Plant Accessions and Field Experiments

In this study, a total of 408 upland cotton accessions were selected, comprising 201 accessions that originated from the Northwestern Inland Region (NIR), 88 that originated from the Yellow River region (YRR), 63 from the Yangtze River Region (YtRR), 29 from the northern specific early maturation region (NSEMR) and 27 introduced from abroad (Supplementary Table S1). All 408 accessions were planted at Shihezi (SHZ) in North Xinjiang (85.94°E, 44.27°N) and at Korla (KRL) in South Xinjiang (86.06°E, 41.68°N) for 2013, 2014, and 2015, denoted SHZ13, KRL13, SHZ14, KRL14, SHZ15, and KRL15, respectively. The field experiments were designed so that each accession was grown in a plot with 40–45 plants in two rows, with 0.10 m between plants in rows and 0.45 m between rows. The field experiments used a randomized complete block design with three replications in each environment. The field management conformed to local practices.