TY - EJOU
AU - Tok, Fatih M.
AU - Dervis, Sibel
AU - Yetisir, Halit
TI - Vegetative Compatibility and Virulence Diversity of Verticillium dahliae from Okra (Abelmoschus esculentus) Plantations in Turkey and Evaluation of Okra Landraces for Resistance to V. dahliae
T2 - Phyton-International Journal of Experimental Botany
PY - 2020
VL - 89
IS - 2
SN - 1851-5657
AB - Forty-four V. dahliae isolates were collected from symptomatic vascular tissues of okra plants each from a different field in eight provinces located in
the eastern Mediterranean and western Anatolia regions of Turkey during 2006-
2009. Nitrate-nonutilizing (nit) mutants of V. dahliae from okra were used to
determine heterokaryosis and genetic relatedness among isolates. All isolates
from okra plants were grouped into two vegetative compatibility groups (VCGs)
(1 and 2) and three subgroups as 1A (13.6%, 6/44), 2A (20.5%, 9/44) and 2B
(65.9%, 29/44) according to international criteria. Pathogenicity tests were performed on a susceptible local okra (A. esculentus) landrace in greenhouse conditions. All isolates from VCG1A and VCG2B induced defoliation (D) and partial
defoliation (PD) symptoms, respectively. Other isolates from VCG2A gave rise to
typical leaf chlorosis symptoms without defoliation. The obtained data showed
that the virulence level of V. dahliae isolates from okra was related to their
VCG belongings. Eighteen okra landraces from diverse geographical origins were
screened for resistance to VCG2B and VCG1A of V. dahliae. The results indicated that all landraces were more susceptible to highly virulent VCG1A-D pathotype displaying D or PD symptoms depending on their susceptibility levels with a
mean disease severity index of 3.52 than to less virulent VCG2B-PD pathotype of
V. dahliae displaying PD and ND symptoms with a mean disease severity index of
2.52. Significant differences were observed among the landraces; however, none
of them exhibited a level of resistance. Okra landraces; Çorum, Hatay Has and
Şanlıurfa displayed the lowest level of susceptibility or little tolerance to both
D and PD pathotypes. VCG2B of PD was prevailing in the surveyed areas and
VCG1A of D was the most virulent of the VCGs identified. Introduction of resistant genotypes to Turkish okra germplasm from different sources and breeding
new resistant okra cultivars are critical for the sustainability of okra production.
KW - Landraces; Malvaceae; nit mutants; pathotypes; VCGs; defoliating; wilt
DO - 10.32604/phyton.2020.08801