Variations in stolon length and in incidence of tuber roots among eight potato cultivars

The stolon length and percentage of tubers with tuber roots were compared for eight cultivars ofSolanum tuberosum L. over two growing seasons. Although stolon lengths varied considerably within cultivars, there were significant differences in the average stolon lengths among cultivars. The cultivars Norchip and Monona had the shortest stolons whereas Norland had the longest average stolons. The length of the stolon did not appear to be related to color type or time of tuber maturity. Since there was no significant difference in stolon length between years, stolon length appears to be a consistent genetic trait. There was no significant correlation between the stolon length and tuber size. The incidence of tuber roots also showed variation among cultivars, although there was significant variability between times of sampling. Recent studies have demonstrated that to maximize calcium uptake by tubers, the calcium must be placed around the tubers and stolons. Since stolon length determines the location of the tubers in the hill, the stolon length of different cultivars may need to be considered for fertilizer application, cultivation or hilling procedures. Thus, to get maximum benefit from supplemental calcium for Norchip and Monona, application would need to be made close to the main stem. However, in the other cultivars, the majority of the hill would have to be enriched in calcium to effectively supply calcium to the various tubers in the hill.     

Biocontrol of Pythium root rot on lisianthus using a new dark septate endophytic fungus Hyaloscypha variabilis J1PC1

European Journal of Plant Pathology - Pythium root rot is one of the most destructive diseases on lisianthus in Japan. Current management strategies against Pythium root rot are insufficient in...     

Middle Paleolithic shell beads in Israel and Algeria

Perforated marine gastropod shells at the western Asian site of Skhul and the North African site of Oued Djebbana indicate the early use of beads by modern humans in these regions. The remoteness of these sites from the seashore and a comparison of the shells to natural shell assemblages indicate deliberate selection and transport by humans for symbolic use. Elemental and chemical analyses of sediment matrix adhered to one Nassarius gibbosulus from Skhul indicate that the shell bead comes from a layer containing 10 human fossils and dating to 100,000 to 135,000 years ago, about 25,000 years earlier than previous evidence for personal decoration by modern humans in South Africa.