The influence of sample temperature on the performance of a near infrared (NIR) calibration equation was evaluated and then the development of a calibration equation, which can compensate for a variation of sample temperature, was examined. The results obtained are as follows. (i) The calibration equations developed using samples at constant temperature were not stable in predicting when the sample temperature varied. (ii) NIR spectra were affected by sample temperature; as sample temperature increased, absorption became stronger at 841 and 966 nm. A similar phenomenon is exhibited by water. (iii) Water absorption is easily influenced by a variation in temperature, therefore it was considered that water was an important factor causing a bias when the sample temperature varied. (iv) The calibration equations developed using samples which had a temperature range from 21 to 31ºC, showed a high accuracy in prediction, even if the sample temperature changed in that range. In consequence, it was concluded that a calibration equation with temperature compensation could be developed using a combined calibration sample set which covered a variation in temperature of the samples in the future.

The objective of this study was to investigate relationships between reproductive traits in heifers and cows and yield traits for Holsteins in Japan. Insemination and lactation records for cows calved between 1990 and 2003 in Hokkaido region were obtained. Age at first service, age at conception, and conception rate for first service were calculated for heifers. Days from calving to first service, days open, and conception rate for first service were calculated for first- and second-parity cows. The yield traits used were 305-d milk, fat, and protein yields. A threshold animal model was applied for the conception rate for first service, and a linear animal model was applied for the other traits. Single-trait and 2-trait genetic analyses were performed by the Bayesian method using Gibbs sampling. Heritability estimates ranged from 0.027 to 0.051 for conception rate for first service, and from 0.074 to 0.128 for the other reproductive traits. If the relationships of other traits were not considered, days from calving to first service was favorable to genetic selection for reproductive traits because of relatively high heritability and because it can be available earlier than the days open. Genetic correlations among reproductive traits were high, especially in cows. The genetic correlations between reproductive traits for heifers and those for cows were lower than the genetic correlations between reproductive traits for first parity and those of second parity, suggesting that reproductive traits for heifers should be evaluated separately from reproductive traits for cows. Genetic correlations between yield and reproductive traits in cows were antagonistic. In contrast, genetic correlations between reproductive traits for heifers and yield traits were slightly desirable. Depending on the reporting rate of insemination records for heifers and the results of investigations for relationships with productive maturity, selection by reproductive traits for heifers will enable the improvement of reproductive performance without a loss in genetic progress for yield traits.

Seven isolates of Polymyxa betae with a different host range were compared with respect to their association with beet necrotic yellow vein virus (BNYVV). When 14 species of plants were inoculated with the fungus isolates under greenhouse conditions, transmission of BNYVV was related to the fungal isolates from sugar beet, spinach and Chenopodium murale which were infective to sugar beet. But the isolates from C. album, Amaranthus re troflexus and Portulaca oleracea which were not infective to sugar beet did not carry the virus. Viruliferous sugar beet isolates became virus-free after being propagated in the roots of C. ficifolium. When these virus-free resting spores were propagated in the roots of sugar beet infected with BNYVV by manual inoculation, the fungus again acquired and transmitted the virus to healthy plants. Infectivity of BNYVV was maintained together with the survival of P. betae in air-dry and moist soil for fifteen years. The virus infectivity was also retained in zoospores of P. betae treated with BNYVV antiserum and resting spores treated with virus antiserum, HCl or NaOH. In ultrathin sections of sugar beet rootlets infected with the viruliferous sugar beet isolate of P. betae, the virus particles were usually encountered in the cytoplasm in contact with the outer plasmodial wall of the infected cells, and were also present in the vacuoles and the protoplasm of immature zoospores of the fungus. No virus particles were observed in resting spores. The virus, however, was de tected by ELISA in the extracts of viruliferous resting spore clusters isolated from root tissues. From these results, it is concluded that BNYVV transmission is depending on strains of P. betae and the plant species which the fungus proliferates. It is suggested that BNYVV remains in P. betae for a long period of time but does not multiply in the fungus.

SUMMARYThe efficiency of transmission by Polymyxa betae of beet necrotic yellow vein virus (BNYVV) isolates containing different RNA components was compared using sugarbeet seedlings as test plants. Isolate S-4, containing RNA-1 + 2 + 4, was transmitted by P. betae about 100 times more efficiently than isolate S-3 (RNA-1 + 2 + 3) and about 1000 times more efficiently than isolate S-0 (RNA-1 +2). Isolate S-34 (RNA-1 + 2 + 3 + 4) was transmitted even more efficiently than isolate S-4. Each isolate retained its characteristic RNA composition after transmission by P. betae. The virus content, measured by ELISA, of infected rootlets was S-34 > S-3 > S-4 > S-0. In inoculated leaves of Tetragonia expansa and Beta macrocarpa, isolates S-3 and S-34 multiplied more extensively than did S-4 and S-0. The inefficient transmission of isolate S-3 by P. betae, as compared with S-4, cannot be attributed to a poorer ability to spread in root tissue, but the difference in transmissibility of S-3 and S-0 may be explained in this way. These results show that RNA-4 of BNYVV is essential for efficient transmission by P. betae, and suggest that RNA-3 may influence the ability of the virus to spread in root tissue. RNA-4 and RNA-3 therefore seem to play important, but different, roles in virus survival and spread in nature.