Host resistance is the most effective and economical method to minimise yield losses caused by rusts. The aim of this study was to detect the presence of resistance in 75 wheat genotypes. The presence of the genes Sr2, Sr24, Lr34, Lr37, Lr46 and Lr68 was investigated using simple sequence repeat and sequence tagged site markers. Quantitative aspects of resistance to leaf rust were assessed through infection response, disease severity, coefficient of infection (CI), disease incidence (DI), leaf tip necrosis (Ltn) and area under disease progress curve (AUDPC) under natural epidemics. Highly significant (p ≤ 0.001) differences were observed among the genotypes for CI, DI, AUDPC and relative AUDPC (rAUDPC). Twenty genotypes exhibited high levels of adult-plant resistance, showing CI less than 20% and AUDPC less than 300%, with moderately susceptible to susceptible reactions. The most frequently occurring gene was Lr46 (21%), followed by Lr68 (20%), Lr34 (19%), Lr37 (11%), and Sr24 (0%). Selection for Lr34 and Lr46 based on Ltn alone can sometimes be misleading because of its variable expression in different genetic backgrounds. Cultivars grown in Zimbabwe lacked important rust resistance genes.
‘Runde’ (Reg. no. CV‐1201, PI 702366; S02147‐7H‐0N‐2H‐0N) soft white spring bread wheat (Triticum aestivum L.) cultivar was developed by Crop Breeding Institute and released in December 2016 through the National Variety Release Committee. Runde was selected from a cross between S98066‐7H‐0G‐1H‐0N and F99012 made in 2002 at Harare Research Station. S98066‐7H‐0G‐1H‐0N is an experimental line made from a cross between F97009 (International Maize and Wheat Improvement Center [CIMMYT] line) and SC91155‐4H‐0G‐0H‐0G‐6G‐0N (Crop Breeding Institute line). F99012 is an experimental line developed by CIMMYT. Runde (S02147‐7H‐0N‐2H‐0N) is a product of a 2002 cross made in Zimbabwe as cross no. 147, using the pedigree method. Runde is an early maturing, rust tolerant, and high yielding cultivar. It is generally large‐seeded (49 g/1000 grains). The genotype was among the best performing cultivars with tolerance to rusts due to the presence of leaf rust and stem rust resistance genes, Lr34, Sr2, and Lr68. It has high flour extraction potential, good dough mixing characteristics, and high flour concentration.
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