Aphidophagous hoverflies reduce foxglove aphid infestations and improve seed set and fruit yield in sweet pepper

2021 ◽  
Author(s):  
Rob Moerkens ◽  
Sten Boonen ◽  
Felix L. Wäckers ◽  
Apostolos Pekas
2011 ◽  
Vol 29 (3) ◽  
pp. 275-281 ◽  
Author(s):  
José S Rubio ◽  
Walter E Pereira ◽  
Francisco Garcia-Sanchez ◽  
Luis Murillo ◽  
Antonio L García ◽  
...  

The objective of the present study was to evaluate the marketable fruit yield of sweet pepper plants (Capsicum annuum cv. Orlando) in function of the management of nutrient solution with training system. Plants were grown on coconut coir dust under greenhouse conditions in the southeast of Spain. A randomized block design in split-split plot with four blocks was used to test the effect of the nutrient solution strength (full or half-strength Hoagland nutrient solution), training system (two and three stems per plant) and water salinity (saline and non-saline) on total and marketable yield, fruit quality, and fruit mineral concentration. Salt treatment decreased fruit yield by decreasing the fruit fresh weight but not the number of fruits per plant. Under saline and non-saline conditions, the higher yield of fruits was obtained in plants watered with half-strength Hoagland solution, and grown with three stems per plant. Blossom end rot incidence increased under saline conditions or using full-strength Hoagland solution, but decreased with the combination of half-strength Hoagland solution and three-stem training system. Salt treatment also decreased fruit quality in all the treatments due to a decrease in PO2-, SO4(2-), Fe2+;3+, Cu1+;2+ and Mn2+ concentrations, and fruit shape index. Likewise, plants exposed to salinity and watered with half-strength Hoagland solution and trained with three stems showed a reduction in juice glucose and fructose concentration. Based on these results, an increase of the marketable fruit yield could be obtained under non or moderate saline conditions with the implementation of suitable culture practices.


Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 733 ◽  
Author(s):  
Khaled A. A. Abdelaal ◽  
Yasser S.A. Mazrou ◽  
Yaser M. Hafez

Silicon is one of the most significant elements in plants under abiotic stress, so we investigated the role of silicon in alleviation of the detrimental effects of salinity at two concentrations (1500 and 3000 ppm sodium chloride) in sweet pepper plants in two seasons (2018 and 2019). Our results indicated that relative water content, concentrations of chlorophyll a and b, nitrogen, phosphorus and potassium contents, number of fruits plant−1, fruit fresh weight plant−1 (g) and fruit yield (ton hectare−1) significantly decreased in salt-stressed sweet pepper plants as compared to control plants. In addition, electrolyte leakage, proline, lipid peroxidation, superoxide (O2−) and hydrogen peroxide (H2O2) levels, soluble sugars, sucrose, and starch content as well as sodium content significantly increased under salinity conditions. Conversely, foliar application of silicon led to improvements in concentrations of chlorophyll a and b and mineral nutrients, water status, and fruit yield of sweet pepper plants. Furthermore, lipid peroxidation, electrolyte leakage, levels of superoxide, and hydrogen peroxide were decreased with silicon treatments.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 532E-532 ◽  
Author(s):  
Elio Jovicich ◽  
Daniel J. Cantliffe ◽  
George J. Hochmuth

In greenhouse crops, fruit yield and quality can be increased by managing shoot pruning and plant density. The effect of plant population density (2, 3, and 4 plants/m2 as function of in-row plant spacings of 66.5, 44.3, and 33.3 cm, respectively), and shoot pruning (one, two, and four main stems) was studied for effects on fruit yield, quality and plant growth of greenhouse-grown sweet pepper (Capsicum annuum L. cv. Robusta) during Summer 1998 in Gainesville, Fla. Red fruit were harvested 84 and 118 days after transplanting (14 Apr.). Additional fruit set was inhibited due to the high temperatures. Marketable yield (number and weight) per square meter increased linearly with plant density and was greater on plants with four stems than in those with two or one stem. Extra-large fruit yield per square meter was not affected by plant density, but was higher in four-stem plants. Total marketable yield and extra-large fruit yields per plant were greatest in the four-stem plants at two plants per square meter. The stem length and the number of nodes per stem increased linearly with the decrease in plant spacing. Stem length and number of nodes per stem were greater in single-stem than in four-stem plants. Number and dry weight of leaves, stem diameter, and total plant dry weight were higher in four- and two-stem plants than in single-stem plants. Results indicated that four plants per square meter pruned to four stems increased marketable and extra-large fruit yield in a short harvest period of a summer greenhouse sweet pepper crop in north central Florida.


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1180 ◽  
Author(s):  
Muneera D. F. ALKahtani ◽  
Kotb A. Attia ◽  
Yaser M. Hafez ◽  
Naeem Khan ◽  
Ahmed M. Eid ◽  
...  

Salinity stress deleteriously affects the growth and yield of many plants. Plant growth promoting rhizobacteria (PGPR) and chitosan both play an important role in combating salinity stress and improving plant growth under adverse environmental conditions. The present study aimed to evaluate the impacts of PGPR and chitosan on the growth of sweet pepper plant grown under different salinity regimes. For this purpose, two pot experiments were conducted in 2019 and 2020 to evaluate the role of PGPR (Bacillus thuringiensis MH161336 106–8 CFU/cm3) applied as seed treatment and foliar application of chitosan (30 mg dm−3) on sweet pepper plants (cv. Yolo Wonder) under two salinity concentrations (34 and 68 mM). Our findings revealed that, the chlorophyll fluorescence parameter (Fv/Fm ratio), chlorophyll a and b concentrations, relative water content (RWC), and fruit yield characters were negatively affected and significantly reduced under salinity conditions. The higher concentration was more harmful. Nevertheless, electrolyte leakage, lipid peroxidation, hydrogen peroxide (H2O2), and superoxide (O2−) significantly increased in stressed plants. However, the application of B. thuringiensis and chitosan led to improved plant growth and resulted in a significant increase in RWC, chlorophyll content, chlorophyll fluorescence parameter (Fv/Fm ratio), and fruit yield. Conversely, lipid peroxidation, electrolyte leakage, O2−, and H2O2 were significantly reduced in stressed plants. Also, B. thuringiensis and chitosan application regulated the proline accumulation and enzyme activity, as well as increased the number of fruit plant−1, fruit fresh weight plant−1, and total fruit yield of sweet pepper grown under saline conditions.


2019 ◽  
Vol 76 (3) ◽  
pp. 446
Author(s):  
Nighat Mushtaq ◽  
Nazeer Ahmed ◽  
Khursheed Hussain ◽  
Nageena Nazir

1997 ◽  
Vol 90 (6) ◽  
pp. 1646-1649 ◽  
Author(s):  
Arnaud Jarlan ◽  
Domingos De Oliveira ◽  
Jean Gingras
Keyword(s):  
Seed Set ◽  

2021 ◽  
Author(s):  
Ανδρέας Ροπόκης

The nutrient to water uptake ratios, henceforth termed “uptake concentrations” (UC), remain relatively constant over time under similar climatic conditions for a particular plant species and developmental stage. Under greenhouses with low temperature (LT) conditions, the uptake of nutrients may be altered in a different manner than that of the water and thus their UC may be different than in greenhouses with standard temperature (ST) conditions. In the Mediterranean regions, sweet pepper is frequently cultivated in unheated greenhouses in which the temperature during the winter may drop to suboptimal or even lower levels. In these areas, the available irrigation water frequently contains sodium chloride but also calcium bicarbonate, which at excessively high concentrations in closed hydroponic crops can impose Ca accumulation in the recycled NS and concomitantly negatively affect fruit yield and quality of the produce.Taking the above into consideration there were established three studies:In the first study, pepper plants of the cultivars ‘Sammy’ and ‘Orangery’, self-grafted or grafted onto two commercial rootstocks ('Robusto' and 'Terrano'), were cultivated in a greenhouse under either ST or LT conditions. The aim of the study was to test the impact of grafting and greenhouse temperature on total yield, water use efficiency and nutrient uptake. The LT regime reduced yield by about 50% in ‘Sammy’ and 33% in ‘Orangery’, irrespective of the grafting combination. Grafting of ‘Sammy’ onto both 'Robusto' and 'Terrano' increased the total fruit yield by 39% and 34% compared with the self-grafted control, while grafting of ‘Orangery’ increased yield only when the rootstock was ‘Terrano’. The yield increase resulted exclusively from enhancement of the fruit number per plant. Both the water consumption and the water use efficiency were suppressed by the LT regime but the temperature effect interacted with the rootstock/scion combination. The LT increased the UC of K, Ca, Mg, N, and Mn, while it decreased strongly that of P and slightly the UC of Fe, and Zn. The UC of K and Mg were influenced by the rootstock/scion combination but this effect interacted with the temperature regime. In contrast, the Ca, N, and P concentrations were not influenced by the grafting combination. The results of the present study show that the impact of grafting on yield and nutrient uptake in pepper depend not merely on the rootstock genotype but on the rootstock/scion combination.In the second study, mean UC of macro- and micronutrients were determined during five developmental stages in different pepper cultivars grown in a closed hydroponic system by measuring the water uptake and the nutrient removal from the RNS. The experiment was conducted in a Mediterranean environment and the tested cultivars were ‘Orangery’, ‘Bellisa’, ‘Sondela’, ‘Sammy’ self-grafted and ‘Sammy’ grafted onto the commercial rootstock `RS10'. ‘Sondela’ exhibited significantly higher ΝΟ3, Μg, Ca and B UC in comparison with all other cultivars, while Bellisa exhibited higher K UC. The UC of all nutrients were similar in the grafted and the non-grafted ‘Sammy’ plants. The UC of macronutrients estimated in the second study (mmol L-1) ranged from 2.4 to 3.7 for Ca, 1.0 to 1.5 for Mg, 6.2 to 9.0 for K, 11.7 to 13.7 for N, and 0.7 to 1.1 for P. The UC of N, K, Ca and Mg were appreciably higher than the corresponding values found under Dutch climatic conditions, while that of P was similar in both environments during the vegetative stage and higher thereafter. The UC of Fe, Zn and B tended to decrease with time, while that of Mn increased initially and subsequently decreased slightly during the reproductive developmental stage.In the third study, irrigation water containing 1.5, 3.0, 4.5 and 6.0 mM was used to prepare NS in a closed hydroponic crop of sweet pepper cultivated in RNS. The aim of the study was to determine maximum Ca levels that do not harm the crop and to simulate the pattern of Ca accumulation when the Ca concentration in the irrigation water is excessive. At 1.5 mM Ca, no Ca accumulation was observed in the RNS, while at 3.0, 4.5 and 6.0 mM the Ca concentration in the RNS, and concomitantly in the root environment, increased to 17, 28 and 37 mM, corresponding to 6.4, 9.0 and 10.8 dS m-1. The accumulation of Ca in the RNS affected both tissue nutrient concentrations and UC of Ca, S and Mg, but this was not the case for N and K. Growth, yield and plant water uptake were restricted at moderate and high external Ca levels. Our results showed that in soilless sweet pepper crops with zero discharge of fertigation effluents, the Ca concentration in the irrigation water should be lower than 3.0 mM to avoid yield restrictions due to salinity.


2021 ◽  
Author(s):  
Baoshi Li ◽  
Wenke K. Liu ◽  
Qi Wang

Abstract Northern China is a major production area for off-season vegetables in Chinese solar greenhouse. Usually, greenhouse gas emission flux and coefficient in Chinese solar greenhouse are higher than those in the open field. The reason for this phenomenon is heavy nitrogen (N) fertilization (esp. chemical N and organic manure N) and frequent irrigation during year-round cultivation. A novel substrate cultivation method for vegetable production in Chinese solar greenhouse, called soil-ridged/substrate-embedded cultivation (SSC), was put forward to reduce environmental pollution and increase use efficiency of nutrients. To clarify the characteristics of SSC root-zone greenhouse gas emissions, and the regulation effects of biochar and DMPP addition, five treatments were designed in Chinese solar greenhouse under the same nitrogen application level, including soil-ridge cultivation (SC, as a control), SSC (peat: vermiculite: perlite (v/v = 2:1:1), SSC-B50% (biochar: vermiculite: perlite,v/v = 2:1:1), SSC-B25% (biochar: peat: vermiculite: perlite, v/v = 1:1:1:1), and SSC-DMPP (SSC supplemented with 1% (w/w) DMPP of N fertilizer). Results showed that SSC improved fruit yield of sweet pepper of by 10.99% compared to SC. SSC-B50% and SSC-DMPP significantly improved sweet pepper growth compared to SSC. Moreover, SSC-DMPP increased sweet pepper yield by 10.30% compared to SSC treatment, while SSC-B50% and SSC-B25% treatments lowered the yield by 47.1% and 13.7% separately. Five treatments presented various root-zone temperature features. Also, substrate pH of SC, SSC-B50%, and SSC-B25% is alkaline, while SSC and SSC-DMPP treatments is acidic. Besides, the Global Warming Potential was significantly mitigated in the SSC cultivation compared with the SC. Similarly, the greenhouse gas intensity decreased from 0.074 to 0.038 kg CO2-eq kg− 1 yield. Compared with the SSC treatment, cumulative N2O emissions were significantly reduced in the SSC-DMPP treatment. The greenhouse gas intensity also decreased from 0.038 to 0.033 kg CO2-eq kg− 1 yield. Thus, we concluded that SSC was a promising method characterized with reduced greenhouse gas emissions and increased fruit yield. Application of DMPP in SSC cultivation significantly reduced N2O emissions. We recommend SSC method use in Chinese solar greenhouse with DMPP addition in substrate to optimize greenhouse gas mission.


2013 ◽  
Vol 29 (1) ◽  
pp. 1-11 ◽  
Author(s):  
C. Leal-Fernández ◽  
H. Godoy-Hernández ◽  
C. A. Núñez-Colín ◽  
J. L. Anaya-López ◽  
S. Villalobos-Reyes ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document