Bread wheat (Triticum aestivum L.), an economically important cereal, is widely cultivated worldwide. Of the nearly 600 Mt of wheat harvested worldwide, about 80% is used as human food . Wheat-breeding programs around the world are working toward improved grain yield with better quality, disease-resistance and agronomic performance.
Knowledge of the genetic diversity within a germplasm collection is the basis for selection of crossing parents, establishing heterotic groups and has a significant impact on the improvement of crops. Therefore, assessment of the extent and nature of genetic variation in bread wheat is important to breeding and genetic resource conservation programs. As molecular markers have been developed, they have been extensively explored for analysis of genetic diversity in common wheat; such markers include restriction fragment length polymorphisms (RFLPs) [2, 3], randomly amplified polymorphic DNA (RAPD) [4, 5], amplified fragment length polymorphisms (AFLP) [6, 7], and simple-sequence repeats (SSR) [8–12].
The 1RS/1BL translocation is one of the most frequently used alien introgressions in wheat-breeding programs throughout the world [13, 14]. In addition to its advantage in disease resistance (Sr31, Lr26, and Yr9) , the 1RS translocation is also useful for its positive effect on agronomic traits including yield performance, yield stability, and wide adaptation [16, 17]. However, 1RS carries the Sec-1 locus coding for ε-secalin, which results in negative effects on bread-making quality, such as poor mixing tolerance, superficial dough stickiness, and low bread volume [18, 19]. Some defects in noodle processing quality are also correlated with this translocation [20, 21]. Various molecular markers, including STS (Sequence-Tagged Site), SCAR (Sequence Characterized Amplified Region), RAPD, and SSR, have been employed to detect the 1RS/1BL translocation [22–24]
Recently, diversity arrays technology (DArT) markers were developed to discover and score genetic polymorphic markers in the whole genome. This technology is a sequence-independent and high-throughput method . DArT markers have been applied to several species including cereals such as barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), and durum wheat (Triticum durum L.). Not only the technology has been used to create high-density genetic maps  and for association studies [27, 28], but it is also expanding into the study of genetic diversity and population genetics [29–31]. Stodart et al.  compared AFLP, SSR, and DArT markers and found that DArT markers are suitable for estimation of genetic diversity in landrace cultivars of bread wheat.
China is the world's most populous nation, accounting for 20% of the global population. Crop yield has always been a primary concern of agronomists in China. Northern wheat production plays an important role in China's food production. Production in the major growing area of northern China, represents 45-53% of wheat acreage, and accounts for 47-61% of the total production . Since 1RS translocations were introduced to China in the early 1970s, they have been widely used in wheat-breeding programs . In some major wheat-growing area of northern China, 1RS/1BL translocations are present in 50 ~ 70% of all wheat cultivars . Therefore, information about the genetic diversity and the distribution of 1RS/1BL translocations within Chinese germplasm is very important for improving wheat yield with better quality in Chinese northern breeding programs.
To help establish heterotic groups of Chinese northern wheat cultivars (lines), we assessed the genetic diversity in a collection of cultivars from northern China using DArT markers and diversity analysis. We also used DArT data to investigate the distribution of 1RS/1BL lines within the northern cultivars.