Selection of hull-less barley lines using the selection index of ideal genotype (SIIG) in Ahvaz and Darab regions

Barley (Hordeum vulgare L.) has the widest geographical range of distribution of all cereals. Hull-less barley research and development is now receiving more emphasis with potential for feed, food and industrial uses. Variety selection is and will become more important as the various industries demand specific characteristics. The purpose of this research was to evaluate and select the best hull-less barley lines with high yield and desirable agronomic characteristics using the selection index of ideal genotype.

To select superior hull-less barley lines in warm regions, especially Ahvaz and Darab, 72 pure lines in the non-repeating Augment design with three controls (Loot cultivar and two promising lines EHB-87-4 and EHB-85-9) was checked. This research was conducted in Fars (Darab Station) and Khuzestan (Ahvaz) Centers of Agricultural Research and Education and Natural Resources during the 2020-2021 cropping year. To select the best hull-less barley lines for Ahvaz and Darab separately and to select the best lines for both regions in terms of grain yield and other studied traits simultaneously, the selection index of ideal genotype (SIIG) was used. SIIG index was calculated based on grain yield, number of days to heading, number of days to physiological maturity, plant height and 1000-grain weight.

The results of analysis of variance of hull-less barley agronomic traits showed that there was no significant difference between the blocks in both Ahvaz and Darab regions (except for 1000-grain weight in Darab). The heritability values of traits in the combination of both Darab and Ahvaz regions were low for lines and control genotypes. The highest and lowest heritability of pure lines were related to the number of days to maturity (0.37) and grain yield (0.01), respectively. The heat maps showed that the maximum maturity, flowering, plant height and grain yield is related to Darab region. In total, the results of SIIG index in Ahvaz showed that 19 hull-less barley lines with SIIG≥ 0.600 and in Darab 24 lines with SIIG≥ 0.500 were among the top lines in these areas. Based on the results of the average SIIG index, lines 52, 22, 33, 66, 5, 53, 24, 48, 18, 27, 51, 25, 81, 21, 46 and 19, respectively, with SIIG≥ 0.500 in both Darab and Ahvaz regions were the top lines.

In total, lines 52, 22, 33, 66, 5, 53, 24, 48, 18, 27, 51, 25, 81, 21, 46 and 19 were selected and recommended for advanced experiments. Also, SIIG index is an effective and useful method to selecting superior genotypes.