• Inheritance studies have shown that resistance genes in each of the cultivars Mexico 54 and BAT 332 to pathotype 63 – 39, one of the most virulent forms of P.griseola in Africa is due to a single dominant gene.  Mexico 54 is resistant to 158 isolates of P. griseola out of the 163 so far characterized in Africa.  BAT is also a very good source of resistance.

• Studies to validate the utility of markers indicated that the SCAR OPNO2_890C was not polymorphic for the Phg-2 gene outside the mapping population and therefore not useful in selecting resistant genotypes in the study populations. On the other hand, the RAPD marker was observed in all resistant individuals and was absent in those scored susceptible based on virulence (plate 1). Use of the RAPD marker OPE-04 has been initiated and efforts are going on to convert it into a SCAR.

• Segregating populations for resistance to angular leaf spot disease have been  generated using Mexico 54 and BAT 332 as resistant parents. The susceptible cultivars included CAL 96 (K 132), Kanyebwa (popular land race), MCM 5001 (K 131), K20 (GLP 2) and Urugezi.  The segregating populations will be evaluated with other partners in the region. In addition to these we have created more segregating populations for multiple parent crosses, to specifically combine angular leaf spot, common bacterial blight, root rots and low soil fertility resistances.

• A backcrossing programme to specifically incorporate angular leaf spot resistance to the commercial, but popular susceptible cultivars (K 132, Kanyebwa, Urugezi and GLP 2 (K20) was initiated.   K 132 is a released variety in Uganda, while Kanyebwa is a popular land race. GLP 2 is grown in Kenya and in Uganda it is known as K20.  Urugezi is popular in Rwanda.

• Farmer participatory variety selection activities were initiated in Kabale (S.W Uganda) and Namulonge. The materials evaluated by farmers consisted of both advanced lines and segregating populations. In Kabale, focus was on the root rot disease. Farmers have selected some genotypes for subsequent evaluations on their fields. Among the popular genotypes selected by farmers were RWR 2075, RWR 1946 and RWR 1873 (these three genotypes have been observed to be tolerant to bean root rot and originated from the BILFA III nursery). Other popular selected genotypes were BACO 2 –4/6, BOA 1 –4/9 and BOA 5 –1/30.

Partners

NARO

CIAT

Makerere University

Farmers

District extension – Kabale and Wakiso