Flavonol glycosides from Aconitum vulparia

The isolation of five flavonol glycosides (1-5) from the flowers of Aconitum vulparia is reported, together with the 1H- and 13C-NMR spectral data in CD(3)OD of compound 3 and 5.     

Improvements to the dry-weight-rank method for measuring botanical composition

Two modifications have been made to the dry-weight-rank (DWR) method for measuring botanical composition. One previous limitation of the method has been that it gives biased results in pastures where there is a consistent relation between quadrat dry matter yield and the order in which species are ranked for yield. A weighting factor, applied to the DWR multipliers and based on pasture yield in quadrats estimated for dry weight rank, can correct for this bias. In routine pasture sampling quadrat yields are often visually estimated in the same quadrats in which composition is assessed by DWR. These estimated quadrat yields can then be used as weighting factors to improve the accuracy of DWR as well as to estimate pasture yield. Dry weight rank has also been unsuited to pastures which are heavily dominated by one species but this problem can be lessened by assigning more than one rank to the dominant species, a method referred to as ‘cumulative ranking’. Both these modifications were found to give a more accurate estimate of composition using data from a wide range of tropical and temperate pastures. On the other hand, creation of new DWR multipliers for particular cases was inadvisable. All data made available for this study and the original data ('t Mannetje and Haydock, 1963) were used to derive new multipliers: 0·705, 0·238 and 0·057. The overall benefits from using the new multipliers will, however, only be slight.     

Inactivation of sclerotia of Rhizoctonia solani on potato tubers by Verticillium biguttatum,a soil-borne mycoparasite

Experiments in the laboratory and on farms with potato tubers in storage are described in which sclerotia ofRhizoctonia solani were inactivated after inoculation of infected tubers with a suspension of conidia and hyphal fragments ofVerticillium biguttatum. Sclerotia on freshly harvested tubers can be killed in a period of six to eight weeks, provided that (1) a direct contact between sclerotia and conidia ofV. biguttatum is obtained, (2) the temperature during the storage period is at least 15 °C, but preferably closer to 20 °C during the first weeks, and (3) the relative humidity of the air between the tubers is at least 99%. Seed tubers are only certified as export quality if the infection withR. solani, visible as sclerotia on the tubers, is assessed as below a specified incidence. To restore the economical value of tubers with many sclerotia, living sclerotia can be inactivated byV. biguttatum. However, also dead sclerotia have to be removed, as dead and living sclerotia cannot be distinguished visually by inspectors. A satisfactory way to remove dead sclerotia from tubers has not yet been found.     

Towards a more efficient utilization of genic male sterility in breeding hybrid barley and wheat

The author suggests that in nature cytoplasms may occur which can restore fertility in male sterile lines in which male sterility is based on one recessive gene ms. If indeed such a fertilizing cytoplasm should be found a male sterile (S) ms ms-line could be increased using the male fertile counterpart (F) ms ms as a male. Thus the female rows in hybrid seed production fields consist of male sterile plants only. A method is outlined to trace a fertility restoring cytoplasm and to introduce it into a male sterile line.     

Ecological characterization of supina bluegrass (Poa supina Schrad.) germplasm from the Italian Alps

A collection was carried out in the Italian Alps to gather local genetic resources and acquire information on the ecological adaptation of supina bluegrass (Poa supina Schrad.), a cool‐season grass native to the Alpine region in Europe. It has potential for pastures and a growing interest for turfs, owing to excellent traffic, shade and cold tolerance. Available germplasm for research and breeding is scant, and extensive collections are needed to enable further development of adapted materials. Alpine germplasm has already proved valuable for breeding at lower altitude in pioneering selection work carried out in Germany. Extensive exploration throughout different environments, mostly above 1600 m elevation, yielded fifty‐five novel populations. Collections largely occurred in environments exposed to heavy disturbance by livestock, but it was also frequently found on very poor substrates along mountain paths and dirt roads, or around buildings. Some populations were present locally in shaded environments. Preliminary ex‐situ observations indicated likely among‐population variation to occur for important traits of breeding relevance such as disease and drought tolerance. Genetic variation for adaptive traits, although unproven, is hypothesized given the diversified habitats where the species was collected across the Italian Alps.