Efficiency of the Use of Doubled-Haploids in Recurrent Selection for Combining Ability
- A. Bouchez *a and
- A. Gallaisbc
In population improvement for combining ability, the use of selfed progenies increases genetic advance per cycle, but it can unduly increase the cycle length. Haplodiploidization (HD) can be very efficient because it induces complete homozygosity in a short period. We compared, from a theoretical approach, the potential of recurrent selection with a tester using doubled haploids (SDHT), with selection with testcrosses of S0, S1, or S2 plants, with or without the use of off-season nurseries, for an annual plant like maize (Zea mays L.). With the same selection intensity, and without off-season nurseries, SDHT with a 4-yr cycle is the most efficient method. Efficiency increases with lower heritability, with an advantage in comparison to the test of S0 plants (S0T) of 40 to 50% at low heritability (h 2 < 0.15) and 12% at high heritability (h 2 = 0.8). Use of off-season nurseries reduces the advantage of SDHT. With a 3-yr cycle, SDHT remains the best at low heritability with a gain of 27% (for h 2 = 0.1) in comparison to S0T with a 2-yr cycle. When using constant effective size, the advantage of SDHT is further reduced or suppressed at the benefit of S0T in 2 yr. The use of HD in recurrent selection for combining ability has its biggest advantage when heritability is low. Consideration of variety development will give more advantage to HD.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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