Iran

Erratic weather patterns associated with climate change pose unique challenges for wheat breeders playing a key part in the fight to ensure global food security. Within the rainfed winter wheat areas of Turkey and Iran this erratic weather patterns may prevent attaining maximum potential increases in winter wheat genetic gains. This is primarily related with the fact that the ranking of tested varieties may greatly change from one year to the other. Erratic weather patterns may interfere with breeders decision on the ideotype(s) they should aim for during selection. To support breeding decisions, this study aimed at optimizing major traits through modelling different combinations of environments and defining probabilities of the range of variation of traits (phenology and pant height) that maximized grain yields. Optimal phenology was found to be highly related with the temperatures at which the winter wheat varieties were exposed at around heading time (20 days before and after heading). Specifically later winter wheat varieties were exposed to higher temperature both before and after heading and this exposure had a negative effect on grain filling duration and final grain yield. Finally, the use of at least five different wheat varieties in one production field (with different phenology and plant height) was compared to a field with monoculture to test for improved resilience. It was concluded that by selecting one best wheat variety in a wide range of environments it was possible to maximize grain yield and that using a set of diverse varieties was not beneficial.

Stem rust is a potentially destructive fungal disease of wheat worldwide. In 1998 Pgt pathotype TTKSK virulent to Sr31 was detected in Uganda. The same pathotype was confirmed in Lorestan and Hamedan provinces of Iran in 2007. We used a derivative of race TTKSK to phenotype 62 Iranian wheat landraces (resistant to stripe rust in a previous study) at the seedling stage to this new pathotype (TTSSK). Twenty eight accessions were evaluated for the presence of resistance genes Sr2, Sr22, Sr24, Sr25, Sr26, Sr35, Sr36 and Srweb using SSR markers. None carried Sr2, Sr24 or Sr26, but the presence of Sr22, Sr25, Sr35 and Sr36 was indicated. Some susceptible landraces predicted to carry Sr2 by marker analysis require further investigation. To evaluate defense gene expression in compatible and incompatible stem rust interactions we sampled resistant and susceptible cultivars at 0, 12, 18, 24, 72 hours post-inoculation (hpi). ?-1,3 glucanase expression was studied using qGLU-S and qGLUU-AS primers and a real-time PCR step-one ABI machine, with ?-tubulin and EF1-? genes used as internal controls. In incompatible interactions defense gene expression was increased at 24 hpi, but in compatible interactions the highest level of expression occurred at 12 hpi and was significantly decreased at 18 hpi. The results revealed that expression of defense genes such as ?-1,3 glucanase was earlier in compatible than in incompatible interactions but the expression level was less in incompatible interactions. On the other hand, in susceptible genotypes the expression of defense genes increased immediately after inoculation and declined sharply after infection. In contrast defense gene expression in resistant genotypes began to increase after establishment of the pathogen.