Differences of Preharvest Sprouting Resistance among Chinese Wheat Cultivars

Preharvest sprouting resistance in 781 leading wheat varieties since 1950 in Yellow and Huai River Valley Winter Wheat Region,the North Winter Wheat Region,the Southwest Winter Wheat Region,the Yangtze River Winter Wheat Region and the Northeast Spring Wheat Region of China was evaluated by testing the sprouting percentage(SP)and falling number(FN)of mature seeds during(20002002) planting seasons.The results indicated that there was highly positive and significant correlation among years.The resistance to preharvest sprouting in the cultivars from the 1980s and the 1990s was lower than those from the 1950s,the 1960s and the 1970s.Cultivars with sprouting resistance from Yellow and Huai River Winter Wheat Region,the Southwest Winter Wheat Region and the Northeast Spring Wheat Region accounted for 1.7%,(4.5%) and 5.7% of total,respectively.The GP of cultivars in the North Winter Wheat Region and the Yangtze River Winter Wheat Region was above 10%.The sprouting resistance in the Northeast Spring Wheat Region was higher than that in other regions.Meanwhile,15 cultivars,i.e.Yiyuan 2,Shuwan 24,Shuwan 761,Shan 160,Mengxian 4,Jing 411,Jing 9428,Jian 26,Yanda 1817,Nongda 45,Hengshui 6404,Jinmai 5,Jinmai 8,E'mai 14 and Kehui,in different regions with late maturity α-amylase(LMA) gene were selected based on the analysis of isoelectric focusing(IEF)pattens from those with lower SP and FN(Table 6).Furthermore,the genetic relationship between wheat genotypes prone to LMA was analyzed based on SSR markers.It was showed that some wheat genotypes,which were quite closely related to genotypes with LMA gene,did not carry the LMA gene.These results suggested that wheat genotypes with the LMA gene were distributed widely in Chinese wheat regions but with low frequency(1.9%).So cultivars without LMA gene may be easily selected in wheat breeding programs.