"Characteristics evaluation of ""KP lines"", genetic resources introduced from Poland."

"Up to the present, our laboratory has bred many cultivars and lines based on the introductions of genetic resources from abroad. Especially since 1986 when payment system based on sugar content started, we aimed mainly at breeding of high sugar content variety. However, recently cultivation of sugarbeet in Hokkaido faced several severe problems. Growing incidence of diseases such as Cercospora leaf spot and Aphanomyces root rot and lasting low sugar content phenomenon since 1998, and in addition competition with other countries in the sugar market created to be solved. In response to these problems, our laboratory tried to breed new cultivars resistant to a number of diseases and high in yield. Against this background, we conducted joint research on breeding disease resistant variety with Sugar Crop Development Fund (S. C. D. F.) since 1998. In this paper we report on the result of characteristics evaluation of KP lines that were introduced by S.C.D.F. from Poland in 1999. The findings were as follows. (1) From the result of investigation of weight of root and crown, root part of KP lines was found quite small (the percentage to ""Monohomare, a standard cultivar in Japan"" was 67 to 85%), and it was thought that KP lines needed to improve the root weight (Table 3). (2) The Brix value of KP lines ranged from 24.0 to 25.5% (the percentage to ""Monohomare"" 119-126%) , and was higher than that of the existing lines. Accordingly, KP lines were found so high in sugar content that no existing cultivars in Japan compared to those lines in terms of sugar content ( Table 3 ). ( 3 ) We conducted artificial test for bolting tolerance of KP lines. It made clear that bolting tolerance of KP lines was not so strong and particularly KP-11-KP-17 ( selected for Aphanomyces resistance ) were weak ( Table 4 ).( 4 ) Combining ability and heterosis of KP lines in connection with root weight were not promising. However, by using KP lines as pollen parents, we can expect to breed promising variety with high sugar content and high quality ( Table 5 ). Although some traits ( root weight, bolting tolerance etc. ) needed to be improved, KP lines have shown the highest quality and sugar content which no existing lines exhibited. As a result, it was concluded that KP lines have the good possibility of being used in the future breeding. The further study on the disease resistance of KP lines, however, will be necessary."