Wheat yellow mosaic virus resistant line, 'Kitami-94', developed by introgression of two resistance genes from the cultivar 'Madsen'

Abstract

'Kitahonami' is a soft red winter wheat (Triticum aestivum L.) cultivar that has high yield, good agronomic performance and good quality characteristics. It currently accounts for 73% of the wheat cultivation area of Hokkaido the northern island in Japan and 42% of Japan's overall wheat cultivation. However, this cultivar is susceptible to Wheat yellow mosaic virus (WYMV). WYMV has become widespread recently, with serious virus damage reported in Tokachi and Ohotsuku districts, which are the main wheat production areas in Hokkaido. Here, we report a new wheat breeding line 'Kitami-94', which was developed over four years by repeated backcrossing with 'Kitahonami' using DNA markers for WYMV resistance linked to the Qym1 and Qym2 from 'Madsen'. Basic maps of Qym1 and Qym2 were created and used to confirm that 'Kitami-94' reliably carried the two resistance genes. 'Kitami-94' demonstrated WYMV resistance, and had agronomic traits and quality equivalent to 'Kitahonami' except for higher polyphenol oxidase activity and lower thousand grain weight. 'Kitami-94' may be useful for elucidating the mechanism of WYMV resistance in the background of 'Kitahonami', and for developing new cultivars.

Keywords: Triticum aestivum L.; Wheat yellow mosaic virus; backcross; breeding; resistance genes.

Fig. 1.

Breeding of ‘Kitahonami’ near-isogenic lines (NILs). NILs are shown in boxes.

Fig. 2.

Frequency distributions of WYMV infection rate, and basic maps of Qym1 and Qym2. a) F_2:3 population segregating for Qym1 while fixed for homozygous ‘Madsen’ genotype at Qym2; b) F_2:3 population segregating for Qym2 while fixed for homozygous ‘Madsen’ genotype at Qym1; c) linkage map of Qym1; d) linkage map of Qym2. Dark-shaded bars represent families judged to be resistant to WYMV; pale-shaded bars represent families with intermediate infection rates; unshaded bars represent families judged to be susceptible to WYMV. Families with intermediate infection rates were excluded from the gene mapping.