Tracing back the origin of pumpkins (Cucurbita pepo ssp. pepo L.) in Mexico

Cucurbita pepo is an economically important crop, which consists of cultivated C. pepo ssp. pepo, and two wild taxa (C. pepo ssp. fraterna and C. pepo ssp. ovifera). We aimed at understanding the domestication and the diversity of C. pepo in Mexico. We used two chloroplast regions and nine nuclear microsatellite loci to assess levels of genetic variation and structure for C. pepo ssp. pepo’s landraces sampled in 13 locations in Mexico, five improved varieties, one C. pepo ssp. fraterna population and ornamental C. pepo ssp. ovifera. We tested four hypotheses regarding the origin of C. pepo ssp. pepo’s ancestor through Approximate Bayesian Computation: C. pepo ssp. ovifera as the ancestor; C. pepo ssp. fraterna as the ancestor; an unknown extinct lineage as the ancestor; and C. pepo ssp. pepo as hybrid from C. pepo ssp. ovifera and C. pepo ssp. fraterna ancestors. C. pepo ssp. pepo showed high genetic variation and low genetic differentiation. C. pepo ssp. fraterna and C. pepo ssp. pepo ...

西葫芦（Cucurbita pepo）是一类具有重要经济价值的作物类群，其包含栽培亚种（C. pepo ssp. pepo）以及两个野生类群：近缘野生亚种（C. pepo ssp. fraterna）与卵果亚种（C. pepo ssp. ovifera）。本研究旨在阐明墨西哥境内西葫芦的驯化历程与遗传多样性特征。本研究选取两个叶绿体基因组区域与9个核微卫星位点，对墨西哥13个采样点的栽培亚种西葫芦地方品种、5个改良品种、1个近缘野生亚种种群以及观赏型卵果亚种西葫芦开展遗传变异水平与群体遗传结构评估。本研究通过近似贝叶斯计算（Approximate Bayesian Computation）检验了4项关于栽培亚种西葫芦祖先起源的假说：分别为以卵果亚种为祖先、以近缘野生亚种为祖先、以未知已灭绝演化支为祖先，以及栽培亚种西葫芦为卵果亚种与近缘野生亚种祖先杂交形成的类群。结果表明，栽培亚种西葫芦展现出较高的遗传变异水平与较低的遗传分化程度。近缘野生亚种与栽培亚种西葫芦……