Genotype by environment interactions, heritabilities and genetic correlations for productive traits of Haliotis rufescens

Autor: William J. Farías, Katherina Brokordt, Federico M. Winkler
Rok vydání: 2017
Předmět:
Zdroj: Aquaculture. 473:407-416
ISSN: 0044-8486
DOI: 10.1016/j.aquaculture.2017.02.030
Popis: A critical aspect of a selective breeding program is whether responses of traits of interest are similar in different environments. The magnitude of the genotype by environment interaction (GEI) together with heritability ( h 2 ) accounts for this aspect. Despite the economic significance of abalones and the interest in genetic improvement programs for their cultivation, only one previous study has reported GEI estimations for this group of mollusks. The objective of the present study was to estimate h 2 and the existence of GEI for growth traits of Haliotis rufescens cultivated in Chilean farms with different environmental and management conditions. A total of 2 cohorts (2007 and 2009) of 50 and 42 families of full sibs (FS), respectively, were used. Replicates of each FS family of the 2007 cohort were distributed in two farms in the northern region of the country and were evaluated after 1 and 2 years of cultivation. For the 2009 cohort, replicates of each family were distributed in a farm in the northern region and a farm in the southern region of the country. The estimated h 2 values were significant for all traits, with the length and width of the shell and total weight varying primarily by cohort between 0.22–0.62, 0.16–0.58 and 0.40–0.53, respectively. The genetic correlations ( r G ) between traits were all higher than 0.82. The expected correlated responses for improving the total weight using the shell length as a selection criterion predict a selection gain (14–51%) similar to what would be obtained by selecting directly for weight (16–51%) in all environments examined. Thus, indirect selection by shell length and the direct use of total weight as a selection criterion would yield similar effects in terms of the increase in weight. High r G , not significantly different from 1, were observed for the analyzed traits between replicates of the families in any of the farms compared, both within the northern region and between the northern and southern regions of the country. These high r G were indicative of non-significant GEI for the analyzed traits. Therefore, results suggest that one selective breeding program could provide improved red abalone for the industry in Chile with consistent results between farms located in different environments. Statement of relevance Abalones are one of the most important mollusks in aquaculture due to their commercial value in international markets, especially in Asia; as such there are several efforts to develop abalone breeding programs in different countries. In this work we addressed a critical aspect for a selective breeding program, which is to know whether responses of productive traits are similar in different environments. Considering that the magnitude of the genotype by environment interaction (GEI) together with heritability ( h 2 ) accounts for this aspect, we estimated these genetic quantitative parameters for growth traits (total mass, shell length and width) in two cohorts of the red abalone, Haliotis rufescens , cultivated throughout Chile. Results indicated that the application of selection by the shell length at age of harvest has the greatest potential for improving the production of H. rufescens . These improvements are practical (ease and accuracy in measurement), have indirect effects on the objective trait of selection (weight), and consist of a trait that is not significantly affected by genotype-environment interactions. In addition, the results obtained suggest that a single selective breeding program would be sufficient for the red abalone industry in Chile, as the response to selection of traits associated with growth would be similar in different environments. Red abalone is naturally distributed in California and Baja California coasts, and this information can be especially useful in planning breeding programs also in the west coast of USA and Mexico.
Databáze: OpenAIRE
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