Economic Botany: Evolution of Cultivated Plants
Adisa, Abolanle .
Responses of field-grown irrigated rice cultivars to varying levels of floodwater salinity under semi-arid conditions. Field Crops Research.
Salinity is the saltiness or dissolved salt content of a body of water. Shallow saline water tables, naturally saline soils and variations in climatic conditions over the two growing seasons, create a harsh environment for irrigated rice production in the Niger River Delta. At the onset of the growing season, salts accumulated by capillary rise in the topsoil are released into the soil solution and floodwater. Rice fields often lack drainage facilities, or drain from one field to the other, thus building-up salt levels during the season. Salt stress may, therefore, occur throughout the growing season and may coincide with susceptible growth stages of the rice crop. The objectives of the present study were to (i) determine varietal responses to seasonal salinity in both the hot dry season (HDS) and the wet season (WS) and (ii) derive guidelines for surface water drainage at critical growth stages. We evaluated responses of three rice cultivars grown in the region, to floodwater salinity (0-1, 2, 4, 6, 8 mS cm-1), applied either at germination, during two weeks at crop establishment, during two weeks around panicle initiation, or during two weeks around flowering. Floodwater electrical conductivity reduced germination rate for the most susceptible cultivar by as much as 50% and yield by 80% for the highest salinity level imposed. . Salinity strongly reduced spikelet number per panicle, 1000 grain weight and increased sterility, regardless of season and development stage. The strongest salinity effects on yield were observed around panicle initiation (PI), whereas plants recovered best from stress at seedling stage. Floodwater EC < 2 mS cm-1 hardly affected rice yield.
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1 - university of ilorin
Presentation Type: Oral Paper:Papers for Topics
Location: Lake Ontario/Hilton
Date: Monday, July 9th, 2007
Time: 8:30 AM