A germplasm collection of 39 eggplant Solanum melongena genotypes and one accession of S. torvum was evaluated for resistance to the rootknot nematode {Meloidogyne javanica) by using controlled greenhouse tests. Different degrees of resistance to the disease caused by this nematode species were observed among the genotypes tested. Complete resistance (no nematode egg mass formation up to 7 weeks after inoculation) was detected in one accession belonging to domesticated S. melongena species. Good levels of incomplete resistance were also observed in some commercial eggplant genotypes. This is apparently the first report of a source of complete resistance to M.javaniea within the S. melongena gene pool and our finding could greatly facilitate the incorporation of this trait into commercial eggplant cultivars. S. torvum, previously described as resistant to several root-knot nematode species (including M. javaniea, M. arenaria, and M. ineognita) was also confirmed as a source of resistance to this Brazilian population of M. javaniea. Therefore, 5'. torvum can be considered as one of the most promising sources of broad-spectrum resistance genes against root-knot nematodes. Broad-spectrum resistance is of paramount importance for breeding programmes focused on the development of cultivars for tropical and subtropical areas of the world where multiple infestation of soils with distinct Meloidogyne species is a very common feature.
Meloidogyne pisi n. sp. is described and illustrated from specimens obtained from roots of pea cv. Mikado in Brasilia, Brazil. The female perineal pattern is variable in shape, most are rounded to ovoid, whereas others have a moderately high, squarish dorsal arch, and can be marked with several striae parallel to the vulva or may be nearly free of striae. Lateral fields may contain a few irregular, wavy, transverse striae or be difficult to discern. Female medial lips are wide and long, sometimes with distinctly indented outer margins; the lateral lips are large and triangular, head annule is wide and marked by incomplete annulations and transverse folds. Stylet is 13-17 µm long with large, elongated knobs and a shaft that is cylindrical, straight and thick. Lumen lining of pharynx containing numerous rounded cuticular thickenings throughout its length; excretory pore located between base of stylet and median bulb. Males are 893-2510 µm long with a 19-26 µm long stylet bearing large elongated knobs, shaft marked with small, rounded projections. Second-stage juveniles are 374-463 µm long with medial lips often indented medially and 10-11 µm long stylet. Tail slender, 42-66 µm long with large irregular annules in posterior region, a slightly pointed tip and hyaline region 9-17 µm long. Many galls and egg masses are produced on tomato, tobacco and varieties of pea and bean. Few galls occur on watermelon and corn and reproduction is poor on pepper. No reproduction occurs on peanut, cotton or soybean.Pea plants (Pisum sativus L.) collected from the Nucleo Rural do Jardim area of Brasilia, Brazil, were severely infected with root-knot nematodes. Symptoms included chlorosis, stunting, root rot, and a complete lack of nodulation by Rhizobium spp. The infected root system was analysed in the EMBRAPA/CNPH (National Research Centre for Vegetable Crops) Nematology Laboratory, Brasilia, Brazil.Research at Virginia Tech on the morphology and host range revealed several unusual morphological characters and a unique host range that indicated it was a new species. The perineal pattern, shape of the female stylet and shape of the male stylet were unique and different from those of any other described species. Meloidogyne
Alambra' was more responsive to treatments than 'Duradoro'. Methyl bromide fumigation and solarization reduced the number and survival of weed seeds in the soil. Solarization increased levels of P and Cu, and reduced levels of Zn in the soil.
Meloidogyne brasilensis n. sp., Londrina and Brasilia populations, is described and illustrated from specimens from tomato cv. Rossol and pea cv. Mikado, respectively, in Brazil. Characteristically, the perineal pattern is elongated to ovoid with a flattened to very high, squarish dorsal arch with widely spaced, coarse striae. The lateral fields may have wing-like striae on one or both sides. The female stylet is 14 μm long with narrow and elongated knobs that are distinctly set-off from the shaft. The excretory pore is variable in location, but generally opens near the anterior portion of the median bulb about 50 μm from the head end. The male is 1.89 mm long and has a high head cap that slopes posteriorly. The labial disc is separated from the medial lips by a deep, rounded groove. The delicate stylet of the male is 23 μm long and has small, rounded knobs that are distinctly set-off from the shaft which has numerous small, rounded projections. Mean second-stage juvenile length is 434 μm. The juvenile head cap is highly elevated, the medial lips are crescent-shaped and unequal in size, and the head region is not annulated. The stylet is 11 μm long and has small, rounded, posteriorly sloping knobs. The tail is 53 μm long; it is marked with large, irregular annules and ends in a bluntly rounded tip. The hyaline tail terminus is short (13 μm). Reproduction occurred on NC95 tobacco, tomato, pea, and bean, whereas pepper, watermelon, peanut, cotton, corn, and soybean were not hosts.
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