From Genetic Maps to QTL Cloning: An Overview for Durum Wheat

Abstract

Durum wheat is one of the most important cultivated cereal crops, providing nutrients to humans and domestic animals. Durum breeding programs prioritize the improvement of its main agronomic traits; however, the majority of these traits involve complex characteristics with a quantitative inheritance (quantitative trait loci, QTL). This can be solved with the use of genetic maps, new molecular markers, phenotyping data of segregating populations, and increased accessibility to sequences from next-generation sequencing (NGS) technologies. This allows for high-density genetic maps to be developed for localizing candidate loci within a few Kb in a complex genome, such as durum wheat. Here, we review the identified QTL, fine mapping, and cloning of QTL or candidate genes involved in the main traits regarding the quality and biotic and abiotic stresses of durum wheat. The current knowledge on the used molecular markers, sequence data, and how they changed the development of genetic maps and the characterization of QTL is summarized. A deeper understanding of the trait architecture useful in accelerating durum wheat breeding programs is envisioned.

Meta-QTL analysis and identification of candidate genes for quality, abiotic and biotic stress in durum wheat

“…A total of 41QTL studies for quality, abiotic and biotic stress reported inColasuonno et al 11 were analysed, including 36 different traits (Table 1 ). The studies involved 34 different mapping populations, including 53 different parental accessions (Table 2 ).…”

“…To correlate between MQTL and previous QTL identified by GWAS, MQTL positions were compared with marker trait associations (MTA) reviewed by Colasuonno et al 11 for abiotic and biotic stress and quality traits. Of the 352 MTA, 58 were located within 33 durum MQTL.…”

“…A thorough bibliographic review was carried out on the literature reported in Colasuonno et al 11 . QTL information on biparental durum wheat populations was retrieved from 41 independent studies, including a total of 36 different traits (Table 1 ) relating to quality (14), biotic stress (22) and abiotic stress (5).…”

“…Information on chromosome location, the most closely flanking markers, QTL position, logarithm of odds (LOD) values, confidence intervals (CIs) and phenotypic variance explained (PVE or r 2 ) values are summarized in the review by Colasuonno et al 11 .…”

“…As mentioned earlier, quality is directly linked to biotic and abiotic stress. In recent years many quantitative trait loci (QTL) studies have focused on these traits, such as fiber content QTL in Marcotuli et al 9 , root and shoot morphological traits in Iannucci et al 10 , and many others reviewed in Colasuonno et al 11 . These studies identified hundreds of QTL in different mapping populations with different types of markers besides.…”