Working group session:
Structural Genomics
Presentation type:
oral
Authors:
Saranga, Yehoshua; Levi, Avishag; Paterson, Andrew
Presenter:
Saranga, Yehoshua
Correspondent:
Saranga, Yehoshua
Abstract:
Marker-assisted selection (MAS) gained a wide recognition as an efficient approach for improving simply inherited traits; however, there are hardly any examples of successful MAS for complex polygenic traits, such as yield and drought resistance. Analysis of interspecific cotton population (Gossypium hirsutum X G. barbadense) revealed a total of 79 quantitative trait loci (QTLs) for ten measures of plant productivity and drought-adaptive physiological traits. Selected QTLs for yield and related physiological traits (osmotic potential, carbon isotope ratio - an indicator of water use efficiency, and leaf chlorophyll content), were exchanged via MAS between elite cultivars of the two parental cultivars. The resulting near isogenic lines (NILs) were examined in three field trials to test the effect of the introgressed QTL alleles on cotton productivity under drought conditions and the underlying physiological traits. A considerable number of NILs exhibited the expected phenotypes in term of greater osmotic adjustment, higher carbon isotope ratio, and higher chlorophyll content. Moreover, a few NILs exhibited modifications in non-targeted traits such as greater photosynthetic capacity under severe drought, modified leaf morphology, and considerable changes in metabolic and mineral profiles. Finally, NILs introgressed with QTL alleles associated with high yield rarely exhibited a yield advantage over the recurrent parent, consistently with other introgression studies, suggesting that that the well balanced genetic and physiological systems of the recurrent parents may be interrupted by these introgressions. We conclude that MAS is a useful approach to enhance drought-adaptive traits in cotton, but complimentary recombination and selection are required to combine these traits with high yield potential.