Abstract
Stripe (yellow) rust disease caused by Puccinia striifarmis f. sp. tritici, is a catastrophic wheat disease in wheat-growing regions around the world. The objective of this study was to investigate potential sources of stripe rust resistance and the yield loss of forty local wheat varieties at four locations in Egypt (Sakha, Mutubas, Qillin and Biyala), under yellow rust disease pressure compared to 'Morroco' variety, as control. To determine slow rusting in the field, the following parameters were recorded: final rust severity (FRS%), average coefficient of infection (ACI), relative resistance index (RRI) and reduction % in the 1000 kernel weight. The severity was higher in the second season than in the first. Seven wheat genotypes ('Shaka 62', 'Shah 9, 'Shah 95', 'Gemmiza 7', 'Sids 14' and 'Misr 3') showed the high level of resistance, and FRS% values ranged from 0 to 20 moderately resistant (MR) during first season and achieved the least value of loss in TKW (1.28%) with 'Misr 3'. Meanwhile, four genotypes ('Sakha 93', 'Sakha 95', 'Sids 14' and 'Gim. 7') remained highly resistant during the second season and identified to have good level of slow rusting resistance, which these genotypes showed FRS% values ranged from 5R to 30 moderately resistant-moderately susceptible (MRMS), ACI values <= 12, RRI values >= 6 and the loss % in TKW not exceed 12.54%. On the other hand, the lines; 'Shaka 69', 'Shah 88', 'Shah 92', 'Giza 160', 'Giza 163', 'Gem 11', 'Sids 2' and 'Sids 6' exhibited complete susceptibility at the four tested sites, recorded FRS% values >50. Meanwhile, cv. 'Gem 11' in 2018/2019 recorded the highest level of ACI >= 55, the lowest level of RRI <= 4.05 and the highest loss% in TKW reached 40.69%. These findings could be used in the national wheat breeding program for stripe rust resistance in Egypt.