Wednesday, October 08, 2003

Journal abstract time, yay!
Genetic Resources and Crop Evolution 50 (8):

Valeria Negri, "Landraces in central Italy: where and why they are conserved and perspectives for their on-farm conservation," 871-885:

Four hundred and twenty-seven landraces belonging to different plant species (forages, cereals, pulses, garden crops and fruit trees) were found on-farm in central Italy during exploration and collecting missions carried out since 1981. Open field crops are mostly grown under modern agricultural techniques by relatively young farmers on quite large farms for Italian standards. Garden crops are mostly grown by elderly farmers, running small farms or home gardens and using traditional farming systems which include the use of mechanical tools for soil preparation and occasionally the use of chemical fertilisers. There is no unique situation in on-farm conservation and management in the investigated area: the main factors involved appear to be a fragmented habitat and the presence of relatively elderly farmers. Most landraces are directly used by farmers' families, but a part is sold at local and wider markets. The main reasons why these landraces have been maintained on-farm are: their resistance/good productivity under difficult or harsh climatic conditions, traditional reasons or organoleptic peculiarities, which make them highly valued and expensive on the local and city markets and/or simply because they are appreciated by the families. Three example cases of effective on-farm conservation are presented. Social problems seem to be the main cause of genetic erosion. Perspectives and constraints to on-farm conservation and management are briefly discussed.
Lu�s Maciel et al., "Genetic relationships and diversity among Brazilian cultivars and landraces of common beans (Phaseolus vulgaris L.) revealed by AFLP markers," 887-893:
The genetic variation and relationships among 31 accessions of Phaseolus vulgaris L., and two representatives of Vigna unguiculata L., were evaluated by AFLP analysis. A total of 263 DNA fragments across all materials were scored using nine primer combinations, averaging 32 per primer. More than 95% of the amplification products showed polymorphism, indicating high variation at the DNA level among these accessions. Pair-wise genetic similarity (Jaccard's coefficient) ranged from 0.553 to 0.840, with a mean of 0.765. Twenty-three accessions (70%) clustered into three groups. A majority of the commercial cultivars (91%) clustered within a single group, whereas the landraces were distributed along all the variation. An apparent correlation with phaseolin types was detected. Results of this study suggest that Brazilian landraces truly represent the overall genetic variability of Phaseolus vulgaris, confirming the multiple origins of these materials, and their potential as a source of variation for breeding programs.
Agribusiness 19 (4):

William Lin, et al., "StarLink: Impacts on the U.S. corn market and world trade," 473-488:

StarLink disrupted the U.S. corn market during the 2000/01 marketing year as a result of inadvertent commingling. The potential, upper-bound volume of marketed StarLink-commingled corn from the 2000 crop located near wet and dry millers prior to October 1, 2000, is estimated at 124 million bushels. The percentage of corn shipments that tested positive mostly ranged from 5 to 10%, varying by mode of transportation. Price differentials between StarLink-commingled and StarLink-free corn commonly ranged between 7 and 12 cents per bushel during the early stage of the incident. These differentials eroded quickly due largely to Aventis' compensation of additional transportation costs when StarLink-commingled shipments had to be rerouted to approved uses. While StarLink had a negative impact on U.S. corn exports, most of the reductions in exports to Japan and South Korea during the period from November 2000 through March 2002 were due to increased competition from rival exporters.
Schroeter and Azzam, "Captive supplies and the spot market price of fed cattle: The plant-level relationship," 489-504:
Numerous articles in the agricultural economics literature investigate the empirical relationship between the spot market price of fed cattle and the volume of packers' precommitted, or captive, supplies of cattle. In this article, we use an extensive data set on the cattle procurement activities of four large packing plants in the Texas Panhandle from early 1995 through mid-1996 to examine this relationship at the plant-level. We find evidence to support the hypothesis that plants that anticipate near-term future deliveries of captive supply cattle that are high relative to their regional-market rivals' degrees of reliance on captive supplies tend to pay spot market prices that are below average. The effect, while statistically significant, is relatively small in magnitude, however.

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