Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Oral Communication Abstract

MOLECULAR MARKERS ASSOCIATED TO FLOUR COLOUR QTL IN DURUM WHEAT (TRITICUM TURGIDUM (L.) THELL. VAR. DURUM)

BLANCO A., SOMMA S., VERONICO P., GADALETA A.

Dipartimento di Biologia e Chimica Agro-forestale ed Ambientale, Università degli Studi di Bari, Via Amendola 165/a, 70126 Bari

blanco@agr.uniba.it

durum wheat, b-carotene, microsatellites markers, bulk segregant analysis, QTL mapping

Durum wheat is mainly used to produce semolina and pasta. A defining factor for the commercial value of pasta is its colour, which depends on the semolina carotenoid pigment content and on the oxidative enzymatic activity. Among carotenoids controlling semolina yellow colour, the presence of b-carotene is very important. In order to answer the demands of the market asking for amber-coloured than clear pasta, breeding programs tend to select varieties with a high grain pigment content.

The aim of this study was to detect quantitative trait loci (QTL) for b-carotene content in a segregant population (120 F₃ and F₄ progenies) derived by crossing the durum wheat cultivars Latino and Primadur, characterised by low and high values of b-carotene content, respectively. Replicated field trials were conducted in one location in 1999 with the F₃ progenies and in two locations in 2000 with the F₄ progenies. Grain b-carotene content showed a wide variability among progenies and a frequency distribution typical of quantitative traits, proving itself very heritable and not much affected by environmental factors. A negative correlation with 1000 kernels weight was observed.

The Bulk Segregant Analysis (BSA) was used to obtain a fast location of molecular markers associated to quantitative trait loci (QTL). A first PCR analysis by using 287 microsatellites primers randomly scattered on the genome was performed on the parental lines. Among 82 polymorphic markers only 7 resulted polymorphic between the high and low pigment content bulks. Finally the analysis was carried out on the whole population. QTLs were mapped by regression analysis on each marker locus for each location and for average across environments. Three different QTLs located on 5B, 7A and 7B chromosomes were identified. Another not yet mapped putative region associated to b-carotene content was identified too.

Molecular markers associated with the pigment content and not with the yield components could be really useful in marker assisted selection programs.