Genotype by environment interaction of tomato blossom-end scar size

Summary Large blossom-end scar is a disorder in tomato fruit which reduces its marketability. The disorder is affected by genotype and by several environmental factors and therefore the genotype by environment interaction was studied by stability analysis. Blossom-end scar size was recorded for 4 tomato cultivars grown in 6 fields. The blossom-end scar size (BSC) was affected by the genotype, the field and their interaction. Stability analysis revealed that most of the interaction resulted from different stability of the cultivars. Heterogeneity of the slopes was significant (P<0.0013). The stability slopes were 0.29, 0.74, 1.11 and 1.85 for BR-214, FA-38, Hayslip and Suncoast, respectively. The stability slopes seemed to associate with the means of the cultivars over all environments, which were 1.57, 2.92, 3.84 and 5.43, respectively. Analysis of a blossom-end scar index (BSI), which also takes fruit size into account, revealed stability similar to BSC. It was concluded, that selection for small BSC under most conditions would yield cultivars with small and stable BSC under most growing environments, however differences between genotypes in non-inducing environments are expected to be small.     

Improving tomato fruit quality and the european regulatory framework

Tomato fruit quality is determined by a complex set of characters. Fruit used by the fresh market industry must have different attributes than those used by the processing industries. We have determined the major targets of the tomato industry and have isolated from the tomato itself genes which based upon their biochemical function are expected to improve texture and rheology, colour, soluble solids and flavour. Our research is aimed at proving this concept. So far we have demonstrated that polygalacturonase (PG) is a major fruit quality gene providing the processing tomato industry with improved viscosity. Commercial tomato hybrids have been developed in collaboration with Petoseeds (USA) which carry this effect gene. The regulatory system in Europe will be reviewed. Field trials are covered by the EC directive 90/220, which has now been implemented by all countries belonging to the European Union. On the contrary there are no European-wide regulations in place to cover the production of genetically modified plants as food sources. The evolving food regulations will be reviewed and evaluated in the context of competitiveness of the European plant biotechnology industry.     

Genotype x environment interaction for root traits in maize,as analysed with factorial regression models

Summary The efficiency of genotopic and climatic characteristics in accounting for the interaction between genotypes and environments has been assessed in a three-year trial involving a set of genotypes presenting a range of root morphology characteristics (number and size). Climatic information on rainfall and temperature was recorded during the experiments, together with extra data on the growth and development of the genotypes. Their effects have been tested in factorial regression models.Climatic covariates were very powerful in accounting for the genotype by year interaction as well as the year main effect alone. For the number of adventitious roots on internode 7, the main effect of year could be described as a linear function of the average temperature and precipitation that occurred during the period of root initiation and growth. For internode 6, no clear conclusion was possible. For the root traits studied, 74 to 98% of the interaction could be explained by one climatic covariate. The regression coefficients can be considered as measures of genotypic stability.The genotypic covariates describing aerial development performed rather poorly, compared with environmental ones, even though the physiological and functional relationships between root and shoot are well known. Neither genotype main effect nor genotype by year interaction could be described sufficiently by factorial regression. Still, the genotypic covariates performing best clearly differed between root counts and size. Also the best genotypic covariates differed for main effect and interaction.     

Inheritance of quality traits in processing tomato (Lycopersicon esculentum Mill.)

Summary The genetic basis of pH, colour and soluble solids in processing tomato is examined. In a first experiment, aimed at identifying the base populations with which to start selection, parents, F₁ and F₂ progenies of an 8 × 8 diallel cross without reciprocals were tested.The results indicate that additive, dominance and additive x additive epistatic effects were noticeable for the three characters. Higher order interlocus interactions were also detected.As to the soluble solids, a trait for which higher order epistatic effects were less marked, the breeding potential of the cross combinations was assessed by calculating the expected mean values at the F generation. Some cross populations having C33 or C35 as parent appeared to be superior.A second experiment was conducted to collect data on the heritability of the foregoing qualitative traits by utilizing the regressions of F₃ offspring on F₂ parents. The low heritability coefficients observed would suggest the ineffectiveness of individual selection in early generations.In both the F₂ and F₃ generations rather low correlation coefficients among the three quality traits were observed.     

Genotype X environment interaction and stability analysis in upland rice (Oryza sativa L.) varieties in Ethiopia

Journal of Crop Science and Biotechnology - Determination of the genotype x environment interaction (GEI) and stability of upland rice varieties for grain yield provides the basis to identify...     

Detection of epistatic and environmental interaction QTLs for leaf orientation‐related traits in maize

Leaf architecture traits in maize are quantitative and have been studied by quantitative trait loci (QTLs) mapping. However, additional QTLs for these traits require mapping and the interactions between mapped QTLs require studying because of the complicated genetic nature of these traits. To detect common QTLs and to find new ones, we investigated the maize traits of leaf angle, leaf flagging‐point length, leaf length and leaf orientation value using a set of recombinant inbred line populations and single nucleotide polymorphism markers. In total, 19 QTLs contributed 4.13–13.52% of the phenotypic effects to the corresponding traits that were mapped, and their candidate genes are provided. Common and major QTLs have also been detected. All of the QTLs showed significant additive effects and non‐significant additive × environment effects in combined environments. The majority showed additive × additive epistasis effects and non‐significant QTL × environment effects under single environments. Common and major QTLs provided information for fine mapping and gene cloning, and SNP markers can be used for marker‐assisted selection breeding.     

Genotype by environment interaction for disease resistance and other important agronomic traits supporting the indication of common bean cultivars

The present work aimed to study the genotype by environment interaction for nine important agronomic traits as a support for the indication of common bean cultivars for the Southern region of Brazil, identifying cultivars that possess high adaptability/stability. We carried out 25 field trials, in the rainy and dry sowing seasons, at different locals in the states of Paraná and Santa Catarina, from 2008 to 2010. The trials included 17 cultivars. Data were obtained for agronomic traits and subjected to variance analyses, and to adaptability and stability analyses according to the Nunes method. The genotype by environment interaction is important for different agronomic traits. There is genetic variation among cultivars and it was identified a different number of superior cultivars for each trait. Considering the means and adaptability and stability scores, 88% of the cultivars were superior for rust, 53% for anthracnose, 41% for grain yield, plant architecture and cycle, 30% for fusarium wilt and lodging, and 18% for angular leaf spot and common bacterial blight. For some of these traits, like angular leaf spot, common bacterial blight, fusarium wilt and lodging, it is necessary to intensify the efforts to provide more cultivars with high resistance or tolerance level, adaptability and stability. BRS Esplendor, a black-seeded cultivar, CNFC 10431 and BRS Sublime, both carioca-seeded cultivars, presented superiority for six of nine traits, being indicated to be used in the Southern region of Brazil. Other cultivars presented advantages for fewer traits and must be used in environments which these traits present greater importance.     

Identification of QTLs for fruit quality traits in Japanese apples: QTLs for early ripening are tightly related to preharvest fruit drop

Many important apple (Malus × domestica Borkh.) fruit quality traits are regulated by multiple genes, and more information about quantitative trait loci (QTLs) for these traits is required for marker-assisted selection. In this study, we constructed genetic linkage maps of the Japanese apple cultivars ‘Orin’ and ‘Akane’ using F₁ seedlings derived from a cross between these cultivars. The ‘Orin’ map consisted of 251 loci covering 17 linkage groups (LGs; total length 1095.3 cM), and the ‘Akane’ map consisted of 291 loci covering 18 LGs (total length 1098.2 cM). We performed QTL analysis for 16 important traits, and found that four QTLs related to harvest time explained about 70% of genetic variation, and these will be useful for marker-assisted selection. The QTL for early harvest time in LG15 was located very close to the QTL for preharvest fruit drop. The QTL for skin color depth was located around the position of MYB1 in LG9, which suggested that alleles harbored by ‘Akane’ are regulating red color depth with different degrees of effect. We also analyzed soluble solids and sugar component contents, and found that a QTL for soluble solids content in LG16 could be explained by the amount of sorbitol and fructose.     

Estimates of genotypic and yearly variations on fruit quality and functional traits for tetraploid table grape breeding

We estimated genetic and environmental variance components for fruit quality traits (cluster weight, berry weight, soluble solids content, total sugar content, sugar composition, free acid content, total amino acid content, amino acid composition), and a functional trait (gamma-aminobutyric acid (GABA) content) of three commercial tetraploid table grape cultivars (Kyoho, Pione, Suiho) grown in Japan over three successive years. ANOVA showed that the effect of genotype was significant (P < 0.05) for all traits except soluble solids content and total sugar content. The effect of the year was significant for all traits except amino acid composition (γ ratio) and GABA content. The variance of genotype (σ _g ²) was highest for γ ratio (63.6%), high in sugar composition (α ratio, 60.3%) and GABA content (58.8%), and negligible for soluble solids content (0.0%) and total sugar content (0.0%). The variance of among years (σ _y ²) was very high in soluble solids content (82.8%), high in total sugar content (60.2%) and negligibly small in γ ratio (8.7%) and GABA content (6.4%). Some effects of genotype × year interaction, among vines within genotypes, and vine × year interaction were statistically significant, but these components were negligibly small. Except for soluble solids content and total sugar content, significant varietal differences in the traits were recorded. Variance estimates for each trait provides useful information for optimal yearly repetition to effectively discriminate genetic differences in fruit quality and functional traits for improving future tetraploid table grape breeding programs.     

Genetic variation in a large population of tomato varieties. 1. Analysis of distribution of single traits

Summary The distribution of vegetative and fruit characters among a large population of parent and F₁ hybrid tomato cultivars is described and heritability estimates are given. Comparison of parent and offspring subpopulations revealed higher overall values in the F₁ hybrids for vegetative characters and lower overall values for fruit characters than in the parents. A general Galtonean feature of higher offspring values for cross combinations with low parent means and lower offspring values for cross combinations with high parent mean is evident in all traits studied. The predictive value of the data given is evaluated.Contribution Volcani Center, Agricultural Research Organization, Bet Dagan, Israel, 1972 Series, No 2228-E. Supported in part by Ford Foundation Grant No A-5.The Israel Institute of Applied Social Research, Jerusalem, Israel.     

Phenotypic diversity and relationships of fruit quality traits in apricot (Prunus armeniaca L.) germplasm

Fruit quality attributes were studied for two consecutive years in forty-three apricot cultivars and selections grown in a Mediterranean climate. Physical parameters (weight, size, flesh and skin colour, percentage of blush, firmness and percentage of dry matter), chemical parameters (total soluble solids content and acidity) and sensory parameters (attractiveness, taste, aroma and texture) were evaluated. A high variability was found in the set of the evaluated apricot genotypes and significant differences were found among them in all studied quality attributes. Year-by-year variations were observed for some pomological traits such as harvest date, flesh colour, fruit weight, firmness and soluble solids content. A high correlation was found among some apricot quality attributes. In addition, principal component analysis (PCA) made it possible to establish similar groups of genotypes depending on their quality characteristics as well as to study relationships among pomological traits in the set of apricot genotypes evaluated.     

Structuring genotype × environment interaction for quality traits in bread wheat, in two multi-location series of trials

Structure of genotype × environment interaction was studied in two series of trials for three quality traits in bread wheat. Two kinds of environments were present in each series of trials: macro-environments defined as locations or location × year combinations and micro-environments induced by diversified cultural practices within each site. For each trait, a simultaneous clustering procedure was used to identify groups of environments which were homogeneous for interaction. An optimised series of trials was proposed from the clusters obtained. The cultural practice based on nitrogen fertilisation seemed to better diversify environments for interaction than use of fungicide, when all quality traits were considered. Determining an optimised series of trials simultaneously for the three traits led to keeping more environments than when one trait was considered. Suggestions for establishing a series of trials for a multi-trait analysis were proposed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Diffusivity of 1-methylcyclopropene in spinach and bok choi leaf tissue,disks of tomato and avocado fruit tissue,and whole tomato fruit

Gaseous 1-methylcyclopropene (1-MCP) has been widely employed for delaying ripening and senescence of harvested fruit and vegetables; however, details on ingress of gaseous1-MCP in plant tissues, which might contribute to differences in responsiveness of different horticultural commodities to 1-MCP, have not been reported. In this study, we used spinach and bok choi leaves, disks from tomato epidermis, stem-scar and avocado-exocarp tissues, and whole tomato fruit to examine ingress of gaseous 1-MCP. Using a dual-flask system, equilibration of 20 μL L⁻¹ (831 μmol m⁻³) 1-MCP through leaf tissue was reached within 1–2 h, and paralleled 1-MCP transfer through glass-fiber filter paper. For disks derived from fruit tissues, changes in 1-MCP concentrations in the dual-flask system showed anomalous patterns, declining as much as 70% in source flasks with negligible accumulation in sink flasks. The pattern of 1-MCP distribution was markedly different from that of ethylene, which approached equal distribution with tomato stem-scar and avocado exocarp but not tomato epidermis tissues. 1-MCP ingress was further addressed by exposing whole tomato fruit to 20 μL L⁻¹ 1-MCP followed by sampling of internal fruit atmosphere. Tomato fruit accumulated internal gaseous 1-MCP rapidly, reaching approximately 8–9 μL L⁻¹ within 3–6 h at 20 °C. Internal 1-MCP concentration ([1-MCP]) declined around 74 and 94% at 1 and 3 h after exposure, respectively. Ingress was similar at all ripening stages and reduced by 45% in fruit coated with commercial wax. Blocking 1-MCP ingress through stem- and blossom-scar tissues reduced accumulation by around 60%, indicating that ingress also occurs through epidermal tissue. Fruit preloaded with 1-MCP and immersed in water for 2 h retained about 45% of post-exposure gaseous [1-MCP], indicating that 1-MCP is not rapidly sorbed or metabolized by whole tomato fruit. Rapid ingress of gaseous 1-MCP was also observed in tomato fruit exposed to aqueous 1-MCP. Both accumulation and post-exposure decline in internal gaseous [1-MCP] are likely to vary among different fruit and vegetables in accordance with inherent sorption-capacity, surface properties (e.g., waxes, stoma), volume and continuity of gas-filled intercellular spaces, and tissue hydration.     

Inheritance mode of fruit traits in melon: Heterosis for fruit shape and its correlation with genetic distance

Fruit quality traits were studied in 12 exotic accessions and their hybrids with a “Piel de Sapo” inodorus melon cultivar. The genetic relationships among these genotypes were assessed with 16 microsatellite markers, which agreed with the classification of Cucumis callosus, C. pubescens and C. trigonus as accessions within C. melo. There were very large differences between all the exotic accessions and “Piel de Sapo” genotype for fruit traits. When the hybrids were analysed, three different situations regarding mid parent heterosis were found, depending on the trait: no heterosis (soluble solid concentration), highly variable, from negative to positive (fruit weight and fruit diameter) and general positive heterosis (ovary shape, fruit length and fruit shape). Best parent heterosis for fruit shape was also common among hybrids. A highly significant correlation (r = 0.81) was detected between fruit shape and fruit length heterosis, suggesting that fruit shape heterosis is caused mainly by the enlargement of the fruit longitudinally. A highly significant correlation (r = 0.84) between heterosis for fruit shape and genetic distance, as estimated with microsatellites, was also found. These results, together with the previously reported observation that melon fruit shape is polygenic and highly heritable, makes the genetics of melon fruit shape a suitable system for dissecting the genetic and molecular basis of heterosis.