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A population of 96 doubled haploid lines (DHLs) was prepared from F 1 plants of the hexaploid wheat cross Chinese Spring × SQ1 (a high abscisic acid-expressing breeding line) and was mapped with 567 RFLP, AFLP, SSR, morphological and biochemical markers covering all 21 chromosomes, with a total map length of 3,522 cM. Although the map lengths for each genome were very similar, the D  genome had only half the markers of the other two genomes. The map was used to identify quantitative trait loci (QTLs) for yield and yield components from a combination of 24 site × treatment × year combinations, including nutrient stress, drought stress and salt stress treatments. Although yield QTLs were widely distributed around the genome, 17 clusters of yield QTLs from five or more trials were identified: two on group 1 chromosomes, one each on group 2 and group 3, five on group 4, four on group 5, one on group 6 and three on group 7. The strongest yield QTL effects were on chromosomes 7AL and 7BL, due mainly to variation in grain numbers per ear. Three of the yield QTL clusters were largely site-specific, while four clusters were largely associated with one or other of the stress treatments. Three of the yield QTL clusters were coincident with the dwarfing gene Rht-B1 on 4BS and with the vernalisation genes Vrn-A1 on 5AL and Vrn-D1 on 5DL. Yields of each DHL were calculated for trial mean yields of 6 g plant −1 and 2 g plant −1 (equivalent to about 8 t ha −1 and 2.5 t ha −1, respectively), representing optimum and moderately stressed conditions. Analyses of these yield estimates using interval mapping confirmed the group-7 effects on yield and, at 2 g plant −1, identified two additional major yield QTLs on chromosomes 1D and 5A. Many of the yield QTL clusters corresponded with QTLs already reported in wheat and, on the basis of comparative genetics, also in rice. The implications of these results for improving wheat yield stability are discussed. [ABSTRACT FROM AUTHOR]

The classification of disease burdens is an important topic that receives little attention or debate. One common classification scheme, the broad cause grouping, is based on etiology and health transition theory and is mainly concerned with distinguishing communicable from noncommunicable diseases. This may be of limited utility to policymakers and planners. We propose a broad care needs framework to complement the broad cause grouping. This alternative scheme may be of equal or greater value to planners. We apply these schemes to disability-adjusted life year estimates for 2000 and to mortality data from Tanzania. The results suggest that a broad care needs approach could shift the priorities of health planners and policymakers and deserves further evaluation. [ABSTRACT FROM AUTHOR]

We compared influxes and internal transport in soybean plants (Glycine max cv. Kingsoy) of Labelled N from external solutions where either ammonium or nitrate was labelled with the stable isotope15N and the radioactive isotope13N. The objective was to see whether mass Spectrometric metric determinations of tissue 15N content were sufficiently sensitive to measure influxes accurately over short time periods. Our findings were as follows. (1) There was a close quantitative correspondence between estimates of N influx of individual plants using 15N or 13N measurements with either NO3- or NH4+ at 4 or 2 mol m-3, respectively in the external solution. (2) Transport to the shoot of N from NO3 absorbed over a 5-15 mm period could be monitored when the external NO3- concentration ranged from 0.05 to 4 mol m-3. NH4+ as the N source labelled shoot tissue more slowly, and estimates of the transport between root and shoot could be made only with 13N. (3) Influx of NO3- into root tissue could be measured by 15N enrichment after 5-10min at concentrations approaching the probable KM of the high-affinity transport system. (4) There was some indication of isotope discrimination, especially with respect to the movement of labelled N to lime shoot, when NO3- is the N source, For many purposes, 15N tracing can be used satisfactorily to estimate influxes of both NO3- and NH4+ in soybean roots. Use of the short-lived radionuclide 13N remains the method of choice for more refined measurements of internal distribution and assimilation. [ABSTRACT FROM AUTHOR]

A study was made of the effects of either 6-benzylaminopurine (BAP), a synthetic cytokinin, or calcium nitrate on the response of the shoots of 13-day-old barley plants to soil waterlogging. Spraying leaves daily with BAP resulted in small improvements in leaf extension and retarded the premature loss of chlorophyll in the older leaves after 7 days waterlogging, but the rates of accumulation of dry matter and inorganic nutrients in shoots were reduced to the same extent as in unsprayed plants. After a further 7 days waterlogging, during which spraying was discontinued, plants treated with BAP were no longer appreciably different from untreated ones. When calcium nitrate was added daily to the surface of the waterlogged soil, no symptoms of waterlogging damage appeared. Leaf extension, shoot weight, emergence of tillers, chlorophyll concentrations and the accumulation of inorganic nutrients in shoots were similar to those in plants in non-waterlogged soil after 7 and 14 days. The effect was dependent on the presence of a narrow zone of aerated soil close to the surface, in which root growth and function could continue. When plants were grown for 13 days in aerated nutrient solution, and then transferred to solutions lacking nitrate, the development of leaf chlorosis, the decrease in the concentration of nitrogen in the shoots and their retarded accumulation of dry matter were all similar to that caused by waterlogging. The premature loss of chlorophyll in the older leaves was retarded by spraying with BAY. Chlorosis of the older leaves could also be promoted in plants in aerated nutrient solution by excising part of the root system. Mechanisms by which BAP and calcium nitrate alleviate symptoms of waterlogging damage, and the significance of nitrogen deficiency and root excision in relation to waterlogging damage, are discussed. [ABSTRACT FROM AUTHOR]