a) Combination Breeding:

• The main aim of combination breeding is the transfer of one or more characters into a single variety from other varieties. these characters may be governed by oligogenes or polygenes.
• The intensity of the character in the new variety is either comparable to or, more generally, lower that in the parent variety from which it was transferred.
• In this approach, increase in the yield of a variety is obtained by correcting the weaknesses in the yield contributing traits, e.g., tiller number , grains per spike, test weight is that for disease resistance.

b) Transgressive Breeding:

• Transgressive breeding aims at improving yield or its contributing characters through transgressive segregation.
• Transgressive segregation is the production of plants in an F2 generation that are superior to both the parents for one or more characters.
• Such plants are produced by an accumulation of plus or favorable genes from both the parents as a must combine well with each other, and should preferably be genetically diverse, i.e., quite different.