Wheat cv. Kingbird is introduced to address a new stem rust threat in Ethiopia
Pgt race TKTTF, virulent for the SrTmp gene present in Ethiopian cv. Digalu and first detected in 2012, caused significant yield losses in Digalu during the 2013 and 2014 seasons. No suitable replacement varieties with significant seed volume were available, and alternate solutions were sought. EIAR, with the support of the DRRW project through CIMMYT-Ethiopia, introduced 5 tonnes of adult plant, rust resistant wheat cv. Kingbird from Kenya. Kingbird was evaluated for agronomic performance at seven locations vs. three checks in 2014, and was also evaluated for stem rust reaction in single-race nurseries (TKTTF, TTKSK, TRTTF and JRCQC). With support from USAID/CIMMYT, seed was concurrently multiplied on 37 ha producing 80 tonnes of seed that was distributed to farmers in 2015. Mean grain yield over locations was 2.76 t ha-1. Mean performance of Kingbird was 3.00 t ha-1 compared to 2.79 t ha-1 for Ogolcho, 2.83 t ha-1 for Biqa and 2.42 t ha-1 for Kakaba. Thus Kingbird gave yield advantages of 5 to 22% over the check varieties. Stem rust severities on Kingbird in the single race nurseries ranged from Tr to 15% and reactions ranged from TMR to SMS. The check varieties rated up to 45% severity with S type reactions. Thus Kingbird was superior in terms of yield potential and stem rust resistance as measured in these trials vs. the check varieties. Stem rust resistance of Kingbird is based on Sr2 and Sr57 and is hypothesized to have at least three additional APR loci. Seedling reactions of Kingbird to races TKTTF and Ug99 are characterized as susceptible. Sr57 is pleiotropic and confers partial resistance to all three rusts, powdery mildew, spot blotch, and BYDV. Based on early maturity, yield performance, and stem rust resistance, Kingbird is recommended for low- to mid-altitude wheat-growing areas of Ethiopia.