Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 192

Design I is a very popular multipurpose design for both theoretical and practical plant breeding applications (Figure 4.5). It is commonly used to estimate additive and dominance variances as well as for evaluation of full‐ and half‐sib recurrent selection. It requires sufficient seed for replicated evaluation trials, and hence is not of practical application in breeding species that are not capable of producing large amounts of seed. It is applicable to both self‐ and cross‐pollinated species that meet this criterion. As a nested design, each member of a group of parents used as males is mated to a different group of parents. NC design I is a hierarchical design with non‐common parents nested in common parents.

Figure 4.5 The North Carolina Design I. (a) This design is a nested arrangement of genotypes for crossing in which no male is involved in more than one cross. (b) A practical layout in the field.

The total variance is partitioned as follows:

Source	df	MS	EMS
Males	n−1	MS1	σ2w + rσ2flm + rfσ2m
Females	n1(n2 – 1)	MS2	σ2w + rσ2flm
Within progenies	n1n2(r − 1)	MS3	σ2w

This design is most widely used in animal studies. In plants, it has been extensively used in maize breeding for estimating genetic variances.