Mating designs commonly used in plant breeding: A review

Mating design represents "rules" for arranging different controlled crossings; a mating design is a procedure of producing progenies. This review describes mating designs commonly used in plant breeding. Biparental is the simplest design in which a number of P plants are paired off to give ½P families; the parents are mated only once in pairs. The design is simple and it provides information needed to determine if significant genetic variation is present in a population for a long term selection program. A polycross is a mating arrangement for interpollinating a group of cultivars or clones using natural hybridization in an isolated crossing block. The design is often used for generating synthetic cultivars. The North Carolina (NC) mating designs permit determination and/or estimation of variance components (additive and dominance components) by using the information from half-sib (HS) families. The experimental material of North Carolina designs I, II and III is developed from F2 generation as a base material. The design III (NCIII) involves backcrossing the F2 plants to the two parental inbred lines from which the F2 were derived. The NCIII design was extended to include a third tester. This third tester is the F1 from the two parental inbred lines; in this extended form, this design is known as the triple test cross (TTC). Line x Tester mating design uses inbred lines as the base population. The design is useful in deciding the relative ability of a number of female and male inbreds to produce desirable hybrid combinations. When the same parents are used as females and males in breeding, the mating design is called diallel. Parents used range from inbred lines to broad genetic base varieties to clones. The design is the most commonly used in crop plants to estimate GCA and SCA and variances. Generally, it should be noted that is not the mating design per se, but the breeder who breeds a new cultivar. Consequently, proper choice and use of a mating design will provide the most valuable information for breeding