ALBERT

Notes: Random amplified polymorphic DNA (RAPD) markers were generated from 20 wheat, Triticum aestivum lines. Fifty-four fragments generated by six primers of a 10-mer arbitrary sequence were used to study their potential power in differentiating parents with different characteristics and predicting the yield performance of hybrids produced from these parents. Experimental results showed that the 20 wheat lines were divided into four groups. Group I was characterized by more grains per spike, group II by heavy grains and group III by more spikes per unit area and short plants; group IV was similar to group III but had a much higher biomass yield and grain yield. Hybrids from parents in different groups were generally superior to most hybrids from parents in the same group. Both yield performance and heterosis of hybrids from parents between group I and group III were much better than those of other intergroup hybrids. These results suggest that, based on RAPD markers, it is possible to differentiate wheat lines with different performances and that the classification of parents from these markers is of predictive value for developing superior hybrids. However, genetic distance (GD) based on RAPD markers was not significantly correlated with hybrid performance and heterosis. It appears to be impossible to predict hybrid performance from GD itself.

Notes: Powdery mildew is an important disease in most of the wheat production areas of the world. The resistance gene Pm21 (6AL/6VS trans-location) derived from Haynaldia villosa confers resistance to all available isolates of Erysiphe (Blumeria) graminis f. sp. tritici in China and Europe. The objective of this study was to develop fast and reliable sequence characterized amplified region (SCAR) markers linked to the Pm21 gene. A random amplified polymorphic DNA (RAPD) marker for Pm21, OPH171400, was converted to SCAR markers after sequencing the two ends of the polymorphic DNA fragment. Two SCAR markers, SCAR1265 and SCAR1400, were developed to detect the Pm21 gene in different genetic backgrounds. The specific SCAR1265 marker enable large-scale accurate screening for the presence/absence of Pm21 allele.

Notes: : This paper considers the distribution of flood flows in the Upper Mississippi, Lower Missouri, and Illinois Rivers and their relationship to climatic indices. Global climate patterns including El Niño/Southern Oscillation, the Pacific Decadal Oscillation, and the North Atlantic Oscillation explained very little of the variations in flow peaks. However, large and statistically significant upward trends were found in many gauge records along the Upper Mississippi and Missouri Rivers: at Hermann on the Missouri River above the confluence with the Mississippi (p = 2 percent), at Hannibal on the Mississippi River (p 〈 0.1 percent), at Meredosia on the Illinois River (p = 0.7 percent), and at St. Louis on the Mississippi below the confluence of all three rivers (p = 1 percent). This challenges the traditional assumption that flood series are independent and identically distributed random variables and suggests that flood risk changes over time.

Notes: The objectives of this study were to compare efficiency of evaluation for resistance to Fusarium head blight (FHB) under two inoculation methods in a recurrent selection programme. Fifty selected homozygous F5 fertile lines, from each of five cycles (C0, C1, C2, C3 and C4) of recurrent selection, and two control cultivars were evaluated in a split-plot design in 1995 and 1996 under the soil-surface inoculation with Fusarium graminearum-colonized kernels and the single-floret inoculation with ascospore suspension. Comparison of the two inoculation methods using means, ranges, coefficients of variation, heritabilities and correlations among infected spikelet rate (ISR), reaction index (RI) and disease index (DI) indicated that FHB resistance could be evaluated with similar accuracy and precision using either of the two inoculation methods. Regressions of disease scores in the soil-surface inoculation on disease scores in the single-surface inoculation were positive and highly significant, showing a strong relationship between both inoculation methods for FHB resistance. The percentage of lines with similar performance for FHB disease scores in both inoculation methods was high. The soil-surface inoculation and single-floret inoculation appear to be useful techniques for evaluating numerous individuals of segregating population and screening advanced homozygous lines for FHB resistance in a recurrent selection programme in wheat, respectively.

Notes: The objectives of this research were to determine the individual and interaction effects of the Ppd-H1 and Sh2 loci on agronomic traits under short- and long-photoperiod regimes. Nineteen doubled haploid (DH) lines from the ‘Dicktoo’בMorex’ mapping population, which represented the four genotypes at the Ppd-H1 and Sh2 loci, were pheno-typed in controlled environment photoperiods. Both Ppd-H1 and Sh2 had significant effects on several agronomic traits, in addition to their role in determining first node appearance and flowering time. The magnitude of these effects depended on daylight. Under long-day conditions (18 h) Ppd-H1, and under short-day conditions (12 h) Sh2 was a significant determinant of most characters. The interactions between these two loci were significant for several characters, particularly for yield components, under both long- and short-photoperiod regimes. Under the long-day treatment, Ppd-H1 influenced plant height through the determination of node number. There was an epistatic association between the two loci for both 1000-kernel weight and tillering. The combination of photoperiod insensitivity and vernalization requirement caused a significant increase in tillering. This was paralleled by a decrease in 1000-kernel weight. Under the long-day treatment, neither Ppd-H1 nor Sh2 influenced plant yield. Under short-day conditions, the combination of photoperiod insensitivity and vernalization requirement had a pronounced negative effect on plant yield.

Notes: The genotype-environment (GE) interaction of barley doubled haploid (DH) lines was studied in relation to some malting quality characters. DH lines were obtained, using the bulbosum method, from F1 hybrids between the cultivars ‘Grit’ and ‘Havila’. Thirty DH lines, the parental forms, F2 and F3 hybrids of ‘Grit’בHavila’ and the standard cultivar ‘Rudzik’ were studied in a series of field experiments repeated at six environments. Malt protein content, Kolbach index, extract yield and malt fine-coarse difference were measured. The statistical analysis was performed using the computer program SERGEN. For protein content, it was found that most of the lines studied were stable, i.e. their GE interactions were not significant. Among the malt traits, phenotypic values of Kolbach index and fine-coarse difference were most dependent on environmental conditions. For Kolbach index, only one line was found to be stable, while for fine-coarse difference, all lines displayed interaction with the environment.

Notes: Soil macropores are widely studied because they are known to serve as avenues for rapid contaminant transport. Currently, it is understood that a macroporous medium develops regions of mobile and immobile water during flow. Consequently, solutes in the mobile phase bypass a considerable portion of the medium, thus limiting their natural attenuation. It is, however, not adequately documented in the literature what role the macropores play during intense rain events that result in variable ponding depths.Macropore flow under ponded water conditions was studied on two undisturbed soil columns taken from the loam soils of northeastern Iowa, U.S. The columns were placed on a four-segment outflow collector system. A slug of water labeled with Br was applied to the columns followed by simulation of 58 mm of rain on column 1 and 53.6 mm on column 2, in one hour, 30 minute, and 15 minute events. During the highest intensity rain event (15 minutes), the total volume of water that exited through the bottom of segments 1,2, 3, and 4 were 21.6%, 34.5%, 28.5%, and 15.4% in column 1, and 1.3%, 15.9%, 72.2%, and 10.5% in column 2, respectively. As the intensity of rain was increased from one hour to the 15 minute event, the total bromide mass recovery increased from 45% (29.2 mg) to 57% (36.9 mg) of the total application (65 mg) for column 1, and from 51 % (33.2 mg) to 59% (38.2 mg) for column 2, respectively. Finally, an examination of dye-stained high flow regions in column 1 demonstrated that macro-porosities made approximately 20% of the total cross-sectional area of the column.These results suggest that solute transport behavior in macroporous soils can be impacted by ponding depths, and intense rain events can severely restrict contaminant degradation in soils.

Notes: 
 A, assimilation rate
a, fractionation against 13C for CO2 diffusion through air
b, net fractionation against 13C during CO2 fixation
Ca, ambient CO2 concentration
Cc, CO2 concentration at the chloroplast
Ci, intercellular CO2 concentration
D, vapour pressure deficit
En, needle transpiration rate
Ep, whole plant water use
gw, leaf internal transfer conductance to CO2
gs, stomatal conductance to water vapour
L, projected leaf area
NUE, nitrogen use efficiency
PEP, phosphoenolpyruvate
Rubisco, ribulose-1,5-biphosphate carboxylase
TDR, time domain reflectometry
WUE, water use efficiency
Δ, carbon isotope discrimination
δ13C, carbon isotope abundance parameter
δ13Ca, carbon isotopic composition of atmospheric CO2
θ, volumetric soil water content

The effect of nitrogen stress on needle δ13C, water-use efficiency (WUE) and biomass production in irrigated and dry land white spruce (Picea glauca (Moench) Voss) seedlings was investigated. Sixteen hundred seedlings, representing 10 controlled crosses, were planted in the field in individual buried sand-filled cylinders. Two nitrogen treatments were imposed, nitrogen stressed and fertilized. The ranking of δ13C of the crosses was maintained across all combinations of water and nitrogen treatments and there was not a significant genetic versus environmental interaction. The positive relationships between needle δ13C, WUE and dry matter production demonstrate that it should be possible to use δ13C as a surrogate for WUE, and to select for increased WUE without compromising yield, even in nitrogen deficient environments. Nitrogen stressed seedlings had the lowest needle δ13C in both irrigated and dry land conditions. There was a positive correlation between needle nitrogen content and δ13C that was likely associated with increased photosynthetic capacity. There was some indication that decreased nitrogen supply led to increased stomatal conductance and hence lower WUE. There was a negative correlation between intrinsic water use efficiency and photosynthetic nitrogen use efficiency (NUE). This suggests that white spruce seedlings have the ability to maximize NUE when water becomes limited. There was significant genetic variation in NUE that was maintained across treatments. Our results suggest that in white spruce, there is no detectable effect of anaplerotic carbon fixation and that it is more appropriate to use a value of 29‰ (‘Rubisco only’) for the net discrimination against 13C during CO2 fixation. This leads to excellent correspondence between values of Ci/Ca derived from gas exchange measurements or from δ13C.

Notes: Genetic distances were lower between Upeneus moluccensis and Pseudopeneus prayensis than between those species and Mullus barbatus and Mullus surmuletus. However, for allozymes, the two Mullus species were found genetically more distinct from U. moluccensis than from P. prayensis, but RAPD and mtDNA analysis showed the opposite. RAPDs revealed less interspecific divergence compared with allozymes and the results they produced were more consistent with mtDNA analysis. Although RAPDs did not add any supplementary taxonomic information, they proved valuable tools for quick and reliable species discrimination compared with allozymes and mtDNA.