Decrease In Marketable Yield Research Articles

PERFORMANCE OF BIODEGRADABLE FLOATING DIRECT COVERS IN THE FIELD PRODUCTION OF BUTTERHEAD LETTUCE DURING SPRING AND AUTUMN TRIALS

Non-degradable polypropylene nonwovens are difficult to dispose and their utilization represents high economic costs. This study was conducted on lettuce cultivated during the spring and autumn seasons in the southern part of Poland to test biodegradable nonwovens as plant covers. Several nonwovens were developed from aliphatic-aromatic copolyesters (ACC), one without modifiers (SB48/11) and three with the addition of fatty acid dimers: two commercial variants (SB20/13, SB21/13) and one made from plant biomass (SB28/13). Nonwoven polypropylene (PP) fleece was included as a control cover. One week after covering with SB48/11, stomatal conductance (gs) increased in lettuce plants in parallel with higher transpiration rate (E) and sub-stomatal CO2 concentration (Ci) relative to the control, but differences in these parameters evened out in mature plants. In the spring, degradable covers with their higher mass per unit area, caused a decrease in marketable yield of lettuce compared to the control PP, resulting mainly from the deterioration of plant quality and lower mean weight per head. In the autumn season, yield was statistically not different between treatments. Yield of spring lettuces was 78% higher compared to the autumn cultivation period. Plants grown under SB20/13 had the lowest dry weight and L-ascorbic acid, while plants under SB21/13 had the highest dry weight and L-ascorbic acid content. Plants under SB28/13 had higher chlorophyll a content. Generally, no effect of covers was noted for carotenoid concentrations. The content of dry weight, L-ascorbic acid, and carotenoids were higher in plants harvested in spring, while no effects of crop season on chlorophyll level were observed. All tested biodegradable nonwovens are a potential substitute for standard polypropylene in autumn trials, but for spring covering unit weight of these materials should be reduced.

Improved Porosity of Insect Proof Screens Enhances Quality Aspects of Zucchini Squash without Compromising the Yield.

In a global climate change environment, assuring optimal growing conditions is a difficult challenge, compromising the food supply for a rapidly rising population. The climatic conditions in the protected environment lead to high temperatures and fast insect development, impacting productivity and vegetables qualitative attributes. Consumers’ interest in healthy food requires sustainable tools to manage biotic and abiotic factors and, from this perspective, anti-insect nets represent an excellent “green” solution. For this purpose, our goal was to compare two different anti-insect nets on microclimate, production, and qualitative traits of Cucurbita pepo L. fresh fruits. The experiment was conducted in three separate polyethylene high tunnels, with 50 mesh anti-insect nets of different porosities being installed on the openings of two tunnels, while the third tunnel was a control without nets. Microclimate measurements, as well as yield, physiological, and phytochemicals variables, were assessed. The 50 mesh net led to a decrease in marketable yield (22.5%), fruit number (18.0%), CO2 net assimilation rate (6.0%), and transpiration rate (29.5%). Total soluble solids, antioxidant activities and total ascorbic acid concentration had an opposite trend. The 50 mesh AirPlus net improved quality aspects of zucchini fruits by increasing total ascorbic acid, total phenols, and antioxidant compounds, with no negative impact on yield.

Synergistic Action of a Microbial-based Biostimulant and a Plant Derived-Protein Hydrolysate Enhances Lettuce Tolerance to Alkalinity and Salinity.

In the coming years, farmers will have to deal with growing crops under suboptimal conditions dictated by global climate changes. The application of plant biostimulants such as beneficial microorganisms and plant-derived protein hydrolysates (PHs) may represent an interesting approach for increasing crop tolerance to alkalinity and salinity. The current research aimed at elucidating the agronomical, physiological, and biochemical effects as well as the changes in mineral composition of greenhouse lettuce (Lactuca sativa L.) either untreated or treated with a microbial-based biostimulant (Tablet) containing Rhizophagus intraradices and Trichoderma atroviride alone or in combination with a PH. Plants were sprayed with PH at weekly intervals with a solution containing 2.5 ml L-1 of PH. Lettuce plants were grown in sand culture and supplied with three nutrient solutions: standard, saline (25 mM NaCl) or alkaline (10 mM NaHCO3 + 0.5 g l-1 CaCO3; pH 8.1). Salt stress triggered a decrease in fresh yield, biomass production, SPAD index, chlorophyll fluorescence, leaf mineral composition and increased leaf proline concentration, without altering antioxidant enzyme activities. The decrease in marketable yield and biomass production under alkali stress was not significant. Irrespective of nutrient solution, the application of Tablet and especially Tablet + PH increased fresh marketable yield, shoot and root dry weight. This was associated with an improvement in SPAD index, Fv/Fm ratio, CAT and GPX activities and a better nutritional status (higher P, K, and Fe and lower Na with NaCl and higher P and Fe with NaHCO3) via an increase of total root length and surface. The combination of microbial biostimulant with foliar application of PH synergistically increased the marketable fresh yield by 15.5 and 46.7% compared to the Tablet-treated and untreated plants, respectively. The improved crop performance of Tablet + PH application was attributed to a better root system architecture (higher total root length and surface), an improved chlorophyll synthesis and an increase in proline accumulation. Combined application of Tablet and PH could represent an effective strategy to minimize alkalinity and salinity stress in a sustainable way.

Effect of Ecklonia maxima seaweed extract on yield, mineral composition, gas exchange, and leaf anatomy of zucchini squash grown under saline conditions

The presence of NaCl in soil or water is one of the most critical environmental stresses limiting crop productivity worldwide. Seaweed extract (SWE) represents an important category of plant biostimulants able to improve crop tolerance to abiotic stresses, such as salinity. The current research aimed at elucidating the physiological and anatomical effects as well as the changes in mineral composition of greenhouse zucchini squash (Cucurbita pepo L.) treated with Ecklonia maxima SWE. Plants were sprayed every 2 weeks with a solution containing 3 mL L−1 of SWE. Zucchini squash plants were supplied with four nutrient solutions: 1 (non-salt control), 20, 40, or 60 mM NaCl. Increased salinity in the nutrient solution triggered a decrease in marketable yield, shoot biomass, Soil Plant Analysis Development (SPAD) index, net CO2 assimilation rate (ACO2), transpiration rate (E), and leaf macronutrient concentration (P, K, Ca, and Mg), whereas it augmented Na and Cl concentrations in leaf tissue without altering PSII photochemistry. Anatomical changes in leaves, including an increase in lamina, palisade, spongy parenchyma thickness, and intercellular spaces, were recorded under saline conditions. Foliar application of SWE increased yield and shoot biomass by 12.0 and 17.4 %, respectively, as well as fruit dry matter and total soluble solid contents in comparison to untreated plants. This was associated with an improvement in ACO2 (+14 %), chlorophyll content (+8 %), and nutritional status (high K and low Na accumulation) in SWE-treated plants. The size of stomata was influenced by foliar application of SWE, since the smallest cell guard length and width were recorded in the leaves of SWE-treated plants. Finally, the phenolic compounds in both palisade and spongy parenchyma were higher in untreated than in SWE-treated plants.

Root growth, yield, and fruit quality responses of reticulatus and inodorus melons (Cucumis melo L.) to deficit subsurface drip irrigation

Water scarcity associated with intense and frequent droughts has increased the need for the implementation of drought adaptation strategies that can save water and sustain crop productivity in water limited environments. A two season (2011 and 2012) study evaluated root growth, yield and fruit quality responses of cvs. Mission (muskmelon; reticulatus), Da Vinci (tuscan; reticulatus) and Super Nectar (honeydew; inodorus) of melon (Cucumis melo L.) to two irrigation rates (100% and 50% crop evapotranspiration (ETc)) on a silty clay soil under the semi-arid conditions of Texas. Deficit irrigation (50% ETc) increased root length density (RLD) in Mission, decreased in Da Vinci and did not affect in Super Nectar. Marketable fruit yield at 100% ETc irrigation was 77.1tha−1 in 2011 and 78.7tha−1 in 2012, but deficit irrigation caused a 30% decrease in marketable yield in both seasons, mainly due to a reduction in fruit size. Yield responses to deficit irrigation also varied with cultivar. A significant yield reduction of 43% in 2011 and 33% in 2012 was measured in Super Nectar, while for cvs. Mission and Da Vinci the reduction in yield was 24% and 30%, respectively in 2012. Deficit irrigation had no adverse impact on melon fruit quality; rather it increased total soluble solids content (23%) in Mission and β-carotene content (25%) in Da Vinci in 2011. At 50% ETc, agronomic water use efficiency (WUE; kgha−1mm−1) was improved in Mission (13%) in 2012 while it decreased in Super Nectar (21%) in 2011. These results showed that deficit irrigation can save 37–45% of irrigation water in Mission and Da Vinci cultivars (reticulatus) with a moderate reduction in economic yield. This practice may not be applicable for cv. Super Nectar (inodorus), as it reduced yield without improving water use efficiency.

EFFECT OF CALCIUM AND TWO EXTRACTS LICORICE AND SOLUAMINE TO DECREASE DAMAGE OF DROUGHT AND IMPROVING YIELD PARAMETERS OF POTATO CV. LATONA

This study was carried out at vegetables field of Horticulture and landscape department. College of Agriculture and Forestry. Mosul University. Iraq, during spring season 2010 , to investigate the effect of water stress: two levels of watering were applied, normal irrigation and exposing plants to water stress by no water supply during period of tubers formation and development (46 and 76 days after planting), calcium ion at 200 mg.L-1 concentration and two natural extracts Licorice at 3 g.L-1 and Soluamine at 2 m.L-1 in additional to control, each treatment applied three times ( first applied at full germination stage, while the second and third application were at 20 days and40 days after the first application. All treatments added by three methods of application (foliar application, adding to soil and foliar application + adding to soil). The experiment included 24 treatments which conducted in a Split – plot system within R.C.B.D Design. Each treatment was replicated three times, analysis of variance and Duncan's multiple range test at 0.05 were applied for all research data. Results obtained could be summarized as follows: Exposing potato plants to water stress caused a significant decrease in marketable yield . Application of calcium, Licorice and soluamine increased tuber 's number , plant yield, and marketable yield and reduced the drought damage on yield parameters. Application of calcium and two natural extracts (Licorice and soluamine) to the soil caused a significant increase in tubers weight, plant yield and total yield as compared to foliar application method. Generally, application of Licorice by third method under normal irrigation was the best interaction treatment

Effect of nitrogen form and nutrient solution pH on growth and mineral composition of self-grafted and grafted tomatoes

Three greenhouse experiments were carried out to determine the effect of the nitrogen form and the nutrient solution pH on growth, yield, leaf gas exchange, carbohydrate, N-compound concentrations and mineral composition of tomato cv. Moneymaker (Solanum lycopersicum L.) self-grafted and grafted onto ‘Maxifort’ (S. lycopersicum L.×S. habrochaites S. Knapp and D. M. Spooner) grown in hydroponics. Exp. 1 included five pH levels in the nutrient solution (3.5, 4.5, 5.5, 6.5, and 7.5) while in the Exps. 2 and 3 four different ratios of NO3− to NH4+ (100:0, 70:30, 30:70, and 0:100) were used. The Exps. 1 and 2 were performed in a short period of time (about 20 days) while Exp. 3 was a long-term experiment. No significant differences among treatments were observed in shoot and root dry biomass of tomato in the pH experiment (Exp. 1), whereas shoot dry biomass, Ca and Mg concentrations decreased sharply when N was exclusively provided as NH4+ (Exp. 2). When averaged over the pH level of the nutrient solution, the highest Ca, Fe, Zn, and Cu concentrations were recorded in grafted than self-grafted plants (Exp. 1), whereas in Exp. 2 shoot and root biomass values recorded in grafted plants were significantly higher than those observed for self-grafted plants, by 20%, and 24%, respectively. In the long-term experiment, the plant growth and yield decreased in response to an increase of NH4+ in the nutrient solution. The decrease in marketable yield with decreasing NO3−:NH4+ ratio resulted mainly from the increase of blossom-end rot, which reduced the number of marketable fruits per plant. The adverse effects of an increased supply in NH4+ have been associated to a fall in Ca and Mg levels in plant tissues. The carbohydrate concentrations, amino acids and proteins increased under NH4+ in comparison to NO3− based nutrition. Moreover, NH4+ toxicity was associated with reduced rates of net photosynthesis. Our results also demonstrated that grafting ‘Moneymaker’ into ‘Maxifort’ did not mitigate the negative effects of ammonium nutrition on tomato productivity.

Yield, fruit quality and mineral composition of grafted melon plants grown under saline conditions

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 EFFECT OF MID-SEASON VINE REMOVAL ON THE GROWTH OF FIVE SWEETPOTATO (IPOMOEA BATATAS L.) CULTIVARS

TU-82-155 and `Georgia-Jet' early maturing. `Carver II', TU-1892 and `Rojo-Blanco' late maturing sweetpotato, cultivars were evaluated in the field for 0.20 and 40% vine removal (VR) at 8 wk after transplanting. Parameters measured were: leaf area index (LAI) recovery, net assimilation rate, foliage crop growth rate (FCGR), storage roots crop growth rate (RCGR). alpha a (the mean relative growth rate in dry wt to the mean relative growth rate in leaf area over a time interval) or the partitioning of assimilates, total and marketable yield. A split. splitplot design was used and plants were sampled at 3 and 8 wk following VR. Except for TU-82-155 all cultivars showed significant LAI recovery above the control at 3 and 8 wk after vine removal when 20% of the vines were removed while at the 40% VR, only 'Georgia-Jet'. TU-1892 and 'Carver II' showed significant increases in LAI for the same periods. Net assimilation rate showed significant interactions while FCGR was not significantly affected by either 20 or 40 VR compared to the control at 3 or 8 wk after VR. RCGR was significantly affected by both levels of VR at 3 and 8 wk after VR and surplus assimilates (alpha a) showed significant interactions between cultivars and % VR. Told yield declined for all cultivars irrespective to maturity groups with the sharpest decrease being at the 20% VR. All cultivars except TU-82-155 showed a decrease in marketable yield, the increase in marketable yield of TU-82-155 was due to a lower non-marketable yield.

Effects of Air Quality on Growth, Yield, and Quality of Watermelon

Watermelon, Citrullus lanatus (Thunb.) Matsum & Nakai cv. Sugar Baby, were grown in the field as a fall crop in open-top chambers (OTC) in southwestern Indiana with either charcoal-filtered (CF) or nonfiltered (NF) air. Ozone and sulfur dioxide were continuously monitored in OTC and ambient air. There was a significant decrease in marketable yield by weight (19.9%, P = 0.05), percentage of marketable fruit by number (20.8%, P = 0.10), and total yield by weight (21.5%, P = 0.05) from plants grown in the NF air treatment compared with those grown in CF air. Ozone-induced foliar injury was significantly greater on plants grown under NF conditions. Ambient concentrations of 03 in southwestern Indiana caused foliar injury (P = 0.10) and significant yield loss to a fall crop of watermelons.

Deficit irrigation effects on head cabbage production

Yield response of head cabbage ( Brassica oleracea capitata) to 10 different trickle irrigation rates was determined in 1983–1987 at Kula, Hawaii. Treatments were arranged in a gradient irrigation design replicated three times, and were irrigated daily with amounts ranging from 0.42 to 1.94 mm. Yield response from a 0 treatment, equal to rainfall, was also measured. Plant density was 17 424 plants/ha from 1983 until the summer 1985 when planting density was decreased to 8712 plants/ha. Marketable yield increased linearly with increased water application up to 49.3 Mg/ha, with an associated irrigation plus rainfall application of 196 mm. The relationship between relative yield (yield divided by maximum yield) and relative evapotranspiration (evapotranspiration divided by maximum evapotranspiration) was linear, with a response coefficient of 0.95. Maximum yield for each experiment was linearly related to the cumulative growing degree days up to final harvest. Marketable percentage of total potential production decreased linearly with a decrease in marketable yield. Marketable yield was linearly related to head weight, but a different linear relationship was derived for the two planting densities.

Effects of limited irrigation on lettuce and chinese cabbage yields

Yield response of lettuce (Lactuca sativa L.) and Chinese cabbage (Brassica campestris L. Group pekinensis) to eight different drip irrigation rates was determined in 1980–1984 at Lalamilo, Hawaii. Treatments were arranged in a gradient irrigation design replicated three times and were irrigated daily with amounts ranging from 0.76 mm to 6.09 mm. Yield response from a 0 treatment, equal to rainfall, was also measured. Marketable yield increased linearly with increased water application up to 49.7 Mg/ha for lettuce and 73.1 Mg/ha for Chinese cabbage with an associated seasonal evapotranspiration of 205 mm and 209 mm for lettuce and Chinese cabbage, respectively. The relationship between deficit relative yield (yield divided by maximum yield) and deficit relative evapotranspiration (evapotranspiration divided by maximum evapotranspiration) was linear with a deficit response coefficient of 1.07 for lettuce and 1.35 for Chinese cabbage. Marketable percentage of total potential biomass production decreased linearly with a decrease in marketable yield. Lettuce head size also decreased linearly with a decrease in marketable yield. Water use efficiency (yield divided by water applied) was 24 and 36 kg/m3 of water for lettuce and Chinese cabbage, respectively.

Influence of Developmental Stage on Susceptibility of Tomato Fruit toPseudomonas syringaepv.tomato

Getz, S., Stephens, C. T., and Fulbright, D. W. 1983. Influence of developmental stage on susceptibility of tomato fruit to Pseudomonas syringae pv. tomato. Phytopathology 73:36-38. Tomato flower buds, flowers, and fruit were inoculated with fruit decreased as diameter at the time of inoculation increased. Lesions did Pseudomonas syringae pv. tomato (= P. tomato) at various developmental not develop on inoculated pink or red fruit. In field studies, lesions did not stages in greenhouse and field studies. In greenhouse studies, inoculation at develop on fruit inoculated when >3 cm in diameter. These results indicate the open corolla stage resulted in a significant decrease in marketable yield that uninjured tomato fruit are most susceptible to infection by P. syringae compared to the uninoculated control. Lesions did not develop on fruit pv. tomato in the period following anthesis and before the fruit reach 3 cm when flower buds were inoculated prior 'to anthesis. Susceptibility of green in diameter.