Flowering dynamic of maize hybrids grown in soils with contrasting agricultural history

MADDONNI, G. A.; IGLESIAS PÉREZ, M. E.; CÁRCOVA, J. AND GHERSA, M. E

MAYDICA

MAYDICA-IST SPER CEREALICOLTUR

Año: 1999 vol. 44 p. 141 - 147

0025-6153

Studies of flowering dynamic in hybrids with contrasting production stability index are rare, and its performances in soil with different agricultural history do not exist. The objectives of this work were to (i) characterize the progress of flowering on a thermal time base, and (ii) explore interactions between hybrids and agricultural history on flowering dynamic. Three maize hybrids characterized by a contrasting production stability index were grown in irrigated and fertilized conditions (control) and in soils with different agricultural history (short: S and long: L) under rainfed conditions in Argentina, on silty clay loam soils (Typic Argiudol) during 1994/95 and 1995/96. Spikeltes ear-1, reproductive organ appearance and the anthesis-silking interval (ASI) differed significantly (P<0.01) among hybrids in control experiments. Thus, reproductive organ appearance was described by sigmoid functions on a thermal time basis, for each organ and hybrid. Crops grown in rainfed experiments were submitted to drought during flowering period. Consequently, reproductive organs appearance was delayed in comparison with flowering dynamic of control experiments, but crops grown in L presented the lowest silking progress rate, and the longest ASI. Hybrid with high production stability index and the shortest ASI in control experiments, presented in S soils the low distance to silk emergence model fitted with control data set, but in L the opposite trend was observed. Thus, ASI analyses under irrigated and fertilized conditions did not reveal genotypic tolerance to drought.