Localized organo-mineral fertilization maintains ultra-early watermelon yield while reducing mineral nitrogen input under temporary film cover

The muskmelon plants allow several ways to manipulate sources/drains ratio. The objective of this work was to evaluate characteristics of the productivity and quality of Cantaloupe melon fruits due to the temporary use of row cover and the number of fruits per plant. The experiment was carried out from August to December 2014, at Universidade Federal de Campina Grande (UFCG), Paraiba State, Brazil. The experimental design was randomized blocks with treatments allocated in split plots 5x3, with four replicates. The authors reported permanence time of the row cover at different times in the plot {20, 24, 28, 32, and 36 days after transplanting (DAT)} and, in the subplots, the number of fruits per plant (plants with one fruit, plants with two fruits and fruit-free setting plants). The authors evaluated traits of production and quality of fruits. The permanence time of row cover and number of fruits per plant promoted changes in the productivity and quality of the muskmelon fruits. The permanence of the row cover from 20 to 36 DAT provided reduction in the total soluble solids. The average fruit mass and fruit yield reached the maximum value with the permanence of the row cover up to 26.6 and 25.1 DAT, respectively. Plants with one and two fruits presented higher average fruit mass, but with lower productivity compared to the plant with fruit-free setting.

Using rootstock to increase watermelon fruit yield and quality at low potassium supply: A comprehensive analysis from agronomic, physiological and transcriptional perspective

Grafting watermelon ( Citrullus lanatus ) is a common practice in many parts of the world and has recently received increased interest in the United States. The present study was designed to evaluate early season growth, yield, and fruit quality of watermelon in response to grafting and in the absence of known disease pressure in a fumigated system. Field experiments were conducted using standard and mini watermelons (cv. Exclamation and Extazy, respectively) grafted onto 20 commercially available cucurbit rootstocks representing four species: giant pumpkin ( Cucurbita maxima ), summer squash ( Cucurbita pepo ), bottle gourd ( Lagenaria siceraria ), and interspecific hybrid squash [ISH ( C. maxima × Cucurbita moschata )]. Nongrafted ‘Exclamation’ and ‘Extazy’ were included as controls. To determine early season growth, leaf area was measured at 1, 2, and 3 weeks after transplant (WAT). At 1 WAT, nongrafted ‘Exclamation’ produced the smallest leaf area; however, at 3 WAT, nongrafted ‘Exclamation’ produced the largest leaf area in 2015, and no differences were observed in 2016. Leaf area was very similar among rootstocks in the ‘Extazy’ study, with minimal differences observed. Marketable yield included fruit weighing ≥9 and ≥3 lb for ‘Exclamation’ and ‘Extazy’, respectively. In the ‘Exclamation’ study, highest marketable yields were observed in nongrafted ‘Exclamation’, and ‘Exclamation’ grafted to ‘Pelops’, ‘TZ148’, and ‘Coloso’, and lowest marketable yields were observed when using ‘Marvel’ and ‘Kazako’ rootstocks, which produced 47% and 32% of nongrafted ‘Exclamation’ yield, respectively. In the ‘Extazy’ study, the highest marketable yield was observed in nongrafted ‘Extazy’, and ‘Kazako’ produced the lowest yields (48% of nongrafted ‘Extazy’). Fruit quality was determined by measuring fruit acidity (pH), soluble solids concentration (SSC), lycopene content, and flesh firmness from a sample of two fruit from each plot from the initial two harvests of each year. Across both studies, rootstock had no effect on SSC or lycopene content. As reported in previous studies, flesh firmness was increased as a result of grafting, and nongrafted ‘Exclamation’ and ‘Extazy’ had the lowest flesh firmness among standard and mini watermelons, respectively. The present study evaluated two scions with a selection of 20 cucurbit rootstocks and observed no benefits in early season growth, yield, or phytonutrient content. Only three of 20 rootstocks in each study produced marketable yields similar to the nongrafted treatments, and no grafted treatment produced higher yields than nongrafted ‘Exclamation’ or ‘Extazy’. Because grafted seedlings have an associated increase in cost and do not produce increased yields, grafting in these optimized farming systems and using fumigated soils does not offer an advantage in the absence of soilborne pathogens or other stressors that interfere with watermelon production.

The objective of this study was to examine the effects of grafting and kinds of rootstocks on yield that are economically feasible for the watermelon producer. Fruit characteristics and quality attributes of grafted plants in open field conditions were also analyzed. The tongue approach grafting method was adopted. Three Watermelon cultivars of ‘Crimson Tide’, ‘Dumara’, and ‘Farao’ were used as the scion. Three hybrid squashes of ‘Dynamo’, ‘RS-841’, and ‘Shintosa’ were used as rootstocks. Results showed that some fruit quality indicators such as dry matter, total soluble solids, total sugar and titratable acid contents were lower in grafted plants while lycopene contents remained unchanged. The pH was slightly altered by grafting. Use of rootstock did not show advantages at comparable fruit quality indicators. Results also showed that fruit shape index, rind thickness, fruit weight, total yield and marketable yield were significantly influenced by grafting. Use of rootstocks significantly increased previously mentioned values which is related with yield, as compared to the non-grafted plant. Analyses proved the use of rootstocks as economically feasible and an advantageous alternative in watermelon production.

SummaryIn many irrigated areas of the Mediterranean region, farmers are forced to use saline water to irrigate their crops due to an inadequate supply of fresh water. Grafting may represent an effective tool to improve crop tolerance to salinity. Two greenhouse experiments were carried out to determine yield, fruit quality and mineral composition of melon plants (Cucumis melo L. cv. ‘Cyrano’), either ungrafted or grafted onto the commercial rootstock ‘P360’ (Cucurbita maxima C. moschata) and cultured in pumice. Plants were supplied with nutrient solutions having electrical conductivities (EC) of 2.0, 4.0, 5.9, 7.8 or 9.7 dS m–1. The saline nutrient solutions (those > 2.0 dS m–1) had the same basic composition, plus an additional 20, 40, 60 or 80 mM NaCl, respectively. In both years (2003 and 2004), increased salinity in the nutrient solution resulted in a linear decrease in marketable yield compared to controls that was due to reductions in the size and number of marketable fruits. Averaged across years and nutrient solution concentrations, marketable fruit yield was 44% higher in grafted than in ungrafted plants. The lowest marketable yield recorded in ungrafted plants was associated with a reduction in both mean fruit weight and in the number of fruits per plant compared to grafted plants. Salinity improved fruit quality in both grafting combinations by increasing firmness, dry matter (DM), acidity and total soluble solids (TSS) contents. The nutritional qualities of grafted melons such as fruit DM, titratable acidity and TSS content were slightly inferior compared to those of ungrafted plants, whereas physical qualities such as fruit firmness and Hunter colour values (L* and a*/b*) were superior compared to those of plants grown with their own roots. Grafted plants could reduce leaf Na+ ion, but not Cl– ion, concentrations. However, the sensitivity to salinity was similar between grafted and ungrafted plants, and the higher marketable yield from grafted plants was mainly due to grafting per se.

The phyto-technical management of crops, such as the conduction system, spatial arrangement of plants and mineral and organic fertilization are pre-harvest agronomic factors that can alter fruit quality. Therefore, this research was developed to evaluate physico-chemical attributes of yellow passion fruit as a function of population arrangement and organomineral fertilization. The experiment was carried in Entisol with free-sand texture under tropical climate with dry summer. The treatments were obtained from the combination of doses of nitrogen (92, 119, 183, 248 and 275 kg ha-1) and soil organic matter (1.3, 1.8, 2.9, 4.0 and 4.5%), through Central Box Compound, plus four additional treatments to study the effect of the number of plants per pit. The evaluations were carried on seven and ten months after the transplanting of the seedlings. A randomized block design with three replications was used. The fruits were harvested at the beginning of the yellowing of the bark and evaluated in the pulp: pH, total titratable acidity (TTA), total soluble solids (TSS), reducing sugars, non-reducing sugars and total sugars, ascorbic acid, TSS/TTA ratio, electrical conductivity and humidity. The harvesting season changed the physico-chemical properties of the passion fruit pulp and interfered with the effects of plant management and fertilization on the quality of passion fruit. For the production of the best quality passion fruit we may cultivate one, two or three plants per pit. With three plants per pit it is recommended to apply 180 kg ha-1 of nitrogen annually and raise the soil organic matter to 4%.

Different potassium fertilization levels influence water-use efficiency, yield, and fruit quality attributes of cocktail tomato—A comparative study of deficient-to-excessive supply

Kaolin improves salinity tolerance, water use efficiency and quality of tomato

Eighteen grape varieties planted in 1997 were evaluated for their performance at Regional Research Station, PAU Bathinda (Latitude 30°17’ N; longitude 74°58’ E; and elevation 211 m amsl) with respect to yield, bunch and berry characteristics, and fruit quality. The early maturing varieties required lesser heat units (890.1 to 1051.1 day °C) as compared to the late maturing varieties (1020.1– 1491.7 days °C). The varieties Angur Early and Banqui Abyad consumed minimum heat units (890.10 day °C) to reach the ripening stage. The variety Arka Shyam consumed highest heat units (1491.7 day °C) from fruit setting to ripening and this was on par with Arka Hans and Arkavati. Perlette consumed 1051.10 day °C heat units. Banqui Abyad required minimum number of days from full bloom to ripening (DFFB; 51.20) that were on par with Angur Early, Khalili, Sindhu, Delight, Beauty Seedless and Perlette. The variety Perlette produced the highest fruit yield (25.07 kg/vine) and was followed by Beauty Seedless (19.90 kg/vine). In respect to the bunch breadth and length, Beauty seedless, Delight and Perlette were found to be good performers. The highest berry weight was found in Cardinal (4.80 g) and it was on par with Banqui Abyad. The highest TSS was found in the variety Delight (18.23%) and it was on par with Beauty Seedless, Khalili, Unknown, Banqui Abyad, Black Muscat, Black Prince, Arkavati, Arka Shyam and Shadipur Local. The cultivars, Perlette and Beauty Seedless were on par with respect to the TSS and acidity. The cultivar Perlette outshined all the other cultivars as far as the fruit yield is considered. INTRODUCTION In India, grapes are grown over an area of 40,000 ha with an annual production of 12,000 thousand MT and the corresponding figures for Punjab are 1, 324 ha and 35,748 MT, respectively (Anon, 2003). The district of Bathinda, in the South Western Punjab is contributing 21,600 MT of grapes from an area of 800 ha, which is more than 60 percent of the total area and production of grapes in the Punjab state. The very short period (April–June) available for the ripening of berries, limits the choice of varieties and only early maturing varieties can be grown in the South Western Punjab. The cultivar Perlette occupies more than 95 percent of the total acreage under grapes in Punjab and the entire northwest India. The monoculture of Perlette in this region leads to a very short harvesting period. This causes a glut in the grape markets and results in very poor market returns. The extremely hot climate during berry development and early monsoon rain further deteriorates the quality of grapes in this region (Chadha, 1999). Hence, in the entire grape growing regions of the southwest Punjab, the climatic conditions are marginal for grape cultivation. Early and mid-season varieties of grapes can be grown successfully in this region. The performance of a variety in respect to the fruit yield and quality varies from location to location. The time required for grapes to reach maturity is determined by the total amount of heat received which is expressed in terms of degree days or heat units from full bloom to ripening. Criteria like, TSS, DFFB and berry colour are being commonly used for determining the maturity of grapes; however, information pertaining to the heat unit Proc. IS on Grape Production and Processing Eds.: P.G. Adsule et al. Acta Hort. 785, ISHS 2008 80 summation for berry ripening in grapes is lacking. Hence, in the present study heat unit requirement of eighteen grape varieties was studied at Punjab Agricultural University Regional Station, Bathinda, India. These varieties were also evaluated for their performance in terms of DFFB, yield and yield contributing factors, and fruit quality. MATERIALS AND METHODS Eighteen grape varieties planted in 1997 at Punjab Agricultural University Regional Station Bathinda (latitude 30°17” N, longitude 74°58” E and altitude 211 m amsl) were used as plant material for the study. One vine of each variety planted at 3 m x 3 m and trained on Bower System formed one replication. The performance of these varieties was examined with respect to the yield, bunch and berry weight, bunch and berry size, total soluble solid (TSS), and acidity during the year 2002–2003 and 2005. The heat units or growing degree days (GDD) was calculated using the following formula described by Rai et al. (2002): tm GDD = Σ {[(Tmax + T min) /2] – Tb} ts where, ts and tm are the time of fruit setting and fruit maturity, respectively. Tmax and Tmin are the maximum and minimum temperatures, respectively. Tb is the base temperature below which fruit growth is arrested. The base temperature for grapes is taken as 10°C (Brar et al., 1992). The yield was recorded at time of harvest. The average bunch weight and bunch size were worked out on the basis of observations from a composite sample of ten bunches chosen at random from every vine of each variety. Average berry weight and berry size were calculated on the basis of a sample of fifty berries randomly picked from ten bunches. The total soluble solids (TSS) were determined with the help of hand refractrometer and acidity was estimated as per the methods in A.O.A.C. (1985). The data presented are the pooled means of three years 2002, 2003 and 2005. The crop was badly damaged in 2004 due to hailstorms. There were three replications, with one vine per replication in a randomized block design. The significance of variation among the treatments was observed by applying ‘F’ test. The least significant difference (LSD) at p=0.05 was calculated by multiplying standard error with ‘t’ value (p=0.05) at error degree of freedom to compare the means of the treatments designs as described by Panse and Sukhatme (1954). RESULTS AND DISCUSSION Heat Unit Requirement, DFFB, Yield and Bunch Characteristics The data pertaining to the accumulation of Heat Units (Growing Degree Days; GDD) by different grape varieties is presented in Table 1. It is evident from the data that the summation of heat units (day °C) ranged from 890.1 (Angur Early and Banqui Abyad) to 1491.7 day °C (Arka Shyam). The early maturing varieties required lesser heat units (890.1to 1051.1 days °C) as compared to the late maturing varieties (1020.1–1491.7 days °C). Makhija et al. (1984) also reported that under Delhi conditions the early maturing varieties required lesser heat units than the late maturing ones. Arka Shyam consumed highest heat units (1491.7 day °C) from fruit setting to ripening and this was on a par with Arka Hans and Arkavati. Angur Early and Banqui Abyad required minimum heat units (890.10 day °C) to reach ripening. These two varieties were on a par with Sidhu, Khalili, Delight and Beauty Seedless as far as heat unit requirement is concerned. The variety Perlette consumed 1051.10 day °C heat units. The variation in heat units or GDD was due to variation in the date of maturity of different grape varieties. The variation in heat unit requirements has been earlier reported to vary with the variation in the date of maturity in Litchi (Rai et al., 2002), Mango (Shinde et al., 2001) and Ber (Singh et al., 1998). The number of days required from full bloom to ripening (DFFB; Table 1) also varied with the variety. Banqui Abyad required minimum number of days from full

The effects of variety and manure application on the growth, yield and nutritional quality of watermelon ( Citrullus lanatus L.) were investigated during the rainy and late cropping seasons in Akure, a rainforest zone of Nigeria. Treatments were a factorial combination of five watermelon varieties and three manure types laid out in a randomized complete block design (RCBD) with three replications. The watermelon varieties were Crimson Sweet, Charleston Grey, Kaolac, Anderson and Sugarbaby, while the manures which were applied at 3 weeks after planting, were organomineral fertilizer (OMF) (5 t/ha), NPK (compound) fertilizer (200 kg/ha) and an unmanured control. The watermelon varieties tested responded differently in terms of growth and yield components due to differences in their genetic composition. In the rainy season, Charleston Grey performed well in terms of growth (biomass) but produced poor fruit yield while Kaolac and Anderson recorded high fruit yields. Late season favored growth and yield in Crimson Sweet and Kaolac, however, Kaolac produced good fruit yields as both rainy and late season crop. Fruit quality parameters such as the number of rotten and cracked fruits differed among the varieties, in both rainy and late season, Charleston Grey and Kaolac produced the highest number of rotten and cracked/split fruits. Sugarbaby and Anderson performed best in both seasons while Charleston Grey is not adequately adapted to rainy season growing environmental conditions. The NPK fertilizer enhanced higher growth and yield over OMF and unmanured control in both seasons. Significant interactions between variety and manuring were found for growth and fruit yield characters of watermelon. In the rainy season crop, application of NPK and organomineral fertilizer enhanced fruit yield components of watermelon varieties (Kaolac, Anderson, Crimson Sweet and Sugarbaby). In the late season, NPK fertilizer enhanced number of fruits per plant in Charleston Grey, highest mean fruit diameter and mean fruit weight per plant in Anderson. The chemical and proximate constituents of fruits of watermelon varieties were significantly affected by manure application. In the rainy season, NPK enhanced fruit contents of N, P, K, moisture, total solids and vitamin C in most varieties except in Anderson. In late season, NPK enhanced the nutritional (total solids) contents of the varieties while OMF enhanced fruit contents of P, Ca, crude fiber, vitamin C and total solids in some of the varieties. However, unmanured Anderson had highest vitamin C content in the late season. It is concluded that application of NPK and OMF fertilizer enhance growth, yield and nutritional quality of watermelon varieties in both rainy and late season in the study area.

Nitrogen fertilization is an important step for watermelon (Citrullus lanatus) production due to its influence over yield, fruit quality, and disease severity. Currently, the gummy stem blight (Didymella bryoniae) and the downy mildew (Pseudoperonospora cubensis) can be taken as the most important watermelon diseases, since they impose severe impairment to the crop. Furthermore, studies focusing on plant responses to nitrogen fertilization regarding fruit yield and quality, and disease resistance are rare. Hence, the present study aimed at evaluating the effect of nitrogen doses on fruit yield and quality, and on disease prevalence in watermelon. Two experiments were carried out at the Universidade Federal de Tocantins, employing sprinkler irrigation, in an area previously used to grow watermelon. The experimental design was blocks at random, with five treatments (N doses, applied twice as side-dressing, in kg ha-1, as follows: T1= control treatment without N, T2= 20, T3= 40, T4= 80, and T5= 120), and four replications. Urea (45% N) was used as the N source. In the first assay, the highest fruit yield and average weight were observed when 40 kg ha-1 of N were applied. The highest severity of the gummy stem blight was observed when the highest nitrogen doses were applied (80 and 120 kg ha-1). In the second assay, the highest severity levels of the gummy stem blight, as well as of mildew, were observed again when N doses were the highest (80 and 120 kg ha-1). The lowest severity levels for both diseases were observed in the control treatment.

Tomato (Solanum lycopersicon L.) is the most important vegetable in the world consumption and production. The fruits significantly contribute to human health, as they are rich in vitamins, minerals, sugars and antioxidants. Therefore, the high demand on tomato fruits consumption as fresh and processed products necessitates yield increase. However, the focus on yield increase does not consider the fruit’s flavor and might dissatisfy the consumers. Most of the consumers store tomatoes after purchasing in household fridge, which decreases the quality and the flavor of these fruits. Nevertheless, an application of particular cultivation management such as optimized plant nutrition could enhance fruit yield and quality. Potassium (K), as one of the essential mineral plant nutrients, is crucially involved in tomato production and fruits quality and has the potential to ameliorate them. It also has a major role in plant-water-relations, e.g. on water-use efficiency WUE. The objectives of the present study were to evaluate the effect of K on the yield production, postharvest behavior, and sensory profile of different tomato cultivars. The effect of K on yield and water-use efficiency (WUE) was investigated in an outdoor pot experiment with two cocktail tomato cultivars Primavera and Yellow Submarine and six K levels from deficiency to overdose. To study the fruit postharvest behavior, another outdoor pot experiment was conducted with two K levels (K low and K high) and two boron (B) levels (B low and B high) on the same cultivars. The breaker fruits were stored at two different conditions: ambient conditions (20 °C) and refrigerated + ambient conditions (4 °C + 20 °C). In a third outdoor pot experiment, the effect of K on the sensory profile of the fruits was studied at three different K levels (named as K low, K moderate and K high) on three tomato cultivars as Lyterno, Primavera and Yellow Submarine. The sensory evaluation was performed by panelists and subsequently, the taste-related analyses were assessed. The yield and WUE increased significantly with rising K but they were declined with K overdose. Similarly, the fruit quality attributes as color, total soluble solids (TSS), titratable acids (TA) and dry matter (DM) increased significantly with K application but further supply to overdose did not reveal any enhancement. The effect of K on the fruit’s postharvest behavior exposed as a significant increase in TSS, TA and DM in both storage regimes. Boron did not show any significant increase on the studied parameters in this experiment. Potassium had a significant influence on the taste-related attributes and some of the sensory traits but not on fruit volatile compounds. Generally, optimal K application enhanced the yield, WUE and the fruit quality attributes, while excessive K application did not possess a significant increment effect. The combination of high K and low B fertilization improved the fruit quality performance only under ambient storage conditions. The positive effect of K on the fruits sensory profile was confirmed to be detectable by the human senses as well as with the instrumental analyses. The conclusions drawn from this study are: that an optimal application of K fertilization on tomato ensures high yields with less water consumption moreover enhances the fruit quality attributes. The adequate application of K on tomato plants reinforces the development process during postharvest of the fruits, which influence positively on the fruit quality under storage conditions. Furthermore, K is important to enhance the flavor of tomato fruits and meet the consumer’s preferences. The present study indicates that potassium nutrition is one of many factors that can influence tomato growth and its potential to enhance yield, fruit quality and WUE essentially depends on all factors’ integration.

Effects of salinity on fruit yield and quality of tomato grown in soil-less culture in greenhouses in Mediterranean climatic conditions

Increasing fruit yield and quality of tomatoes under organic low-input conditions remains a challenge for producers and breeders. Therefore, it is necessary to identify superior tomato cultivars that are suitable for production and use as parents in breeding programmes. In the present study, the variations in plant morphology and fruit quality characteristics of tomato cultivars were assessed to reveal the traits associated with improved yield and fruit quality. Sixty diverse tomato cultivars were screened in 2015, and in 2016, a subset of 20 cultivars was selected for further evaluation under organic low-input conditions. The results showed high variability among cultivars in all 28 traits that were observed. Salad cultivars had lower plant growth and fruit quality (minerals, dry matter, total soluble solids, and total phenolics) by 10–70%, but they displayed 10–60% higher fruit yield and leaf minerals than cocktail cultivars. Salad tomato cultivars with superior yield and harvest index were mainly derived from breeding for intensive indoor production. Cocktail cultivars with superior yield were mainly derived from organic and outdoor breeding programs. There was a trade-off between fruit yield and quality, indicating a challenge for simultaneous improvement of yield and quality. The importance of Mg was highlighted because of its contribution to the fruit mineral concentration and fruit quality. Cultivars superior in one trait or trait combination under organic low-input conditions were identified to be used by producers and breeders as superior cultivars to meet their production targets and breeding objectives. The importance of Mg provides a novel path for further research on improving soil-available Mg in organic tomato production to enhance fruit mineral concentration and fruit quality in general.

Globally, there has been an increase in stringent regulations governing the use of chemical soil fumigants for controlling diseases, pests, and weeds. Grafting has been identified as an effective alternative to soil fumigation for managing soilborne diseases and pests in intensive vegetable cropping systems. The majority of watermelon ( Citrullus lanatus ) grafting research confirms that selected rootstocks play a role in improving plant resistance or tolerance to common soilborne diseases. Currently, there is a lack of evidence-based literature on the effects of grafting on watermelon fruit quality attributes and yield components. Previous reviews report wide variation in the impact of grafting on watermelon production, depending on rootstock–scion combinations and environmental conditions. This review employed evidence-based synthesis methods to comprehensively and methodically summarize research results of the impact of grafting on watermelon, with a focus on fruit quality and yield. In this systematic review, 548 citations (studies published during 2011–21) were screened against strict inclusion criteria, and data were extracted from 47 studies. Meta-analysis of percent differences between the grafted watermelon treatment and the nongrafted or self-grafted watermelon control was performed using extracted data of yield components and a wide range of fruit quality attributes. Meta-analysis of research data with variance measures was also conducted based on a rather limited number of studies. Our findings showed higher levels of total yield, average fruit weight, fruit length and width, fruit lycopene and soluble solids content, rind thickness, flesh firmness, lightness, chroma, and flesh nitrogen (N) content in grafted watermelon treatments compared with the nongrafted or self-grafted control. In particular, total yield, average fruit weight, and flesh firmness exhibited significant increases of a more than 10% difference. In contrast, grafted plants demonstrated decreases in fruit pH, hue angle, and flesh calcium content, although the reduction was not greater than 10% relative to the control. Meta-analysis of research data with variance measures further confirmed significantly greater total yield and flesh N content in grafted watermelon treatments compared with the nongrafted or self-grafted control. In addition, the meta-analysis results confirmed greater benefits of watermelon grafting in the presence of known soilborne disease pressure in contrast to the production scenarios without soilborne disease problems.