Phenotyping for waterlogging tolerance as a proxy for Phytophthora medicaginis resistance in chickpea

Phytophthora root rot (PRR) caused by the soil-borne oomycete Phytophthora medicaginis is a significant constraint to chickpea (Cicer aretinium) production across the northern grains region of Australia. In flooded soil, which is conducive to PRR disease development, up to 70% yield loss can occur in the most resistant Australian cultivars. Incorporating waterlogging tolerance in soybean (Glycine max) has been shown to improve quantitative resistance to Phytophthora sojae. Root growth of three chickpea genotypes were assessed at the seedling stage under waterlogging, PRR and the combination of these abiotic and biotic constraints. Levels of waterlogging tolerance in chickpea are inherently low; yet selected genotypes displayed variability in root traits linked to improved waterlogging tolerance. The PRR moderately susceptible chickpea cultivar Yorker and PRR very susceptible Rupali demonstrated an eight-fold increase in early adventitious root growth from the epicotyl region under waterlogging stress, compared to the PRR resistant interspecific backcross genotype 04067-81-2-1-1 (C. echinospermum x C. aretinium*2). Selection for primary root depth, which was significantly greater in 04067-81-2-1-1 under waterlogging, appears to improve PRR resistance compared with root replacement traits. Soil-borne Phytophthora spp. are reportedly attracted to branch sites and leached exudates. We propose that compromised root barriers at emergence sites of adventitious roots under waterlogging conditions hasten hyphal entry, potentially increasing susceptibility to PRR. Hence, screening for root depth and absence of adventitious root development under waterlogged conditions may offer a novel proxy phenotyping method for PRR resistance traits at early stages of chickpea breeding.

An Integrated Linkage Map Of Interspecific Backcross 2 (Bc2) Populations Reveals Qtls Associated With Fatty Acid Composition And Vegetative Parameters Influencing Compactness In Oil Palm

Background Molecular breeding has opened new avenues for crop improvement with the potential for faster progress. As oil palm is the major producer of vegetable oil in the world, its improvement, such as developing compact planting materials and altering its oils’ fatty acid composition for wider application, is important. Results This study sought to identify the QTLs associated with fatty acid composition and vegetative traits for compactness in the crop. It integrated two interspecific backcross two (BC2) mapping populations to improve the genetic resolution and evaluate the consistency of the QTLs identified. A total 1,963 markers (1,814 SNPs and 149 SSRs) spanning a total map length of 1793 cM were integrated into a consensus map. For the first time, some QTLs associated with vegetative parameters and carotene content were identified in interspecific hybrids, apart from those associated with fatty acid composition. The analysis identified 8, 3 and 8 genomic loci significantly associated with fatty acids, carotene content and compactness, respectively. Conclusions Major genomic region influencing the traits for compactness and fatty acid composition was identified in the same chromosomal region in the two populations using two methods for QTL detection. Several significant loci influencing compactness, carotene content and FAC were common to both populations, while others were specific to particular genetic backgrounds. It is hoped that the QTLs identified will be useful tools for marker-assisted selection and accelerate the identification of desirable genotypes for breeding.

An Integrated Linkage Map Of Interspecific Backcross 2 (Bc2) Populations Reveals Qtls Associated With Fatty Acid Composition And Vegetative Parameters Influencing Compactness In Oil Palm

Background Molecular breeding has opened new avenues for crop improvement with the potential for faster progress. As oil palm is the major producer of vegetable oil in the world, its improvement, such as developing compact planting materials and altering its oils’ fatty acid composition for wider application, is important. Results This study sought to identify the QTLs associated with fatty acid composition and vegetative traits for compactness in the crop. It integrated two interspecific backcross two (BC2) mapping populations to improve the genetic resolution and evaluate the consistency of the QTLs identified. A total 1,963 markers (1,814 SNPs and 149 SSRs) spanning a total map length of 1793 cM were integrated into a consensus map. For the first time, some QTLs associated with vegetative parameters and carotene content were identified in interspecific hybrids, apart from those associated with fatty acid composition. The analysis identified 8, 3 and 8 genomic loci significantly associated with fatty acids, carotene content and compactness, respectively. Conclusions Major genomic region influencing the traits for compactness and fatty acid composition was identified in the same chromosomal region in the two populations using two methods for QTL detection. Several significant loci influencing compactness, carotene content and FAC were common to both populations, while others were specific to particular genetic backgrounds. It is hoped that the QTLs identified will be useful tools for marker-assisted selection and accelerate the identification of desirable genotypes for breeding.

AN INTEGRATED LINKAGE MAP OF INTERSPECIFIC BACKCROSS 2 (BC2) POPULATIONS REVEALS QTLs ASSOCIATED WITH FATTY ACID COMPOSITION AND VEGETATIVE PARAMETERS INFLUENCING COMPACTNESS IN OIL PALM

Background Molecular breeding has opened new avenues for crop improvement with the potential for faster progress. As oil palm is the major producer of vegetable oil in the world, its improvement, such as developing compact planting materials and altering its oils’ fatty acid composition for wider application, is important. Results This study sought to identify the QTLs associated with fatty acid composition and vegetative traits for compactness in the crop. It integrated two interspecific backcross two (BC 2 ) mapping populations to improve the genetic resolution and evaluate the consistency of the QTLs identified. A total 1,963 markers (1,814 SNPs and 149 SSRs) spanning a total map length of 1793 cM were integrated into a consensus map. For the first time, some QTLs associated with vegetative parameters and carotene content were identified in interspecific hybrids, apart from those associated with fatty acid composition. The analysis identified 8, 3 and 8 genomic loci significantly associated with fatty acids, carotene content and compactness, respectively. Conclusions Major genomic region influencing the traits for compactness and fatty acid composition was identified in the same chromosomal region in the two populations using two methods for QTL detection. Several significant loci influencing compactness, carotene content and FAC were common to both populations, while others were specific to particular genetic backgrounds. It is hoped that the QTLs identified will be useful tools for marker-assisted selection and accelerate the identification of desirable genotypes for breeding.

An Integrated Linkage Map of Interspecific Backcross 2 (BC2) Populations Reveals QTLs Associated With Fatty Acid Composition and Vegetative Parameters Influencing Compactness in Oil Palm

Background Molecular breeding has opened new avenues for crop improvement with the potential for faster progress. As oil palm is the major producer of vegetable oil in the world, its improvement, such as developing compact planting materials and altering its oils’ fatty acid composition for wider application, is important. Results This study sought to identify the QTLs associated with fatty acid composition and vegetative traits for compactness in the crop. It integrated two interspecific backcross two (BC 2 ) mapping populations to improve the genetic resolution and evaluate the consistency of the QTLs identified. A total 1,963 markers (1,814 SNPs and 149 SSRs) spanning a total map length of 1793 cM were integrated into a consensus map. For the first time, some QTLs associated with vegetative parameters and carotene content were identified in interspecific hybrids, apart from those associated with fatty acid composition. The analysis identified 8, 3 and 8 genomic loci significantly associated with fatty acids, carotene content and compactness, respectively. Conclusions Major genomic region influencing the traits for compactness and fatty acid composition was identified in the same chromosomal region in the two populations using two methods for QTL detection. Several significant loci influencing compactness, carotene content and FAC were common to both populations, while others were specific to particular genetic backgrounds. It is hoped that the QTLs identified will be useful tools for marker-assisted selection and accelerate the identification of desirable genotypes for breeding.

REVEALING QTLs ASSOCIATED WITH FATTY ACID COMPOSITION AND COMPACTNESS ON AN INTEGRATED LINKAGE MAP OF OIL PALM INTERSPECIFIC BACKCROSS 2 (BC2)

Background Molecular breeding has opened new avenues for crop improvement with the potential for faster progress. As oil palm is the major producer of vegetable oil in the world, its improvement, such as developing compact planting materials and altering its oil’s fatty acid composition for wider application, is important. Results This study sought to identify the QTLs associated with fatty acid composition and vegetative traits for compactness in the crop. It integrated two separate interspecific backcross two (BC2) mapping populations to improve the genetic resolution and evaluate the consistency of the QTLs identified. A total of 1,963 markers (1,814 SNPs and 149 SSRs) spanning a total map length of 1793 cM were integrated into a consensus map. For the first time QTLs associated with vegetative parameters were identified in an interspecific hybrid population, and carotene content apart from these associated with fatty acid composition. The QTL analysis observed 9, 4 and 8 genomic loci associated significantly with fatty acids, carotene content and compactness, respectively. Conclusions Major genomic region influencing the parameters associated with compactness and fatty acid composition was identified across separate populations using two different methods for QTL detection. Other significant locus influencing compactness, carotene content and FAC were identified either being common to both populations or specific to a particular genetic background. It is hoped that the QTLs identified will be useful tools for marker-assisted selection and accelerate the process of identifying desirable genotypes for breeding.