Increasing Strawberry Fruit Sensorial and Nutritional Quality Using Wild and Cultivated Germplasm

Background

Increasing antioxidant levels in fruit through breeding is an important option to support higher antioxidant intake particularly when fruit consumption is low. Indeed, if nutritional components are also combined with a high standard of sensorial fruit quality, the perspective for consumer health can be further improved by encouraging more fruit consumption. Wild species are valued by strawberry breeders as sources of novel traits, especially for pest resistance and abiotic stress tolerance. Furthermore, previous investigations have shown improvements in fruit nutritional quality in breeding material that originated from Fragaria virginiana ssp. glauca (FVG) inter-species crosses. Recently, commercial varieties of strawberries have also shown interesting variability in fruit nutritional quality.

Results

Strawberry fruit sensorial and nutritional qualities generated by Fragaria inter-species and intra-species crosses were evaluated on 78 offspring derived from 8 families: two that originated from F. × ananassa intra-species crossing; three from back-crossing of F1– FVG × F. × ananassa; and three from back-crossing of BC1– FVG × F. × ananassa. The genetic variability from the three types of cross combinations was analyzed by calculation of the correlations among the fruit sensorial and nutritional parameters. The results obtained show that two subsequent back-crossing generations from an inter-species crossing combination with F. virginiana ssp. glauca provides useful improvement of the fruit nutritional and sensorial qualities that is combined with agronomic standards that are close to those requested at the commercial level. Improvements of these traits can also be achieved by programming F. × ananassa intra-species crosses and producing progeny with productivity traits more similar to those of the commercial cultivars.

Conclusions

The two types of combination programs (inter-species back-crosses, and intra-species crosses) can be used to improve strawberry nutritional quality.     

Advances in improvement of quality and resistance in a multipurpose crop: sea buckthorn

Sea buckthorn is a berry crop with multiple uses. The berries are highly appreciated for their unique taste but are also very rich in bioactive compounds with powerful nutritional and medicinal values. In addition, the plants grow well under adverse conditions, and are often used to fight soil erosion. Utilization of sea buckthorn has therefore increased around the world but serious problems have, nevertheless, been encountered due to drought, salinity, diseases and insect pests. This review covers important aspects of sea buckthorn research, such as heritable and environmentally induced variation in biochemical compounds, causes and effects of the devastating dried-shrink disease, susceptibility to insect pests, methods for conventional breeding, and the utilization of DNA markers for taxonomical and population genetic analyses, and for investigating the inheritance of quality and resistance traits. We also present possibilities to implement innovative biotechnological breeding methods, especially metabolite profiling and MAS/GRC-based markers, for fast and efficient development of elite genotypes with specific nutritional- and health-related bioactive compounds and strong resistance to biotic and abiotic stress.     

Biotechnology of temperate fruit trees and grapevines

Challenges concerning fruit trees and grapevines as long lived woody perennial crops require adapted biotechnological approaches, if solutions are to be found within a reasonable time frame. These challenges are represented by the need for correct identification of genetic resources, with the foreseen use either in conservation or in breeding programmes. Molecular markers provide most accurate information and will be the major solution for questions about plant breeders rights. Providing healthy planting material and rapid detection of newly introduced pathogens by reliable methods involving serological and molecular biological tools will be a future challenge of increases importance, given the fact that plant material travels freely in the entire European Union. But also new breeding goals and transgenic solutions are part of the biotechnological benefits, e.g. resistance against biotic and abiotic stress factors, modified growth habits, modified nutritional properties and altered processing and storage qualities. The successful characterization of transgenic grapevines and stone fruit trees carrying genes of viral origin in different vectors constructed under ecological consideration, will be presented. Beyond technical feasibility, efficiency of resistance, environmental safety and Intellectual Property Rights, also public acceptance needs consideration and has been addressed in a specific project. The molecular determination of internal quality parameters of food can also be addressed by the use of biotechnological tools. Patient independent detection tools for apple allergens have been developed and should allow to compare fruits from different production systems, sites, and genotypes for their content of health threatening compounds.     

Biotechnological advances in pomegranate (Punica granatum L.)

Pomegranate (Punica granatum L.) is known for its nutritional, medicinal, and ornamental importance. It is conventionally propagated by hardwood and softwood cuttings, but about 1 yr is needed before the rooted cuttings can be transplanted to the field. Propagation by seed is undesirable as populations are heterozygous and seed propagation leads to wide variations in tree and fruit characteristics. Several studies have been conducted on in vitro culture of pomegranate, and protocols have been developed for plant regeneration through organogenesis and embryogenesis from various types of explants. Tissue culture has enabled mass propagation of superior genotypes of both wild and cultivated varieties. However, successful application of tissue culture systems for genetic engineering of pomegranate is still limited. Molecular markers are essential for identification and discrimination of genotypes for genetic conservation, crop improvement, breeding programs, and commercialization of superior genotypes. These techniques may also be applicable to rapid identification and indexing of disease-free planting material. This review focuses on the biotechnological approaches that are being used for pomegranate improvement.     

Improvement of the nutritional quality of legume seed storage proteins by molecular breeding

Legume seeds contain a large amount of proteins and are one of the essential protein sources for humans and animals. However, the protein, in legume seeds is usually poor in sulfur-containing amino acids, and its nutritional value is lower than the protein from animal sources. Recently plant breeding has become available by the introduction of molecular biology, and a technique, called molecular breeding, was applied to the production of legume seeds that contain proteins with high nutritional quality. This review describes the expression of legume seed protein genes and the transformation of legume plants. Approaches to improve the legume seed storage protein will be discussed.     

Simulating genotypic variation of fruit quality in an advanced peach x Prunus davidiana cross

Ecophysiological models are increasingly expected to describe genotypic variation within breeding populations. Accordingly, the ability of an ecophysiological model of peach to explain variation in fruit quality among 100 genotypes of a second backcross progeny derived from a clone of wild peach (Prunus davidiana) crossed with two commercial nectarine (Prunus persica) varieties was explored. Experimental measurements were carried out to calibrate the model for each genotype. The predictive quality of the model was tested on several independent datasets. The genotypic variation in dry and fresh growth of the fruit and the stone were effectively described by the model. Prediction of the amount of total sugar in flesh at maturity was accurate, whereas prediction of flesh dry matter content and total sugar concentration was suitable but less accurate. This approach and the results have allowed physiological processes to be ranked according to their contribution to the variation in fruit quality between genotypes. Fruit growth demand and the hydraulic conductance in the fruit were the main processes that explained the fruit quality variation. Shortcomings and further potential uses of the model are discussed.     

QTL mapping of fruit mineral contents provides new chances for molecular breeding of tomato nutritional traits

Key message

Agronomical characterization of a RIL population for fruit mineral contents allowed for the identification of QTL controlling these fruit quality traits, flanked by co-dominant markers useful for marker-assisted breeding.

Abstract

Tomato quality is a multi-variant attribute directly depending on fruit chemical composition, which in turn determines the benefits of tomato consumption for human health. Commercially available tomato varieties possess limited variability in fruit quality traits. Wild species, such as Solanum pimpinellifolium, could provide different nutritional advantages and can be used for tomato breeding to improve overall fruit quality. Determining the genetic basis of the inheritance of all the traits that contribute to tomato fruit quality will increase the efficiency of the breeding program necessary to take advantage of the wild species variability. A high-density linkage map has been constructed from a recombinant inbred line (RIL) population derived from a cross between tomato Solanum lycopersicum and the wild-relative species S. pimpinellifolium. The RIL population was evaluated for fruit mineral contents during three consecutive growing seasons. The data obtained allowed for the identification of main QTL and novel epistatic interaction among QTL controlling fruit mineral contents on the basis of a multiple-environment analysis. Most of the QTL were flanked by candidate genes providing valuable information for both tomato breeding for new varieties with novel nutritional properties and the starting point to identify the genes underlying these QTL, which will help to reveal the genetic basis of tomato fruit nutritional properties.

     

Transformation of fruit trees. Useful breeding tool or continued future prospect?

Regeneration and transformation systems using mature plant material of woody fruit species have to be achieved as a necessary requirement for the introduction of useful genes into specific cultivars and the rapid evaluation of resulting horticultural traits. Although the commercial production of transgenic annual crops is a reality, commercial genetically-engineered fruit trees are still far from common. In most woody fruit species, transformation and regeneration of commercial cultivars are not routine, generally being limited to a few genotypes or to seedlings. The future of genetic transformation as a tool for the breeding of fruit trees requires the development of genotype-independent procedures, based on the transformation of meristematic cells with high regeneration potential and/or the use of regeneration-promoting genes. The public concern with the introduction of antibiotic resistance into food and the restrictions due to new European laws that do not allow deliberate release of plants transformed with antibiotic-resistance genes highlight the development of methods that avoid the use of antibiotic-dependent selection or allow elimination of marker genes from the transformed plant as a research priority in coming years     

Plasticity of photosynthetic processes and the accumulation of secondary metabolites in plants in response to monochromatic light environments: A review

Light spectra significantly influence plant metabolism, growth and development. Here, we review the effects of monochromatic blue, red and green light compared to those of multispectral light sources on the morpho-anatomical, photosynthetic and molecular traits of herbaceous plants. Emphasis is given to the effect of light spectra on the accumulation of secondary metabolites, which are important bioactive phytochemicals that determine the nutritional quality of vegetables. Overall, blue light may promote the accumulation of phenylpropanoid-based compounds without substantially affecting plant morpho-anatomical traits compared to the effects of white light. Red light, conversely, strongly alters plant morphology and physiology compared to that under white light without showing a consistent positive effect on secondary metabolism. Due to species-specific effects and the small shifts in the spectral band within the same color that can substantially affect plant growth and metabolism, it is conceivable that monochromatic light significantly affects not only plant photosynthetic performance but also the “quality” of plants by modulating the biosynthesis of photoprotective compounds.     

Phytochemical Variation in <Emphasis Type="Italic">Fritillaria cirrhosa</Emphasis> D. Don (<Emphasis Type="Italic">Chuan Bei Mu</Emphasis>) in Relation to Plant Reproductive Stage and Timing of Harvest<Superscript>1</Superscript>

Phytochemical Variation in Fritillaria cirrhosa D. Don ( Chuan Bei Mu ) in Relation to Plant Reproductive Stage and Timing of Harvest. Economic development in southwest China and the increasing use of traditional Chinese medicine (TCM) worldwide have led to intensified collection of native medicinal plants. Fritillaria cirrhosa D. Don (Chuan Bei Mu), commonly used for the treatment of cough in TCM, is endemic to the Hengduan Mountain region of southwest China and is under increasing pressure from over-collection and decreasing suitable alpine habitat. The bioactive compounds in F. cirrhosa bulbs, isosteroidal alkaloids, are greatly influenced by environmental conditions and fluctuate in content and concentration with plant age and reproductive stage. Aiming at obtaining useful information for the sustainable management of wild F. cirrhosa populations, we evaluated how the phytochemical composition of F. cirrhosa bulbs varies at various stages of plant reproductive development. Using chemical methods and high-performance liquid chromatography, we extracted and analyzed two major bioactive alkaloids from F. cirrhosa bulb samples collected throughout the Hengduan Mountain region. Plant reproductive stage was found to affect the concentration of bioactive alkaloids in F. cirrhosa bulbs. Bulb alkaloid concentration was highest during the early stages of fruit development and decreased significantly with fruit maturation. These results lend biochemical support to the practice of harvesting F. cirrhosa during the early stages of plant senescence (i.e., early fruit development).     

Grafting under water stress in tomato cherry: improving the fruit yield and quality

As the concentrations of essential vitamins and minerals and a number of other health‐promoting compounds are often low in stable crops, research is under way to understand and increase synthesis of phytochemicals in order to improve crop nutritional quality. The question addressed in this study is whether shoot genotypes or root genotypes with tolerant drought character are able to increase the fruit quality and production under moderate water stress. Zarina (drought tolerant) and Josefina (drought sensitive) were grafted self and reciprocally. The results showed that the use of cv. Zarina (drought tolerant) as rootstock (Zar × Jos) results in a greater number of fruits under water‐stress conditions, a moderate increase in some antioxidant compounds, such as ascorbic acid, phenols and flavonoids and lycopene and β‐carotene, and Zar × Jos showed high levels of sugars and organic acids, sweetness index and sugars : acids ratio, as well as important minerals, such as K and Mg, which could increase its nutritional quality under stress conditions. Overall, the use of drought‐tolerant rootstock could provide a useful tool to improve fruit yield and quality of cherry tomato fruit under moderate water stress, which in turn could mean lower costs in the use of irrigation water.     

MATERNAL INVESTMENT AND FRUIT ABORTION IN PHASEOLUS VULGARIS

Plants lose some of their parental investment through fruit abortion. Resource conservation theory predicts that the maternal plant should abort those fruits furthest from maturity in order to conserve scarce resources. Embryo-quality theory predicts that the maternal plant should favor offspring of particular genotypes. I recorded the patterns of maternal investment in floral cohorts of domesticated and wild beans, Phaseolus vulgaris L. In accord with the resource conservation theory, late pod cohorts have the highest fruit abortion rates. When domesticated beans are grown in smaller pots, late cohort survivorship declines. When domesticated beans are crossed with pollen donors of different degrees of relatedness, the fruit abortion rate is the same even though seeds from the outbred crosses weigh more. The challenge for ecologists is to model and test the combined and possibly conflicting effects of selection for resource conservation and high offspring quality.     

Identification of novel quantitative trait loci for increased lycopene content and other fruit quality traits in a tomato recombinant inbred line population

Epidemiological and clinical studies indicate that a steady dietary intake of bioavailable lycopene, a C₄₀ carotenoid and potent natural antioxidant, may be associated with a decreased incidence of prostate cancer in humans. Since fresh tomatoes and processed tomato products represent approximately 85% of the average human??s dietary lycopene intake, the identification of novel genetic factors which regulate high fruit lycopene content in tomato is imperative for the improvement of nutritional quality in this commercially valuable specialty crop. To understand the genetic control of the extraordinarily high fruit lycopene content in an accession (LA2093) of the tomato wild species Solanum pimpinellifolium, a quantitative trait locus (QTL) mapping study was conducted using a recombinant inbred line (RIL) population of a cross between LA2093 and a cultivated tomato (S. lycopersicum) breeding line, NCEBR-1. The parental lines, F1 progeny, and F7-F10 RIL populations were grown in replicated field trials in four successive years and evaluated for lycopene content as well as several other traits, including fruit fresh weight, soluble solids content, pH of puree, and plant maturity. The lycopene content of ripe fruit was estimated using three methods: high-performance liquid chromatography (HPLC), spectrophotometry, and colorimetric assays. Based on these measurements, QTL were identified and compared across generations. Among the QTL identified for lycopene, two QTL, located on chromosomes 7 and 12, had very large effects and were consistent across generations. The genomic intervals in which these two QTL reside do not correspond to known map positions of carotenoid biosynthetic genes, indicating that these QTL may represent novel alleles with potentially important implications for tomato breeding as well as increased understanding of carotenoid accumulation in tomato. Several QTL were also identified for fruit weight, soluble solids content and plant maturity. The potential implications of these results for tomato crop improvement are discussed.     

秦岭黄果悬钩子野生种质资源与引种试验研究

对黄果悬钩子在秦岭山区的分布、习性、果实经济性状、营养成分、产量构成以及引种栽培条件下的物候期、根系特征、发枝习性,繁殖特点等内容的研究结果表明,黄果悬钧子植株矮小,具有较耐旱的根系组成特点;果大,质优、风味好,营养丰富;适应性较强,容易繁殖,是一种优良的栽培树萄果树引种驯化,矮化育种野生种质资源。     

Variations in the leaf metabolite profile between hydroponic and field grown Moringa oleifera Lam. genotypes

Medicinal and herbal plants are increasingly cultivated on commercial scale all around the world, to satisfy the large demand for natural remedies associated with plant bioactive compounds. Moringa oleifera Lam. is one of these attractive plant species, being cultivated across the world, with most of the production in Africa and Asia. However, it is increasingly reported that the composition and concentration of bioactive compounds in medicinal plants, are largely influenced by factors such as the growing environment, harvesting time, and climatic factors among others. The aim of this study was therefore to determine the differences in the leaf metabolite profile between hydroponic and field grown M. oleifera plants due to cultivation system, harvesting time and genotypes. ¹H NMR was used for data acquisition, and MestReNova software was used for the pre-processing of the spectral data. Multivariate data analysis by means of PCA and OPLS-DA was conducted, followed by targeted metabolite analyses. The results show variations in the leaf metabolite profile as influenced by cultivation systems, harvesting time and genotypes. In both PKM-1 and Malawi hybrid genotypes, the concentration level of chlorogenic acid, ferulic acid, vanillic acid, and wogonin compounds were higher in the hydroponic leaf material, whereas the concentration level of esculetin, niazirin and GABA were slightly higher in the field harvested leaf materials. With regards to harvesting time effect, the concentration level of all seven targeted compounds were higher in February (summer) harvest as compared to May (autumn) harvest. Among the genotypes, PKM-1 showed to have higher concentration of certain targeted compounds as compared to Malawi hybrid, but on the other hand certain compounds from the Malawi hybrid showed also higher concentrations. These results provide insight on the possible alternative production system that can be adopted to optimise and improve accumulation of bioactive compounds in M. oleifera leaf materials.     

The allometry of the weight of fruit on trees and shrubs in Barbados

Summary Branch sampling of branch diameter and fruit crop on 22 species of Barbadian trees and shrubs provided sufficient data to build regressions between plant size and fruit crop weight. Orchard plants bear much more fruit than wild, feral or garden plants of similar size, but this difference disappears in multiple regression of fruit crop weight (F in g, fresh mass) on branch or stem diameter (D in cm) and individual fruit weight (W in g): F=22D^1.2 W^0.57. This explains 89% of the variation in F and successfully predicts crop weight for wild tropical and temperate trees and shrubs, but underestimated the crops on commercial, temperate, fruit trees by an order of magnitude. Comparisons of crop weight for feral, wild, and garden plants (F_f) using a simple regression F_f=47D^1.9 show that crop weight is a minor load relative to branch weight for larger branches. Although fruit crops represent a declining proportion of total plant weight as plants become larger, the crops become larger relative to leaf and twig weight and in this sense, reproductive investment increases in larger plants. Finally, our equations, combined with the self-thinning rule, suggest that stands of large species of fruit plants produce more fruit per unit of land area than stands of small ones.     

Searching for the optimum multivariate profile of an ash gourd [<Emphasis Type="Italic">Benincasa hispida</Emphasis> (Thunb.) Cogn.] genotype

Ash gourd is an important vegetable especially in the Indo-China region, but also in America and Africa. It is a monotypic genus, and its genetic pool is considered little diverse, which makes breeding of good ash gourd cultivars difficult. A pool of 56 genotypes, of which 10 are released cultivars and 46 indigenous lines collected from different parts of India, was studied in a two-year experiment. Various traits are important when breeding new cultivars, so an optimum multivariate performance is studied in this germplasm, with a special focus on traits of the greatest importance, namely fruit yield per plant, flesh thickness, vine length, and number of days to female and male flowering. Such performance is studied for the best-yielding genotypes, and promising genotypes in terms of multivariate performance are selected.     

半干旱黄土丘陵区沙棘优良品种引种选育试验研究

1985-1998年先后在黄土高原半干旱区的陕西吴旗,安塞县进行了沙棘优良品种引种选育试验研究。通过引种国内不同地理种源20余种优良沙棘类型。引进俄罗斯优良沙棘品种,采用家系选择法进行试验研究,初步筛选出生态经济型5种沙棘类型,经济型2种类型。前者生长迅速,树冠好,根系发达,郁闭快,水土保持效益好,且果实较大（果径0.8-0.9cm,百果重20-31g),单株产果量为2-3.5kg,Vc和含油量较高,其生态,经济性状较当地野生沙棘为好。此种类型沙棘适于在黄土丘陵大面积荒沟,荒坡种植,通过引种俄罗斯大果,无刺沙棘为好。此种类型沙棘适于在黄土丘陵大面积荒沟,荒坡种植,通过引种俄罗斯大果,无刺沙棘优良品种与本地野生中国沙棘对比分析看,出,其适应性,抗性较中国沙棘差,经济性状较好,通过试验筛选出2种优良类型,果径为0.9-1.3cm,百果重46-52g,单株产果量2-3.5kg,无刺或少刺,此项研究为在半干旱黄土丘陵区大面积荒山,荒沟建造高产,优质沙棘林,高效,持续发展沙棘产业具重要意义,在引种试验中必须掌握好其关键技术,建立好采穗圃,种子园,并建立一定面积的集约经营的高产,优质沙棘园及良种繁育基地,掌握好抚育管理技术,特别是水,肥管理技术。     

Metabolic profiling of leaves and fruit of wild species tomato: a survey of the Solanum lycopersicum complex

The domestication of the tomato Solanum lycopersicum and associated selective pressures eventually led to the large-fruited varieties cultivated today. S. lycopersicum varieties are generally red-fruited, but display considerable variance in fruit colour intensity, shape, and quality. The increase in productivity on cultivation is, however, somewhat offset by the narrowing of the crops genetic base which leads to increased susceptibility to biotic and abiotic stresses. Since S. lycopersicum can easily be crossed with its wild species relatives, this exotic germplasm can provide a valuable source for the improvement of agriculturally important traits. A GC-MS based survey is presented here of the relative metabolic levels of leaves and fruit of S. lycopersicum and five wild species of tomato that can be crossed with it (S. pimpinellifolium, S. neorickii, S. chmielewskii, S. habrochaites, and S. pennellii). Changes in metabolite contents were identified in the wild species that are potentially important with respect to stress responses, as well as in metabolites of nutritional importance. The significance of these changes is discussed with respect to the use of the various wild species for metabolic engineering within wide breeding strategies.