Screening maize (<I>Zea mays</I> L) cultivars for chilling tolerance using chlorophyll fluorescence technique

Abstract

In this study photoinhibition as a photosynthetic characteristic was used to evaluate tolerance to chilling in a range of Zea mays L., cultivars. When chilled at 7-8°C and 1500 μmol photons m-2 s-1 for 6 hours, the cultivars exhibited significant differences in tolerance to chill-induced photoinhibition, estimated from the maximum photochemical efficiency of PSII (i.e., dark-adapted Fv/Fm). Chlorophyll fluorescence technique was used to test its value in assessing chilling tolerance in a range of Zea mays cultivars. Two parameters were used to assess the degree of chilling tolerance in six field-grown maize cultivars: (i) absolute decrease in Fv/Fm ratio immediately following the chilling stress, (ii) the integrated units above the time courses in the development of photoinhibition and recovery from photoinhibition. Generally FANION followed by FR2 appeared more tolerant to chill-induced photoinhibition than other cultivars (CO255, B73, MO17 and ZD146). It was concluded from this study that chlorophyll fluorescence can be used as a rapid probe to assess level of tolerance or susceptibility to chill-induced photoinhibition.

Keywords: Zea mays, cultivars, photoinhibition, chlorophyll fluorescence, integrated units

Botswana Journal of Technology Vol. 14(2) 2005: 45-50