What is convergent improvement ?

 

    This is modified form of backcross method. It was proposed by Richey in 1927. This is a system of double backcrossing that is used to improve each of the two inbred lines simultaneously. Two inbreds say A and B each with some desirable charcaters are selected.

A cross is made between A and B inbred lines . The F1 is backcrossed to both A and B lines. Backcross of F1 with B line will retain some desirable genes of A lines in B lines and backcross of F1 with A line will retain some desirable genes of B line in A line. Thus improveent is achieved in both the inbreds. Three to four backcrosses followed by 2-3 generations of selfing produced inbreds that were somewhat superior to original inbred in maize. How ever the improvement was not appreciable and probably due to this reason this method is not used widely in improving inbreds.