Search

Shiratae Nijo is a new two-rowed food barley cultivar bred at the National Agricultural Research Center for Kyushu Okinawa Region (KONARC) in collaboration with the National Institute of Crop Science (NICS) and released in 2009. Shiratae Nijo is a proanthocyanidin-free cultivar bred by backcross breeding using a leading cultivar Nishinohoshi as a recurrent parent and a foreign proanthocyanidin-free mutant ant28-494 as a non-recurrent parent. The agronomic characteristics of Shiratae Nijo are almost the same as those of Nishinohoshi which has high yield performance and high resistance to barley yellow mosaic virus (BaYMV) type I and powdery mildew. Like Nishinohoshi, Shiratae Nijo shows high resistance to Fusarium head blight (FHB) at the anthesis stage but is susceptible 10 days after anthesis. Shiratae Nijo exhibits significantly weaker seed dormancy than Nishinohoshi. Shiratae Nijo has excellent pearling quality, and the pearled grains show no discoloration and high whiteness after cooking because of the lack of catechin and proanthocyanidin in the grains.

In wheat (Triticum aestivum L.), Fusarium head blight (FHB) resistance is an important breeding target to reduce yield losses and mycotoxin contamination. We hypothesized that cleistogamous (CL, closed flowering) cultivars have a lower risk of FHB infection than chasmogamous (CH, opened flowering) cultivars because FHB infection usually occurs in the inside of florets or extracted anthers and FHB resistance in CL cultivars decreases mycotoxin accumulation. To test these hypotheses, we produced 126 recombinant inbred lines (RILs) derived from a cross between common wheat varieties ‘U24’ (CL variety) and ‘Saikai 165’ (CH variety). Although ‘U24’ and ‘Saikai 165’ are both resistant to FHB infection, ‘U24’ is susceptible to FHB spread, grain deterioration, and mycotoxin accumulation compared with ‘Saikai 165’. Among the RILs, there were significant differences in all of the tested traits. Although the CL RILs showed less initial FHB infection than CH RILs, there were no significant differences in grain deterioration and mycotoxin accumulation between the 2 groups. An FHB-resistant quantitative trait locus (QTL) located on chromosome 3BS increased resistance to FHB spread, grain deterioration, and mycotoxin accumulation; however, not all CL RILs with this QTL accumulated less mycotoxin than ‘Saikai 165’.

Fusarium head blight (FHB) is the most serious disease affecting wheat (Triticum aestivum L.) because of its impact on yield and grain quality and its associated mycotoxin accumulation. This study was conducted (1) to develop efficient methods to evaluate varietal resistance against fungal spread after infection, (2) to investigate varietal differences in resistance to FHB infection, FHB spread, and mycotoxin accumulation in 23 Asian varieties, and (3) to analyze relations among FHB-resistant types. Inoculation of Fusarium graminearum isolate, causing virulence to detached spikes, enabled evaluation of FHB spread in a shorter period and smaller space than conventional methods. Among the varieties, the FHB spread differed significantly. ‘Sumai 3’ and its derivatives showed higher resistance to FHB spread than other varieties. The FHB spread showed no significant correlation with FHB infection. It showed significant positive correlation with DON, but some varieties with high resistance to FHB spread showed moderately high DON. Results show that improved methods to evaluate FHB spread can be effective to screen numerous materials. The FHB resistance of western Japanese varieties depends mainly on resistance to FHB spread. For development of FHB resistant varieties, due attention should be devoted to DON.