Estimating the Effects of Seven Decades breeding and Releasing of Cultivars on increasing Barley yield in Iran

The study of genetic improvement and the recognition of traits that have played a role in it are important in assessing the effectiveness of breeding methods used in the past as well as defining new goals in breeding projects in the future. The aim of this study was to estimate the amount of genetic improvement and awareness of the level of variation in barley cultivars that were released in Iran between 1951 and 2013.

This study was conducted in Gorgan University of Agricultural Sciences and Natural Resources during the years 2017 to 2018. The evaluated materials were compromised a sample of 21 barley cultivars released in the period 1951 to 2013 in Iran. In the field section, the cultivars were planted in a randomized complete block design with three replications to evaluate plant variables including per plot, plant height, number of spikes, number of seeds per spike, spike length, number of tillers, 1000-seed weight and days to maturity. ISSR markers were used to evaluate the diversity and grouping of cultivars. Initially, 23 ISSR random primers were used, from which seven primers with high polymorphism were selected for final evaluation and marker production.

Analysis of variance revealed significant differences between cultivars for grain yield, grain weight, number of spikes, number of grains per spike, number of tillers, spike length and stem length. Of the studied traits, effects of breeding were considerable and significant for grain yield and tiller number. Cluster analysis of the morphological data by dividing barley cultivars into three groups (released from 2011 onwards), middle (released between 2011 and 1961) and old (released between 1951 to 1961) confirmed the achievement of genetic improvement. The Nei and Shannon indexes for ISSR markers also indicated significant genetic diversity among the studied cultivars. Based on the PIC values, primers 15, 18, and 23 will be useful for identifying parents to produce segregating populations or for marker assisted selection.

Among the studied decades, the cultivars of the seventh decade (2011 to 2013) had the highest grain yield and among them two cultivars Zahak and Nik were the best. The results showed that the average progress of barley cultivars during seven decades of breeding was approximately equal to 3.7 kg per year.