Reproductive potential of caucasian clover at four locations within New Zealand

Abstract

Seedlings of KZ2 caucasian clover (Trifolium ambiguum) were grown at 4 sites within New Zealand (Kerikeri 36°S, Palmerston North 40°S, Lincoln 43°S and Gore 46°S) where they received natural daylight and temperatures during 1997. Northernmost plants produced more vegetative primary crown shoot buds than southernmost. In the first growing season numbers of flowering shoots formed per plant were: K 17.9, P 10.0, L 10.2 and G 5.7. In spring of the second growing season, mean numbers of primary crown flowering shoots per plant at peak flowering in December 1997 were: K 19, P 30, L 55, G 20. Fewer flowering shoots formed at upturned rhizome tips. Daylength was not the major factor controlling flowering, the results instead supporting the hypothesis that low temperatures provided the main flowering stimulus. Lincoln was the best of the four locations overall for flowering shoot production. Fewer flowering shoots at Gore probably resulted from slower growth in cooler conditions. Poorer flowering at Kerikeri in the second season might have resulted from the warmer northern winter or been linked to the overproduction of vegetative buds in the first season. Stronger flowering at Kerikeri during the first season raises the possibility, though, of growing caucasian clover as an annual crop for seed production in Northland if sown early in spring. Keywords: caucasian clover, daylength, flowering, low temperature, seed production, Trifolium ambiguum