Occurrence Of Blossom-end Rot Research Articles

Influence of Calcium, Potassium and Watering Regimes on Blossom End Rot in Two Varieties of Tomato (Solanum lycopersicum) in Mandera County, Kenya

Blossom end rot (BER) is one of the physiological disorders of economic importance in tomato farming since it significantly reduces yield and thus affects profit margins. Most tomato disorders are due to mineral deficiencies and unbalanced nutrition. Improving the supply of specific nutrients and uniform soil moisture can reduce their occurrences. This study was conducted to evaluate the influence of watering regimes, Calcium (Ca) and Potassium (K) on blossom end rot occurrence in two tomato varieties in Maslah and Guul sites. The trials were laid out in a randomized complete block design (RCBD) in split-split plot arrangement with watering regimes (daily, thrice and twice a week) as main plots, tomato varieties (Riograde and Rionex) as sub plots, and 3 levels of Ca and K (0 Kg/ha, 25 Kg/ha, 50 kg/ha) as the sub-sub plots and replicated three times. Calcium treatments had the lowest score of blossom end rot compared to control. In Guul, the highest BER score (2.83) was observed under the control treatment while the lowest score (1.06) was recorded on the 50 kg/ha, Ca rate. Similar results were observed in Maslah with the control having the highest score of BER (3.22) while Ca 50 kg/ha scored lowest (1.11). No statistical differences were observed in the K treatments in the two study sites, however it was notable that lower rates of K reduced the blossom end rot incidences. Water stress led to increase in severity of the BER in the two study sites. In Guul, the highest score was in minimal watering regime (twice a week) of 2.36 score and lowest was at optimal watering regime (daily) of 1.08 score whereas in Maslah the highest blossom end rot score was in minimal watering regime (twice a week) of 3.19 and the lowest score of 1.19 on medium watering regime (Thrice a week).Therefore, optimal application of Ca, K, at 50 kg/ha with adequate and uniform soil moisture can improve management of blossom end rot in tomatoes thus raising farmer’s returns.

Amplification of gibberellins response in tomato modulates calcium metabolism and blossom end rot occurrence

Blossom end rot is one of the main physiological disorders of the tomato crop. Usually, the blossom end rot (BER) occurrence is associated with fruit calcium (Ca2+) deficiency; however, increasing evidence of Ca2+ disorders and hormonal regulation has emerged. Therefore, the present work was undertaken to investigate the role of gibberellin (GA) signaling on the control of tomato plant responses to Ca2+ deficiency. In this study, we used the tomato mutant procera (pro), which has a constitutive response to GA, and its isogenic line cv. Micro-Tom (MT) grown in a hydroponic system with or without Ca2+. Subsequently, the analysis of the growth of the shoot and the root system was performed, and the contents of photosynthetic pigments and oxidative stress were also analyzed. Furthermore, the fruit production, BER incidence, accumulation and metabolism of Ca2+ were also analyzed. The deficiency of Ca2+ reduced both shoot and root growth in both genotypes. Likewise, photosynthetic pigment degradation and oxidative stress were induced by Ca2+ deficiency. However, only pro plants exhibited the inhibition of fruit dry mass, as well as a higher incidence of BER, when exposed to Ca2+ deficiency compared to MT plants. In accordance with the greater pro susceptibility to Ca2+ deficiency, the efficiency of the transport, use and accumulation of Ca2+ in fruits was lower in pro when compared to the MT. Thus, we conclude that the higher sensitivity to GA in pro plants impairs Ca2+ metabolism and favors the occurrence of BER in tomato fruits, opening new approaches for the GA signaling on BER response.

Optimization of calcium and magnesium concentrations for fertigation of tomato with desalinated water

Desalinated water has become a legitimate alternative water resource for the irrigation of intensive crops in semiarid regions. The concentrations of calcium (Ca) and magnesium (Mg) in water (C Ca and C Mg , respectively) supplied from desalinated plants are much lower than the values typically found in irrigation water resources in semiarid regions. blossom-end rot (BER), a physiological disorder at the blossom-end part of the fruit resulting in tissue disintegration and dehydration, is considered a Ca-related disorder and therefore the optimization of C Ca has to consider not only total fruit production but also the occurrence of BER. There is a lack of information regarding the optimal C Ca and C Mg and Ca/Mg ratio in low-salinity water under Mediterranean conditions for high-quality yield of tomato fruits.The main objective of the research was to optimize C Ca and C Mg for the production of high tomato fruit yield with minimal occurrence of BER. A secondary objective was to determine critical levels of Ca, Mg and Ca/Mg ratio in leaves in relation to yield and the occurrence of BER.Tomato plants were grown in an inert media and fed with a wide range of C Ca and C Mg . Fruit yield was shown to decrease significantly when C Ca was at or below 0.40 mmol l –1 . In moderate C Mg (1.4 mmol l –1 ) treatment, BER was negatively correlated to Ca level up to and including 1.4 mmol l –1 and was not manifested above that level under the prevailing conditions. Elevating C Mg above 0.25 mmol l –1 enhanced BER occurrence. Concentrations of Ca and Mg in tomato organs increased with the respective mineral concentration in irrigation solution, whereas each element was reduced in organs as a function of the increased solution concentration of the other. The Ca concentration in diagnostic leaves (the diagnostic leaf is the fully developed youngest leaf) for optimal fruit yield with minimum BER was found to be 1.6%. The optimum C Ca for high fruit yield with minimal BER occurrence was found to be in the range of 1.5–2.5 mmol l –1 combined with C Mg at 0.25 mmol l –1 .

Comparison of Calcium Content between Blossom-End Rot and Healthy Fruits in Red Pepper (Capsicum annuum L.) Grown in Open Field

The causes of blossom-end rot (BER) are still not understood clearly, although there was a lot of research on the development of BER over 100 years. This experiment was conducted to investigate the influence of Ca content of fruit on the incidence of BER in red pepper. BER affected fruits and healthy fruits had been harvested and the samples were divided into two parts, the upper and the lower, for chemical analysis to determine the content of mineral nutrients in the tissue. The content of nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg) was higher in the BER affected fruits and the difference of each nutrient content was revealed much larger in the lower part of the fruit but there were no significant differences in calcium content between the BER and the healthy fruits of red pepper, in this experiment. The results indicate that it is difficult to find a certain relation between the calcium content of the fruit and the occurrence of blossom-end rot.

Changes in ascorbic acid concentration, ascorbate oxidase activity, and apoplastic pH in relation to fruit development in pepper (Capsicum annuum L.) and the occurrence of blossom-end rot

SummaryWe recently suggested that the occurrence of ascorbic acid (AsA) in the apoplast of bell pepper fruit may be part of the protection mechanism against blossom-end rot (BER). In the present study, we determined AsA concentrations, changes in pH, and the activities of ascorbate oxidase (AO) in the apoplast and symplast of pepper fruit, in relation to fruit development and the occurrence of BER. In healthy pepper fruit, the concentrations of AsA in the symplast and apoplast increased during fruit development, whereas the activity of AO decreased when measured at the pH typical of each developmental stage. The apoplastic pH decreased from 6.2 in young fruit to 4.8 in mature red fruit; while the symplastic pH did not change during fruit development. Following high-temperature treatment (35°C for 48 h in the dark), the concentration of apoplastic AsA, and the activity of galacturonic acid reductase (which participates in the AsA biosynthetic pathway), decreased, while there was an increase in apoplastic pH. The AsA content decreased in the apoplast of BER-affected fruit, and the pH was more alkaline (pH 6.9) than in healthy fruit (pH 6.0). In young fruit with BER, the apoplastic AO activity increased and the symplastic galacturonic acid reductase activity was inhibited. We suggest that a reduction in apoplastic AsA concentration, an increase in apoplastic AO activity, and changes in apoplastic pH in fruit prone to BER may be part of the mechanism which leads to the occurrence of BER symptoms. Whether or not there are causal relationships between these changes is not yet clear.

PHYSIOLOGICAL AND BIOCHEMICAL MECHANISMS LEADING TO BLOSSOM-END ROT IN GREENHOUSE-GROWN PEPPERS, IRRIGATED WITH SALINE SOLUTION

Blossom-end rot (BER) is a fruit physiological disorder that occurs under salinity stress and is known to be associated with impairment of calcium translocation to the fruit tip. In the present study we investigated the possibility that oxidative stress is part of the causative mechanism of BER in pepper (Capsicum annuum L.). Pepper plants of two cultivars ('Silica', not sensitive to BER and '107', sensitive) were grown in a greenhouse and irrigated with nutrient solution made up with either desalinated water (control – E.C 1.9), or saline water (salinity – E.C. 3.7-7.0). Irrigation was applied by a circulation system. BER symptoms were observed in '107' throughout the experiment while in 'Selica' the amount of BER was minimal. BER occurrence was significantly increased under salinity in the sensitive but not in the insensitive cultivar. The fruit calcium concentration in both sensitive and resistant cultivars was not changed by salinity. The oxidative stress-related enzymatic activities in the fruit were dependent on the fruit developmental stage. Under salinity, oxygen radical and hydrogen peroxide production, and NAD(P)H oxidase activity were all enhanced at the most sensitive developmental stage. In contrast, the anti-oxidative activities of superoxide dismutase (SOD) and catalase were not affected by salinity. The results suggest that generation and scavenging of oxygen free radicals may be part of the mechanism that leads to the appearance of BER symptoms in pepper fruits under saline conditions. We suggest that measures to alleviate oxidative stress in greenhouses would reduce the risks of blossom-end rot in peppers.

Metabolic fingerprinting of salt-stressed tomatoes

The aim of this study was to adopt the approach of metabolic fingerprinting through the use of Fourier transform infrared (FT-IR) spectroscopy and chemometrics to study the effect of salinity on tomato fruit. Two varieties of tomato were studied, Edkawy and Simge F1. Salinity treatment significantly reduced the relative growth rate of Simge F1 but had no significant effect on that of Edkawy. In both tomato varieties salt-treatment significantly reduced mean fruit fresh weight and size class but had no significant affect on total fruit number. Marketable yield was however reduced in both varieties due to the occurrence of blossom end rot in response to salinity. Whole fruit flesh extracts from control and salt-grown tomatoes were analysed using FT-IR spectroscopy. Each sample spectrum contained 882 variables, absorbance values at different wavenumbers, making visual analysis difficult and therefore machine learning methods were applied. The unsupervised clustering method, principal component analysis (PCA) showed no discrimination between the control and salt-treated fruit for either variety. The supervised method, discriminant function analysis (DFA) was able to classify control and salt-treated fruit in both varieties. Genetic algorithms (GA) were applied to identify discriminatory regions within the FT-IR spectra important for fruit classification. The GA models were able to classify control and salt-treated fruit with a typical error, when classifying the whole data set, of 9% in Edkawy and 5% in Simge F1. Key regions were identified within the spectra corresponding to nitrile containing compounds and amino radicals. The application of GA enabled the identification of functional groups of potential importance in relation to the response of tomato to salinity.

Effect of Excess Accumulation of Salts on Outbreak of Blossom-End Rot of Tomato and Population of Microorganisms in Soil Environment

The effect of successive fertilization of the excess farmyard manure on the tomato yield, the occurrence of blossom-end rot and change of meso-faunas and microorganisms population in soil were studied under greenhouse condition. The results obtained were as follows.The farmyard manure used in this study contained 2.8% nitrogen, 2.8% potassium and 2.4% calcium.The fruit yield obtained from the plot which was supplied 5 t/10 a farmyard manure was 1.2 t/10 a more than that from 50 t/10 a at the first cropping. But, the yield from heavily manured plot and that from light manured plot were reversed at 2nd cropping.In the 3rd cropping, the fruit yield reached the maximum during all croppings, even when blossom-end rot occurred. Outbreak and severity of blossom-end rot increased by fertilization of heavy manure and by accumulation of salts. Accordingly, in the 4th (1981) and the 5th (1982) croppings the fruit yields decreased markedly by blossom-end rot and Fusarium wilt.Blossom-end rot and disorders of tomatoes increased with a decreasing K/Ca ratio in the culture soil. The K/Ca ratios in the soils of 2nd and 3rd cropping which supplied 50 t/10 a farmyard manure were 0.25 and 0.2, respectively.It seems that the increase of blossomend rot was caused by the salts accumulation and ammonium production at early fruiting season.The populations of bacteria and fungi in the soils which supplied 50 and 5 t/10 a farmyard manure and was disinfected and not-disinfected varied with the growth of crops.The populations of Nematoda, Enchytraeidae and Acari increased remarkably from 1st to 2nd cropping, but decreased suddenly in 3rd one. It is not clear whether this sudden change was caused by a saltaccumulation or any other complex factors.

Nutrient Film Technique における培養液温がトマトの生育, 収量, 養分吸収に及ぼす影響

Using the recently developed Nutrient Film Technique, growth, fruit yield and nutrient absorption were studied with tomato plants grown at different solution temperatures.Within the range from 15°C to 30°C, higher solution temperatures encouraged nutrient absorption and growth rates of shoot and root. Although solution temperature had little influence on total fruit yield, the percentage of marketable fruits seemed to increase with decreasing solution temperature; 20°C solution producing the highest marketable fruit yield.The occurrence of blossom-end rot, found to increase with increasing solution temperature, could not be explained by calcium absorption or calcium content in the leaves.The ambient temperature in summer was found to have negligible influence on the temperature of solution circulating in the present system. Solution supply, at the rate of 2 litres per plant per hour, being carried out for 15 minutes per hour, was found to provide adequate nutrition and sufficient dissolved oxygen.

Macro-Element Nutrition of the Tomato Plant as Correlated with Fruitfulness and Occurrence of Blossom-End Rot

1. A population of 1044 plants of an inbred strain of Bonny Best tomatoes was grown in sand culture. The effects of eighty-seven different nutrient solutions varying in the relative proportions of macro-nutrient elements were studied in relation to fruitfulness and the occurrence of blossom-end rot. The data were reduced and analyzed by statistical methods. 2. In general, variations in amounts of calcium and nitrate in the nutrient medium resulted in greater differences in fruitfulness over wider ranges in concentrations than did the other elements. 3. Greatest fruitfulness occurred in treatments relatively high in nitrate and low in sulphate and phosphate in the anion triangle and in treatments relatively high in calcium and low in magnesium and potassium in cation triangle. 4. The percentage of diseased fruits on each plant increased with decreasing calcium concentrations in the nutrient medium. This correlation is largely independent of magnesium and potassium concentrations, and no correlation with any anion was observed. 5. Fruits produced in treatments where the rot was most severe were low in calcium content and high in potassium and magnesium content. 6. The occurrence of the rot was definitely associated with calcium nutrition.