*3.1. Phenotyping of the Resistance for Bacterial Wilt Disease*

In order to evaluate bacterial wilt (BW) resistance, we observed phenotypes for 5–21 days after inoculation of *R. solanacearum* suspension into parental lines and 94 F2 lines. The degree of disease severity was evaluated as disease index (DI), with disease scale ranging from 0 (no symptoms) to 4 (76 to 100% wilted leaves) (Figure 1A). Among the 94 inoculated plants, 16 plants were observed with no visible symptoms (DI = 0), representing a resistant line to BW, whereas 49 plants were observed with 76–100% wilted leaves (DI = 4), representing a susceptible line to BW (Figure 1B). In addition to this, we observed 14 plants with 1 to 25% wilted leaves (DI = 1), 7 plants with 26 to 50% wilted leaves (DI = 2), and 8 plants with 51 to 75% wilted leaves (DI = 3) (Figure 1B). Overall, the average DI value of the F2 population was 2.638, and the wilt rate (%) was 68.085. The skewness and kurtosis

value of the DI was −0.604 and −1.352, respectively, suggesting that the resistance level of the plants to *R. solanacearum* is susceptible, and the population might be a non-normal distribution rather than a normal distribution (Table 1).

**Figure 1.** Distribution of the disease index after inoculation with *R. solanacearum*. (A) disease index was classified into disease scales of 0–4, where 0 = no visible symptoms, 1 = 1 to 25% wilted leaves, 2 = 26 to 50% wilted leaves, 3 = 51 to 75% wilted leaves, and 4 = 76 to 100% wilted leaves, and (B) disease index (DI) was recorded in F2-segregating populations, including 94 genotypes from the cross between a resistant parent (KC352) and a susceptible parent (14F6002-14).



<sup>a</sup> Wilting rate was defined as DI that was more than 2. <sup>b</sup> Average was calculated on the basis of 0–4 rating scale as follows: DI = ∑(disease score x the number of plants corresponding to each disease score)/total number of plants.
