Exploitation of heterosis is an efficient strategy to increase crop production, improve quality, and enhance resistance to biotic and abiotic stresses. However, heterosis shows significant genetic × environment effects. Nitrogen is an important nutrient that affects crop development and grain yield. Hybrid maize performs significantly and differently depending on the nitrogen conditions, but the genetic basis of maize heterosis under different nitrogen conditions is unclear. In this study, a test population comprising a set of single segment substitution lines (SSSLs) was used to identify heterotic loci (HL) for root-related traits of maize seedlings under two nitrogen conditions. We identified 80 HL for the root system and related traits in maize seedlings, consisting of 16, 18, 10, 11, 11, and 14 HL associated with root length (RL), root surface area (RSA), root average diameter (RAD), shoot dry weight (SDW), root dry weight (RDW), and plant height (PH), respectively. Among them, 13% of the HL were detected under both nitrogen conditions simultaneously, including the HLs hRL1b, hRL7, hRL9, hRSA7a, hRSA9a, hRAD1a, hSDW6, hSDW7a, hSDW7b, and hPH6a, but most of the HLs (87%) were not detected under both nitrogen conditions. The results indicated that, in maize, heterosis also exists in the interaction between genotype and nitrogen level.

利用杂种优势是提高作物产量，提高品质并增强对生物和非生物胁迫的抵抗力的有效策略。但是，杂种优势表现出显着的遗传×环境效应。氮是影响作物生长和粮食产量的重要营养素。杂交玉米的表现根据氮条件的不同而有显着差异，但尚不清楚在不同氮条件下玉米杂种优势的遗传基础。在这项研究中，包括一组单节段替换系（SSSLs）的测试种群用于识别在两个氮条件下玉米幼苗根系相关性状的杂种位点（HL）。我们确定了玉米幼苗根系和相关性状的80个HL，包括与根长（RL）相关的16、18、10、11、11和14个HL，根表面积（RSA），根平均直径（RAD），枝干重（SDW），根干重（RDW）和植物高度（PH）。其中，在两种氮条件下同时检测到13％的HL，包括HLshRL1b，hRL7，hRL9，hRSA7a，hRSA9a，hRAD1a，hSDW6，hSDW7a，hSDW7b和hPH6a，但在两种氮条件下均未检测到大多数HL（87％）。结果表明，在玉米中，基因型与氮水平之间的相互作用还存在杂种优势。