Background and Aims. In ancient grapevine varieties, the experimental design of field trials is crucial to providing a reliable evaluation of quantitative traits. The main purposes of this study are ...to demonstrate the benefits of the resolvable row-column design (RCD) for quantifying intravarietal variability and performing polyclonal selection and to compare the efficiency of fully and partially replicated designs for quantifying intravarietal variability to implement the latter designs for a preliminary analysis of that variability. Methods and Results. Linear mixed models were fitted to yield data obtained in field trials with fully and partially replicated designs. The results pointed out the importance of the RCD in controlling the spatial variability present in large field trials. Although less precise, a partially replicated design proved to be useful in evaluating intravarietal variability when the average of years was used. Conclusions. The results reinforced the importance of the RCD in increasing the efficiency of intravarietal variability quantification and polyclonal selection. The partially replicated design proved to be useful when the only objective was to perform a preliminary analysis of intravarietal variability. Significance of the Study. Understanding the role of experimental design in grapevine selection field trials will help grapevine breeders enhance their knowledge about variability within ancient varieties and implement more successful polyclonal selection.
There are thousands of ancient grapevine varieties in Europe, each one having a high level of intra-varietal diversity with regard to important economic traits (yield, soluble solids content, ...acidity, anthocyanins, and others). However, this potential has become exposed to a process of genetic erosion since the middle of the last century. The main objective of this work is to present experimental strategies for conservation and utilization of intra-varietal diversity. A concrete example is given about the actions performed in Portugal since 1978. Two main approaches for the conservation of intra-varietal diversity were performed: (1) strict conservation (in pots and in the field without experimental design) for future generations; and (2) conservation and, simultaneously, evaluation of the intra-varietal variability for selection to fulfil the immediate needs of the grape and wine sector (in the field with experimental design). More than 30,000 accessions of Portuguese autochthonous varieties are conserved. Using the theory of mixed models, intra-varietal diversity of the yield was found for the 59 varieties studied. The conservation and the evaluation of the intra-varietal diversity for quantitative traits will allow to extract high economic value, as well as to ensure its utilization to meet the objectives of the vine and wine sector.
The antiquity and diversity of traditional grapevine varieties guarantee a strong historical and natural character and add high economic value to viticulture and wine. A high level of intra-varietal ...diversity of quantitative traits was naturally created and accumulated over centuries. Nowadays, this diversity allows one to carry out selection within a variety and adapt it to the most diverse environmental, agricultural, and market contexts. However, an unusually intense process of genetic erosion of intra-varietal diversity broke out in the 1980s and threatens to destroy within a few decades the diversity created over centuries and millennia. Therefore, the definition of strategies and methods for conserving and exploring intra-varietal genetic variability is crucial for the sustainability of viticulture rich in history and traditions. Those strategies are presented in this work.
High temperatures and extreme drought are increasingly more frequent in Portugal, which represents a strong threat to viticulture in certain regions of the country. These multifactorial abiotic ...stresses are threatening viticultural areas worldwide, and the problem can hardly be overcome only by changing cultural practices. This scenario has raised a major challenge for plant scientists to find ways to adapt existing varieties to the new conditions without loss of their characteristic flavors, yield, and associated varietal character of wines. Aragonez (syn. Tempranillo) is one such variety, widely cultivated in Portugal and Spain, with specific characteristics associated with
. In this context, insight into intravarietal variability to enable its exploitation for selection becomes an important tool to mitigate the effect of multifactorial stresses driven by climate changes. The present work describes an innovative selection approach: selection for abiotic stress tolerance, measured by the leaf temperature of clones under environmental conditions of drought and extreme heat. This evaluation was complemented with values of yield and quality characteristics of the must (pH, acidity, °Brix, and anthocyanins). The application of this methodology was done in an experimental population of 255 clones of Tempranillo for 3 years. The genotypes were then ranked according to their level of tolerance to abiotic stress without loss of yield/quality. To understand the differences at the transcription level that could account for such variability, several of the most tolerant and most sensitive genotypes were analyzed for key genes using reverse transcriptase-quantitative polymerase chain reaction. The results enabled the selection of a group of genotypes with increased tolerance to stress, in relation to the average of the variety, which maintained the typical must quality of Aragonez. In parallel, several transcripts previously acknowledged as markers for abiotic stress tolerance were identified in several clones and are possible targets for plant breeding and genetic modification and/or to develop screening procedures to select genotypes better adapted to the abiotic stress driven by climate change.
The valorisation of genetic variability through the identification suitable genotypes for traits such as yield and must quality is an effective strategy used for grapevine selection. Currently, ...climate change-driven heat waves and drought affect plant growth and wine quality, but little information is available on intravarietal variability regarding responses to stress. In the current work, the intravarietal genetic variability of the Portuguese variety Arinto was studied for yield, must quality, and tolerance to abiotic stress. An innovative approach using rapid, and nondestructive measurements of surface leaf temperature (SLT), Normalized Difference Vegetation Index (NDVI), Photochemical Reflectance Index (PRI), and chlorophyll content (SPAD), was used in an experimental population of 165 clones of Arinto installed according to a resolvable row-column design with 6 replicates. Also, yield and quality characteristics of the must were quantified. Linear mixed models were fitted to the data, and the empirical best linear unbiased predictors (EBLUPs) of genotypic effects for each trait were obtained as well as the coefficient of genotypic variation (CVG) and broad sense heritability. The results enabled the selection of a group of genotypes with increased tolerance to stress, which maintained the must quality of Arinto.
Since the last decade of the last century, it is known that many old grapevine varieties are descendants of other varieties through natural crossing. Portugal has an important program for the ...conservation of representative samples of intra-varietal variability of all autochthonous varieties, managed by the Portuguese Association for Grapevine Diversity (PORVID), which makes looking for genotypes with dubious identification an important activity from a perspective of its valorisation. This communication presents the results of the molecular analysis of 5,000 samples (accessions) from the PORVID’s collection, using nine microsatellite
loci
currently recommended by the International Organization of Vine and Wine (OIV) for genetic grapevine identification. The results obtained confirmed the molecular identity of 4,220 samples corresponding to 214 varieties present in the official list of Portuguese varieties. In 780 samples, 95 profiles with a plural number of accessions revealed not to be listed in the Vitis International Variety Catalogue (VIVC) database, corresponding to possible varieties either descendent from natural crossing from at least one known parental variety, or from undetermined origin. Furthermore, the need for a comprehensive strategy aimed at uncovering other hidden varieties is discussed to prevent their imminent loss, deepen understanding of their origin, and add economic value and sustainability to the vine and wine sector.
This work addresses to the genetic analysis and selection in populations where the whole genotypic value is transmitted through generations, using grapevine yield data as a case study. Several models ...were applied to different types of data sets. The individual and mean year yield and the balanced and unbalanced data resulting from various experimental designs (completely randomized, randomized complete block and row–column) were used. The aims of present work were to study: (1) the applicability of a generalised measure of broad-sense heritability to evaluate the success of the genotypic selection and compare it with the classical approach; and (2) the effect of different models on the accuracy and precision of the genotypic variance component and on the generalised broad-sense heritability estimates. The results showed that the computation of a measure of generalised broad-sense heritability is very feasible and useful for evaluating the efficiency of genotypic selection. In this study, 88 % of the fitted models did not comply with the standards for applying the classical concept of heritability. The differences between both the classical and generalised broad-sense heritability estimates increased with the complexity of the model. Higher broad-sense heritability estimates were consistently obtained with the mean years. The most accurate and precise estimates of the genetic parameters were obtained with the spatial models. Finally, the genotypic variance component of yield and the generalised broad-sense heritability were consistently significant for all grapevine varieties.
Clonal selection allows control of virus diseases and selection of genotypes on agronomic, viticultural or enological criteria. Clonal selection has the major drawback that it impoverishes genetic ...diversity and exposes growers to environmental instability of clones (genotype X environment interaction). Clonal selection has become the almost unique way of propagating plant material for vineyards, hence threatening the genetic diversity of the grapevine. For major grapevine varieties, some genetic diversity is maintained in institutional collections. However, this way of conservation is insufficiently developed, it is expensive and remains fragile. A cost effective way to preserve intra-varietal diversity is to maintain a limited proportion of mass selection in vine propagation. Private clonal selection can also contribute, in a more limited way, in maintaining genetic resources. Another approach to carry out conservation and selection of grapevine is the methodology followed in Portugal. This strategy is exemplified with the conservation/selection of an ancient Portuguese variety. The work begins with the “ex situ” conservation of a representative sample of the intravarietal diversity of the variety, which, in practice, corresponds to a large field trial with hundreds of clones under an experimental design suitable for reducing random variation of quantitative traits. From evaluating those traits (yield and must quality traits), the intravarietal diversity is quantified and the range of the predicted genotypic effects for each of those traits is analyzed. Different mass selections (polyclonal selections) are carried out for distribution and planting of new vineyards. These different mass selections provide high economic gains and also the preservation of diversity in a complementary manner to that which started the work on-farm conservation.
Grapevine (
L.) diversity richness results from a complex domestication history over multiple historical periods. Here, we used whole-genome resequencing to elucidate different aspects of its recent ...evolutionary history. Our results support a model in which a central domestication event in grapevine was followed by postdomestication hybridization with local wild genotypes, leading to the presence of an introgression signature in modern wine varieties across Western Europe. The strongest signal was associated with a subset of Iberian grapevine varieties showing large introgression tracts. We targeted this study group for further analysis, demonstrating how regions under selection in wild populations from the Iberian Peninsula were preferentially passed on to the cultivated varieties by gene flow. Examination of underlying genes suggests that environmental adaptation played a fundamental role in both the evolution of wild genotypes and the outcome of hybridization with cultivated varieties, supporting a case of adaptive introgression in grapevine.
The conservation of the genetic diversity within ancient grapevine varieties, which are rarely grown nowadays and are subject to genetic erosion, is extremely important in guaranteeing future ...utilization. This article studies the use of unreplicated trials as a way of preserving the genetic variability of those varieties and quantifying their intravarietal diversity as the raw material for future selections. Through simulation, several experimental situations were generated, varying the numbers of test and check treatments and the type of experimental design associated with the check treatments (augmented randomized complete block design and alpha–alpha design). The quality of the estimates of genotypic variance increased with the increase of the number of genotypes in the conservation collection and with the frequencies of plots with check genotypes. A greater precision was achieved in the quantification of the genetic diversity of ancient grapevine varieties when collections of over 250 genotypes and a minimum of 33 % of plots containing check genotypes were used.
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