The introduction of mid-altitude climbing beans to Africa has been one of CIAT's most dramatic impact stories, whereby yields of beans were tripled compared to yields of bush beans available at that time. But climbing beans continue to be limited in their extension by their relative heat sensitivity that does not permit planting them at mid-low elevations (below 1200 masl).

This year we report on high yielding climbing beans adapted at CIAT headquarters, at an elevation of approximately 1000 masl. A total of 40 advanced F_5.7 lines were selected for yield testing which had been evaluated with marker-assisted selection using the SCAR marker for bc3 resistance. The local landrace Calima Voluble Darién (itself well adapted at 1500 masl) yielded only 1009 kg ha^-1, while improved lines produced as much as 2746 kg ha^-1. Several of these including the two highest yielding also carry bc-3 resistance to BCMNV. Grain type in these families is of the highly commercial Andean types, making them especially attractive to farmers.

In Uganda an improved climbing bean for lower altitudes, MAC 31, has been released already. These heat tolerant climbing beans will be incorporated into the breeding program for improved nutritional value.

Contact: Matthew Blair and Francisco Morales