تعيين مكان هاي ژنهاي كنترل كننده صفات كمي (QTL) عملكرد و اجزاء عملكرد در رگه هاي جو هاپلوئيد مضاعف شده

Determination QTLs of Yield and Yield Components in Double Haploid Barley Lines (Hordeum vulgare L.)

Seventy-two double haploid barley lines and their parents, "Steptoe" and "Morex", were planted in a randomized complete block design with three replications at the research farm of the University College, of Agriculture and Natural Resouces, University of Tehran for two growing seasons (2003, 2004). In order to find the QTLs for drought resistance, one of the replications was irrigated 5 times (normal practice in the area), and the other two irrigated only 2 times (Sowing and heading stages) to induce water stress for an evaluation of drought tolerance. Each plot consisted of a 2-m row. Ten agronomic traits studied were: seed yield per plot (syi in gr), days to flowering {/Jo), spike per plant {spi), date of maturity (mat), height (hei in cm), seed per spike (sps), spike initiation (spp), spike length (spl mm), 1000-seed weight (tew gr) and protein content (prp). Analysis of variance indicated that the genotypes were significantly different for all studied traits. Genotype environment interactions (G x E), were also significant for spike length, date of flowering, date of spike initiation, spike per plant as well as for protein content. QTL analysis was carried out through MULTIQTL software using the G x E option which allows for more accuracy in analysing data from either environment and in a "multi-trait" approach. A genetic map comprising of 327 molecular markers was recovered from Grain Genes and employed for QTL analysis. QTLs were identified to tolerance index as well as to all the traits on any one of the chromosomes. Highest LOD score (18.1) was obtained on chromosome 3H for spike length stress treatment and normal irrigation, (11.1) for plant height on chromosome 2H, and (10.1) for date of flowering. Another QTL for protein concentration was detected on chromosome 4H. The detected QTLs for date of flowering, date of spike initiation on chromosome 5H were associated with alleles positive for seed yield. Another QTL for date of maturity was found on chromosome 3H, co-located with a QTL for spike length.