Concepts of varietal value and of test value in autotetraploids. Application to genetic advance in population improvement

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Abstract
The application to autotetraploids of the concepts of varietal value and of test value allows the derivation of expressions of genetic advance for the different types of varietal values (per se value, line value, single-cross or double-cross values, synthesizing ability) according to the testing system used to select the intercrossed plants. Formulae are given for series of intrapopulation schemes and for reciprocal recurrent selection. With autotetraploids, if non-inbred plants are intercrossed and when epistasis is not involved, there is a contribution of additive effects and of dominance effects for the considered testing systems. However, it is shown that, except for mass selection or S1 selection devoted to improve the per se value of the population, the contribution of dominance is very low. The formulae are exactly the same as for diploids if the contribution of dominance variance is neglected.Key words: autopolyploid, quantitative genetics, varietal ability, test value, recurrent selection.