Biochemical and molecular characterization of Alternaria alternata isolates highly resistant to procymidone from broccoli and cabbage

Table 3 Mycelial growth rate, sporulation and virulence in Pro^S and Pro^HR isolates of Alternaria alternata from cabbage and broccoli

Isolate	Sensitivity	Origin	Mycelial growth (cm)	Sporulation (×10⁵ spores/mL)	Virulence (lesion area, cm²)
C10	Pro^S	Cabbage	7.49 ± 1.15a	11.58 ± 1.97bc	1.56 ± 0.08bc
C28	Pro^S	Cabbage	7.53 ± 0.85a	10.15 ± 1.03c	1.68 ± 0.23b
B16	Pro^S	Broccoli	7.63 ± 0.13a	9.95 ± 0.95 cd	1.53 ± 0.26bc
B21	Pro^S	Broccoli	7.35 ± 1.54a	12.63 ± 1.32b	1.51 ± 0.43bc
C5	Pro^HR	Cabbage	7.02 ± 1.46b	0.28 ± 0.09gh	0.58 ± 0.27de
C13	Pro^HR	Cabbage	5.82 ± 0.78d	2.59 ± 0.15e	1.05 ± 0.64c
C40	Pro^HR	Cabbage	6.68 ± 1.06c	0.61 ± 0.12 g	0.62 ± 0.07d
B30	Pro^HR	Broccoli	5.37 ± 0.53ef	0.87 ± 0.13 g	0.55 ± 0.14de
B35	Pro^HR	Broccoli	5.53 ± 0.84e	1.25 ± 0.81f	2.38 ± 0.84a
B46	Pro^HR	Broccoli	6.84 ± 1.12bc	23.25 ± 1.85a	0.46 ± 0.12e
B53	Pro^HR	Broccoli	6.51 ± 0.25c	4.97 ± 1.02d	2.05 ± 0.23ab
B88	Pro^HR	Broccoli	6.91 ± 0.66b	12.57 ± 0.76b	0.63 ± 0.04d
B102	Pro^HR	Broccoli	6.24 ± 1.18 cd	4.52 ± 1.18de	0.48 ± 0.12e
B108	Pro^HR	Broccoli	5.65 ± 0.57de	0.97 ± 0.08 g	0.45 ± 0.05e

Radial mycelial growth of A. alternata isolate was measured after 7 days of incubation on potato dextrose agar (PDA) plates at 25 °C. Spores were harvested from the surface of 7-day-old PDA colony with sterile water (0.1% Tween 20). Lesion areas were determined on broccoli leaves at 7 days post-inoculation (dpi). The mean value ± SD of each isolate was calculated from three independent experiments. Means in a column followed by the same letter are not different according to Fisher’s least significant difference (P = 0.05). Pro^S, procymidone-sensitive isolates; Pro^HR, high-level procymidone-resistant isolates