A non-flowering natural cabbage mutant among the open-pollinated line ‘T15’ was found 42 years ago. The mutant was named ‘nfc’ (non-flowering cabbage) and has been propagated vegetatively by cuttings. ‘nfc’ hardly flowers during the spring season even after plenty of low-temperature periods. This study characterized the non-flowering trait of ‘nfc’ and assumed the mechanism. In the first experiment, we investigated the flowering characteristics of ‘T15’ and ‘nfc’ over three years. Throughout the 3-year cultivation period, all ‘T15’ plants flowered, while the flowering ratios of ‘nfc’ propagated by cuttings at the 1st, 2nd, and 3rd year were 0%, 32%, and 4%, respectively. In the last two years, other traits were also investigated in detail. The flowering dates of ‘nfc’ flowering plants were later than those of ‘T15’, and the average numbers of flowering shoots per flowering plant of ‘nfc’ were lower than those of ‘T15’. Moreover, the terminal bud of ‘nfc’ flowering plants continued to grow vegetatively, even when their lateral shoots flowered. In the second experiment, to verify the hypothesis that ‘nfc’ is a chimeric plant, we investigated protoplast-regenerated plants’ flowering characteristics from mesophyll protoplasts of ‘nfc’. We obtained colonies derived from different protoplasts of ‘nfc’ and regenerated plants from each colony (nfcPP lines). Suppose the ‘nfc’ is a chimeric plant, in that case, protoplast-regenerated plants’ flowering characteristics should be the same for each colony they derived. However, both flowering and non-flowering plants appeared in the same nfcPP lines derived from a single colony. From this, we concluded that ‘nfc’ is not a chimeric plant on flowering characteristics. These results indicate that ‘nfc’ is a mutant that maintains its flowering ability, but its flowering is strongly suppressed by some factors other than its structural characteristics.

42 年前在开放授粉品系“T15”中发现了一种不开花的天然卷心菜突变体。该突变体被命名为“nfc”（不开花的卷心菜），并通过插条进行无性繁殖。'nfc' 即使在经历了大量的低温期之后，在春季也几乎不开花。该研究表征了'nfc'的非开花特性并假设了该机制。在第一个实验中，我们调查了 'T15' 和 'nfc' 三年的开花特性。在整个3年栽培期间，'T15'植株全部开花，而'nfc'在第1年、第2年和第3年扦插繁殖的开花率分别为0%、32%和4%。在过去的两年中，还详细研究了其他性状。'nfc'开花植物的开花日期晚于'T15'，'nfc'每株开花的平均花芽数低于'T15'。此外，“nfc”开花植物的顶芽继续营养生长，即使它们的侧枝开花。在第二个实验中，为了验证“nfc”是嵌合植物的假设，我们从“nfc”的叶肉原生质体中研究了原生质体再生植物的开花特征。我们从每个菌落（nfcPP 系）和再生植物的不同原生质体中获得了菌落。假设“nfc”是一种嵌合植物，在这种情况下，原生质体再生植物的开花特征对于它们衍生的每个菌落应该是相同的。然而，开花植物和非开花植物都出现在源自单个菌落的相同 nfcPP 品系中。由此，我们得出结论，'nfc' 不是开花特征的嵌合植物。这些结果表明'nfc'是一种保持其开花能力的突变体，但其开花受到结构特征以外的一些因素的强烈抑制。