Compatibility between wild and cultivated common bean (Phaseolus vulgaris L.) genotypes of the Mesoamerican and Andean gene pools: Evidence from the inheritance of quantitative characters

The extent and distribution of incompatibility between gene pools (Mesoamer ican and Andean) and evolutionary classes (wild, landrace and bred) of the common bean (Phaseolus vulgaris) was explored by seeking anomalous values o f highly heritable quantitative traits in the progeny of crosses. Clear inc ompatibility (no progeny or sterile or deformed progeny) was shown by 28 cr osses in a 12-parent wild x bred diallel cross, and 37 crosses in a 12-pare nt landrace x bred diallel cross. Incompatibility was particularly common i n the progeny of certain genotypes, but was not consistently associated wit h the division between gene pools or evolutionary classes. When crosses sho wing clear incompatibility were eliminated from the data, days to flowering , number of seeds per pod, log (weight per seed) and seed roundness in the F-1 generation gave a good fit to an additive-dominance model, confirming t hat there is no overall tendency to incompatibility between the gene pools. There was a division between the gene pools with regard to log (weight per seed), as expected, but there was no such division, with regard either to the means of the parent lines or the distribution of the statistics V-r and W-r (which indicate the distribution of dominant alleles between genotypes ), for the other quantitative variables. Differences between reciprocal cro sses were strikingly widespread, and appeared generally to be due to cytopl asmic effects or cytoplasmic x nuclear interactions rather than maternal ef fects, indicating that the direction in which a cross is made may have a pe rceptible effect on the progeny that can be obtained from it.