Triple test cross and six-population techniques for partitioning the components of genetic variance in faba bean (Vicia faba)

The efficiency of the triple test cross (TTC) and the six-population biometrical analyses was compared in terms of assessing and quantifying the components of genetic variance for two faba bean crosses: Triple White x Giza 843 and NA112 x Giza 429. Several traits were studied including days to first flower, plant height, branches/plant, pods/plant, seeds/pod, 100-seed weight and seed yield/plant. The results supported the triple test cross biometrical approach as it uses first degree statistics and can be applied to any population irrespective of its genetic architecture. Absence of a scalar relationship between triple test cross families (orthogonality) ensures independence between means and variance with no restrictive assumptions. Both methods provided evidence for epistasis, and both additive and dominance genetic components in the genetic control of the studied traits.