STUDIES ON MORPHOLOGICAL AND MOLECULAR DIVERSITY FOR CULTIVAR IDENTIFICATION IN BOUGAINVILLEA

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Date
2014
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DIVISION OF FLORICULTURE AND LANDSCAPING INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI-
Abstract
A study was undertaken to identify microsatellite markers, characterize and analyze diversity among the bougainvillea (Bougainvillea spp.) cultivars using morphological DUS descriptors and SSR markers. A total of thirty-eight morphological descriptors were recorded for 100 cultivars and significant variation was observed for all the descriptors except for the presence of thorns. For quantitative characters, highest variability was observed for peduncle length (0.89), leaf length (0.80) and bract length (0.57) while, all the qualitative characters were observed to be stable in both the years. According to the DUS characterization, cultivars were grouped into different categories for each character studied which may be used as reference cultivars for DUS testing and also in future breeding programme. Based on the bract colour compared with Royal Horticultural Society (RHS) colour chart, the cultivars were broadly divided into nine categories and majority of the cultivars (60) were placed in Red-Purple colour groups. The cultivars were grouped into twelve different clusters based on morphological characters. The clustering was more distinct for bract type, leaf variegation however, it was difficult to distinguish among the single bracted types. Thus, morphological DUS descriptors can be effectively employed for cultivar identification in bougainvillea. For the first time in bougainvillea, a total of 175 SSR markers were developed to characterize and investigate the molecular diversity of 125 cultivars. Eighty-three markers produced clear amplification out of which 33 markers were found to be highly polymorphic. The di (AT, TA) and tri (AAT, ATA) nucleotide repeats motifs were found to be most common and these accounted for higher polymorphism. These polymorphic markers detected on an average of 5 alleles per locus with a range of 2-9 in the amplicon size range of 90- 320bp. Gene diversity and polymorphism information content values ranged from 0.13-0.91 and 0.134-0.958 with a mean value of 0.71 and 0.678, respectively. Based on molecular divergence, cultivars were grouped into seven clusters. Clustering was not species specific but clearly conveyed the extent of molecular diversity present in bougainvillea. The genetic distance estimates ranged from 0.089 (between Mrs. Mc Clean and Scarlet Glory Variegata) to 0.86 (Los Banos Beauty and Gloriosus) with an average of 0.56. These markers were also found to be effective in distinguishing closely related cultivars which can help in IPR protection. Estimation of existing genetic diversity and identification of trait specific cultivars could be effectively utilized in future bougainvillea improvement programmes to enhance the aesthetic beauty.
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t-9067
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