Cytological and pigmentation studies in certain cultivars and mutants of Bougainvillea

Abstract

Studies were carried out to compare the cytological pigment differences associated with varied bract colours in certain Bougainvillea cultivars and mutants. The Bougainvillea genotype including induced mutants were selected. The quantitative and qualitative status of pigments showed considerable variations. The estimated betacyanin content expressed as O.D. value was observed to be maximum in cv. Elizabeth (1.7638) followed by colchicines induced mutant ‘Zakariana’ (1.2007) with the lowest bract (pH 5.87). Estimated bract betaxanthin content was found to be maximum in cv. Mrs. Enid Lancaster (1.5422) followed by cv. Tomato Red (1.0922). Therefore the ratio was of bract betacyanin to betaxantin was the highest in cv. Dr. H.B. Singh (2.4901) with highest record bract pH (6.53) and the lowest betacyanin to betaxanhin ratio was observed in cv. Lady Mary Baring (0.1497). Qualitative estimation of bract pigments by paper chromatography on the basis of Rf values were grouped. Two betaxanhin bands were observed in all the genotypes studies except in cv. Dr.H.B.Singh. this variation in pigment content seems to influence upon light and dark coloured bracts of induced mutants. Cytological studies in the cultivars and mutants indicated no loss of the chromosomes in gamma irradiated and colchicine treated mutants. Miotic behaviour varied from normal behavior showing less number of univalents and pollen mother cells having laggards. Whereas in highly abnormal behavior more number of univalents and laggards were observed in metaphase I and anaphase I and II, respectively. Among the mutants gamma rays induced mutant ‘Zakariana’ had less miotic behavior than its parent. Thus the uniformity in gametic chromosome number and variations in bract colour is attributed to the effects of genes controlling the bract colour expression.