Resumo

TSOUGKRIANIS, Nikolaos; PENA-VALDIVIA, Cecilia Beatriz; TREJO LOPEZ, Carlos  e  MOLINA GALAN, José Domingo. The substrate water potential in the drought tolerant and sensitive maize germination. Agric. Téc. Méx [online]. 2009, vol.35, n.4, pp.363-369. ISSN 0568-2517.

The objective of this study was to characterize seed germination of drought sensitive and tolerant maize in laboratory conditions. Cafime O, QPM (quality protein maize) H519, Tuxpeño Sequia C0 and Zacatecas 58 O, drought sensitive, and Cafime SM16 Sequia, Tuxpeño Sequia C8 and Zacatecas 58 SM19 Sequia, drought tolerant cultivars, were evaluated. The seeds were germinated in vermiculite with Ψ_w of-0.03 MPa (well watered), -1.28, -1.41, -1.58 y -2.05 MPa (with 6% of humidity), were weighted every 12 h and the percentage of water absorbed and germination was calculated. The maximum imbibition (up to germination) in the Ψ_w of -0.03 MPa of all cultivars was significantly major compared with the other Ψ_w evaluated and it reached between 40% and 70%, in variable times between the cultivars, from 48 h (cv. Caf. Seq.) untill 170 h (cv Tux. Seq. C8). The Cafime SM16 and Zac. 58 SM19 cultivars reached maximum germination four times higher with the Ψ_w of -2.05 MPa compared with their respective drought sensitive cultivars. The drought tolerance of some drought tolerant cultivars, like Cafime SM16, is expressed since the germination stage; even though this respond contrasts between cultivars. Some drought tolerant cultivars react negatively at the high substrate Ψ_w and reach germination percentages significantly higher when the substrate Ψ_w is significantly lower, between -1.28 and -1.58 MPa.

Palavras-chave : water deficit; vermiculite; Zea mays L.