Knowledge Center Catalog

Resistance to stem rust race Ug99 in selected wheat germplasm

Nzuve, F.

Resistance to stem rust race Ug99 in selected wheat germplasm - 2011 - p. 172

Abstract only

Race Ug99, or TTKSK, of Puccinia graminis tritici, causing stem or black rust on wheat (Triticum aestivum), has been recognized as a major threat to global wheat production as the pathogen has virulence for a number of important resistance genes. New variants of the UG99 lineage with virulence to Sr24 and Sr36 indicates that the pathogen is continuing to evolve; they have rendered more than half of the previously known Ug99- resistant wheat germplasms susceptible. Identifying and characterizing new sources of resistance within breeding materials, commercial cultivars and related species will ensure future genetic diversity. A study was carried out at KARI (Kenya Agricultural Research Institute), Njoro to identify sources of resistance to stem rust. Twenty-five wheat lines selected from previous wheat screening nurseries (2008) carry both seedling and adult plant resistances to stem rust. Five resistant wheat lines, including CWANA 1st SR RESIS. ON-ETH-OS71, MON?S?/ALD?S?//TOWPE?S?, THELIN#2/ TUKURUCGSS02Y 00118S-099M-099Y-099M-16Y-OB, PBW343*2 /KUKUNA //PBW343*2 /KUKUNA /3/ PB W343, and SUNCO//TNMU/TUI, R07F4-21258, and the susceptible parent, CANADIANCUNNINGHAM//KENNEDY were crossed in a partial diallel to develop populations for studying the genetics of resistance. Mapping studies will be conducted to identify and characterize genes for resistance. The wheat lines exhibited varied rates of disease progression. Further studies are focusing on combining genes for stem rust resistance, while introgressing the resistance genes into high yielding Kenyan backgrounds. These elite lines will form the basis for durable resistance in wheat breeding programs to avert further yield losses.


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