Does transfer of awn controlling genes to the Roshan bread wheat cultivar affect yield and yield components of this cultivar under well-watered conditions?

Awns increase photosynthesis, reduce bird damage, and play a distinct role in grains spreading of wild species. However, there are some challenges to its effect on grain yield under irrigated conditions. The objective of this research was evaluation the effect of awns on important agronomic traits including grains number per spike, 1000-grain weight and earliness. For this purpose, near-isogenic line in Roshan’s background was developed to assess the effect of this trait on yield and yield components.

In the present study, in a 10-year wheat breeding program (from 2010 to 2020), awny head characteristic was transferred from Mahdavi to Roshan using backcrossing. In the second generation of the fifth backcross (BC5F2), awny and awnless progenies (isogenic lines with the genetic background of Roshan) were selected. Isogenic lines and their parents (Roshan and Mahdavi) were evaluated in a randomized complete block design with five replications in the 2021-2022 cropping season under irrigated conditions.

In the present research, the awny head character was successfully transferred from Mahdavi to the Roshan cultivar. The awny Roshan was cultivated under farm conditions (300 plants m-2). The results of mean comparisons showed that, out of the 16 evaluated agronomical traits, only three traits including grains number per spike, spikelet number per spike, and plant height were affected by awns. Awny head characteristic increased grain yield by 820 kg/ha in comparison with Roshan, but it was not significant. Awny Roshan produced 26% more grains number per spike than Roshan. The significant increase of spikelet number per spike in awny line also confirmed the increasing of grains number per spike. In comparison with Roshan, awnd isogenic line had 12 cm higher plant height, where 6 cm was due to awn length.

Awns not only did not hurt the wheat yield under irrigated conditions of Kerman but also potentially can increase grain yield by increasing the number of grains per plant. Due to the reduction of bird damage, the promising line produced in the present research can be an appropriate alternative for the Roshan cultivar.