Relationships between floret size and grain weight in aneuploid lines of homoeologous group-5 chromosomes of common wheat (Triticum aestivum L.) cv. Chinese Spring

Abstract

Various aneuploids of common wheat (Triticum aestivum L.) cv. Chinese Spring were used to study the dosage effect of group-5 chromosomes on spike morphology, size of floral organs, and grain weight. Reduced dosage resulted in smaller floral organs, smaller floret cavities, and lighter grains than in the euploid, while increased dosage had the opposite effects. Chromosome 5A was the most effective in inducing these changes, whereas in most cases 5B was the least effective. Based on the various lines studied, a high linear correlation was found between the weight of the basal grains in the central spikelets and the volume estimates of the florets in which they were developed. The different lines exhibited a considerable similarity between the size distribution of floral organs and the grain weight distribution in the main spike. Pleiotropic effects of genes located on group-5 chromosomes on size of floral organs and grain weight are suggested.Key words: Wheat, aneuploids, group-5 chromosomes.