Trichomes are differentiated epidermal cells and can be found on above ground organs of nearly all land plants. Results from previous studies show that trichomes play important roles against a wide range of both biotic and abiotic stresses. By examining differences between parental genotypes of available populations, we identified a population of recombinant inbred lines showing clear segregation for trichome density and length. Assessing the F8 lines of the population growing in the field detected a major locus on chromosome arm 4BL. This locus was detected based the assessments of either fully expanded third leaves or flag leaves after anthesis. Based on the position of the QTL, an SSR marker was used to identify heterozygous plants at this locus from F5 lines derived from the same cross for the F8 population. Three pairs of near isogenic lines targeting this locus were obtained from these heterozygous plants. Difference in trichome length between the two lines with opposite alleles for each of these NIL pairs were similar to that between the two parental genotypes for the mapping populations, confirming that this single locus is mainly responsible for the trichome characteristics measured in this study. The allele with long and dense trichome is dominant as this characteristic was shown by the heterozygous individuals at this marker locus. Apart from the targeted locus, NIL pairs have highly homogeneous genetic backgrounds. Thus, the NILs could be invaluable in understanding the relationship between trichome density and resistance or tolerance to various biotic and abiotic stresses.

毛状体是分化的表皮细胞，几乎可以在所有陆地植物的地上器官中找到。先前的研究结果表明，毛状体在对抗各种生物和非生物胁迫方面发挥着重要作用。通过检查可用群体的亲本基因型之间的差异，我们鉴定了重组自交系群体，其毛状体密度和长度显示出明显的分离。评估田间生长的群体的 F8 系时，发现了染色体臂 4BL 上的一个主要基因座。该基因座是根据开花后完全展开的第三叶或旗叶的评估来检测的。基于 QTL 的位置，使用 SSR 标记从源自 F8 群体相同杂交的 F5 品系中鉴定该基因座上的杂合植物。从这些杂合植物中获得了三对针对该基因座的近等基因系。这些 NIL 对中的每对具有相反等位基因的两个品系之间的毛状体长度差异与作图群体的两个亲本基因型之间的毛状体长度差异相似，证实该单一基因座主要负责本研究中测量的毛状体特征。具有长而密的毛状体的等位基因占主导地位，因为该标记位点的杂合个体显示了这一特征。除了目标基因座外，NIL 对还具有高度同质的遗传背景。因此，NIL 对于理解毛状体密度与对各种生物和非生物胁迫的抗性或耐受性之间的关系非常有价值。