Variation of the genomic proportion of the recurrent parent in BC ₁ and its relation to yield performance in sorghum (Sorghum bicolor) breeding for low-input conditions

In order to define the variation of the genomic proportion of the recurrent parent [G(RP)] and its relation to yield, G(RP) of individual BC1 plants of two sorghum populations composed of a high-yielding cultivar as recurrent parent (RP) and a donor with superior drought resistance or grain quality, respectively, was estimated using AFLPs and SSRs. G(RP) in BC₁ ranged from 0.53 to 0.95 and averaged to 0.76 in the population (NP4453 x 'SV-2') x 'SV-2'. G(RP) varied between 0.60 and 0.86 and averaged to 0.74 in the BC1 of (ICV-219 x 'SV-2') x 'SV-2'. Results show that plants with a G(RP) equivalent to BC₂ (0.875) or BC₃ (0.938), respectively, can be selected from BC₁. Yield performance of BC₁S₁ families was tested in field trials carried out in South Africa. The correlation between yield and G(RP) in BC₁ was low. Selection according to G(RP) did not result in an effective preselection for yield. © 2006 The Authors.