An impact of polyploidization on the dimensions of red clover flowers, species' composition and number of insect pollinators
1999
Bender, A. (Estonian Agricultural Univ., Tartu (Estonia). Jogeva Plant Breeding Inst.)
In 1993 a field experiment was established to study the range of morphological and secretory transformations of the flowers of tetraploid red clover varieties 'Varte' (early) and 'Ilte' (late), both bred at Jogeva, and the possible effect of these changes to the species' composition and number of pollinators. The results of measurements indicated that the tetraploid varieties, derived by experimental polyploidization prior to selection, possess ca 10 per cent longer corolla tube, the orifice of which is 30 per cent more spacious. Pre-cutting of the herbage reduced the length of corolla tube of the florets of both early di- and tetraploid red clover varieties and reduced the width of corolla tube orifice as compared with spring growth. The floret's corolla tube shortened in the following years. The eight of nectar level measured at the spring growth of the early red clover varieties referred to a more intense nectar secretion in the case of tetraploid variety. Altough more abundant nectar secretion partly compensates the increase of the corolla tube length, the tetraploid variety 'Varte' had significantly longer distance between the orifice of the corolla tube and nectar in the florets than the diploid variety 'Jogeva433'
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