MAPPING QTL CONTROLLING YIELD AND YIELD COMPONENTS IN A SPRING BARLEY(HORDEUM-VULGARE L) CROSS USING MARKER REGRESSION

An RFLP map constructed from 99 doubled haploid lines of a cross betwe en two spring barley varieties (Blenheim x Kym) was used to localize q uantitative trait loci (QTL) controlling grain yield and yield compone nts by marker regression and single-marker analysis. Trials were condu cted over three years. Genotype-by-year interaction was detected for p lant grain weight and ear grain weight so they were analysed separatel y for each year. None was detected for thousand-grain weight and ear g rain number so data were pooled over years. A total of eleven QTL were detected for plant grain weight over two years and fourteen for ear g rain weight over three years. Seven QTL were detected for plot yield. The locus with the largest effect was on chromosome 2(2H)L and account ed for 19% of the Variation in the progeny. Eight QTL were detected fo r thousand-grain weight and five for ear grain number. Many of the QTL detected were in comparable positions in each year. Yield and yield c omponents were only partly correlated. Comparisons based on common RFL P markers showed that some QTL were found in positions similar to thos e identified in other studies. For a number of QTL the identification of linked markers provided suitable opportunities for marker-assisted selection and improvement of barley and reference markers with which t o analyse the homoeologous chromosome regions of wheat and other cerea ls.