Natural selection in four common bean traits.

Three segregating bulk populations derived from the cross between one early (Manteigao Fosco 11) and three normal cycle (Carioca MG, Ouro and Milionario) dry bean cultivars were assessed for natural selection effects. The populations were advanced from F2 to F13. A seed sample was kept to represent the generation and the remnant used to obtain the following generation. Populations from each cross and their respective parents were assessed in randomized complete blocks with four replications, in three sowing seasons (February, July and November). The traits growth habit (determinate or indeterminate), weight of 100 grains (g), reaction to Colletotrichum lindemuthianum and grain yield were scored. Natural selection effects were observed on grain yield, growth habit and weight of 100 grains in all crosses. Individuals with indeterminate growth habit and smaller seeds were predominantly kept. The reaction to C. lindemuthianum was neutral to natural selection