Variation of morphological descriptors for the evaluation of tomato germplasm and their stability across different growing conditions

Abstract

Germplasm and breeding materials are usually characterized using morphological and agronomic descriptors, which should have a high heritability. Despite the widespread use of tomato (Solanum lycopersicum) standardized descriptors, little information exists on environmental effects on descriptor values and their heritability. We have evaluated 12 tomato accessions from seven cultivar groups in three different environments (openfield conventional, open-field organic, and greenhouse) and characterized them with 36 descriptors. A wide range of variation was found for most descriptors, demonstrating their utility for describing tomato materials and their diversity and relationships. The analysis of descriptors variation reveals that while for some descriptors with a simple genetic control the accession effect accounts for 100% of the variation, for others like yield per plant only 10.83% of the variation observed is due to the accession effect. Although significant differences were found among environments for most descriptors, including a much higher yield in the open-field conventional environment than in the two others, the environmental effect was low for most traits. However, the genotype × environment effect generally had an important contribution to the structure of variation for many descriptors, and for three traits it had the highest contribution to the percentage of the sum of squares. As a result of the variation structure, the heritability values are high (>0.7) for only 10 descriptors, while for five is low (<0.3). Principal components analysis (PCA) reveals that projections in the PCA graph of a same accession grown in different environments plot together in the same area of the PCA graph. Although cultivar groups are generally clearly separated in the PCA graph, 2 accessions from the same cultivar group in some cases are intermixed. These results have important implications for detecting tomato duplicates and establishing core collections, as well as for analyzing germplasm and breeding results, when using data sets containing data of accessions grown in different environments.

Insights Into the Adaptation to Greenhouse Cultivation of the Traditional Mediterranean Long Shelf-Life Tomato Carrying the alc Mutation: A Multi-Trait Comparison of Landraces, Selections, and Hybrids in Open Field and Greenhouse

“…Traditional long shelf-life tomato varieties carrying the alc mutation are well-adapted to open field cultivation and have specific characteristics that make them of special interest, like their tolerance to drought, extended post-harvest conservation period without refrigeration, and high contents in soluble solids (Mutschler et al, 1992; Conesa et al, 2014; Figàs et al, 2015b; Fullana-Pericàs et al, 2017, 2018). The two types of cultivation environment (OF and GH) are very different and our study was aimed at evaluating the performance of the tomatoes carrying the alc mutation under these two contrasting cultivation environments, which present many differences from the agronomic and management points of view, apart from taking place in different seasons of the year (Csizinsky, 2005; Peet and Welles, 2005; Figàs et al, 2018). As a consequence, the physiological mechanisms for growth and development processes acting in OF or GH conditions may be different, due to the great differences in temperature, solar radiation, wind, air humidity, and agricultural practices, among others (Tardieu, 2013).…”

“…In particular, environmental effects are important for fruit quality, defined by Kyriacou and Rouphael (2018) as “ a dynamic composite of physicochemical properties and evolving consumer perception ,” which embraces organoleptic, nutritional, and bioactive compounds (Hounsome et al, 2008; Barrett et al, 2010; Kaushik et al, 2015). In other works in tomato, G × E interaction in tomato varieties when comparing open field and greenhouse conditions has been very important for both yield and quality traits (Kuti and Konuru, 2005; Roselló et al, 2010; Adalid et al, 2012; Figàs et al, 2018). However, to our knowledge there are no comprehensive evaluations of traits of interest to producers (plant and fruit morphology, agronomic traits), traders (fruit characteristics, post-harvest performance), and consumers (fruit morphology, composition) of a significant number of long shelf-life tomato varieties from different origins and types, including landraces and commercial selections and hybrids.…”

A step towards Balkan Capsicum annuum L. core collection: Phenotypic and biochemical characterization of 180 accessions for agronomic, fruit quality, and virus resistance traits

“…Phenotypic characterization can be a daunting task that needs a well-thought strategy and prolonged efforts [ 19 ]. Even then, phenotypic characterization is difficult to evaluate when inter-varietal differences are minute and subtle [ 20 ]. Conventionally, the characterization of pepper genetic resources has always been wont to investigate phenotypic variability.…”

Phytochemical Assessment of Native Ecuadorian Peppers (Capsicum spp.) and Correlation Analysis to Fruit Phenomics

“…Nonetheless, highly precise phenotyping based on objective scales is much more limited. Historically, pepper morphological characterization has been performed with conventional heritable descriptors based on manual and visual inspections, which can be strongly biased [ 13 , 14 ]. High-throughput automated phenotyping tools are being continuously developed [ 15 ].…”