SUMMARY
Martínez-Fuentes, R., A. Tovar-Soto, R. Torres-Coronel, y A. E. Brechú-Franco. 2009. Histopathology of bean (Phaseolus vulgaris L.) cultivars non-host to Nacobbus aberrans (Thorne, 1935) Thorne y Allen, 1944. Nematropica 39:311-317. We describe the histopathological changes caused by a Nacobbus aberrans population from Chapingo, Mexico on bean cultivars Negro Querétaro and Canario, which are non-hosts to this population. The plants were inoculated with 15,000 eggs and evaluated 15, 45, and 90 days after inoculation (dai). For each date, the roots were embedded in Tissue Teck® O.C.T. Compound™ and 10 Um-thick sections were cut with a Microm HM505N® cryostat at -30°C and then stained with basic fuschsine-fast green. At 15 dai on both cultivars, nematodes were trapped in lignified cavities surrounded by hypertrophied cells. The nematodes present were third (J3) and fourth stage juveniles (J4), identified by morphological characters, and remained in these stages until 90 dai. Genetic variability of the nematode populations and of the host cultivars is discussed as related to the diverse histopathological reaction responses on bean.