Gandhi Sonali D, Heesacker Adam F, Freeman Carrie A, Argyris Jason, Bradford Kent, Knapp Steven J
Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331, USA.
Theor Appl Genet. 2005 Aug;111(4):619-29. doi: 10.1007/s00122-005-1934-7. Epub 2005 Jul 21.
Wild populations of common sunflower (Helianthus annuus L.) are self-incompatible and have deep seed dormancy, whereas modern cultivars, inbreds, and hybrids are self-compatible and partially-to-strongly self-pollinated, and have shallow seed dormancy. Self-pollination (SP) and seed dormancy are genetically complex traits, the number of self-compatibility (S) loci has been disputed, and none of the putative S loci have been genetically mapped in sunflower. We genetically mapped quantitative trait loci (QTL) for self-incompatibility (SI), SP, and seed dormancy in a backcross population produced from a cross between an elite, self-pollinated, nondormant inbred line (NMS373) and a wild, self-incompatible, dormant population (ANN1811). A population consisting of 212 BC(1) progeny was subsequently produced by backcrossing a single hybrid individual to NMS373. BC(1) progeny produced 0-838 seeds per primary capitula when naturally selfed and 0-518 seeds per secondary capitula when manually selfed and segregated for a single S locus. The S locus mapped to linkage group 17 and was tightly linked to a cluster of previously identified QTL for several domestication and postdomestication traits. Two synergistically interacting QTL were identified for SP among self-compatible (ss) BC(1) progeny (R(2)=34.6%). NMS373 homozygotes produced 271.5 more seeds per secondary capitulum than heterozygotes. Germination percentages of seeds after-ripened for 4 weeks ranged from 0% to 100% among self-compatible BC(1)S(1) families. Three QTL for seed dormancy were identified (R(2)=38.3%). QTL effects were in the predicted direction (wild alleles decreased self-pollination and seed germination). The present analysis differentiated between loci governing SI and SP and identified DNA markers for bypassing SI and seed dormancy in elite x wild crosses through marker-assisted selection.
普通向日葵（Helianthus annuus L.）的野生种群是自交不亲和的，且种子具有深度休眠，而现代栽培品种、自交系和杂交种则是自交亲和的，部分至高度自花授粉，且种子休眠较浅。自花授粉（SP）和种子休眠是遗传复杂的性状，自交亲和性（S）位点的数量一直存在争议，且在向日葵中尚未对任何假定的S位点进行遗传定位。我们在一个回交群体中对自交不亲和性（SI）、SP和种子休眠的数量性状位点（QTL）进行了遗传定位，该回交群体由一个优良的、自花授粉的、无休眠的自交系（NMS373）与一个野生的、自交不亲和的、休眠的群体（ANN1811）杂交产生。随后通过将一个单一的杂交个体与NMS373回交产生了一个由212个BC(1)后代组成的群体。BC(1)后代在自然自交时每个主头状花序产生0 - 838粒种子，人工自交时每个次头状花序产生0 - 518粒种子，且在一个单一的S位点上发生分离。S位点定位于连锁群17，并且与先前鉴定的几个驯化和驯化后性状的QTL簇紧密连锁。在自交亲和（ss）的BC(1)后代中鉴定出两个协同相互作用的SP QTL（R(2)=34.6%）。NMS373纯合子每个次头状花序比杂合子多产生271.5粒种子。在自交亲和的BC(1)S(1)家系中，经过4周后熟的种子发芽率在0%至100%之间。鉴定出三个种子休眠QTL（R(2)=38.3%）。QTL效应呈预测方向（野生等位基因降低自花授粉和种子发芽率）。本分析区分了控制SI和SP的位点，并鉴定出了通过标记辅助选择在优良×野生杂交中绕过SI和种子休眠的DNA标记。
