PAG-V: P177 - QTLS FOR PARTIAL RESISTANCE TO LEAF RUST (<i>Puccinia hordei</i>) IN BARLEY ARE PLANT AGE DEPENDENT

Plant & Animal Genome V Conference

Town & Country Hotel, San Diego, CA, January 12-16, 1997.

P177

QTLS FOR PARTIAL RESISTANCE TO LEAF RUST (Puccinia hordei) IN BARLEY ARE PLANT AGE DEPENDENT

QI, XIAOQUAN, Rients Niks, Piet Stam, Pim Lindhout
Graduate School of Experimental Plant Sciences, Dept. of Plant Breeding, Wageningen Agricultural University, PO Box 386, NL-6700 AJ Wageningen, The Netherlands

In barley (Hordeum vulgare), partial resistance to leaf rust (Puccinia hordei) is associated with a longer latent period (LP) and is assumed to inherit polygenically (Parlevliet, 1978). We have constructed a molecular genetic map containing about 540 AFLP markers based on 103 recombinant inbred lines (F₉) derived from the cross between the susceptible parent L94 and the resistant parent Vada. Linkage groups were assigned to chromosomes by making use of common AFLP markers (see previous poster). In addition, in greenhouse tests with seedlings and adult plants and in a field test the partial resistance of each RIL was evaluated. QTLs for partial resistance to leaf rust were mapped on the barley genome. Four QTLs for partial resistance to leaf rust were detected, together explaining more than 50% of the phenotypic variation. One QTL (on chromosome 6) was effective in the seedling as well as in the adult plant stage; two (on chromosome 1 and 2) were affecting LP in seedlings, whereas the other one (on chromosome 7) affected LP in adult plants in the greenhouse as well as the field resistance (AUDPC). In conclusion: three QTLs were dependent on the development stage and one was continuously expressed. By marker assisted selection near isogenic lines are being developed to study the QTLs individually.References: Parlevliet, J.E., 1978. Further evidence of polygenic inheritance of partial resistance in barley to leaf rust, Puccinia hordei. Euphytica 27: 369-379.