For the last five years an average 14,761 ha of white clover has been grown for seed, with 77%, 8% and 15% sown in public cultivars, New Zealand and overseas proprietary cultivars, respectively. The area presently contaminated by proprietaries is estimated at 20,000 ha. New Zealand requirements for cultivar-change are more effective than OECD requirements. The five-year break period enables suc...

The degree of resistance by a cotton plant to Meloidogyne incognita is affected by soil temperature, particularly in moderately resistant cultivars, The total number of nematodes in the resistant and moderately resistant rools at 35 C was equal to, or greater than, the number in susceptible roots at 20, 25, or 30 C. A shift in numbers to developing and egg-bearing forms of nematodes in the susc...

Eight cultivars Sorghum bicolor (L.) Moench were grown as callus cultures under induced, prolonged water stress (8 weeks), with polyethylene glycol in the medium. Concentrations of soluble carbohydrates and organic acids in callus were measured at the end of the growth period to determine differences in response to prolonged water stress. Sucrose, glucose, fructose, and malate were the predomin...

the potato tuberworm, phthorimaea operculella (zeller) (lepidoptera: gelechiidae), is one of the most damaging pests of cultivated potato (solanum tuberosum l.) crop, in both field and stores in tropical and subtropical regions. the biological parameters of this pest were evaluated in the growth chamber at 24±1ºc, 65±5% rh and photoperiod of 14:10 h (l:d) on leaves of ten potato cultivars, agri...

In undertaking cultivar trials, the variability of the response of the cultivars to the di¡erent environments in which they are grown introduces the possibility of release errors and non-release errors in the decisions made on the basis of the trial results. In this article a model is developed that accounts for the economic costs of those errors as well as the costs of operating the trials, an...

plant quality in herbivores’ diet may affect the performance of both herbivore and its parasitoids. in the present research, parasitism capacity of diadegma semiclausum (hellen) on plutella xylostella (l.) reared on different genetically manipulated brassica plants including the canola’s progenitor (brassica rapa l.), two cultivated canola cultivars (cultivar-opera and cultivar-rgs003), one hyb...

Phenols are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potential antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. The objective of this study was to investigate a suitable method for determination...