Parallel Evolution Under Domestication and Phenoty

Authors: Harry S Paris Ales Lebeda Eva Křistkova Thomas C Andres Michael H Nee

Publish Date: 2012/01/31

Volume: 66, Issue: 1, Pages: 71-90

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Abstract

Parallel Evolution under Domestication and Phenotypic Differentiation of the Cultivated Subspecies of Cucurbita pepo Cucurbitaceae Cucurbita pepo pumpkin squash gourd Cucurbitaceae is an ancient North American domesticate of considerable economic importance Based on molecular genetic polymorphisms two cultivated lineages of this species each consisting of very many edible–fruited cultigens have been recognized C pepo subsp pepo and C pepo subsp texana However the phenotypic commonalities and differences between these two subspecies have not as yet been systematically collected and organized Among the evolutionary developments common to the two subspecies are the increased size of the plant parts less plant branching and premature loss of chlorophyll in the exocarp of the fruits In both subspecies bush growth habit conferred by allele Bu is common to the cultigens grown for consumption of the immature fruits as is the deviation from the 11 ratio of fruit length to fruit width A major characteristic differentiating between the edible–fruited cultigens of the respective subspecies are the longitudinal protrusions in subsp pepo versus depressions in subsp texana of the fruit surface corresponding with the subsurface primary carpellary vein tracts Subsp pepo also has larger fruits and larger and longer seeds In addition some alleles affecting stem color leaf mottling multiple flower bud production and fruit characteristics are frequently occurring to nearly fixed in one subspecies but are rare to less common in the other

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