Genetic diversity in rye (Secale cereale L.) landraces based on agro-morphological traits under the semi-arid conditions of Iran

Rye (Secale cereale L.) as a tolerant cereal crop to drought, salt, and aluminum stresses is utilized for bakery, animal feed, and bioenergy. Landraces are important for managing genetic variation in rye and genetic improvement projects. The goal of the current study was to assess the morphologic diversity of 64 rye genotypes across two years, to identify genotypic clusters with more contributing roles in the total variance. The high amounts of coefficient of variation (CV) were recorded for the weight of total spikes, 33.3 and 33.4% across the first and second year respectively. Also, the weight of whole straws, above-ground biomass, spike number per area, weight of gains per spike, and grain yield indicated high CV values across two years. The first six factors described 83.7 and 82.8% of the overall variance in the first and second years, respectively; and were named remobilization, sink potential, performance, length properties, leaf length, and spikelet factors. Rye genotypes were categorized into three major groups in both years based on the hierarchical clustering method. In the first year, Cluster-I (20 genotypes) had the highest grain yield (3325 kg ha-1), Cluster-II (6 genotypes) had low or moderate values for most traits and Cluster-III (38 genotypes) indicated the highest 1000-grain weights (30.9 g). In the second year, Cluster-I (20 genotypes) showed more grain yield (3362 kg ha-1), Cluster-II (7 genotypes) had low or moderate values for most traits and Cluster-III (37 genotypes) indicated the highest 1000-grain weights (32.2 g). Comparing clustering across two years demonstrated that all genotypes except three cases (were categorized in the same group, so the performing ability of these genotypes was not affected by the interaction between genotypes by environmental factors. The identified genetic diversity confirms current rye germplasm as a good plant material for yield increase, showing an excellent option for the next breeding programs for rye.