ANALYSIS OF HYBRIDS OF DURUM-WHEAT WITH THINOPYRUM JUNCEIFORME USING RAPD MARKERS

The objective of this study was to detect the presence of alien chroma tin in intergeneric hybrids of durum wheat (Triticum turgidum, 2n = 4x = 28; AABB genomes) with the perennial grass Thinopyrum junceiforme ( 2n = 4x = 28; J(1)J(1)J(2)J(2)) using RAPD markers. The first step was to identify amplification of species-specific DNA markers in the pare ntal grass species and durum wheat cultivars. Initially, the genomic D NA of five grass species (Thinopyrum junceiforme, Th. bessarabicum, Lo phopyrum elongatum, Leymus karataviensis and Elytrigia pycnantha) and selected durum cultivars ('Langdon','Durox', 'Lloyd','Monroe', and 'Me dora') was screened with 40 oligonucleotide primers (nano-mers). Three oligonucleotides that amplified DNA fragments specific to a grass spe cies or to a durum cultivar were identified. Primer PR21 amplified DNA fragments specific to each of the five durum cultivars, and primers P R22 and PR23 amplified fragments specific to each of the grass species . Intergeneric hybrids between the durum cultivars 'Langdon', 'Lloyd' and 'Durox' and Th. junceiforme, and their backcross (BC) progeny were screened with all 40 primers. Six primers amplified parent-specific D NA fragments in the F-1 hybrids and their BC1 progeny. Three primers, PR22, PR23 and PR41, that amplified Th. junceiforme DNA fragments in b oth F-1 and BC1 were further analyzed. The presence of an amplified 1. 7-kb Th. junceiforme DNA fragment in the F-1 hybrids and BC1 progeny w as confirmed using Southern analysis by hybridization with both Th. ju nceiforme genomic DNA and Th. junceiforme DNA amplified with primer PR 41. With the exception of line BC1F2 no. 5, five selfed progeny of BC1 and a BC2 of line 3 (BC1F2 no. 3 x 'Lloyd') from a cross of 'Lloyd' x Th. junceiforme showed the presence of the 1.7-kb DNA fragment. All s elfed BC1 and BC2 lines retained the 600-bp fragment that was confirme d after hybridization with Th. junceiforme me DNA amplified with prime r PR22. Other experiments using RFLP markers also showed the presence of up to seven Th. junceiforme DNA fragments in the F-1 hybrids and th eir BC progeny after hybridization with Th. junceiforme DNA amplified with primer PR41. These studies show the usefulness of molecular marke rs in detecting alien chromatin/DNA fragments in intergeneric hybrids with durum wheat.