Seed Development: Applied Aspects of Dormancy, Preharvest Sprouting

SÁNCHEZ R. A.; RODRÍGUEZ M.V.; BENECH-ARNOLD R.L.

Encyclopedia of Applied Plant Sciences - Second Edition

Elsevier

Año: 2016; p. 540 - 545

Dormancy can be defined as the failure to germinate becauseof some internal block of the seed that prevents the completionof the germination process. While the adaptive significance ofdormancy is quite evident for plants living in the ?wild,? ithas been seen always as a complication in seeds from plantsthat are grown as crops. Indeed, no farmer would tolerateuncertainty on the emergence of a crop because of the possibleexistence of remnant dormancy in the seed lot that is used togenerate a new crop. For that reason, crops that originallymust have had dormancy have been selected heavily againstdormancy throughout their domestication process. In somecases, this selection against dormancy has gone too far andthe seeds are germinable even prior to crop harvest. This situation,combined with rainy or damp conditions prevailingduring the last stages of maturation, may lead to germinationin the mother plant, a phenomenon that is better known aspreharvest sprouting (PHS). Though its occurrence has been reportedfor several cultivated plants, PHS is predominantlya feature of cereal crops (e.g., wheat, sorghum, barley, oats,rye, rice, and even millets) (Figure 1). Therefore, the cerealgrain will constitute the ?model system? for discussing thedifferent aspects of this adversity that are dealt with throughoutthis article