The New Zealand Institute for Plant and Food Research Ltd (Plant & Food Research), Te Puke, New Zealand.
Plant & Food Research, Lincoln, New Zealand.
G3 (Bethesda). 2021 Jul 14;11(7). doi: 10.1093/g3journal/jkab142.
Commercially grown kiwifruit (genus Actinidia) are generally of two sub-species which have a base haploid genome of 29 chromosomes. The yellow-fleshed Actinidia chinensis var. chinensis, is either diploid (2n = 2x = 58) or tetraploid (2n = 4x = 116) and the green-fleshed cultivar A. chinensis var. deliciosa "Hayward," is hexaploid (2n = 6x = 174). Advances in breeding green kiwifruit could be greatly sped up by the use of molecular resources for more efficient and faster selection, for example using marker-assisted selection (MAS). The key genetic marker that has been implemented for MAS in hexaploid kiwifruit is for gender testing. The limited marker-trait association has been reported for other polyploid kiwifruit for fruit and production traits. We have constructed a high-density linkage map for hexaploid green kiwifruit using genotyping-by-sequence (GBS). The linkage map obtained consists of 3686 and 3940 markers organized in 183 and 176 linkage groups for the female and male parents, respectively. Both parental linkage maps are co-linear with the A. chinensis "Red5" reference genome of kiwifruit. The linkage map was then used for quantitative trait locus (QTL) mapping, and successfully identified QTLs for king flower number, fruit number and weight, dry matter accumulation, and storage firmness. These are the first QTLs to be reported and discovered for complex traits in hexaploid kiwifruit.
商业化种植的猕猴桃（猕猴桃属）通常有两个亚种，其基础单倍体基因组有 29 条染色体。黄色果肉的中华猕猴桃亚种。中华猕猴桃 var. chinensis，为二倍体（2n = 2x = 58）或四倍体（2n = 4x = 116），而绿色果肉的栽培品种 A. chinensis var. deliciosa "Hayward"，则为六倍体（2n = 6x = 174）。通过利用分子资源进行更高效和快速的选择，例如使用标记辅助选择（MAS），可以大大加快绿色猕猴桃的选育进程。在六倍体猕猴桃中，用于 MAS 的关键遗传标记是性别测试。其他多倍体猕猴桃的果实和产量性状的标记 - 性状关联报道有限。我们使用基于测序的基因型（GBS）为六倍体绿色猕猴桃构建了高密度连锁图谱。获得的连锁图谱由 3686 个和 3940 个标记组成，分别组织在雌性和雄性亲本的 183 个和 176 个连锁群中。两个亲本的连锁图谱都与猕猴桃的 A. chinensis "Red5"参考基因组共线性。然后，该连锁图谱用于数量性状基因座（QTL）作图，并成功鉴定了雄花数量、果实数量和重量、干物质积累和贮藏硬度的 QTL。这是首次在六倍体猕猴桃中报道和发现复杂性状的 QTL。
