Reed S M, Schneider S M
J Nematol. 1992 Jun;24(2):253-6.
No currently available tobacco cultivar possesses resistance to Meloidogyne incognita race 4, nor has any source of resistance been reported within Nicotiana tabacum. The purpose of this study was to evaluate N. otophora acc. La Quinta as a source of resistance to this pathogen. Plants of tobacco cvs. NC 95 and NC 2326, N. otophora La Quinta and N. repanda were inoculated with second-stage juveniles of M. incognita race 4. Gall indices and egg-mass ratings were assessed at 4 and 8 weeks after inoculation. The two N. tabacum cultivars were heavily galled and had numerous egg masses at both rating periods. Nicotiana repanda was only weakly resistant. The galls on this species were very small and present at a low to moderate level; however, egg-mass ratings approaching those of the tobacco cultivars were observed 8 weeks after inoculation. In contrast, low gall indices and egg-mass ratings were found for N. otophora La Quinta at both the 4- and 8-week rating periods. In addition, little variability was observed within this species for either disease rating. Therefore, it appears that the La Quinta accession of N. otophora is a very promising source of M. incognita race 4 resistance for transfer to N. tabacum.
目前没有任何烟草栽培品种对南方根结线虫4号小种具有抗性，烟草属内也未报道过任何抗性来源。本研究的目的是评估耳状烟草品种La Quinta作为该病原菌抗性来源的情况。烟草品种NC 95和NC 2326、耳状烟草La Quinta和绒毛烟草的植株接种了南方根结线虫4号小种的二龄幼虫。在接种后4周和8周评估根结指数和卵块评级。两个烟草品种在两个评级时期根结都很严重，且有大量卵块。绒毛烟草仅有微弱抗性。该物种上的根结非常小，数量处于低到中等水平；然而，接种8周后观察到其卵块评级接近烟草品种。相比之下，耳状烟草La Quinta在4周和8周评级时期的根结指数和卵块评级都很低。此外，该物种在两种病害评级上几乎没有变异性。因此，耳状烟草La Quinta似乎是将南方根结线虫4号小种抗性转移到烟草属的一个非常有前景的来源。
