Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 190

In this design, the breeder selects a large number of plants (n) at random and crosses them in pairs to produce ½ n full‐sib families. The biparental (BIP) is the simplest of the mating designs. If r plants per progeny family are evaluated, the variation within and between families may be analyzed as follows:

Source	df	MS	EMS
Between families	(½ n) − 1	MS1	σ2w + rσ2b
Within families	½ n(r − 1)	MS2	σ2w

where σ²b is the covariance of full‐sibs (= ½ V_A + ¼ V_D + V_EC = 1/r (MS₁ − MS₂) and σ²w = ½ V_A + ¾ V_D + V_EW = MS₂)

The limitation of this otherwise simple to implement design is its inability to provide the needed information to estimate all the parameters required by the model. The progeny from the design comprise full‐sibs or unrelated individuals. There is no further relatedness among individuals in the progeny. The breeder must make unjustifiable assumptions in order to estimate the genetic and environmental variance.