Evaluating yield loss of winter wheat in competition with wild rye: a case study of Shahkoh region, Golestan province

Wild rye (Secale cereale) is considered one of the most important winter cereal weeds in the world. The damage resulting from the interference of this weed with wheat is more than other species of weed. This species is known as the most important wheat weed in the southern highlands of Golestan province (Shahkouh region). Since the area under wheat cultivation in the southern highlands of Golestan province (Shahkoh region) is much lower compared to the plains and low-altitude areas, no attention has been paid to the problems of wheat production, including the presence of Wild rye in the mentioned region.

This experiment was designed and carried out as a survey method in 30 wheat fields at Alvand and Omid cultivars in Shahkoh region of Golestan province. Sampling was done from each field in the wheat harvest stage at ten points in quadrats measuring 1 x 1 square meter. All wheat and wild rye plants were harvested at each point and transferred to the Plant Physiology Laboratory of Gorgan University of Agricultural Sciences and Natural Resources to determine plant density, yield and yield components.

The results showed that the number of wild rye plants in the fields varied from 0 to 9 plants per square meter. The number of spikes. m-2, grain yield and biomass yield of wild rye in all densities were higher in interference with Alvand cultivar than Omid cultivar. With increasing the density of rye, the studied traits decreased in wheat cultivars. With the introduce of each rye plant, the number of spikes.m-2, number of seeds per spike, 1000-seed weight, seed yield, biological yield and harvest index were 6.64%, 3.50%, 2.47%, 9.28%, 5.38% and 9.43% in Omid cultivar and 4.74%, 4.19%, 2.93%, 7.30%, 3.77% and 7.15% in Alvand cultivar, respectively. A lower decrease in the number of spikes.m-2 and 1000-seed weight in the Alvand cultivar can indicate its higher competitive power compared to the Omid. On the other hand, the seed yield of these cultivars in terms of non-interference with wild rye in fields under self-consumption seeds was almost similar to fields under certified seeds (without contamination with rye).

These findings showed that wild rye has an important role in reducing the yield of wheat cultivars in Shahkooh region; Alvand cultivar is considered as a more suitable cultivar due to its higher yield potential in both interference and non-interference conditions; The use of certified seeds may be the main strategy to control wild rye in Shahkuh region.