Bioactive content and antioxidant capacity of Cape gooseberry fruit

At present, Cape gooseberry (Physalis peruviana) fruit is one of the less used raw materials of plant origin, which can be used for human nutrition. This fruit, as well as alimentary products made of it, were used by healers in folk medicine in the distant past. The aim of this study was to monitor and evaluate the antioxidant capacity of fresh fruit of three Cape gooseberry cultivars ‘Giant’, ‘Golden berry’ and ‘Inka’. Antioxidant capacity was also tested, on the basis of the scavenging effect of reactive oxygen species (ROS) and lipid peroxidation of methanolic extracts made of fresh fruit. These results were further extended and supplemented with determinates of the vitamin C and total phenolic contents. These analyses were made for three consecutive years. The highest values of antioxidant capacity were observed in the ‘Inka’ cultivar (9.31 grams of ascorbic acid equivalents kg⁻¹ of fresh mass). In this cultivar, the obtained results were corroborated also in ROS and the contents of vitamin C and total phenolics. Due to a high antioxidant capacity of this fruit species, the results presented should increase its popularity above all as a promising raw material, which can be used for human nutrition.     

Identification and molecular mapping of loci controlling fruit ripening time in tomato

Using RAPD marker analysis, two quantitative trait loci (QTLs) associated with earliness due to reduced fruit-ripening time (days from anthesis to ripening = DTR) were identified and mapped in an F₂ population derived from a cross between Lycopersicon esculentum’E6203’ (normal ripening) and Lycopersicon esculentum’Early Cherry’ (early ripening). One QTL, on chromosome 5, was associated with a reduction in both ripening time (5 days) and fruit weight (29.3%) and explained 15.8 and 13% of the total phenotypic variation for DTR and fruit weight, respectively. The other QTL, on chromosome 12, was primarily associated with a reduction only in ripening time (7 days) and explained 12.3% of the total phenotypic variation for DTR. The gene action at this QTL was found to be partially dominant (d/a=0.41). Together, these two QTLs explained 25.1% of the total phenotypic variation for DTR. Additionally, two QTLs associated with fruit weight were identified in the same F₂ population and mapped to chromosomes 4 and 6, respectively. Together, these two QTLs explained 30.9% of the total phenotypc variation for fruit weight. For all QTLs, the ’Early Cherry’ alleles caused reductions in both ripening time and fruit weight. The polymorphic band for the most significant RAPD marker (OPAB-06), linked to the reduced ripening time QTL on chromosome 12, was converted to a cleaved amplified polymorphism (CAP) assay for marker-aided selection and further introgression of early ripening time (DTR) into cultivated tomato. Received: 15 March 1999 / Accepted: 29 April 1999     

Effect of ethephon on sweet cherry pedicel-fruit retention force and quality is cultivar dependent

Ethephon (2-chloroethyl phosphonic acid) is effectively used to promote development of the pedicel-fruit abscission zone in tart cherry (Prunus cerasus) for mechanical harvest. Our research program is investigating the use of ethephon to promote pedicel-fruit retention force (PFRF) reduction on new sweet cherry (P. avium) cultivars to assist mechanized harvest and its affect upon fresh market quality fruit. Ethephon treatments were made at different timings and rates to ‘Bing’ and ‘Chelan’ during the 2006 season. Ethephon applications to ‘Bing’ trees more than 10 days prior to harvest were effective at reducing PFRF and facilitating mechanical harvest, irrespective of rate (1.2, 3.5, 5.8 L ha⁻¹ [1, 3, 5 pt A⁻¹]). Ethephon applied fewer than 10 days prior to harvest did not reduce PFRF sufficiently. In contrast, no rate or timing of ethephon studied induced a reduction in ‘Chelan’ PFRF sufficient for mechanical harvest. Accompanying PFRF analyses, fruit quality was assessed by measuring firmness (g mm⁻¹), soluble solids (oBrix), weight (g) and color (CTIFL, scale 1–7). Ethephon applied 22 days before harvest at a rate of 3.5 L ha⁻¹ enhanced exocarp color in ‘Bing’ by 27%, while reducing firmness in both ‘Bing’ (−19%, 22 days prior to harvest) and ‘Chelan’ (−15%, 20 days prior to harvest). We observed a significant natural decline in ‘Skeena’ PFRF to levels acceptable for mechanical harvest. This research documents genotypic-specific pedicel-fruit abscission characteristics and the potential to facilitate mechanical harvest of fresh market quality sweet cherry fruit using ethephon.     

Direct estimation of the effects of meiotic recombination on potato traits via analysis of 4x-2x progenies from synaptic mutants with 2n-pollen formation by FDR without crossing-over

Diploid potato clones with 2n-pollen formation by first-division restitution without crossing-over (FDR-NCO) are ideal testers to estimate the breeding value of elite 4x cultivars by virtue of transmitting their genotypes practically intact to their progenies. This characteristic facilitates genetic analysis, since meiotic recombination would take place only in the 4x parent and not in the diploid parent. We evaluated (under short-day conditions) families from complete factorial crosses between four 4x cultivars and five 2x(FDR-NCO) clones. Families were compared with two standard 4x cultivars (’Bintje’ and ’Delta’) for total tuber yield (TTY), commercial yield (CY), haulm maturity (HM), plant vigor (PV), plant-top uniformity (PU), eye depth (ED), number of tubers per hill (NTH), and the CY/TTY index (CTI). For TTY, the contrasts family group (310 g/ hill) vs ’Delta’ (430 g/hill) and the family group vs ’Bintje’ (210 g/hill) were significant. Only 25% of the families were different from ’Delta’ and 20% of them outyielded ’Bintje’. For CY, differences were observed between families (240 g/hill) vs ’Delta’ (340 g/hill) and families vs ’Bintje’ (150 g/hill). The two best families had 53% CY over ’Bintje’. Surprisingly, only one family had a higher NTH than ’Bintje’. No differences were observed for HM. Seventy five and 30% of the families had an ED similar to ’Delta’ (ED = 2) and ’Bintje’ (ED = 1), respectively. A multivariate analysis indicated that 63% of the data variability could be explained by two factors. TTY, CY, and PV had high loading on the first factor, whereas ED, PU and HM had high loading on the second factor; CTI and NTH had equal sizes on both factors. High TTY and PV were associated with high NTH and CTI. Deep eye, PU, and late maturity were associated with high NTH and reduced CTI. The distributions of factor scores of the entries indicated that some 2x parents had strong influences (irrespective of the direction of their effects) on the crosses. Six crosses due to two 2x males were in the ’Bintje’ quarter with negative scores for both factors (implying low TTY, poor vigor, and low NTH). Also three crosses due to another 2x clone were distributed in the quarter of positive factor 1 and negative factor 2. These crosses plus another one were in the same quarter of ’Delta’ (implying high yields, low ED, low PU, and early maturity). The FDR-NCO clones provide a homogeneous sample of heterozygous 2n-gametes allowing the unique opportunity to estimate the relative contribution of the random meiotic products (from the 4x parents) and the ’somatic’ 2x genome for the phenotypic expression of quantitative traits. The interesting result was that measurable effects (favorable or not) on the data variability were mainly determined by the genomic contribution of the haploid-species hybrids. Three out of five 2x-male parents showed rather strong effects on progenies. No such effects were observed on the four 4x-female parents. Received: 3 September 1999 / Accepted: 24 November 1999     

Postulation of resistance genes to barley diseases in heterogeneous varieties

Resistance to causal agents of diseases is an important varietal characteristic that influences the management practice of crop plants and thus production costs of commodities. At present, almost all European barley varieties possess at least one major gene for resistance to powdery mildew. After hybridizing selected parental varieties, resistance genes often segregate in subsequent generations and, therefore, some varieties comprise lines that differ in the number or combinations of resistance genes. The objective of this research was to describe the various methods available for postulating resistance genes to pathogens in heterogeneous varieties using resistance to powdery mildew of barley as an example. Four spring barleys (‘Orbit’, ‘Malva’, ‘Tocada’ and CLE 233), and a six-row variety of winter barley, F 12872, were screened. For postulating resistance genes, several testing procedures and many Blumeria graminis f.sp. hordei isolates were used. Minimum amounts of seed were determined and different methods of obtaining homogeneous seed samples from heterogeneous varieties were compared. It was found that ‘Orbit’ and ‘Malva’ are composed of three and ‘Tocada’, CLE 233 and F 12872 of two lines with different resistances to powdery mildew. Problems of postulating resistance genes in heterogeneous varieties and the advantages of testing leaf segments instead of young plants are discussed.     

Factors influencing induction and maintenance of <Emphasis Type="Italic">Vitis rotundifolia</Emphasis> Michx. embryogenic cultures

Unopened leaves, petioles and fully opened leaves from micropropagation cultures of five Vitis rotundifolia Michx. varieties were cultured on induction medium to study their embryogenic response. Among the various explants tested, the maximum number of varieties produced embryogenic cultures from unopened leaves followed by fully opened leaves and petioles. Based on morphological differences, two types of embryogenic cultures were identified. Friable cultures typically arose as proembryonic masses (PEM) on induction medium, whereas somatic embryo production without an intervening PEM stage was observed in compact cultures. Of the five varieties tested, the highest frequency of embryogenic response was observed from fully opened leaves of ‘Supreme’ and unopened leaves and petioles of ‘Delicious’. Attempts to initiate suspension cultures from varieties resulted in proliferation and maintenance of ‘Alachua’ and ‘Carlos’ cultures in liquid medium for 16 weeks. Embryogenic potential of varieties was studied on cultures growing on embryo development medium. The maximum number of cotyledonary stage somatic embryos from 0.2 g proembryonic masses were observed in ‘Carlos’ (379.3) followed by ‘Alachua’ (350.0) and ‘Delicious’ (305.0). Cotyledonary stage somatic embryos germinated when cultured on Murashige and Skoog medium containing 1 μM Benzyladenine (BA). Although high embryo germination rates (80–100%) were observed in the varieties tested, plant recovery from germinated somatic embryos ranged from 6–47%. Embryogenic cultures could be maintained on X6 medium and used in genetic engineering studies.     

Steroidal glycoalkaloid content of potato,tomato and their somatic hybrids

Summary Analyses of leaves and ‘tubers’ from somatic hybrids of potato and tomato (‘pomato’ with plastids of potato, ‘topato’ with plastids of tomato) produced by fusion of protoplasts from liquid cultures of dihaploid potato and mesophyll of tomato revealed the presence of the two major potato glycoalkaloids (α-solanine and α-chaconine) as well as the tomato glycoalkaloid (αtomatine). The total alkaloid content of leaves was greater than that of ‘tubers’ and similar to levels in the foliage of parent plants. However, glycoalkaloids were more abundant in hybrid ‘tubers’ than in normal potato tubers by a factor of 5–15. In hybrid foliage, approximately 98% of the alkaloid present was of potato origin whereas in ‘tubers’ the reverse was the case, with tomatine comprising 60–70% of the total alkaloid. The similarities in alkaloid content and ratios between the pomato and the topato lines indicate that plastomes do not influence the biosynthesis and distribution of these alkaloids. The results indicate that major secondary metabolites may prove useful for assessing the hybrid nature of such plants.     

QTL mapping of aroma compounds analysed by headspace solid-phase microextraction gas chromatography in the apple progeny ‘Discovery’ × ‘Prima’

Improving fruit quality of apple varieties is an important but complex breeding goal. Flavour is among the key factors of apple fruit quality but in spite of the analytical and biochemical knowledge about volatiles little is known about the genetic and molecular bases of apple aroma. The aim of this study was to use a saturated molecular linkage map of apple to identify QTLs for aroma compounds such as alcohols, esters and terpenes, but also for a number of unidentified volatile compounds (non-targeted analysis approach). Two parental genetic maps were constructed for the apple cultivars ‘Discovery’ and ‘Prima’ by using mainly AFLP and SSR markers. ‘Discovery’ and ‘Prima’ showed very different volatile patterns, and ‘Discovery’ mostly had the higher volatile concentrations in comparison with the Vf-scab resistant ‘Prima’ which has its origin in the small-fruited apple species Malus floribunda. About 50 putative QTLs for a total of 27 different apple fruit volatiles were detected through interval mapping by using genotypic data of 150 F₁ individuals of the mapping population ‘C3’ together with phenotypic data obtained by head-space solid phase microextraction gas chromatography. QTLs for volatile compounds putatively involved in apple aroma were found on 12 out of the 17 apple chromosomes, but they were not evenly dispersed. QTLs were mainly clustered on linkage groups LG 2, 3 and 9. In a first attempt, a LOX (lipoxygenase) candidate gene, putatively involved in volatile metabolism, was mapped on LG 9, genetically associated with a cluster of QTLs for ester-type volatiles. Implications for aroma breeding in apple are discussed.     

Alternate bearing influences annual nutrient consumption and the total nutrient content of mature pistachio trees

The influence of alternate bearing on nutrient utilization and total tree nutrient content was investigated in mature pistachio (Pistacia vera L. cv Kerman trees). Removal of N, P and Zn in fruit and abscised leaves of cropping (‘on’) trees averaged 5, 6, and 2 times, respectively, the removal in abscised leaflets of the non-fruiting, ‘off’ year trees. One hundred and thirty-five kg N, 131 kg K, 86 kg Ca, 39 kg Mg and 18 kg P per hectare were removed in fruits and abscised leaves in ‘on’ year trees. Tree nutrient contents and, presumably, the size of nutrient storage pools in dormant trees varied between ‘on’ and ‘off’ years. There was 22% and 14% more N and P, respectively, in dormant trees following ‘off’ than ‘on’ years. The greater N and P accumulation in ‘off’ year trees is depleted in support of the large fruit demand for N and P during ‘on’ years. In contrast to N and P, there was greater K and Ca accumulation in perennial tree parts during ‘on’ years than during ‘off’ years. The greater K accumulation in perennial tree parts and approximately 30% greater removal of K in annual organs during ‘on’ than ‘off’ years suggests that K uptake could be 4 times higher in ‘on’ year trees than in (non-cropping), ‘off’ year trees.     

Localization of the rice stripe disease resistance gene, Stv-bi, by graphical genotyping and linkage analyses with molecular markers

 We used graphical genotyping and linkage analyses with molecular markers to determine the chromosomal location of the rice stripe disease resistance gene, Stv-b ⁱ . The stripe resistance gene from the indica rice (Oryza sativa) cv ‘Modan’ was introgressed into several Japanese rice varieties. We found 4 RFLP markers in ‘Modan’, five susceptible parental rice varieties (‘Norin No. 8’, ‘Sachihikari’, ‘Kanto No. 98’, ‘Hokuriku No.103’ and ‘Koganebare’) and four resistant progeny varieties (‘St. No. 1’, ‘Aichi No. 6’, ‘Aoisora’ and ‘Asanohikari’). Graphical genotyping of the resistant progeny revealed a chromosomal segment ascribable to ‘Modan’ and associated with stripe resistance. The chromosomal segment from ‘Modan’ was located at 35.85 cM on chromosome 11. Linkage analysis using 120 F₂ individuals from a cross between ‘Koshihikari’ (susceptible) and ‘Asanohikari’ (resistant) revealed another 8 RFLP markers in the same chromosome. We performed a bioassay for rice stripe resistance in F₃ lines of the F₂ individuals using infective small brown planthoppers and identified an 1.8-cM segment harboring the rice stripe disease resistance gene, Stv-b ⁱ , between XNpb220 and XNpb257/ XNpb254. Furthermore, Stv-b ⁱ was linked by 0.0 cM to a RFLP marker, ST10, which was developed on the basis of the results of RAPD analysis. These DNA markers near the Stv-b ⁱ locus may be useful in marker-assisted selection and map-based cloning of the Stv-b ⁱ gene. Received: 26 September 1997 / Accepted: 4 November 1997     

Influence of NaCl in the irrigation water on yield and quality of sweet pepper (Capsicum annuum)

Summary A field experiment was designed to determine the salt tolerance of three varieties of sweet pepper for paprika, studying the effects of four increasing levels of sodium chloride in the irrigation water (5, 10, 29 and 42 meq/l) on soil salinity, yields, and quality of the fruits. EC_5:1 and the soluble sodium and chloride contents increased with increasing salinity. The yields were reduced by 5 per cent for variety ‘Ramillete’, 19 per cent for ‘Tres cascos’, and 40 per cent for ‘Bola’ at the highest level. The fruit quality variables studied (colour index and chloride contents) differed with the variety. re]19750925     

Contributions of apoplasmic cadmium accumulation,antioxidative enzymes and induction of phytochelatins in cadmium tolerance of the cadmium-accumulating cultivar of black oat (<Emphasis Type="Italic">Avena strigosa</Emphasis> Schreb.)

The contributions of cadmium (Cd) accumulation in cell walls, antioxidative enzymes and induction of phytochelatins (PCs) to Cd tolerance were investigated in two distinctive genotypes of black oat (Avena strigosa Schreb.). One cultivar of black oat ‘New oat’ accumulated Cd in the leaves at the highest concentration compared to another black oat cultivar ‘Soil saver’ and other major graminaceous crops. The shoot:root Cd ratio also demonstrated that ‘New oat’ was the high Cd-accumulating cultivar, whereas ‘Soil saver’ was the low Cd-accumulating cultivar. Varied levels of Cd exposure demonstrated the strong Cd tolerance of ‘New oat’. By contrast, low Cd-accumulating cultivar ‘Soil saver’ suffered Cd toxicity such as growth defects and increased lipid peroxidation, even though it accumulated less Cd in shoots than ‘New oat’. Higher activities of ascorbate peroxidase (EC 1.11.1.11) and superoxide dismutase (EC 1. 15. 1. 1) were observed in the leaves of ‘New oat’ than in ‘Soil saver’. No advantage of ‘New oat’ in PCs induction was observed in comparison to Cd-sensitive cultivar ‘Soil saver’, although Cd exposure increased the concentration of total PCs in both cultivars. Higher and increased Cd accumulation in cell wall fraction was observed in shoots of ‘New oat’. On the other hand, in ‘Soil saver’, apoplasmic Cd accumulation showed saturation under higher Cd exposure. Overall, the present results suggest that cell wall Cd accumulation and antioxidative activities function in the tolerance against Cd stress possibly in combination with vacuolar Cd compartmentation.     

Selection of Highly Informative Microsatellite Markers to Identify Pollen Donors in ‘Hass’ Avocado Orchards

‘Hass’ is the most popular avocado (Persea americana Mill.) cultivar in the world. It has been characterized as a crop requiring cross-pollination. However, the potential extent of self-pollination and the most effective pollen donors (best cross-pollinizing cultivars) have not been determined. In this study, 56 markers were screened against ‘Hass’ and nine commonly used pollinizing cultivars grown in southern California: ‘Bacon,’ ‘Ettinger,’ ‘Fuerte,’ ‘Harvest,’ ‘Lamb Hass,’ ‘Marvel,’ ‘Nobel,’ ‘Sir Prize,’ and ‘Zutano.’ Seventeen microsatellite, i.e., simple sequence repeat (SSR) markers, were found to be very promising for paternity analysis. Four highly informative SSR markers were selected to accurately and unequivocally identify pollen parents of ‘Hass’ fruit from an orchard interplanted with these pollinizing cultivars. From 2003 to 2006, 7,984 ‘Hass’ fruit were analyzed for their paternity. Overall, the pollen parents of 99.55% of the analyzed fruit could be unequivocally identified with a single multiplex polymerase chain reaction (PCR). Only 36 fruits (<0.45%) required a second PCR reaction to reach unequivocal identification of the pollen parents.     

Selection for virus resistance in tomato exposed to tissue culture procedures

Protocols elaborated with the objective of achieving valuable material for selection procedure of variants with virusresistance traits in tomato genotypes are presented. Preliminary results are demonstrated in the domain of testing for variability in somaclones obtained through indirect adventitous organogenesis initiated on leaf explants of cultivated tomato (Lycopersicon esculentum Mill.). Somaclones were grown in greenhouse conditions and variation of their symptoms upon infection with tomato mosaic (ToMV) or cucumber mosaic (CMV) respectively was observed. Tests for resistance to the local isolates of the above cited viruses were performed using enzyme linked immunosorbent assay and back inoculation onto diagnostic plants. Screening data are presented. Desirable variants were selected from cultivars ‘Moneymaker’, ‘Potentat’ and ‘Rutgers’. Some of the ‘Moneymaker’ somaclones exhibited increased tolerance to cucumber mosaic virus, a few seemed to be even fully resistant though most were susceptible as donor plants. The most favourable somaclonal lines are actually further tested and monitored for changes in horticultural characteristics. The described procedure of searching for resistance trait in specific pathogen-free (SPF) plants regenerated from infected tissue looks promising and thus can serve as aid in attaining appropriate objectives of breeding programme. Additionaly experiments were initiated to obtain somaclones from cultivars ‘Beta’, ‘Krakus’ and Stevens Rodade hybrid via regeneration of isolated protoplasts. To this end the callus stage was obtained from all donors.     

Effect of low doses of gamma irradiation on in vitro growth of grapevine

Shoot tips and single node explants of two rootstocks (R.99 and 3309) and two varieties (‘Helwani’ and ‘Cabernet Franc’) of grapevine cultured on DSD1 media for a period of 60 days, were irradiated with 0, 2, 5 and 7 Gy doses of gamma irradiation. Shoot length of ‘Helwani’ and ‘Cabernet Franc’ was increased by 7 Gy irradiation. The 5 Gy dose increased the number of roots in plants of the two rootstocks and ‘Helwani’. Root length of ‘Helwani’ and ‘Cabernet Franc’ at the 2 and 7 Gy doses were significantly higher than those of the non-irradiated control. A similar effect was noticed on R.99 rootstock subjected to 5 Gy. Five Gy also increased the dry weight of the R.99 rootstock, whereas 2 and 7 Gy had a similar effect on ‘Helwani’ and ‘Cabernet Franc’. Number of leaves of plants exposed to 5 and 7 Gy was increased when compared with the non-irradiated control. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro assay of native Iranian almond species (<Emphasis Type="Italic">Prunus</Emphasis> L. spp.) for drought tolerance

Eight native Iranian almond species from three sections, ‘Euamygdalus’ (Prunus communis; Prunus eleagnifolia and Prunus orientalis); ‘Lycioides’ (Prunus lycioides and Prunus reuteri) and ‘Spartioides’ (Prunus arabica, Prunus glauca and Prunus scoparia) were in vitro screened for drought tolerance using sorbitol and polyethylene glycol (PEG) as an osmoticum. Different levels of water stress were induced using five concentrations of either sorbitol or polyethylene glycol in Woody Plant Medium (WPM). Water potential of various media ranged from −0.80 to −2.05 MPa and water stress in culture medium adversely affected plantlet growth. Wild species from ‘Spartioides’ were less affected than ‘Lycioides’ and ‘Euamygdalus’. At the same level of water potential, sorbitol had lower adverse effects than PEG; the latter being severe. Prunus × sorbitol and Prunus × PEG interactions were significant. At 0.2 M sorbitol and 0.003 M PEG, ‘Spartioides’ produced significantly more roots with higher total root length and root volume, as well as root-dry weight than those of ‘Lycioides’ and ‘Euamygdalus.’ It is concluded that in vitro screening of native Iranian almond species under specific and limited water-stress conditions may provide a system for effectively differentiating the wild species of almond for their expected root mass production under field conditions.     

A parentage study of closely related Ukrainian wine grape varieties using microsatellite markers

Four bred grapevine varieties released for commercial cultivation in Ukraine, namely ‘Antey Magarachskii’, ‘Rubinovyi Magaracha’, ‘Granatovyi Magaracha’ and ‘Rubin Golodrigi’, and their putative parental forms were genotyped using six microsatellite loci. Genotypes were compared with breeding records to verify genetic relationships among varieties. Results of the analysis confirmed four of six parent-offspring relationships. Results of the analysis allow to assume that genotype ‘Seyve Villard 20347’ is the direct parent of ‘Antey Magarachskii’ instead of its grandparent. The first-studied accession believed to be that of ‘Granatovyi Magaracha’ was identified as impurity. In order to verify the parentage of ‘Granatovyi Magaracha’, rest accessions of that variety and its putative parent ‘Antey Magarachskii’ were additionally genotyped at 13 nuclear loci and at three chloroplast loci. The parent-offspring relationship was confirmed, as all ‘Granatovyi Magaracha’ accessions had a common allele with the parent variety ‘Antey Magarachskii’ at each locus and the same chlorotype A. Different ‘Granatovyi Magaracha’ accessions could have been obtained via vegetative propagation of two seedlings which arose from one crossing.