Performance of commercial soybeans in Illinois, 1982. 1210

Cover title."December, 1982."-- p. [3]

Performance of commercial soybeans in Illinois, 1982. 1210

Cover title."December, 1982."-- p. [3]

Performance of commercial soybeans in Illinois, 1981.

Cover title."December, 1981.

Occurrence and characterization of Alternaria

The global demand for rapeseed makes it one of the fastest growing markets in crop production, with a need for increasing growing area and productivity, both of which depend on effective pathogen control strategies. Alternaria pathogens cause serious losses of brassica crops and occur in most rapeseed-growing regions around the world. In this study, morphological, molecular, and pathogenic analyses of 113 isolates collected from nine important rapeseed-growing areas in Serbia identified four pathogens: Alternaria brassicae, A. brassicicola, A. japonica, and A. alternata, causing leaf spot disease. Molecular analyses of ITS, GAPDH, Alt a1, and ATP sequences revealed one multilocus haplotype for A. brassicae and A. japonica isolates, whereas for A. brassicicola and A. alternata three and five haplotypes were distinguished, respectively. Pathogenicity tests showed that A. brassicicola was the most virulent while A. brassicae and A. japonica exhibited the same level of pathogenicity. The A. alternata population was generally weakly pathogenic with one nonpathogenic, genetically separated but closely related group of isolates, suggesting that pathogenicity is more unstable in this phylogenetic lineage. The data recorded on rate of growth and sporulation of isolates at 0, 5, 10, 15, 20, 25, 30, 35, and 40 °C revealed significant differences in evolutionary strategies among species, as A. alternata had the widest optimum range and the fastest growth rate, A. brassicicola showed the highest sporulation intensity, and A. brassicae expressed lower optimum temperatures for sporulation compared to other groups. All species indicated the potential for cross-infection of cabbage, and some haplotypes of A. brassicicola were previously isolated from horseradish in Serbia, suggesting the presence of one persistent Alternaria population on multiple brassica hosts in the region. This report describes the first detailed study of Alternaria spp. in rapeseed in Serbia

Growth, productivity, and competitiveness of introgressed weedy Brassica rapa hybrids selected for the presence of Bt cry1Ac and gfp transgenes

Concerns exist that transgenic crop × weed hybrid populations will be more vigorous and competitive with crops compared with the parental weed species. Hydroponic, glasshouse, and field experiments were performed to evaluate the effects of introgression of Bacillus thuringiensis (Bt) cry1Ac and green fluorescent protein (GFP) transgenes on hybrid productivity and competitiveness in four experimental Brassica rapa × transgenic Brassica napus hybrid generations (F1, BC1F1, BC2F1 and BC2F2). The average vegetative growth and nitrogen (N) use efficiency of transgenic hybrid generations grown under high N hydroponic conditions were lower than that of the weed parent (Brassica rapa, AA, 2n = 20), but similar to the transgenic crop parent, oilseed rape (Brassica napus, AACC, 2n = 38). No generational differences were detected under low N conditions. In two noncompetitive glasshouse experiments, both transgenic and nontransgenic BC2F2 hybrids had on average less vegetative growth and seed production than B. rapa. In two high intraspecific competition field experiments with varied herbivore pressure, BC2F2 hybrids produced less vegetative dry weight than B. rapa. The competitive ability of transgenic and nontransgenic BC2F2 hybrids against a neighbouring crop species were quantified in competition experiments that assayed wheat (Triticum aestivum) yield reductions under agronomic field conditions. The hybrids were the least competitive with wheat compared with parental Brassica competitors, although differences between transgenic and nontransgenic hybrids varied with location. Hybridization, with or without transgene introgression, resulted in less productive and competitive populations

伊勢物語の相補的解釈 ―一章段内の部分単位での考察―

Many crops transformed with insecticidal genes isolated from Bacillus thuringiensis (Bt) show resistance to targeted insect pests. The concentration of Bt endotoxin proteins in plants is very important in transgenic crop efficacy and risk assessment. In the present study, changes in levels of CrylAc protein in the leaves of transgenic Bt oilseed rape (Brassica napus) carrying a Bt crylAc gene under the control of the cauliflower mosaic virus 35S promoter were quantified during vegetative growth by enzyme-linked immunosorbent assay. Plants were grown in a glasshouse, sampled at 2, 4, 5 and 6 weeks, and the concentration of CrylAc was quantified in basal, top and previous top leaves. The mean concentration differed between sowing dates when CrylAc concentration was expressed as ng g-1 fresh leaf weight but not when expressed as ng mg-1 total soluble protein. It was demonstrated that CrylAc concentration increased significantly as the leaf aged, while the total soluble plant protein decreased significantly. Levels of CrylAc were therefore higher in leaves at the base of the plants than in leaves close to the growing point. However, even young leaves with very low CrylAc concentrations caused high mortality in the larvae of a CrylAc-susceptible laboratory strain of the diamondback moth. The feeding area of leaves consumed by larvae in vivo and in situ was similar. Leaf damage caused by sampling (i.e. artificially) or by feeding of larvae did not affect the levels of CrylAc in the leaves under the experimental conditions in this study