Field Screening of Primary and Secondary Tritipyrum Genotypes using Selection Indices based on BLUP under Saline and Normal Conditions

Abstract

This is the first report of secondary tritipyrum recombinant inbred lines derived from Iranian wheat cultivars (Triticum durum Desf./Triticum aestivum L. × Thinopyrum bessarabicum Savul. & Rayss). An experiment was performed under normal (1 dS m−1) and saline (12 dS m−1) conditions during the 2013 to 2015 growing seasons in Kerman, Iran (29.48° N, 57.64° E) to evaluate the potential of tritipyrum, a new salt‐tolerant cereal. The genotypes examined were 13 non‐Iranian primary tritipyrum lines (NIPTLs, 2n = 6x = 42; AABBEbEb), 144 new Iranian secondary tritipyrum lines (ISTLs) derived by crossing NIPTLs with four Iranian bread wheat (Triticum aestivum L.) cultivars, two tetraploid wheat varieties, and six Iranian wheat cultivars. The agronomic traits were measured and the results showed spikes in the weight per plant and 1000‐grain weight that can be used as index traits for NIPTLs and ISTLs for selection under normal as well as saline conditions. Although the Smith–Hazel and Pesek–Baker indices indicated that the best response of the ISTLs to selection was related to the number of sterile florets and grains per spike under normal conditions, under saline conditions, the most effective trait was the number of fertile tillers. The breeding value for the NIPTLs and ISTLs were the best linear unbiased prediction values calculated using the results of the selection indices. The ISTLs crosses ‘Roshan’ × (Az/b), ‘Niknejad’ × (Ka/b)(Cr/b), and ‘Omid’ × (Ka/b)(Cr/b) showed the highest average breeding value and are suitable for use in breeding programs for new ISTLs that are salt‐tolerant cultivars with high yield potential in saline soil and brackish water.