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PERFORMANCE OF TOMATO HYBRIDS UNDER HYDROPONIC CULTURE
Abstract
An experiment was conducted for the hydroponic culturing of three tomato hybrid genotypes under the green house conditions at in vitro Preservation Laboratory of Plant Genetics Resources Institute (PGRI), National Agriculture Research Centre (NARC), Islamabad. The experiment was laid out in two factor randomized complete block design (RBCD). Three tomato hybrids were assigned as Factor A, whereas, two nutrient solutions were assigned as Factor B. The differences between the nutrient solutions in channel-1 and channel-2 was the additional supplementation of MgSO(4 center dot)7H(2)O at the initial stage and K(2)HPO(4) at the final phase in channel-2. Parameters included in this study were: plant height (cm), number of nodes per plant, number of fruits per plant, fruit yield per plant (g), fresh and dried shoot weight (g) and fresh and dried root weight (g). Amongst the hybrids, Gala and Roma produced statistically alike results for plant height (72.8 and 69.6 cm), number of nodes per plant (17.60 and 17.00), number of fruits per plant (28.8 and 34.4), fresh shoot weight (216.0 and 219.6 g) and dried shoot mass (61.52 and 63.13 g) respectively. However, hybrid Roma excelled all the hybrid genotypes for fruit yield per plant (451.3 g), fresh root mass (142.7 g) and dried root mass (16.65 g). For the nutrient solutions, the result indicated that nutrient solution in channel-2 excelled the channel-1 in almost all the parameter studied. Keywords: Tomato, Lycopersicon esculentum, hydroponics, plant height, fruit yield, shoot and root weight
... Significant mean square (Table 2) emphases considerable scope of improvements in tested traits moreover the C.V being in proper limits validate the data set as described earlier elsewhere (Fozia et al., 2010;Jilani et al., 2013). Higher PCOV value in comparison to GCOV showed the sensitivity of the material to the environment this might be due to genetically diverse material in our investigation. ...
... Negative but non-significant correlation of both rg and rp were with lycopene and vitamin c contents with yield per plant, however rg correlation coefficient was negative and non-significant while rp coefficient of correlation was positive for total carotenoids with yield per plant. These findings were validated by the earlier findings of Fozia et al. (2010) and Jilani et al., (2013) Independent characters viz via number of flowers per cluster, fruit width, fruit length, plant height, fruit firmness and total Carotenoids had direct positive effect on the yield per plant. A number of workers pointed out the greater role for the improvement in dependent factor yield maintaining the adequate amount of fruit quality (Hannan et al., 2007;Al-Aysh et al., 2012). ...
... Appropriate growth media is the best way for plant survival. Several soilless substrates are being utilized to grow seedlings, propagate plants, and generate ornamental plants (Ahmad, 1989 andFozia et al., 2010). Growth media should be able to provide great water retention capacity, adequate drainage, and sufficient cation exchange capacity (Hamidpour et al., 2013). ...
The objective of the current study to evaluate rooting media, growth biostimulants and their interactions on rooting, vegetative growth and chemical constituents of rose cuttings. This investigation was laid out in a factorial experiment, the main factor (rooting media) consists of three treatments sand, palm peat and sand + palm peat (1:1 v:v), while the secondary factor consists of seven treatments control (tap water), Aloe vera gel extract (AVE) at 2 and 4%, moringa leaf extract (MLE) at 2 and 4% and seaweed extract (SWE) at 2 and 4%, as soaking-cuttings treatments. The obtained data showed that rooting media of sand + palm peat (1:1 v:v) caused a significant increase in all traits of rose, which includes rooting percentage, root length, root number, root fresh weight and root dry weight, plant height, branch number, stem diameter, leaf number, shoot fresh weight and shoot dry weight, total chlorophyll content and total carbohydrates %. As for soaking-cuttings treatments with growth biostimulants found that most concentrations significantly increased these traits under study, as compared to control. Clearly, the highest values were obtained by soaking rose cuttings in moringa leaf extract (MLE) at 4% over control. Regarding to the combined between two examined factors, the best results in rooting and growth rose cuttings were obtained using the mixture of rooting media sand + palm peat (1:1 v:v) with moringa leaf extract at 4% or moringa leaf extract at 2%, in most cases, during the two experimental seasons.
... Appropriate growth media is the best way for plant survival. Several soilless substrates are being utilized to grow seedlings, propagate plants, and generate ornamental plants (Ahmad, 1989 andFozia et al., 2010). Growth media should be able to provide great water retention capacity, adequate drainage, and sufficient cation exchange capacity (Hamidpour et al., 2013). ...
... Presently, several soilless substrates are used to grow seedling, to propagate the plants, and to produce ornamental plants [2,3]. The elements of the soilless compounds should bear stable physical and chemical features during the plants' cultivation [4]. ...
The studied substrates included soil, soil + leaf mold, soil + cocopeat, soil + perlite, and soil + vermicompost arranged in a Randomized Complete Block Design with three replications. The results showed that the highest germination speed (18) was related to soil and that the highest flower fresh weight (9.25) and flower diameter (52.3) were related to soil + perlite. Substrates did not impact floret number, root length, and flowering time significantly. The highest flower longevity (7 days) was observed in soil + leaf mold. Results of analysis of variance did not display the significant influence on stem length, root length, floret number, leaf number and chlorophyll and flowering time. The results showed that the addition of materials such as vermicompost to soil could improve the important traits of Narcissus flower, including flower life, germination rate and stem diameter, thus reducing the use of chemicals.
... Tomato (Solanum lycopersicum), an important summer vegetable crop is considered as the pillar of kitchen gardening and is always the companion of salads, various foodstuff compositions and sauces (Noureen et al., 2010). Although the area under tomato cultivation has been increased from 29 to 52 thousand hectare, yet the average yield has been stagnated within the tune of 9.6 to 10.7 tonne hectare -1 during the last decade. ...
... Soilless substrates are used in horticulture for growing seedlings, plant propagation and ornamental plant production (Noureen et al., 2010;Ahmad et al., 2012). Annual ornamental plants require growing media with adequate water retention and aeration (Erstad & Gislerǿd, 1994) and a fertilizer formulation that ensures a continuous nutrient supply (Macz et al., 2001). ...
An experiment was conducted to evaluate the growth and flowering of gerbera grown in various horticultural substrates combined with conventional media (composed of garden soil, silt and sand in equal proportions) which is commonly used for its commercial production in the country. Two horticultural by-products viz. coconut coir and spent mushroom compost were tested for their suitability to be used as growing media for cut flower production. No major differences in yield were observed between conventional media and both horticultural by-products; however, flower quality was improved when both of the substrates were used in combination with conventional media. Growing substrate choice also influenced flower stalk length and diameter which revealed positive correlation of these substrates with various attributes of flower quality but not flower yield. Moreover, incorporation of coconut coir and mushroom compost lowered pH and increased available organic matter and electrical conductivity of conventional media which improved nutrient uptake by the plants.
... Tomato (Solanum lycopersicum), an important summer vegetable crop is considered as the pillar of kitchen gardening and is always the companion of salads, various foodstuff compositions and sauces (Noureen et al., 2010). Although the area under tomato cultivation has been increased from 29 to 52 thousand hectare, yet the average yield has been stagnated within the tune of 9.6 to 10.7 tonne hectare -1 during the last decade. ...
Blight diseases are one of the serious causes of low tomato productively in Pakistan. Two susceptible but high yielding lines Riogrande and Roma were crossed with LB2, LB3, LB4 and LB7 following line x tester mating design to generate 8 F1 hybrids. All genotypes were evaluated to find high yielding and disease resistant combiners and their hybrids against check hybrid T-1359. Whole plant assay elucidated LB2, Roma x LB3 and Roma x LB4 tolerant to late blight. The same assay also expounded LB3, LB4, LB2, LB7 and Riogrande x LB2 tolerant to early blight. Non-additive gene action was observed to control each blight type, fruit length, fruit weight and 1000-seed weight except number of fruits per plant and fruit diameter. Female x male interaction affixed highest place to line x tester interaction by 48% for late blight and 84% for early blight.
Riogrande, LB2 and LB7 were good general combiner for tolerance to early blight while Roma and LB3 for late blight. The perusal of high mean performance, specific combining ability effects and commercial heterosis simultaneously led to the isolation of two promising hybrids Roma x LB3, Roma x LB4 for late blight and Riogrande x LB2 for early blight. These three hybrids have been submitted in competitive multi-location field trails to adjudge their yield performance and blight response before commercialization.
... Tomato (Lycopersicon esculentum Mill) is an important vegetable of exceptionally high nutritive value and versatile food use (Afroz et al., 2009;Saleem et al., 2009;Noureen et al., 2010). Late blight, caused by the oomycete pathogen Phytophthora infestans (Mont.) ...
The reaction of 82 tomato genotypes belonging to 8 Solanum and a Lycopersicon species against Phytophthora infestans causing late blight was determined using detached-leaf and whole-plant assays. None of the test genotypes was immune or highly resistant. Of the 82 commercial and wild genotypes only TMS-2 (male-sterile and characterized by indeterminate growth) belonging to Lycopersicon esculentum was resistant with severity index of 2.4 in the detached-leaf assay on 0-5 scale (where 5 was highly susceptible) and percent disease index (%DI) of 23.3% under the whole-plant assay. Among the remaining genotypes, 41 were susceptible and 40 were highly susceptible under the detached-leaf assay, while 18 were susceptible and 63 were highly susceptible under the whole-plant assay. However, there was a significant difference in %DI for genotypes under the whole-plant assay. The response of whole-plants to inoculation with P. infestans in the detached-leaf assay was similar in all cases. The overall screening results indicate that TMS-2 is a good source of resistance and it can be useful for the development of tomato hybrid cultivars resistant to late blight.
... Analysis of variance revealed highly significant mean squares for all traits ( Table 2) that show the existence of genetic variability among the genotypes as reported elsewhere (Noureen et al., 2010;Jilani et al., 2013). Coefficient of variation (C.V) was less than 20% for each trait indicating the precision in the data recorded (Table 2). ...
Twenty-five F1 hybrids generated from 5×5 diallel crosses were evaluated to study the quantitative genetics of yield and some yield related traits during 2009-10. Worth of room was realized for improvement due to highly significant genetic variations among all traits studied. The highest estimates of genotypic and phenotypic coefficients of variability were recorded for number of fruits per plant while fruit width was the most heritable trait. Plant height, number of fruits per plant and fruit weight revealed significant positive genotypic and phenotypic association along with direct positive effect on fruit yield per plant. It is therefore, recommended that fruit weight, number of fruits per plant and plant height should be given due importance in selection of promising crosses to develop commercial hybrid variety in tomato.
... Analysis of variance revealed highly significant mean squares for all traits ( Table 2) that show the existence of genetic variability among the genotypes as reported elsewhere (Noureen et al., 2010;Jilani et al., 2013). Coefficient of variation (C.V) was less than 20% for each trait indicating the precision in the data recorded (Table 2). ...
Twenty-five F1 hybrids generated from 5×5 diallel crosses were evaluated to study the quantitative genetics of yield and some yield related traits during 2009-10. Worth of room was realized for improvement due to highly significant genetic variations among all traits studied. The highest estimates of genotypic and phenotypic coefficients of variability were recorded for number of fruits per plant while fruit width was the most heritable trait. Plant height, number of fruits per plant and fruit weight revealed significant positive genotypic and phenotypic association along with direct positive effect on fruit yield per plant. It is therefore, recommended that fruit weight, number of fruits per plant and plant height should be given due importance in selection of promising crosses to develop commercial hybrid variety in tomato.
Tomato cultivation in Northeast India faces a formidable challenge from late blight, caused by Phytophthora infestans (Mont.) de Bary. Field experiments conducted during 2021–2023 have shed light on effective management strategies. Among these, copper oxychloride at 0.25% emerged as the most effective treatment, closely followed by copper hydroxide at 0.25%. An optimized spray schedule revealed that six canopy sprays of copper oxychloride at 6-day intervals, in conjunction with black polythene soil mulching, achieved the highest disease control at 92.04%. Five sprays offered 89.77% control, while four sprays provided 81.82% control. The pooled mean yield for copper oxychloride-treated tomatoes was a remarkable 9.25 t/ha, surpassing that of copper hydroxide treatments. Furthermore, an evaluation of eight germplasms under natural epiphytotic conditions identified Arka Abhed F1 as resistant to late blight. Consequently, for effective management of late blight in high rainfall areas, it is recommended to cultivate Arka Abhed F1 or implement six canopy sprays of copper oxychloride with soil mulching for susceptible varieties/hybrids. These findings offer a sustainable and potent strategy for combating late blight, ensuring healthier yields for tomato growers in the region.
This article presents the effects of nitrate/ammonium ( NO(3)(-)/NH(4)(+)), applied at different proportions to the root media with or without 5 mmol bicarbonate ( HCO(3)(-)), on the yield and chemical composition of tomato fruit. Tomato plants were grown hydroponically ( pH 6.9) in glasshouse conditions. The yield of fruit fresh matter from four clusters obtained from plants grown on the medium with NH(4)(+) was about 25% lower than from the plants grown on the medium containing NO(3)(-) as the nitrogen ( N) source. Supplying NO(3)(-)/NH(4)(+) at a ratio of 4: 1 increased the fruit yield by about 20% in comparison with the value recorded for NO(3)(-)-plants. The enrichment of the medium with HCO(3)(-) stimulated the bearing, while the result depended on the ratio of NO(3)(-)/NH(4)(+). A combined treatment of HCO(3)(-) with NO(3)(-) or NH(4)(+) in the medium increased yields by about 28% and 11%, respectively, in comparison to plants cultivated without HCO(3)(-). The application of NO(3)(-)/NH(4)(+) at ratios of 4: 1 and 1: 1 with HCO(3)(-) increased the respective yields by about 16% and 10% in comparison with plants grown without HCO(3)(-). Modifications in the composition of the media affected the accumulation of organic solutions in the fruit. The NH(4)(+) nutrition effected a 20% decrease in the accumulation of reducing sugars in the fruit in comparison to the fruit of plants grown in media with NO(3)(-). In the cultivation of plants in media with various NO(3)(-)/NH(4)(+) proportions the intermediate values of the reduced sugar concentrations were recorded in comparison with the values obtained for NO(3)(-)-plants and NH(4)(+)-plants. The enrichment of media with HCO(3)(-) increased the concentration of sugars in fruit from about 28% ( for NO(3)(-)-plants) to about 10% ( for NH(4)(+)-plants).
A short term experiment with tomato (Lycopersicon esculentum) cvs. Blizzard, Liberto, and Calypso was carried out in a controlled temperature room to investigate the effectiveness of phosphorus (P) and iron (Fe) supplemented in nutrient solution on plant growth at high zinc (Zn) (77.0 μmol L). Zinc concentrations in complete nutrient solution were either 7.7 or 77.0 μmol L. One week after application of high Zn, supplementary P and Fe at 1 and 0.05 mmol Lrespectively were added into nutrient solution for three weeks. There were significant reductions in both dry weights and chlorophyll contents in the plants grown at high (77.0 μmol L) Zn compared with those in the control treatment for all three cultivars. Application of supplementary P and Fe resulted in marked increases in both dry weight and chlorophyll concentrations for all three cultivars achieving values not significantly different to the control. Zinc concentration in plant tissues increased to toxic levels for all three cultivars in the high Zn treatment. Application of supplementary P and Fe decreased Zn concentration in the leaves and roots of plants grown at high Zn, but Zn concentrations were still at toxic levels. Phosphorus and Fe concentration in leaves declined to a deficient level in the high Zn treatment, but was markedly increased in the roots. Application of supplementary P and Fe corrected both P and Fe deficiencies in leaves of plants grown at high Zn and reduced root P and Fe concentrations.
The effect of different calcium (Ca) doses in the nutrient solution used to cultivate tomato plants on the nutrient and carotene levels of tomato (Lycopersicon esculentum Mill. Cv. Jumbo) fruit was studied. The experiment was conducted in a greenhouse hydroponically using a modified Hoagland solution containing different Ca concentrations (0.2, 2.5, 5.0, 10.0, 15.0, and 20.0 mmol L). The experiment was conducted in a fully randomized design with three replications. The fruits of the second and third clusters were picked after full ripening and analyzed for their Ca, magnesium (Mg), potassium (K), lycopene, and total carotene levels. Calcium levels in the fruit increased with increasing Ca concentrations in the nutrient solution, reaching a maximum value of 0.17 dag kg at a Ca nutrient solution concentration of 19.79 mmol L. In the 0.2 mmol Ca L treatment, the plants died without reaching fructification. The fruits of the plants treated with 2.5 mmol L Ca showed blossom‐end rot although this symptom did not occur in the first or second cluster. At this Ca dose, the seeds were small, malformed, and black in color. Magnesium and K levels, however, decreased with increasing Ca concentrations in the nutrient solution, demonstrating the competitive effect of this ion for the sites of absorption and transport in the plant. The total lycopene and carotene levels decreased with increasing Ca concentration in the nutrient solution, possibly due to the reduction in K absorption with minimum levels of 21.50 μg g at the Ca concentration of 13.66 mmol L in the nutrient solution.
Salinity tolerance in some plant species has been related to characteristics of potassium (K) and sodium (Na) uptake and transport. Tomato (Lycopersicon esculentum Mill., cv. Rossel) plants were grown in nutrient solution to determine effects of two K levels [0.2 (low) and 2 mmol (high)] combined with 0, 100, and 200 mmol NaCl on growth, and on Na and K uptake and translocation. Net uptake rates of Na and K were determined by disappearance in the growth medium and by plant accumulation. At the low level of K in solution, salinity decreased shoot and root dry weight and leaf area. Addition of 2 mmol K ameliorated of the added NaCl effects and improved growth parameters. Salinity reduced net K uptake rates and to a lesser extent K translocation from root to shoot, which resulted in higher K shoot concentration and a lower K root concentration. The inhibitory effect of salinity on K translocation was greater with low K level in nutrient solution. Net uptake of K was dependent on K level in the growth medium. Addition of K resulted in decreases of shoot Na uptake. The translocation of Na from roots to shoots was reduced by K level in nutrient solution. These results indicate that K supply and K accumulation and regulation in plant tissue contribute to salt tolerance and growth enhancement.
An experiment was carried out to investigate the role of zinc (Zn) in physiological and nutritional development of the tomato (Lycopersicon esculentum Mill.) cultivar Moneymaker grown hydroponically in a controlled temperature room. The experiment was a 2 × 3 factorial arrangement with two levels of nutrient solution Zn concentrations, 0.01 or 0.10 mg L, and three levels of foliar applied Zn, 0, 23, or 230 mg L. Low (0.01 mg L) nutrient solution Zn seems to be inadequate for optimum plant growth; in this treatment plants showed Zn deficiency symptoms. Foliar application of Zn at 23 mg L alleviated Zn deficiency by enhancing Zn concentration in the leaves, dry weight, and chlorophyll content. However, foliar application of Zn at 230 mg L Zn caused adverse effects on both dry weight and chlorophyll content. Phosphorus (P) reached a detrimental level in the leaves of plants grown at 0.01 mg L Zn in nutrient solution, but 23 mg L Zn applied via the leaves reduced P concentrations from toxic to adequate levels. Concentration of iron (Fe) was also higher but not detrimental in the leaves of plants grown at 0.01 mg L Zn. Foliar application of both concentrations of Zn slightly reduced Fe concentration in the leaves. Membrane permeability was impaired both in the plants grown at low Zn and in those receiving the high (230 mg L) foliar application. Foliar Zn at 23 mg L maintained membrane permeability by decreasing electrolyte leakage from leaves of Zn-deficient plants. Low (0.01 mg L) Zn in the nutrient solution resulted in plants with very leaky root systems as measured by high potassium (K) efflux; this leakiness was ameliorated by foliar application of Zn at 23 mg L. Cumulative potassium release from intact roots was higher in both the Zn-deficient plants (0.01 mg L) and those receiving high (230 mg L) foliar Zn. These data show that Zn nutritional status affects root membrane integrity.
A glasshouse pot experiment, with three tomato cultivars (CVs), Blizzard, Calypso, and Liberto, was carried out to investigate the effects of three levels of Zn (0.01, 0.5, and 30 mg L−1), supplied in nutrient solution, on plant growth, fruit yield, and nutrient composition. Maximum plant growth and fruit yield in all three cultivars were in the 0.5 mg L−1 treatments. Plants treated with Zn at 30 mg L−1 had lower total dry matter content at fruit set as compared with the 0.5 mg L−1 treatment (reduced by 34% in Calypso, 30% in Blizzard, and 21% in Liberto). The percent reduction was similar at the low-Zn treatment (27, 27, and 29%, respectively), and plants exhibited Zn deficiency symptoms. Fruit yield was significantly reduced under both conditions of Zn stress, but only in Calypso was the yield significantly lower at the high rather than at the low-Zn treatment. Zinc concentrations in all plant parts (in particular in roots) increased with increasing Zn concentration in nutrient solution. Concentrations of phosphorus (P), magnesium (Mg), potassium (K), and iron (Fe) in the leaves and fruit of plants grown at 30 mg L−1 Zn were significantly lower than the 0.5 mg L−1 treatment and, with the exception of P in the leaves, lower than in the 0.01 mg L−1 treatment. Zinc stress appears to affect the distribution of macro- and micronutrients in tomato plants with corresponding adverse effects on growth and yield. In this experiment there were no consistent cultivar differences at these zinc concentrations.
Farmers are interested in hydroponic tomato cultivation because of the high demand of high quality products by the consumers. Three trials here carried out under greenhouse conditions in Marília, SP, Brazil, using the hydroponic nutrient film technique, in order to evaluate yield and quality of long-life salad tomato (Lycopersicon esculentum) varieties, during 1998 and 1999. Four varieties (Carmen, Diva, Graziela, and Vita) were tested using a randomized block design, with six replications. The variety x crop season interaction effect was significant, meaning that varieties have distinct performances during the different cropping seasons. The Vita variety presented commercial valid yield, with mean fruit weights higher than the other varieties.
Critical concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), and manganese (Mn) with respect to dry matter yield end antagonistic and synergistic relationships among these nutrients were studied in which tomato (Lycopersicon esculentum L.) was grown in recirculating nutrient solution (NFT). Increments of nutrient elements in the nutrient solution increased the proportional rate of the corresponding nutrient elements. Increasing levels of N negatively correlated with plant P and positively correlated with Ca, Fe, and Zn. Iron and Mn contents of the plants were increased and N, K, Ca, and Mg were decreased as a function of P applied. Increases in K in the nutrient solution caused increases in the concentrations of K, N, P, and Zn, and decreases in the concentration of Ca and Fe. Applied Ca increased the concentrations of Ca and N, and decreased the concentrations of P, Mg, Fe, Zn, and Mn. Potassium, Ca, and Fe contents of the plants were decreased and Zn increased, while N, P, and Mn were not affected by the increasing levels of external Mg. Iron suppressed the plant Mg, Zn, and Mn contents. Synergism between Zn and Fe was seen, while P, K, Ca, Mg, and Mn contents were not affected by Zn levels. Potassium, Ca, Mg, and Fe were not responsive to applied Mn, however, N and P contents of the plants were decreased at the highest levels of Mn.
Tomato plants (Lycopersicon esculentum, Mill) were grown in nutrient solution to observe the combined effect of three NaCl levels (1,20, and 60 mM) and four magnesium (Mg) levels (0.5,1.0,5.0, and 10.0 mM) on fruit yield, water relations and mineral composition. Salinity at 20 and 60 mM NaCl reduced the marketable fruit yield compared to 1 mM NaCl. In non‐saline conditions (1 mM NaCl), Mg concentrations of 1 mM or greater progressively reduced fruit yield, whereas in saline solutions (20 and 60 mM NaCl) fruit yield was depressed by Mg concentrations of 5 and 10 mM. The marketable fruit yield reduction was well correlated with salinity and Mg concentrations in the external medium (R=0.83). This harmful effect was related to the influence which NaCl and Mg had on plant water relationships and toxicity and/or imbalances in the mineral nutrition. In the conditions of this experiment, all components of the leaf water status were significantly altered and it was clear that calcium (Ca)‐Mg and potassium (K)‐sodium (Na) interactions took place. Therefore, the concentrations of Mg in the nutrient solution could be an important factor in the hydroponic culture of tomato grown under saline conditions.
Tomato plants (Lycopersicon esculentum Mill. cv. Momotaro) were cultured in nutrient solution supplying 35 meq or 50 meq of nitrate (NO3) per plant weekly from the flowering stage of the first truss in two cropping seasons. The effects of NO3 supply levels and cropping season on fruit growth of tomato were investigated. Furthermore, the relationship between the results of the plant sap analysis and fruit growth of tomato was analyzed. In the spring to summer cropping, NO3 supplied was almost all absorbed and high productivity of tomato fruits was obtained in each treatment. In the fall to winter cropping, however, high NO3 supply did not increase the uptake of NO3, but tended to decrease the rate of fruit set and marketable yield. Accumulation of NO3 in the petiole sap was found with high NO3 supply in the fall to winter cropping. Cropping season greatly influenced not only fruit growth but also the concentration of NO3 in the petiole sap in relation to the ability of tomato plants to use available nitrogen (N). Furthermore, reduction in the rate of fruit set and weight of tomato fruit were found to relate to the low concentration of NO3 in the petiole sap of the leaf just below this fruit truss. High NO3 supply tended to increase potassium (K) concentration and electrical conductivity (EC) value, and to decrease phosphate (P), calcium (Ca), and magnesium (Mg) concentrations in the petiole sap. On the whole, concentrations of these elements in the petiole sap consistently reflected their uptake rates in two cropping seasons.
Eggplant (Solanum melongena L.) grown under winter conditions in unheated polyethylene covered greenhouse displays unmarketable red color fruit skin. The purpose of this work was to study the effect of potassium (K), phosphate and total salinity levels in the irrigation solution on the quality of eggplant fruit grown at winter and spring seasons. Eggplant was grown in containers filled with basalt erupted tuff scoria. The fertigation solutions were composed of three levels of P: 18, 36, and 54 g P m, using mono K phosphate (MKP). Each level of P was applied on two levels of total K concentrations, 475 and 920 g K m composed of K nitrate, MKP, and K chloride (KCl). The KNO3 fertilizer was used in all treatments at 150 g N m. Increasing the KCl concentration increased the average electrical conductivity (EC) in the irrigation solution from 2.3 to 3.9 dS m, reduced class A fruit number and weight, but had no effect on the skin color. During the cold winter period the intensity of the skin color was weaker than in the normal hot growing period. Increasing the average phosphorus (P) concentration in the irrigation solution throughout the growing season from 36 to 54 g m increased the number of fruit per plant, the number of class A fruits but has no significant effect on total fruit yield. Increasing the total electrical conductivity of the nutrient solutions by K fertilizers above 3.8 dS m decreased fruit yield and total dry matter in the spring growth period.
A 3-year field study, on Pellic Vertisol, investigated the response of trickle-irrigated potato (Solanum tuberosum L.) to four P levels applied with the irrigation water. Waters supplied with 130 and 120 mg l–1 of N and K, respectively, and with P levels of 0, 20, 40 and 60 mg l–1, were applied when the soil water potential was between 0.03 and 0.04 MPa. The water applied at each irrigation was equivalent to 0.8 of pan evaporation from a screened USWB Class A pan. With the application of 40 mg P l–1 no P accumulation deeper in the soil profile occurred, whereas P in petioles was at levels recommended for high yield of good quality. At this P concentration in irrigation water, removal of P from soil by tubers was 22 kg/ha/year. The highest yield of good quality was obtained at 40 mg P l–1.
Potato, wheat and sugar beet were grown in a growth chamber in tanks with flowing solutions containing K-concentrations of
1.5, 5, 15, 50 and 200 μM to find reasons for different K contents of solution needed to reach 90% maximum dry matter accumulation
(external K requirement). All species showed variation in dry matter accumulation with varying K levels. To reach 90% maximum
dry matter accumulation potato needed 40 μM K, whereas wheat and sugar beet needed 6.4 and 4.4 μM K respectively. These differences
in external K requirement could not be explained by differences in their internal K requirement since the internal requirement
of potato (7.7% K) was about one and a half times of that of sugar beet (5.4%) but its external requirement was nine times
of that of sugar beet. At low K supply potato plants showed a lower influx and a reduced root growth as compared with wheat
and sugar beet.