Some data on selection in tetraploid rye

1. 1.
   Six populations of winter rye were chromosome-doubled in 1951 by means of colchicine. After one generation of multiplication the populations were grown as spaced plants (1954). Records were taken on a number of quantitative characters. Grain yield and number of ears per plant showed very skew distributions, whereas strawlength was approximately normally distributed. Highly significant positive phenotypic correlations were found between grain yield and ear number per plant, and between grain yield per plant and strawlength.     

Pleiotropic effects on the ml-o mildew resistance gene in barley in different genetical backgrounds

Summary The effects on quantitative characters of the ml-o5 allele has been investigated by means of doubled haploid lines produced by the Hordeum bulbosum method. In one series of experiments the genetic background in each cross was found significantly to modify the negative pleiotropic effects. Doubled haploids were also produced from a F1 cross and tested in the field during two years, one with strong and one with weak mildew infections. In the first year only an insignificant reduction in grain yield was detected in the mlo lines, in the second it was significantly reduced with 5.9%. Thousand grain weights were, however, higher in the resistant lines. In both series of experiments the possibility to extract very high yielding mlo genotypes was demonstrated. The nature of the genetic background effect is discussed.     

Genetic variation in cocksfoot (Dactylis glomerata L.) populations for mottle virus resistance

Summary Highly significant and continuous variation in the degree of injury due to cocksfoot mottle virus (CfMV) infection was found among clones of 7 cocksfoot (Dactylis glomerata L.) populations, taken at random among surviving plants in 9 year old swards. Broad sense heritabilities for CfMV injury ranged from 0.52 to 0.91 within populations, and genotypic correlations between CfMV injury and total DM-yield ranged from –0.46 to –0.88. The relationship between CfMV injury and DM-yield could be described by a second degree curve. CfMV injury was to some extent genotypically correlated in the positive direction with crude protein content and digestibility, and negatively with crude fiber content, especially in the first cut. Artificial infection of plants from the original populations with CfMV in a simulated sward experiment, did not reveal any significant differences between populations in tolerance towards CfMV infection. Infection caused a 54.5% increase in the number of dead plants per plot, relative to uninfected plots, but only a 4.5% reduction in dry matter yield. There is a clear tendency that synthetic populations selected for high yield are less tolerant towards CfMV infection than unselected or low yielding populations. The resistance found in these cocksfoot populations is a sort of tolerance, and the results indicate that the level of tolerance can be increased by selection.     

Breeding for resistance to neck rot (Botrytis allii) in onions (Allium cepa)

Summary For 10 years the method developed by Van der Meer et al, (1970) to test neck rot resistance in onions has been applied in a breeding programme. From experiments with market varieties, inbred lines and half-sib families it is concluded that neck rot resistance as determined by this method is a quantitative character, which shows continuous variation and is in part fixable by selection. The practical importance of this type of neck rot resistance is not yet clear.Report no. 68     

Winter hardiness in marginal populations of timothy

Summary A comprehensive collection of local fodder grass populations was carried out in the northern regions of Norway in 1972 and 1973. The main purpose was to find ecotypes with extreme winter hardiness. This paper gives results from experiments carried out with some of the timothy populations collected.After testing in dense stand a few of the most promising populations were selected for investigation of genetic variation within populations by growing in duplicate blocs of 100 clones from randomly selected plants. Twenty-two clones were selected from each of six populations and planted in separate isolated polycross fields. During 1986 to 1990 the half-sib families from these polycrosses were grown in two series of experiments laid out at two locations, Tromsø and Alta.Significant genetic variations were found for winter hardiness within all six populations tested, as well as interaction between families and locations, while the interaction effects between families and years were small and insignificant in all cases.Winter hardiness was strongly genotypically correlated in the positive direction with visually estimated general performance, but not correlated with digestibility.     

ORIGINAL ARTICLE: Intravenous injections of cobalt reduce fatty acid desaturation products in milk and blood of lactating cows

The objective of this study was to determine whether intravenous infusion of Co affects levels of fatty acid desaturation products in bovine milk. Six cows were assigned to two replicated 3 × 3 Latin squares with 14‐day periods. Treatment occurred on days 1 to 5 and depuration occurred on days 6–14. Two treatments were tested, the first consisting of per os supplementation of 3.5 g Co daily in the form of Co acetate and the second consisting of intravenous injection of 175 mg Co daily in the form of Co acetate diluted in saline solution. The third treatment was a control. Both Co treatments decreased cis‐9 18:1 levels from approximately 18 to 14 g/100 g fatty acids, and increased 18:0 levels from 11 to 17 g/100 g fatty acids in milk fat (p < 0.001). The proportions of cis‐9 10:1, cis‐9 12:1, cis‐9 14:1, cis‐9 16:1 and cis‐9 17:1 decreased (p < 0.001), whereas 17:0 and trans‐11 18:1 increased (p < 0.001). In blood plasma, levels of cis (6,9,12) 18:3 (p < 0.001) and cis (8,11,14,17) 20:4 (p = 0.008) decreased after both the Co treatments. It is concluded that intravenous supply of Co reduces levels of fatty acid desaturation products in both bovine milk and blood.     

Effects of Tank Wall Color and Up-welling Water Flow on Growth and Survival of Eurasian Perch Larvae (Perca fluviatilis)

The influence of tank wall color and up‐welling water flow on growth and survival of Eurasian perch larvae (Perca fluviatilis) was tested in an intensive culture system. Newly hatched larvae were fed Artemia nauplii, later combined with dry feed, and reared for 5 wk in either black tanks with up‐welling water flow or in gray tanks with or without up‐welling water flow. The perch larvae grew significantly faster in black tanks than in gray tanks regardless of water flow. Two weeks after hatching, a significantly higher mean weight was shown in larvae reared in black tanks compared to larvae reared in gray tanks with up‐welling water flow, and after 4 wk, the mean weight was significantly higher than in both of the other treatments. The difference in growth was further enhanced during the last week of the experiment, and the final mean weights were 51.1 ± 1.9 mg in black tanks with up‐welling water flow, 23.8 ± 2.1 mg in gray tanks with up‐welling water flow, and 23.7 ± 2.2 mg in gray tanks without up‐welling water flow. The cumulative mortality at the end of the experiment averaged 75% in all treatment groups. Taken together, the enhanced growth of Eurasian perch larvae in black tanks could be explained by high prey contrast and increased prey consumption. Up‐welling water flow had no impact on growth and survival of the perch larvae in gray tanks, indicating that the availability and consumption of the prey were independent of water movement.     

Mycotoxin production by Fusarium avenaceum strains isolated from Norwegian grain and the cytotoxicity of rice culture extracts to porcine kidney epithelial cells

The secondary metabolites of 24 isolates of Fusarium avenaceum from Norwegian cereals and grown on rice have been characterized. Moniliformin (MON), enniatins (ENNs), and beauvericin (BEA) were analyzed by high-performance liquid chromatography. Porcine kidney epithelial cells (PK15, American Type Culture Collection) were used to study the cytotoxicity of MON in the extracts. The following metabolites were produced by all isolates, ranked by concentration in rice cultures: ENN-B, MON, ENN-B1, and ENN-A. BEA was produced by eight isolates. The productions of BEA and ENN-A were significantly correlated, as was the case with ENN-B and ENN-B1. MON production was correlated neither to any of the other toxins nor to toxicity.