Wednesday, November 15, 2006

Mapping of Spike Density in Chinese Barley.

Guotai Yu and Jerome Franckowiak. North Dakota State University, "101 B Court, University Village", Fargo, ND 58102, United States of America

Spike density or rachis internode length in barley (Hordeum vulgare L.) is a characteristic that is related to agronomically important traits such as kernel plumpness, shattering, and Fusarium head blight (FHB) reaction,.. In North America, cultivars with intermediate to moderately lax spikes are common while in East Asia many cultivars have dense spikes. The objective of this study is to identify QTLs for spike density using molecular mapping of the whole genome. A recombinant inbred line population of 93 lines was developed from a cross between ZAU 7, a Chinese cultivar from Zhejiang University at Hangzhou, and ND16092, a breeding line from North Dakota State University at Fargo. Although both cultivars have strap shaped spikes, ZAU 7 has a compact phenotype while ND16092 is moderately lax. One hundred eleven Diversity Array Technology (DArT) and simple sequence repeat (SSR) markers were used to construct a linkage map of 1158 cM. Using simplified composite interval mapping (sCIM), QTLs for spike density were detected on the long arm of chromosomes 2H and 3H. The QTL on 2HL from ZAU 7 accounted for about 60% of the phenotypic variation for spike density.