The influence of source and rate of potassium fertilizer on the quality of potatoes for french fry production

Summary Trials were carried out in 1984, 1985 and 1986, on a sandy loam soil with an average content of 133 mg/l available potassium in which the effect of source (KCl, K₂SO₄) and rate (0, 300, 600, 900 kg K₂O/ha) of potassium fertilizer on yield, tuber size, dry matter, reducing sugar, fry test colour and finish fried quality was examined for two cultivars (Pentland Dell, Maris Piper). The results indicate a strong influence of cultivar on all measured characters, the rate of potassium fertilizer also gave significant changes in quality and yield and there were significant year effects. The effect of source of potassium was not significant.     

Electron microprobe and neutron activation analysis for the determination of elemental distribution in hollow heart potato tubers

Electron microprobe and neutron activation analysis were used to evaluate the distribution of elements within potato tubers having the physiological disorder hollow heart. Both methods of analysis correlated well for all elements tested. In hollow heart tubers, there were significantly higher Ca⁺⁺ levels in the stem end than in the bud end; however, a Ca⁺⁺ gradient in the control was not evident. The stem to bud end ratios for Ca⁺⁺ were highest in the hollow heart tubers. A Cl^? gradient from stem to bud end was obvious in both the hollow heart and control tubers. In the control tubers, K⁺ was highest in the bud end and lowest in the stem end. There was no K⁺ gradient in hollow heart tubers, but in the area adjacent to the hollow it was higher than at both ends.     

Heterogeneity in soil chemistry relates to urbanization while soil homogeneity relates to plant invasion in small temperate deciduous forests

Landscape Ecology - Soil heterogeneity versus homogeneity patterns are observed within and across urban landscapes at multiple scales. To fully evaluate human-mediated influences on soil properties...     

Identifying resistance in wild and ornamental cherry towards bacterial canker caused by Pseudomonas syringae

Bacterial canker is a major disease of stone fruits and is a critical limiting factor to sweet cherry (Prunus avium) production worldwide. One important strategy for disease control is the development of resistant varieties. Partial varietal resistance in sweet cherry is discernible using shoot or whole tree inoculations; however, these quantitative differences in resistance are not evident in detached leaf assays. To identify novel sources of resistance to canker, we used a rapid leaf pathogenicity test to screen a range of wild cherry, ornamental Prunus species and sweet cherry × ornamental cherry hybrids with the canker pathogens, Pseudomonas syringae pvs syringae, morsprunorum races 1 and 2, and avii. Several Prunus accessions exhibited limited symptom development following inoculation with each of the pathogens, and this resistance extended to 16 P. syringae strains pathogenic on sweet cherry and plum. Resistance was associated with reduced bacterial multiplication after inoculation, a phenotype similar to that of commercial sweet cherry towards nonhost strains of P. syringae. Progeny resulting from a cross of a resistant ornamental species Prunus incisa with susceptible sweet cherry (P. avium) exhibited resistance indicating it is an inherited trait. Identification of accessions with resistance to the major bacterial canker pathogens is the first step towards characterizing the underlying genetic mechanisms of resistance and introducing these traits into commercial germplasm.