The influence of early yield on the accumulation of major taste and health-related compounds in black and red currant cultivars (Ribes spp.)

The focus of our study was to investigate the effect of crop load on the accumulation and composition of primary metabolites (sugars and organic acids), selected groups of flavonoids (anthocyanins and flavonols), and total phenolics in two subsequent years in four black currant cultivars ('Titania', 'Triton', 'Tsema', and 'Cacanska crna') and three red currant cultivars ('Junifer', 'Rolan', and 'Stanza'). For the determination and quantification of compounds, high-performance liquid chromatography-photodiode array with a mass spectrometer was used. Significant differences among cultivars were detected in all analyzed compounds. Anthocyanins were the predominant phenolic group and were more abundant in black currant cultivars as compared to red ones. Similar amounts of sugars and organic acids were measured in both Ribes species; however, vitamin C was 3-fold higher in black currants. A larger crop load in the second year had a negative effect on the sugar content of berries and promoted a higher degree of acids, with the exception of vitamin C, which was higher in the year with a lower crop load. On the other hand, the content of anthocyanins and flavonols was higher in the year with a larger crop load, while there were no differences in total phenolic content.     

Intra and interlocus interactions between alcobaça (alc), crimson (og c ), and high pigment (hp) loci in tomato Lycopersicon esculentum Mill.

The ripening mutant allele alcobaça (alc/alc) may be deployed to extend shelf life in tomatoes, but has reportedly negative effects on fruit colour development. Colour enhancing mutants crimson (og ^c /og ^c) and high pigment (hp/hp) could potentially overcome this limitation, but a detailed account of their interactions with alc is not available. In this paper, we report on intra-allelic (additive and dominant) interactions within these 3 loci, and on their possible interallelic (epistatic) interactions. Eight near-isogenic (NIL) tomato lines in background Flora-Dade were obtained, representing all possible 2ⁿhomozygous combinations in the n = 3 loci. The 8 NIL were crossed in all possible combinations (reciprocals excluded), to obtain 28 hybrids that were heterozygous in at least one locus. The 36 treatments (= 8NIL + 28 hybrids) were grown in a randomized complete block design with 4replications, and the following traits were evaluated: total yield, average fruit mass, fruit firmness at harvest (= breakerstage) and 6 days after harvest (d.a.h)., % coloured fruit surface, fruit lycopene and beta-carotene contents, fruit % soluble solids and solids/acidity ratio, internal and external fruit colour. The loci alcobaça, crimson and high pigment or their epistatic interactions had significant influence on the expression of all traits measured. Epistatic effects were responsible for most of the variation among genotypes (with a minimum of 48.1%of the total sum of squares for % coloured fruit surface and a maximum of 82.8% for total yield). External fruit colour was defficient in all alc/alc genotypes, and their commercial use is impaired, in spite of improvements in fruit internal and external colour brought about by deployment of specific genotypic constitutions in lociog ^c and hp. Some but not all alc ⁺ /alc genotypes were firmer and showed improved fruit quality over the normal Flora-Dade (alc ⁺ /alc ⁺ og ^c+ /og ^c+ hp ⁺ /hp ⁺) background. The following genotypic combinations represented good compromises between yield, long shelf life and fruit quality traits: alc ⁺ /alc og ^c+ /og ^c hp ⁺ /hp, alc ⁺ /alc og ^c /og ^c hp ⁺ /hp ⁺ and alc ⁺/alc og ^c+/og ^c+ hp ⁺ /hp     

Contents Volume 127 2002

Volume Contents

Contents Volume 127 2002     

Diversity among melon landraces (Cucumis melo L.) from Greece and their genetic relationships with other melon germplasm of diverse origins

Diversity among 17 melon landraces and inbred lines of Group Cantalupensis, Inodorus, and Flexuosus germplasm from Greece was assessed using 24 RAPD primers, 11 morphological traits of fruit, two yield-related characteristics, and resistance to powdery mildew. Accessions were genetically diverse and the greatest variation was detected in Group Flexuosus. Comparative analysis of Greek germplasm and an array of previously characterized reference accessions [RA; 68 from Africa (15), United States (U.S.; 5), Central Europe (14), Japan (19), and Spain (15)], spanning major market classes employing 19 RAPD primers (standard marker array), indicates that all but one of the accessions from Greece showed genetic affinities among themselves and with 23 RA of various origin (i.e., Japan, U.S., Central Europe, Spain and Israel) and market class. Accessions from Greece were, however, distinct from the African landraces and most Spanish melons. Greek accessions also showed little genetic affinity with the Casabas (Blanco and Crenshaw), Ogen, and U.S. Eastern Market accessions. Group Flexuosus and Inodorus accessions from Greece possessed genetic affinities with Western Asian (Group Conomon) and Mediterranean (Group Inodorus) market classes, respectively. The uniqueness of Greek melon landraces portends their potential usefulness for the enhancement of U.S., European, and Asian melon market classes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Estimation of between and within accession variation in selected Spanish melon germplasm using RAPD and SSR markers to assess strategies for large collection evaluation

The population structure of 15 Spanish melon (C. melo L.)accessions, mostly of Group Inodorus, was assessed by the analysis of 16individuals of each accession using 100 random amplified polymorphic DNA (RAPD) bands produced by 36 primers, and allelic variation at 12microsatellite (SSR) loci (23 alleles). A relatively high level of polymorphism (25.6%) was detected using RAPD markers, and eight SSR loci (66.7%) were useful in discriminating accessions. Cluster analysis using RAPD- and SSR-based genetic distance estimates resulted in similar and consistent groupings of most of the accessions studied. The mean genetic distance and standard error among accessions estimated by RAPD variation was 0.421 ± 0.099, and mean SSR-based genetic distance estimate was 0.285 ± 0.141. Albeit many dominant markers examined were fitted to a 3:1 test ratio, deviation from this ratio and from Hardy-Weinberg expectations for many SSR loci suggests that some populations were in genotypic disequilibrium. Moreover, a higher level of genetic variation was observed between Cassaba market classes than within accessions, suggesting that, depending upon the accession, allelic fixation has occurred in these populations. The relatively high level of heterogeneity observed (different band morphotypes and cluster grouping within a particular market class), however, indicates that the Spanish melons examined possess a relatively broad genetic background. An appraisal of accession population structure such as the one reported herein indicates that bulk sampling techniques coupled with molecular analysis techniques that employ a unique array of discriminating markers can provide information leading to effective strategies for diversity analyses of large collections. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genotypic differences in polyembryo formation and somatic embryogenesis increment in wheat (Triticum aestivum L.), following 2,4-D treatment

Summary In the course of experiments performed to obtain haploid wheat plants in which 2,4-dichlorophenoxyacetic acid (2,4-D) was applied to developing spikes, it was found that three cultivars showed a different ability to produce polyembryos (Thatcher 20.19%, Chris 7.06%, Dollar 0%). This behaviour was related to their capacity to form somatic embryos. Diploid immature embryos cultured in vitro after 2,4-D treatment, gave a higher frequency of embryogenic callus in Thatcher and Chris than in Dollar. As the common factor in both experiments was the 2,4-D treatment we propose that the three cultivars showed a differential sensitivity to 2,4-D.     

Nitrogen compound pollution associated with the use of sewage sludge compost and limestone outcrop residue under saline irrigation

Purpose

The use of composted sewage sludge and limestone outcrop residue in land rehabilitation, soil improvement, and technosol making can influence the mobility of nitrogen compounds in groundwater.

Materials and methods

This experiment analyzed this source of possible pollution under an experimental design based on the use of columns (0–30 cm) formed by both wastes and a heavy irrigation regime. Two waters of different quality (saline and non-saline) were used for irrigation. The presence of nitrate, nitrite, and ammonium in the leachates was checked.

Results and discussion

The environmental risk due to the presence of nitrogen species associated with the use of these materials was very low in general, although nitrate was the most important compound affected by the use of sewage sludge compost and saline water.

Conclusions

The combination of saline water for irrigation with the compost has to be seriously considered as a source of pollution for surface and ground waters, and the use of both resources may be a key factor to be studied (low-quality water and sewage sludge compost).

     

Degradation studies on benzoxazinoids. Soil degradation dynamics of (2R)-2-O-beta-D-glucopyranosyl-4-hydroxy-(2H)- 1,4-benzoxazin-3(4H)-one (DIBOA-Glc) and its degradation products, phytotoxic allelochemicals from Gramineae

Wheat (Triticum aestivum L.) has been found to possess allelopathic potential and studies have been conduced to apply wheat allelopathy for biological weed control. 2,4-Dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA) is a common product found in wheat, corn, and rye exudates and it can be released to the environment by that way. In this report, the stability of DIBOA is studied in two soils from crop lands of wheat cv. Astron and cv. Ritmo. These varieties were selected by their concentrations of DIBOA and 2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one (DIMBOA) from aerial parts and by the bioactivities of their aqueous extracts in the growth of wheat coleoptile sections. The degradation rate of DIBOA in these soils was measured in laboratory tests during 90 h by high-pressure liquid chromatography methods. These analyses demonstrate that DIBOA was transformed primarily into 2-benzoxazolinone (BOA). This transformation was similar in both soil types with an average half-life of 43 h. The degradation studies for BOA show its biotransformation to 2-aminophenoxazin-3-one (APO) with a half-life of 2.5 days. Therefore, BOA is an intermediate product in the biotransformation from DIBOA to APO in these wheat crop soils and is consistent with previous findings. APO was not degraded after three months in soil, suggesting that its degradation rate in soil is very slow.     

Complexation of imazalil with beta-cyclodextrin,residue uptake,persistence, and activity against penicillium decay in citrus fruit following postharvest dip treatments

A method for the inclusion of imazalil (IMZ) in the beta-cyclodextrin (betaCD), structural characterization of the inclusion complex and its antifungal activity against Penicillium digitatum and P. italicum assessed by in vitro and in vivo tests are reported. According to the starting stoichiometry of betaCD with respect to IMZ, an equimolar ratio beta-cyclodextrin-IMZ (betaCD-IMZ) was detected by (1)H NMR. In vitro assays showed that the freshly prepared betaCD-IMZ was as effective as IMZ, although 1- and 4-day-old betaCD-IMZ mixtures were more effective. Studies on Star Ruby grapefruit showed no significant differences in residue uptake between treatments with an IMZ commercially available fungicide (Deccozil) or betaCD-IMZ when equal active ingredient (a.i.) concentrations (250 mg/L) and dip temperatures (20 or 50 degrees C) were used. By contrast, treatments of Tarocco oranges and Di Massa lemons with 250 mg/L betaCD-IMZ at 50 degrees C produced significant differences in residue uptake in comparison with 250 mg/L Deccozil treatments at 50 degrees C. The a.i. degradation rate in grapefruit during postquarantine and simulated marketing period (SMP) at 20 degrees C was not affected by the type of formulation used, whether at 20 or 50 degrees C. Conversely, IMZ in oranges and lemons had greater persistence when applied at 50 degrees C. All fungicide treatments showed a comparable efficacy against decay in grapefruit and oranges, whereas treatment in lemons at 250 mg/L a.i. of heated fungicides had higher suppressive effects against decay than unheated chemicals having equal a.i. concentrations and comparable activity at 1200 mg/L IMZ at 20 degrees C.     

Levels of phytosterol oxides in enriched and nonenriched spreads: application of a thin-layer chromatography-gas chromatography methodology

The content of phytosterol oxidation products (POPs) in enriched and nonenriched commercial spreads was evaluated by thin-layer chromatography-gas chromatography (TLC-GC). Oxides of beta-sitosterol, campesterol, and stigmasterol were produced by thermo-oxidation (7-hydroxy, 7-keto, and epoxy derivatives) and chemical synthesis (triol derivatives), which were then separated and identified by TLC-GC. Their identification was further confirmed by GC-mass spectrometry (GC-MS). The total amounts of phytosterols found were 6.07 and 0.33 g/100 g of sample in phytosterol-enriched and nonenriched spread, respectively, whereas the total POPs contents were 45.60 and 13.31 mg/kg of sample in the enriched and nonenriched products. The main POPs found were the 7-keto derivatives of all phytosterols analyzed; 7-ketositosterol was the most abundant one (14.96 and 5.93 mg/kg of sample in phytosterol-enriched and nonenriched spread). No beta-epoxy and triol derivatives were detected in both types of samples. The enriched spread presented a lower phytosterol oxidation rate (0.07%) than the nonenriched one (0.41%).