This paper reviews the use of purple/green coleoptiles in wheat variety description, the identification of the anthocyanidins and anthocyanins of the purple coleoptile, its genetics and association with other characteristics.
The geographical distribution of 902 Old World local varieties or their selections with purple or green coleoptile were investigated . It appears that there is no clear distribution although in some regions only varieties with green coleoptile occur . It is possible that each of the 3 Re loci has a special geographical distribution which has not been investigated yet .
REVIEW General remarks and influence of environment
Wild and cultivated grasses are marked by various colourations in different parts of the plant. VAVILOV (1949/50) established homologous series for these characters for several cereals and their wild relatives . Excluding green, the pigmentation is generally caused by the presence of anthocyanins .
In wheat plants various parts may be coloured . They are coleoptile, first leaf or its sheath, culm, ring under node, auricle, ligule, rachis, glume and parts of it, awn, anther, pericarp and aleurone layer. ELLIS (1971) distinguished the colour of coleoptile as weak, red and purple . No particular colour is given for weak .
The presence or absence of pigmentation is used to describe a variety . From the purple pigmented plant parts expecially the purple coleoptile is used (Voss, 1930 ;SIMON, 1957 ;KOCETOVA, 1965 ; TERNING, 1967, to mention a few) . However, as en-. vironment influences the production of anthocyanins the milieu in which the described varieties have grown should be mentioned . High light intensity, low temperature am. good nutrient generally promote the synthesis of anthocyanins (