Principles of Plant Breeding (2+1)

Reciprocal Recurrent selection (RRS)

• This method was proposed by Comstock, Robinson and Harvey 1949.

Objectives:
To improve two different populations in their combining ability simultaneously whentwo populations A and B, are involved in reccurent selection. A serve as a tester for the population B, and B serves as a tester for the plants selected from A. A and B population has broad genetic base and genetically heterogenous. Selection for SCA inbreds derived from each population are crossed to derive hybrid. The method allows for the selecting both GCA and SCA.

First Year:
Several plants are selected from the population A and B on the basis of their phenotype. Each of the selected plants form the population A is crossed as male with several randomly selected plants from the population B used as female. Similarly population B as male and population A as female. All selected plants are selfed, selfed seed is harvested separately.

Second Year:
Two replicated trials are conducted for the test cross progeny of the plants selected from population A and population B. On the basis of progeny test plants producing superior test cross progenies are identified.

Third year:
Selfed seed of selected plants on the basis of progeny test are planted in two separate crossing blocks as individual plant progeny rows. Progeny rows of two crossing block are planted separately. All possible inter crosses are made and equal amount of seeds from all inter cross in the crossing block A are mixed to carry to next generation of population A and B. This completes the original selection cycle.

Fourth Year:
Population A and B are planted from the composited seeds from all intercross in block A and B separately.

Fifth Year:
Operation of second year is repeated.

Sixth Year:

Operation of the third year is replanted and this completes the first recurrent selection cycle.