Fig. 4
From: Recent progress on the genetics and molecular breeding of brown planthopper resistance in rice
An integrated strategy of MAS and conventional breeding. MAS strategy is in the center position throughout the entire process of breeding. The primary goal is development of useful markers tightly linked to target QTLs/genes by QTL mapping experiments (primary mapping, fine mapping and QTL validation). MABC include three generations of backcrosses and one generation of selfing, accompanied by positive and negative selection for minimizing the donor segments linked to target gene, and background selection for maximizing the recurrent genome. After phenotype evaluation of BC3F2 lines, NILs containing single target gene are obtained. Multiple NILs that carrying different genes are crossed each other to produce pyramided lines. MAS based conventional breeding include 8–9 generations of selfing, accompanied by multiple cross within three parents, field and MAS selection in a large F2 population, preliminary and further yield trials in F3 and F4-8 population. After phenotype evaluation, the F8-9 progenies with enhanced target traits and high yield potential could be obtained, designated as ‘improved versions’