Experimental designs for evaluation of genetic variability and selection of ancient grapevine varieties: a simulation study

Abstract

Classical methodologies for grapevine selection used in the vine-growing world are generally based on comparisons among a small number of clones. This does not take advantage of the entire genetic variability within ancient varieties, and therefore limits selection challenges. Using the general principles of plant breeding and of quantitative genetics, we propose new breeding strategies, focussed on conservation and quantification of genetic variability by performing a cycle of mass genotypic selection prior to clonal selection. To exploit a sufficiently large amount of genetic variability, initial selection trials must be generally very large. The use of experimental designs adequate for those field trials has been intensively recommended for numerous species. However, their use in initial trials of grapevines has not been studied. With the aim of identifying the most suitable experimental designs for quantification of genetic variability and selection of ancient varieties, a study was carried out to assess through simulation the comparative efficiency of various experimental designs (randomized complete block design, a design and row-column (RC) design). The results indicated a greater efficiency for a and RC designs, enabling more precise estimates of genotypic variance, greater precision in the prediction of genetic gain and consequently greater efficiency in genotypic mass selection.

The utilization of unreplicated trials for conservation and quantification of intravarietal genetic diversity of rarely grown ancient grapevine varieties

“…Consequently, it became a good practical quantifier of genetic diversity. The models and the values for the model parameters used for the data generation were supported by some results already described for large grapevine selection field trials conducted in Portugal according to randomized complete block (RCB) designs (Gonçalves et al 2007(Gonçalves et al , 2010. We therefore aimed to evaluate the quality of the estimates of genetic parameters in large collections of genotypes, with different intravarietal genetic variability, and organized according to different variants of unreplicated trials.…”

“…The success of the results obtained from these trials in the quantification of genetic diversity and in the mass genotypic selection depends on the genetic variability of the variety and of the tools utilized for controlling environmental variation. These tools are: (1) efficient experimental designs (appropriate for trials with a large number of treatments), namely, alpha and row-column designs (Gonçalves et al 2010); and (2) efficient models for data analysis (Gonçalves et al 2007).…”

Genetic Variability Evaluation and Selection in Ancient Grapevine Varieties

“…The use of these designs in initial trials of grapevines was studied by Gonçalves et al (2010). In that work, the authors compared several experimental designs via simulations, including randomised complete block, alpha and row-column designs, with the aim of identifying the designs that are most suitable for quantifying and utilising the genetic variability.…”

“…Examples of mixed spatial models that are applied to grapevine initial field trials are described in Gonçalves et al (2007). Models for data analysis of different experimental designs, namely, models for the analysis of randomised complete block, alpha, row-column and latinised designs, are described in Gonçalves et al (2010). where t represents the number of the evaluated traits and, for example, 1 y is a vector with 1 n observations for yield, 2 y is a vector with 2 n observations for ºBrix, etc., and 1 e , 2 e , etc., are the correspondent vectors of random errors.…”

The preservation of genetic resources of the vine requires cohabitation between institutional clonal selection, mass selection and private clonal selection

“…This approach is supported by an association that brings together universities, companies and organizations representing the wine industry (PORVID). The methodology develops over three cycles [4][5][6]: 1) sampling variability in different regions where the variety is grown (hundreds of mother plants in ancient vineyards); 2) planting a large field trial with sampled plants (100 to 400, each one vegetatively propagated originating a clone) with the objectives of conservation, quantification of the genetic variability of agronomic and qualitative traits and mass selection of a group of clones for immediate use and intermediate selection of clones to enter cycle 3; 3) planting multienvironmental trials with clones selected from cycle 2 focusing on evaluation of environmental stability (low genotype by environment interaction) and quality of wine. This paper covers the quantification of genetic diversity and mass selection of clones within ancient variety "Arinto" (cycles 1 and 2 as referred above, that is, ex situ conservation and mass selection only).…”