Phosphorus (P) efficiency (relative growth), which is described as the ratio of shoot dry matter or grain yield at deficient P supply to that obtained under adequate P supply, was compared in 25 winter wheat cultivars grown under greenhouse and field conditions with low and adequate P levels in a P-deficient calcareous soil. Adequate P supply resulted in significant increases in shoot dry weigh...

Selected cotton cultivars were evaluated for resistance to the southern root-knot nematode, Meloidogyne incognita, in greenhouse and field experiments. Cotton cultivars LA 887, Auburn 634, and NemX cotton were highly resistant to three North Carolina populations of root-knot nematode in greenhouse experiments compared to susceptible cultivars. The relative susceptibility of cultivars tested in ...

The reproduction of a Wyoming population of Heterodera schachtii was determined for resistant trap crop radish (Raphanus sativus) and mustard (Sinapis alba) cultivars, and resistant and susceptible sugar beet (Beta vulgaris) cultivars in a greenhouse (21 degrees C/16 degrees C) and a growth chamber study (25 degrees C). Oil radish cultivars also were field tested in 2000 and 2001. In the greenh...

Several abiotic and biotic stresses can affect soybean in a growing season. Heterodera glycines, soybean cyst nematode, reduces yield of soybean more than any other pathogen in the United States. Field and greenhouse studies were conducted to determine whether preemergence and postemergence herbicides modified the reproduction of H. glycines, and to determine the effects of possible interactive...

Most of the 15 carrot cultivars tested were moderate to good hosts to Meloidogyne chitwoodi race 1, whereas all except Orlando Gold were nonhosts or poor hosts for M. chitwoodi race 2. All carrot cultivars were good hosts for M. hapla. The plant weights of the carrot cultivars Red Cored Chantenay and Orlando Gold infected with either race of M. chitwoodi were significantly less than uninoculate...

Root-infecting nematodes are a major cause of white clover, Trifolium repens, not reaching its potential in New Zealand pastures. Resistance and/or tolerance are the preferred control options. Greenhouse-based, recurrent selection programs have developed resistance to Meloidogyne trifoliophila and Heterodera trifolii, and a field-based program has developed tolerance. Lines from these programs ...

The suitability of five maturity group (MG) III and five MG IV soybean, Glycine max, cultivars as hosts for Meloidogyne incognita and M. arenaria was evaluated in a greenhouse. 'Forrest', a MG V cultivar, was used as the standard of comparison for M. incognita resistance. With M. incognita, root-gall and egg-mass indices and reproductive factors for 'Asgrow 3307', 'FFR 398', and 'Pioneer 9442' ...

This investigation was carried out with the aim of determining the effect of polyethylene glycol 6000 (PEG; 0, 3%, 6% and 9% w/v) treatment on six cultivars of Medicago sativa. PEG treatment significantly decreased the germination index in cultivars of Isfahani, Hamedani, Bami, Baghdadi, Yazdi and Ghare-Medicago, with the highest reduction in Ghare-Medicago and Hamedani cultivars by about 50% a...

Reproduction of Pratylenchus penetrans on the potato cultivars Hudson, Katahdin, and Superior was determined in greenhouse and field microplot experiments. Although all three cultivars were good hosts for P. penetrans, differences in reproductive rate were found. In one greenhouse experiment, Katahdin plants inoculated with 1,500 or 15,000 P. penetrans per pot had larger population densities at...

Criconemoides xenoplax and Meloidogyne incognita were the nematode species most frequently associated with peach in North Carolina. Other nematodes often found in high numbers on that crop were Pratylenehus vulnus, Helicotylenchus spp., Trichodorus christiei, Xiphinema amerieanum and Tylenchorhynchus claytoni. P. vulnus and P. penetrans reproduced well on rootstocks of 21 peach cultivars tested...