Principles of Plant Breeding (2+1)

Estimation of Heterosis

1. Average heterosis:
It is the heterosis where F1 is superior to mid parent value. In otherwords superior to average of two parents.
F1 - MP
--------- x 100
MP
Where F1 = Mean of hybrid
             MP = Mid parental value.
  (P1 + P2) where P1 = Parent 1
MP = ---------- P2 = Parent 2
This type of heterosis is of no use in agriculture since the superiority is below the better parent value

2. Heterobeltiosis:
Superiority of F1 over the better parent.
F1 - BP
--------- x 100
BP
Where BP = Mean of Better Parent.

3. Economic heterosis:
Superiority of the F1 compared to the high yielding commercial variety in a particular crop.
F1 - CV
--------- x 100
CV
Where CV = Mean of Commercial Variety.

4. Negative heterosis:
Performance of F1 inferior to better parent / mid parent value. - e.g. Duration.