Fruit size and shape are critical agronomical and pomological attributes and prime targets in peach breeding programs. Apart from the flat peach type, a Mendelian trait well-characterized at the genetic level, ample diversity of fruit size and shapes is present across peach germplasms. Nevertheless, knowledge of the underlying genomic loci remains limited. In this work, fruit size and shape were assessed in a collection of non-flat peach accessions and selections, under controlled fruit load conditions. The architecture of these traits was then dissected by combining association and linkage mapping, revealing a major locus on the proximal end of chromosome 6 (qSHL/Fs6.1) explaining a large proportion of phenotypic variability for longitudinal shape and also affecting fruit size. A second major locus for fruit longitudinal shape (qSHL5.1), probably also affecting fruit size, was found co-localizing at locus G, suggesting pleiotropic effects of peach/nectarine traits. An additional QTL for fruit longitudinal shape (qSHL6.2) was identified in the distal end of chromosome 6 in a cross with an ornamental double-flower peach and co-localized with the Di2 locus, controlling flower morphology. Besides assisting breeding activities, knowledge of loci controlling fruit size and shape paves the way for more in-depth studies aimed at the identification of underlying genetic variant(s).

中文翻译：

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遗传和表型分析揭示了与非扁平桃系列（P. persica L. Batsch）中果实大小和形状性状相关的主要数量基因座

果实大小和形状是桃子育种计划中的关键农艺和果树学属性和主要目标。除了扁平桃型外，在遗传水平上很好地表征了孟德尔性状，桃种质中果实大小和形状具有丰富的多样性。然而，对潜在基因组位点的了解仍然有限。在这项工作中，在受控的果实负荷条件下，对一组非扁平桃种质和选择的果实大小和形状进行了评估。然后通过结合关联和连锁作图来剖析这些性状的结构，揭示了 6 号染色体近端的一个主要基因座。qSHL/Fs6.1）解释了纵向形状的大部分表型变异性并影响果实大小。果实纵形的第二个主要基因座（qSHL5.1），可能也影响果实大小，被发现在基因座 G 共定位，表明桃/油桃性状的多效性。果实纵形的附加 QTL (qSHL6.2) 在 6 号染色体的远端与观赏性重瓣桃杂交，并与Di2位点，控制花的形态。除了协助育种活动外，控制果实大小和形状的基因座知识还为旨在识别潜在遗传变异的更深入研究铺平了道路。