AUTHOR=Basnet Ram K. , Duwal Anita , Tiwari Dev N. , Xiao Dong , Monakhos Sokrat , Bucher Johan , Visser Richard G. F. , Groot Steven P. C. , Bonnema Guusje , Maliepaard Chris 

TITLE=Quantitative Trait Locus Analysis of Seed Germination and Seedling Vigor in Brassica rapa Reveals QTL Hotspots and Epistatic Interactions

JOURNAL=Frontiers in Plant Science

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2015.01032

DOI=10.3389/fpls.2015.01032

ISSN=1664-462X

ABSTRACT=<p>The genetic basis of seed germination and seedling vigor is largely unknown in <italic>Brassica</italic> species. We performed a study to evaluate the genetic basis of these important traits in a <italic>B. rapa</italic> doubled haploid population from a cross of a yellow-seeded oil-type yellow sarson and a black-seeded vegetable-type pak choi. We identified 26 QTL regions across all 10 linkage groups for traits related to seed weight, seed germination and seedling vigor under non-stress and salt stress conditions illustrating the polygenic nature of these traits. QTLs for multiple traits co-localized and we identified eight hotspots for quantitative trait loci (QTL) of seed weight, seed germination, and root and shoot lengths. A QTL hotspot for seed germination on A02 mapped at the <italic>B. rapa Flowering Locus C</italic> (<italic>BrFLC2</italic>). Another hotspot on A05 with salt stress specific QTLs co-located with the <italic>B. rapa Fatty acid desaturase 2</italic> (<italic>BrFAD2</italic>) locus. Epistatic interactions were observed between QTL hotspots for seed germination on A02 and A10 and with a salt tolerance QTL on A05. These results contribute to the understanding of the genetics of seed quality and seeding vigor in <italic>B. rapa</italic> and can offer tools for <italic>Brassica</italic> breeding.</p>