Genetic Diversity of Potato Genotypes in Bangladesh and Their Molecular Characterization by RAPD Marker

Abstract

Several hundred potato genotypes are grown throughout the world. They differ in appearance, tuber structure, size and color, time of maturity, cooking and marketing qualities, yield and resistance to pests and diseases. A variety that grows well in one area may do poorly in another. Potato genotypes that are cultivated in Bangladesh are broadly categorized into two groups, local or indigenous and high yielding. We collected ten local and seventeen high yielding potato genotypes in order to study their diversity at morphological, phytochemical and molecular levels. At morphological level the diversity among the potato genotypes was evaluated based on 20 morphological markers. In molecular level we analyzed their diversityusing RAPD based DNA fingerprinting method. Diversity in phytochemical activities was also evaluated among 27 potato genotypes particularly in terms of their antioxidant activity and hemagglutination activity. Under the purview of morphological study the characters of potato plant were analyzed during its growth period. Nature and extent of variability, characters association, stability of performance and genetic diversity at germplasm level were studied for 27 potato genotypes. The genotypes showed significant variation in respect of morphological characters. Genetic advance as percent of mean was highest for potato weight/plant, number of potato/plant and plant dry weight indicating important role of genetic factor towards expression of these characters. Thus, for these characters, there is maximum possibility of fruitful phenotypic selection. Inter nodal distance, number of leaf per plant and plant leaf area had high positive direct effect on tuber yield. Therefore, suggested that inter nodal distance, number of leaf per plant and plant leaf area are the main components of yield should be given high priority in the selection program. Significant difference of D2 values in respect of yield and yield contributing characters indicating a wide range of diversity among the genotypes at the germplasm level. Based on the D2 values, 27 potato genotypes under the study were grouped into IV distinct clusters. The results obtained from the stability analysis indicated that none of the genotypes could be identified as stable one for tuber yield in strict sense of stability performances. Ausha, Indurkani, Lady Rosette, Sadaguti and Sui:jamukhi could be suggested for wide cultivation as these varieties exhibited high mean performance and more or less low mean square deviation. Diversity in Phytochemical activities was determined by antioxidant activity test and hemagglutination assay. Among the indigenous varieties, Sindurkouta showed highest antioxidant activity (ICso value 14.1 μg/ml) and among the High Yielding varieties, Sprite showed highest antioxidant activity (ICso value 22.2 μg/ml). Potato genotypes having high antioxidant activity should be given preference to get their health benefit and reduce the free radical in human body. Hemagglutination activity results indicated that Asterix, Sindurkouta, Shilbilati, MF- 2, Lady Rosette, Sprite, Dheera showed high lectins activity (128 HAU), so further research may proceed to find out their toxicity and medicinal value based on the type of lectins present in them. Surjamukhi, Sadaguti, Patnai had no hemagglutination activity and they are the local varieties of Bangladesh. DNA fingerprinting of 27 genotypes of potato were performed using RAPD primers in the present investigation. A total of 80 primers were used in RAPD experiments. However, the best result was obtained using the RAPD primer A-1, A-2, A-3, A-4, D-11 and D-13.Therefore, these RAPD primers can be usedas genetic markerfor the proper identification of the genotypes. These six primers generated different banding pattern with size ranging from 300bp to 5000 bp. Out of the 60 bands, 55 scorable bands (91.66%) were found to be polymorphic and 5 bands (8.34%) were found to be monomorphic. Consensus phylogenetic dendogram based on the banding pattern by different primers used in this study revealed that 27 potato genotypes were divided into five groups. The data generated from this morphological, phytochemical and molecular study showed that there are significant genetic differences among the potato genotypes cultivated in Bangladesh and that they could be used to strengthen the future potato genotypes improvement programme effectively by incorporating potential progenitors from the available potato germplasm.