ISSN:
1573-5060
Keywords:
breeding efficiency
;
bulk breeding
;
sampling losses
;
single seed descent
;
selection
;
variation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The consequences of sampling losses that occur with the bulk breeding method are studied. The expected extinction rates are computed for various population sizes and various distributions of the number of seeds per plant (multiplication rates), using algebraic formulas in simple cases and computer simulations in more complex ones. Expected extinction rates are always high: they exceed 20 per cent after one generation. If the multiplication rate is not too variable, about 36, 50, 60 and 66 per cent of the lines are lost after 1, 2, 3 and 4 generations of bulk propagation respectively. The expected extinction rate increases almost linearly with the coefficient of variation of the multiplication rate after the first generation of bulk propagation. Random losses only partially add to sampling losses. Their effect is enhanced by a high coefficient of variation of the multiplication rate, but it is more and more reduced as generations advance. The selection resulting from sampling is also studied. It is shown that the response to selection is equal to the response that would be observed in a truncation selection procedure with an intensity equal to the coefficient of variation of the heritable component of the multiplication rate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00039397
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