Differences in seed dormancy associated with the domestication of Cucurbita maxima: elucidation of some mechanisms behind this response

MARTÍNEZ, ANALÍA B.; LÓPEZ ANIDO, FERNANDO; CAPPARELLI, AYLEN; BARTOLI, CARLOS G.; LEMA, VERÓNICA; BENECH-ARNOLD, ROBERTO

SEED SCIENCE RESEARCH

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2017 p. 1 - 7

0960-2585

This work presents theresults of physiological studies developed to understand modifications linked tothe reduction of seed dormancy provoked by domestication processes. Theexperiments performed compared wild and domesticated Cucurbita subspecies and their hybrids developed by reciprocalcrossings. Seeds of two accessions of the wild subsp. presented dormancy but itwas largely reduced in seeds from the domesticated genotype, and partiallyreverted in hybrids, especially in those obtained when the domesticatedgenotype was used as the mother plant. In addition, naked embryos of all subsp.did not display dormancy when incubation was performed at 28 ºC, but embryo germinationwas progressively reduced only in the wild genotype under decreasing incubationtemperatures (22 and 16 ºC). In the embryos, abscisic acid (ABA) concentrationswere similar in both domesticated and wild subsp. whereas in the seed coat, it wasthree fold higher in the wild subsp. The naked embryos from the wild subsp.were far more responsive to ABA than those from the domesticated subsp. Theseresults indicate that dormancy in the wild subsp. is imposed by the seed coattissues and that this effect is mediated by their high ABA content and thesensitivity of the embryos to ABA. These physiological aspects were apparentlyremoved by domestication along with the temperature-dependent response forgermination.