G. Atuahene-amankwa et al., Early generation testing of common bean (Phaseolus vulgaris L.) populations in sole crop and in maize/bean intercrop, CAN J PLANT, 78(4), 1998, pp. 583-588
Few plant-breeding studies have examined methodology for improving common b
ean (Phaseolus vulgaris L.) yields by selecting in an intercrop situation.
We hypothesized that early-generation testing would be as useful in a maize
(Zea mars L.)/bean intercrop as in sole crop for identifying superior bean
populations for yield. F-2 to F-5 bulks of six selected crosses and their
F-5-derived advanced lines were evaluated in sole crop or intercrop. The F-
2 and F-5 bulks were evaluated together in a preliminary trial in one locat
ion, while the advanced lines were evaluated with the F(3)s in one location
, and with the F(4)s in two locations. Within sole crop, selection of the b
est three populations, based on F-2 performance, provided 67% of the top ad
vanced lines. The rank correlation between average bulk yield across genera
tions and the average line yield was positive and significant. Within inter
crop, selection of the best three populations provided 56% of the top advan
ced lines. The rank correlation between advanced line yield and bulk yield
across generations was positive but not significant. Also, the top three F-
2 populations selected in sole crop produced 89% of the top advanced lines
in intercrop. Advanced line performance showed a positive significant corre
lation with mean F-4 bulk performance for grain yield, 100-seed weight and
seeds per pod within sc,le crop, while positive significant correlation was
seen with pods per plant and seeds per pod in intercrop. Results indicate
that F-2 bulk yields can be used to discard the least promising crosses in
both cropping systems.