INSTITUTO DE INVESTIGACIONES EN CIENCIAS AGRARIAS DE ROSARIO
Unidad Ejecutora - UE
Differences in seed dormancy associated with the domestication of Cucurbita maxima: elucidation of some mechanisms behind this response. S
VERÓNICA LEMA; ROBERTO L. BENECH-ARNOLD; ANALÍA MARTÍNEZ; FERNANDO LÓPEZ ANIDO; AYELÉN CAPPARELLI; CARLOS BÁRTOLI
SEED SCIENCE RESEARCH
CAMBRIDGE UNIV PRESS
Lugar: Cambridge; Año: 2018 vol. 28 p. 24 - 33
This work presents the results of physiological studies developed to understand modificationslinked to the reduction of seed dormancy provoked by domestication processes. The experimentsperformed compared wild and domesticated Cucurbita subspecies and their hybridsdeveloped by reciprocal crossings. Seeds of two accessions of the wild subspecies presenteddormancy, but it was largely reduced in seeds from the domesticated genotype, and partiallyreverted in hybrids, especially in those obtained when the domesticated genotype was used asthe mother plant. In addition, naked embryos of all subspecies did not display dormancywhen incubation was performed at 28°C, but embryo germination was progressively reducedonly in the wild genotype under decreasing incubation temperatures (22 and 16°C). In theembryos, abscisic acid (ABA) concentrations were similar in both domesticated and wild subspecies,whereas in the seed coat, it was threefold higher in the wild subspecies. The nakedembryos from the wild subspecies were far more responsive to ABA than those from thedomesticated subspecies. These results indicate that dormancy in the wild subspecies isimposed by the seed coat tissues and that this effect is mediated by their high ABA contentand the sensitivity of the embryos to ABA. These physiological aspects were apparentlyremoved by domestication along with the temperature-dependent response for germination.