Efecto del envejecimiento artificial de semillas de maíces criollos azules en su germinación y huella genómica

Abstract

In order to establish the genomic fingerprint and to estimate the degree of tolerance to aging, seeds from four blue maize landraces (Zea mays L.), 'Cuijingo', 'Cocotitlán', 'Puebla' and 'Oaxaca', were subjected to two types of artificial aging: humid heat (HH, 41 0C, 100 % RH, 72 h) and dry heat (DH, 60 0C, 0 % RH, 48 h), with respective controls without aging. Radicle protrusion from 0 to 72 h of imbibition and 7 after d at 25 0C, number of normal and abnormal seedlings and dead seeds, and dry matter accumulation (plumule, radicle and total), were measured Molecular characterization of treatments was carried out using RAPD markers, and dendrograms were constructed. Radical protrusion was significantly susceptible to the HH treatment, while DH injuries were expressed as reductions in number of normal seedlings and dry matter accumulation, as well as higher proportion of dead seeds. Seeds of var. 'Oaxaca' stood out for their ability for radicle protrusion and generation of normal seedlings with high capacity to accumulate biomass, both in controls and under HH conditions. The genomic fingerprint was specific for each variety and in dendrograms both control seeds and those subjected to either type of aging, became separated with a specific coefficient of similarity for each variety: 'Oaxaca' (31.6 %), 'Cocotitlán' (25.8 %), 'Puebla' (19.6 %) and 'Cuijingo' (18.6 %). These values might be related to the genetic aptitude to tolerate or restore damages caused on DNA by artificial aging, directly manifested as better physiological performance of 'Oaxaca' seeds.