Abstract
This report describes the construction of integrated genetic maps in pearl millet involving certain purple phenotype and simple sequence repeat (SSR) markers. These maps provide a direct means of implementing DNA marker-assisted selection and of facilitating "map-based cloning" for engineering novel traits. The purple pigmentation of leaf sheath, midrib and leaf margin was inherited together 'en bloc' under the control of a single dominant locus (the 'midrib complex') and was inseparably associated with the locus governing the purple coloration of the internode. The purple panicle was caused by a single dominant locus. Each of the three characters (purple lamina, purple stigma and purple seed) was governed by two complementary loci. One of the two loci governing purple seed was associated with the SSR locus Xpsmp2090 in linkage group 1, with a linkage value of 22 cM, while the other locus was associated with the SSR locus Xpsmp2270 in linkage group 6, with a linkage value of 23 cM. The locus for purple pigmentation of the midrib complex was either responsible for pigmentation of the panicle in a pleiotropic manner or was linked to it very closely and associated with the SSR locus Xpsmp2086 in linkage group 4, with a suggestive linkage value of 21 cM. A dominant allele at this locus seems to be a prerequisite for the development of purple pigmentation in the lamina, stigma and seed. These findings suggest that the locus for pigmentation of the midrib complex might regulate the basic steps in anthocyanin pigment development by acting as a structural gene while other loci regulate the formation of color in specific plant parts.
Highlights
Integrated genetic maps involving molecular and phenotypic markers provide a direct means for investigating the number of genes influencing a trait, their location along the chromosomes and the effects of variation in their dosage
Despite the considerable attention that pearl millet has received from agronomists, plant breeders and cytogeneticists, and the availability of molecular maps, the tagging of genes that can be used as molecular markers for various characters in this cereal is still in its initial stages
The first RFLP-based genetic linkage map in pearl millet was reported by Liu et al (1994) and has since been updated by the addition of more RFLP and simple sequence repeat (SSR) markers (Qi et al, 2004)
Summary
Integrated genetic maps involving molecular and phenotypic markers provide a direct means for investigating the number of genes influencing a trait, their location along the chromosomes and the effects of variation in their dosage. These maps provide the information needed to implement DNA marker-assisted selection, an approach of growing importance in plant and animal improvement that facilitates “map-based cloning” for engineering novel traits. These markers have improved our understanding of the complex relationship between the pearl millet genome and those of other cultivated graminaceous species (Devos et al, 2000), in addition to being useful in studies of aspects such as marker-assisted breeding (Hash, 2004; Serraj et al, 2005)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
