Clonal Variation and Heritability of Foliage Infestation by Clostera anastomosis tristis in Populus maximowiczii

1985

4 Abb., 2 Tab.

Unselbständiges Werk

6974

200014132

In poplar plantations occasionally occur severe foliage infestation in early summer caused by black back prominent (Clostera anastomosis tristis Standinger). Wide variation of infestation among trees was found suggesting genetic resistance to this insect. Artificial infestation tests were made by the following procedure. Testing leaves of about 30 pieces were arranged on the plate of 50x40 cm size and covered by vinyl film like a tent. Twenty larvae of 2.0 - 3.0 cm body length were released in tent and tested one night. Extent of infestation was scored on a 1 - 6 basis, a rating of 1 indicated 0%, 2 (0.1 - 20%) 6 (81-100%). 1. Variation among provenances and clones. A total of 125 clones, selected 4 regions of Hokkaido (northern, eastern, southeastern and southern region) were tested with 5 replications. The mean value of scores among provenances were 2.54 - 3.11 and no significant differences were found among provenances, but highly significant differences at 0.1% level were found among clones of each provenance. Selection of resistant clones were made at the base of significant at 5% level from the mean value of each provenance, as a result, 30 clones were selected as a resistant clone. 2. Heritability estimates. Materials for feeding experiments were 8-year-old 5x4 progenies and their parental clones. Extent of average fed percent in leaf area was 2.3 - 81.7 in female clones, 1.4 - 62.8 in male clones and 3.6 - 64.0 in crossed progenies. Highly significant differences at 0.1% level were found among families as well as female and male parents. Highly narrow sence heritability of (Formel) was found in susceptibility, and also highly significant correlation coefficient of r = 0.904 was found between crossed progenies and mid-parent. These results indicated that the resistance appear to be under strong genetic control.