was collected on ten plants determining fruit number, fruit mass, unmarketable yield, marketable yield and total yield for all treatments. Stem pruning to four stems without removing any flowers at a plant population of 3 plants/m 2 resulted in the highest yield and quality. Pruning the first two or four fruits seemed to have no significant influence on yield. Results showed that sweet pepper yield and quality can be effectively manipulated by plant population and stem pruning, while flower pruning had insignificant (p<0.05) effect.

Produtividade de híbridos de tomate submetidos ao cultivo superadensado

Os tomaticultores da região de Caçador-SC necessitam de resultados experimentais do cultivo superadensado, com os híbridos cultivados nas condições edafoclimáticas da região, para que possam decidir sobre a adoção deste sistema. Desta forma, o objetivo deste trabalho foi avaliar o cultivo superadensado de tomate com híbridos utilizados em Caçador. Dois experimentos foram realizados na Epagri em Caçador, durante as safras 2007/2008 e 2008/2009. Os tratamentos, na safra 2007/2008, consistiram na combinação de dois híbridos (Miramar e T92), dois métodos de tutoramento (vertical e em "V") e dois métodos de condução de plantas (uma haste por planta no espaçamento de 0,15 m entre plantas e duas hastes por planta no espaçamento de 0,3 m entre plantas). Na safra 2008/2009, os tratamentos consistiram na combinação de dois híbridos (Paron e Plutão) e dois métodos de condução de plantas superadensado (uma haste por planta no espaçamento entre plantas de 0,15 m e duas hastes por planta no espaçamento entre plantas de 0,3 m). Foi incluído ainda o método de condução e densidade de plantas tradicional (duas hastes por planta no espaçamento entre plantas de 0,6 m). O delineamento experimental foi de blocos completos ao acaso, com quatro repetições, no esquema de parcelas sub-subdivididas, na safra 2007/2008, e de parcelas subdivididas, na safra 2008/2009. Os tratamentos possuíam 44.444 hastes/ha, com exceção dos tratamentos com condução tradicional de plantas (22.222 hastes/ha). Foram analisados a produtividade total, comercial e descarte, massa média de frutos comerciais, frutos comerciais (%) e descarte (%) em relação ao número total de frutos e severidade de doenças foliares. Os híbridos testados não interferem nas respostas agronômicas ao adensamento de plantas. O sistema superadensado de tomate proporcionou aumento, em média, de 73,2% na produtividade comercial de frutos, em relação à densidade tradicional de plantas. A produtividade comercial de frutos no tomateiro superadensado tutorado em "V" foi 19,2% maior que o tomateiro superadensado tutorado verticalmente. A condução de uma haste por planta aumentou 10,4% a produtividade comercial de frutos em relação à condução de duas hastes por planta no tomateiro superadensado. O tomateiro superadensado proporcionou aumento da severidade foliar de pinta-preta, em relação à densidade tradicional de plantas.

Effect of plant population, fruit and stem pruning on yield and quality of hydroponically grown tomato

A study was conducted in 2009 to 2010 and 2010 to 2011 to investigate the effect of plant population, and fruit and stem pruning of hydroponically grown tomatoes in a 40% (black and white) shade-net structure at the ARC-Roodeplaat VOPI. An open bag hydroponic system containing sawdust as a growing medium was used in this experiment. Tomato plants were subjected to three plant populations (2, 2.5 or 3 plants/m2), two stem pruning treatments (one stem and two stems) and three fruit pruning treatments (four fruits, six fruits per truss, and no fruit pruning). Experimental layout was a complete randomized block design with three replicates. Data on fruit number, fruit mass, unmarketable yield, marketable yield and total yield was collected from 10 plants for all treatments. Plants pruned to two stems with zero fruit pruning or pruned to six fruits produced significantly higher marketable and total yield, as compared to the other treatments. Plant population of 3 plants/m2, resulted in significantly higher marketable yield of tomatoes, compared to 2.5 and 2 plants/m2. Results showed that tomato yield and quality can be effectively manipulated by plant population and stem pruning, while fruit pruning had only a limited effect. Key words: Fruit cracking, open-bag hydroponic system, plant population, pruning, shade-net structure, fruit yield.

English

The purpose of this study was to evaluate the effects of different organic fertilizers on yield and fruit qualities of indeterminate tomato. Influences of different organic and inorganic fertilizers on yields and fruit qualitiy of tomato were compared during 2006 and 2007 growing periods under field conditions. In 2006 growing period, organic fertilizes used were Ormin K (250 kg/ha before planting; 30 kg/ha after first flowering; 80 kg/ha after first harvest), Coplex (50 kg/ha every week from planting to last harvest), Nof (40 kg/ha every week, from planting to last harvest), composted poultry manure (CPM) (1 t/ha before planting; 0.5 ton/ha after first flowering and 0.5 ton/ha after first harvest (liquid form)) and composted cattle manure (CCM) (60 t/ha before planting; 5 ton/ha after first flowering and 5 ton/ha after first harvest (liquid form)). Based on the first year results, organic fertilizers used during 2007 growing periods were F1 (20 ton/ha CCM before planting; 1 t/ha CPM before planting; 40 kg/ha Coplex and 20 kg/ha Nof every week) and F2 (20 t/ha CCM before planting; 500 kg/ha Ormin K before planting; 30 kg/ha Coplex and 30 kg/ha Nof every week). Inorganic fertilizers used as a control were N: 450, P2O5: 350, K2O: 600, CaO:50, S: 200, and Mg:50 kg/ha. Tomato cultivars used in this study were Alida FA± in 2006 growing period and Alida FA±, YankA± FA± and Maya FA± in 2007 growing period. In 2006, the highest yields obtained from CPM, CCM, and control treatments were 128.12, 122.92 and 115.24 t/ha respectively. In 2007, marketable yield obtained from F1 fertilizer treatment was similar to the control application. Unmarketable yield was not effected from the different fertilizer treatments. There was no significant difference among the treatments. However fruit cracking rates were higher in organic fertilizer treatments than the inorganic fertilizer treatment. Finally, application of 20 to 40 t/ha composted cattle manure befor planting and addition of commercial organic fertilizers such as coplex, nof and ormin K can be used as an alternative to the chemical fertilizers in indeterminate tomato cultivation. Key words: Tomato, organic fertilizer, cattle manure, poltry manure, yield.

Comparative performance of tomato cultivars cultivated in two hydroponic production systems

Cultivar selection for different hydroponic production systems is an important management decision, potentially impacting the tomato grower’s profitability. Knowledge on the performance of tomato cultivars, in specific hydroponic systems (open-bag and closed system) under South African conditions, is still very limited. The performance of four cultivars was evaluated in an open and a closed hydroponic (gravel-film technique) system. The commonly grown cultivars evaluated in each of the two hydroponic systems were ‘FA593’, ‘Malory’, ‘Miramar’ and ‘FiveOFive’. For each experiment a randomized complete block design was used with four replicates. Total, marketable and unmarketable yields, as well as internal fruit quality characteristics (total soluble solids (°Brix) and pH) were determined. Although no significant differences in total yield could be established - neither in the open nor in the closed hydroponic system - differences in marketable yield were observed. ‘Miramar’ and ‘Five-OFive’ produced the highest marketable yield in the closed system; the high unmarketable yield of ‘FA593’ and ‘Malory’ in the closed hydroponic system could be attributed to the high number of cracked fruit due to their inherent larger fruit size. There were no significant differences in °Brix between cultivars in the closed system. Cultivar ‘FiveOFive’, ‘FA593’ and ‘Miramar’ produced higher marketable yields than cultivar ‘Malory’ when grown in the open-bag system. ‘Malory’ and ‘FA593’ produced the highest number of fruit exhibiting fruit cracking in the open bag system. In the open system, only cultivar ‘Malory’ had a higher °Brix than ‘Miramar’ and ‘FiveOFive’. The most promising cultivars for local hydroponic tomato production, with regard to yield and quality, were identified as ‘Miramar’ and ‘FiveOFive’, with ‘FA593’ performing equally in the open system only. Further studies need to be undertaken on economical comparison of the two production systems.

EFFECT OF COMPOST, FOLIAR SPRAYING WITH POTASSIUM AND BORON ON GROWTH, YIELD AND FRUIT QUALITY OF STRAWBERRY

This work was carried out in the two successive summer season plantations of 2006/ 2007 and 2007/2008 on strawberry cv. Sweet Charlie at south Tahrir district, newly reclaimed sand soils at Experimental Station Farm, Horticultural Research Station, Behiera Governorate, to study the influence of compost manure at a rate of 20 t/fed. compared with mineral nitrogen fertilizer at a rate of 200 kg N/feddan (100 % of the recommended rate as a check) and complied with foliar spraying of potassium ( 46% K2O) as potassium citrate at a doses of 1% and/or boron 50 ppm on plant growth, yield and its components, fruit quality as well as chemical contents. A randomized complete block design with three replications was used in both growing seasons. The results indicated that plant growth characters (plant length, number of crowns, number of runners, number of leaves and foliage fresh and dry weight, likewise, early yield, total yield and marketable yield gave the highest values with the treatment which received mineral nitrogen fertilizer combination with foliar spraying of potassium and boron and total titratable acidity were the highest with the plants supplied mineral nitrogen fertilizer alone. Moreover, potassium percent in the leaves and the fruits were recorded with mineral nitrogen fertilizer combination with foliar application potassium and boron and/or potaasium alone in the first and seconed season. On the same trend, the highest values of average fruit weight, total soluble solids and vitamin C as well as fruit juice % with plants supplied by compost manure with foliar spraying by potassium and boron in both growing seasons. On the other hand, the lowest value of fruit moisture % in the fruits and unmarketable yield were obtained when plants applied by compost manure with foliar addition of potassium and boron.

Espaçamento entre plantas e cachos por haste no tutoramento vertical do tomateiro

O presente trabalho objetivou avaliar o efeito do espaçamento entre plantas e do número de cachos por haste sobre a produtividade e a qualidade de frutos do tomateiro conduzido no método de tutoramento vertical com fitilho. Experimentos foram conduzidos nas safras 2006/07 e 2007/08, na Epagri-Estação Experimental de Caçador-SC. Os tratamentos consistiram da combinação de três espaçamentos entre plantas (30, 45 e 60 cm), quatro alturas de desponta das plantas (sem desponta, cinco, sete e nove cachos por haste) e duas cultivares na safra 2006/07 (Débora Max e Nemo Netta) e uma cultivar na safra 2007/08 (Takii 92). Avaliou-se a produtividade de frutos total, comercial e descarte, a massa média de frutos comerciais e a porcentagem de frutos comerciais e descartados. Não houve interação entre os fatores cultivar, espaçamento entre plantas e níveis de desponta. A redução do espaçamento entre plantas de 60 para 45 cm aumentou de 15,2 a 17,2% a produtividade de frutos comerciais, sem comprometer a qualidade. Não houve diferença entre altura de desponte para produtividade de frutos comerciais.

COMPARATIVE PERFORMANCE OF TOMATO CULTIVARS IN SOILLESS VS. IN-SOIL PRODUCTION SYSTEMS

A study was conducted to compare yield and quality parameters of tomato cultivars cultivated in-soil under a shadenet structure with an open bag hydroponic (soilless) system in a plastic tunnel. Four tomato cultivars, namely, 'FA593', 'Malory', 'Miramar' and 'FiveOFive' were included using a randomized complete block design with four replicates for both trials. Total, marketable and unmarketable yield, plant height, total soluble solids (%Brix) as well as the pH of the tomato juice were determined. Results showed that plants in the soilless system developed faster with higher total yield compared with in-soil cultivation. The average marketable yield using soilless cultivation was 92.1%, while in-soil cultivation was only 77.0%. There was no significant difference in %Brix between cultivars under in-soil cultivation, while under soilless conditions 'Malory' and 'FiveOFive' had a higher %Brix than 'FA 593' and 'Miramar'. The pH of tomato juice was highest in 'Miramar' and 'FA593' under both production systems. The most promising cultivars with regard to yield and quality were 'Miramar', followed by 'FA593' when grown in the soilless system, while there were no significant differences between any of the tested cultivars under in-soil cultivation. Results indicate that soilless cultivation can improve yield and quality, with cultivar selection playing an important role when utilizing this production system.

'ELSANTA' AUTUMN CROP PERFORMANCE USING DIFFERENT PLANT TYPES AND PLANTING DATES

To evaluate the crop performance of 'Elsanta' strawberry plants grown in a soilless culture and under polyethylene tunnels for autumn production, a field experiment was established with different plant types and planting dates. Four types of cold stored plants, bare-rooted plants (A, A + and waiting bed - WB) and tray plants, and three planting dates, 28 September, 10 October and 17 October were compared. Tray, WB and A + plants had higher initial fresh plant weight, crown number and diameter than A plants. Cropping performance was more affected with plant type rather than with planting date. However, delaying planting date induced plants to produce in December and January with increasing proportion of unmarketable yield. The highest productivity was obtained with tray plants followed by WB and A plants that performed squally. Fruit quality did not vary between plant types. In general, plants of the 2 nd planting date showed higher TSS values. Although yields were not affected by planting dates, earlier plantings should be considered to achieve most profitable autumn production with fruits of good quality.

Influence of Salinity and Fertilization Level on Greenhouse Tomato Yield and Quality

The objective of this study was to evaluate the effects of two irrigation water qualities and three different levels of nitrogen–phosphorous–potassium (NPK) rates applied by fertigation on yield and quality of tomato fruit. The experiment was carried out in a polyethylene greenhouse on ‘Pitenza’ tomato grown on a sand‐mulched sandy loam soil using a trickle irrigation system. The treatment consisted of two irrigation water qualities (C2S1 and C3S2) and three fertilization levels: 50%, 100%, and 200% [7.1 mmol L−1 nitrate (NO3) N, 0.5 mmol L−1 P, and 3.1 mmol L−1 K] for each water quality category. The dry‐matter content of fruit (DMC), number of fruit, fruit weight per period (g), weight per fruit (g), number of trusses, fruits per truss, and unmarketable fruit were monitored. Quality was evaluated using fruit firmness (Kg), total soluble solids (°Brix), pH, and tritable acidity (meq citric acid L−1 of juice). The increased salinity of the irrigation water did not affect the marketable and unmarketable yield of fruit but did produce an increase in the number of fruits per truss at 127 days after transplanting (DAT) (10%) and in the DMC percentage at 127 and 179 DAT, being 9 and 6.8% respectively. High‐salinity irrigation water reduced the firmness of the fruit at 127 and 179 DAT (9% and 22%, respectively); it increased the soluble solids for all the dates analyzed as well as the fruit's tritable acidity with significant differences at 127 and 206 DAT. The fertilization level increased the marketable yields, fruit number, and number of trusses during all stages. Treatment F1 produced a yield 28% lower than F2, whereas F3 was 10% higher than F2. The results show that irrigation water electrical conductivity (EC) of 2.2 dS m−1 is adequate for high yield and quality of tomato in the commercial cycle.

INFLUENCE OF GRAFTING ON YIELD AND FRUIT QUALITY OF PEPPER (CAPSICUM ANNUUM L.) GROWN UNDER GREENHOUSE CONDITIONS

With the aim of determining whether grafting could improve the agronomic behaviour of pepper (Capsicum annuum L.), a greenhouse experiment was carried out to determine growth, yield and fruit quality of two bell pepper hybrid cultivars (Edo and Lux), either ungrafted or grafted onto five commercial rootstocks ‘Snooker’, ‘Tresor’, ‘RX360’, ‘DRO8801’ and ’97.9001’. Grafted plants were 29 and 28% taller than control for ‘Edo’ and ‘Lux’ cultivars, respectively. Total yield, marketable yield and fruit number were significantly influenced by rootstock, whereas no significant difference was observed on unmarketable yield, marketable fruit mean weight and fruit shape index for both cultivars. Grafted plants produced 22-46% more marketable yield than control plants for ‘Edo’. A similar trend was also observed on ‘Lux’, where the grafted plants had 25% more marketable yield in comparison to ungrafted plants. The lowest marketable yield recorded on ungrafted plants for ‘Edo’ and ‘Lux’ was related to a reduction in fruit number and not to the fruit mean weight. Nutritional qualities of grafted peppers such as fruit dry matter, total soluble solids contents, titratable acidity were similar in comparison to those of ungrafted plants. Since grafting increased the crop vigour and yield, and following the abandonment of methyl bromide, grafting technique should be useful for lowinput sustainable horticulture of the future. INTRODUCTION Pepper (Capsicum annuum L.) is a crop of high economic importance in the Mediterranean region. The area of protected pepper grown in Italy is 2,794 ha (20.3% of the total pepper cultivation area; ISTAT 2005). In the last three decades, pepper cultivation in greenhouses has become increasingly dependent on methyl bromide fumigation. This is due to continuous cropping and, consequently, to increasing crop damage due to the specific pathogens, Phytophthora capsici, Verticillium dahliae and Meloidogyne spp. (Morra and Bilotto, 2006). Because methyl bromide is highly toxic to humans and the environment (Ristaino and Thomas, 1997), 168 countries including Italy, have agreed to gradually reduce the use of methyl bromide. Research and technology transfer will therefore be necessary to fully implement an alternative to methyl bromide pest management systems for greenhouse vegetable crops (Batchelor, 2001). One way of avoiding or reducing losses in production caused by pathogens in high-yielding genotypes would be to graft them onto rootstocks capable of reducing soil-borne diseases and increasing yield (Lee, 1994). The aim of this study was to investigate and evaluate the agronomic performance of two popular Italian commercial hybrid peppers under greenhouse conditions following grafting on five newly resistant pepper rootstocks, in comparison with ungrafted plants. MATERIALS AND METHODS The F1 hybrids ‘Edo’ (red type; SAIS, Italy) and ‘Lux’ (yellow type, SAIS, Italy), were grafted on five commercial rootstocks, ‘Snooker’ (Syngenta, USA), ‘Tresor’ (Nuhmens, Holland), ‘RX360’ (Royal Sluis, Holland), ‘DRO8801’(De Ruiter, Holland) and ‘97.9001’ (SAIS, Italy) coming from the hybridization of Capsicum annuum L. using Proc. IV IS on Seed, Transplant and Stand Establishment

Effects of interlighting on yield and external fruit quality in year-round cultivated cucumber

The effects of interlighting and of the proportion of interlight on the yield and fruit quality of year-round cultivated cucumber ( Cucumis sativus L. cv. Cumuli) were investigated for this study. Artificial lighting was provided by high pressure sodium (HPS) lamps and the lighting regimes included top lighting (TL), top + interlighting 24% (T + IL24) and top + interlighting 48% (T + IL48). In TL, all of the lamps were mounted above the canopy. In T + IL24 and T + IL48, top lamps covered 76 and 52% of the lighting, respectively, while 24 and 48% of the lighting came from interlighting lamps which were mounted vertically 1.3 m above the ground between the single plant rows. The outdoor daily light integral (DLI) varied greatly during the cultivation periods; the mean values were 36.8, 5.3 and 19.9 mol m −2 day −1 for the summer, autumn–winter and spring stands, respectively. Lighting regime affected both yield and external fruit quality. Interlighting increased first class yield and decreased unmarketable yield, both in weight and number. The increase in the annual first class yield in weight was 15% in the two T + IL regimes. Interlighting improved energy use efficiency in lighting, being for the whole year 120, 130 and 127 g total yield kW h −1 in TL, T + IL24 and T + IL48, respectively. Interlighting increased the fruit skin chlorophyll concentration in all seasons, but had only a minor effect on the fruit dry matter concentration. The mean total chlorophyll concentration in fruit skin was 70.8, 76.7 and 82.2 μg cm −2 in TL, T + IL24 and T + IL48, respectively. In addition, interlighting extended the post-harvest shelf life of cucumber fruits in spring. Besides interlighting per se, also the higher proportion of interlight tended to further improve the fruit quality. For example, the fruit skin chlorophyll concentration increased along with the higher proportion of interlighting. In general, the effects of lighting regime were more prominent in lower natural light conditions in winter and spring. It is concluded that interlighting is a recommendable lighting method in cucumber cultivation, especially in lower natural light conditions.

Edamame Production as Influenced by Seedling Emergence and Plant Population

Eight edamame (Glycine max) cultivars were evaluated in the field in 2002, 2003, and 2004 to determine suitability for growing in central Pennsylvania. Data collection included plant populations (percent stand), marketable and unmarketable yields and edamame pod and bean quality indicators. Plant populations varied by year and cultivar and were generally below 80%. The effect of temperature on seedling emergence, and therefore plant populations, was evaluated for four edamame cultivars by using growth chambers programmed with varying day/night temperature regimes. Seedling emergence varied by cultivar and was generally below 80% with two exceptions. When grown in a 70/60 °F day/night temperature regime, `Butterbeans', and `Early Hakucho' exceeded 80% seedling emergence. In the field trial, plant populations affected marketable yields. Pod and bean quality were dependent on cultivar. Results indicated that `Butterbeans', `Early Hakucho', `Green Legend', `Shironomai', `Butterbaby', and `Lucky Lion' appear promising for growing in Pennsylvania based on pod and bean quality. However, the issue of poor seedling emergence and plant populations presents a major constraint to commercial production and needs to be studied further.

537 Impacts of Farming Systems and Soil Characteristics on Processing Tomato Fruit Quality

A 2-year field study was conducted within the Sustainable Agriculture Farming Systems Project at the Univ. of California, Davis, to evaluate the effects of long-term conventional (CONV), low-input (LOW), and organic (ORG) production practices on processing tomato fruit mineral composition and quality. To establish relationships between soil chemical properties, soil water content, fruit mineral composition, and quality, this study characterized soil chemical properties and monitored soil water content through each tomato season. Soil total C, N, soluble P, exchangeable Ca, K,and Na were higher in the organic system than in the conventional system. Higher soil electrical conductivity was found in the CONV system compared to the other systems. Low input plots had soil characteristics intermediate to the other farming systems. Marketable and unmarketable yields were similar among the farming systems. Fruit N and Na were lower in the organic and low-input systems than in the conventional system. Fruit P and Ca contents were higher in the organic system than in the conventional system as a result of 11 years of manure applications. Soluble solids content, titrable acidity, color, and soluble solids yield were lower in 1998 in the organic system than in the conventional system, while no differences were found in 1999. Soil water content during the ripening stage was the major factor affecting the soluble solids content of the organic system. In the low input and conventional systems soluble solids content was most related to soil exchangeable Ca and EC, respectively.