Submitted to: HortScience
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/11/2007
Publication Date: 4/1/2008
Citation: Gaikwad, A.B., Singh, A.K., Behera, T.K., Chandel, D., Staub, J.E. 2008. AFLP Analysis Provides Strategies for Improvement of Momordica Charantia L. (Bitter Gourd). HortScience. 43(1)127-133. Interpretive Summary: By taxonomic classification bitter gourd (Synom. balsam pear, bitter melon, bitter cucumber, and African cucumber), is a member of the family Cucurbitaceae which houses such economically important plants as cucumber and melon. The morphologically diverse bitter gourd is one of most widely grown and economically important vegetables grown in tropical regions where it varies in mature fruit size, color, surface texture, and edible maturity. Although the general chemical composition of immature bitter gourd fruit is similar to other cucurbit species, it possesses comparatively high concentrations of ascorbic acid (vitamin C) and iron making it an important food source for improved human health in the countries where it is cultivated. Obtaining estimates of genetic diversity (GD; differences among plants) is of extreme importance to plant improvement since it increases the efficiency and effectiveness of selection of improved cultivars. The GD of bitter gourd is not known. Therefore, a study was undertaken to define the GD of bitter groud accessions in the country of origin, India, using DNA analysis. DNA analysis of 38 accessions of diverse geographic origin indicated that GD among some accessions was great. This information can be used by public and private plant breeders to increase their managerial effectiveness for developing new, more genetically diverse bitter groud varieties for human consumption. Since bitter gourd is high in nutritive value and can be grown in the U.S. as a “new crop” this information provides for opportunities for growers to expand their crop array and increase their global competitiveness.
Technical Abstract: Monoecious bitter gourd (Momordica charantia L. var. minima and maxima Williams & Ng), a cucurbit of major economic importance, is widely cultivated in India, China, Africa, and South America. Although the morphology (i.e., growth habit and fruit shape, size, color and surface texture) of Indian bitter gourd is diverse and gynoecious sex forms exist, a comprehensive diversity assessment of ecotypes has not been performed. Therefore, the genetic relatedness of 38 Indian cultigens (commercial varieties, and cultivated landrace accessions originating from different agro-ecological zones) was determined by amplified fragment length polymorphism (AFLP) analysis. Six primer combinations yielded a total of 519 bands of which 404 (77.8%) were polymorphic among the accessions examined. Unweighted pair group cluster analyses were performed using Jaccard's genetic similarities to define genetic relationships among cultigens. Genetic similarities among accessions ranged between 0.44 to 0.88, indicating that the bitter gourd cultigens examined were genetically diverse. Moreover, putative AFLP loci defined genetic relationships that allowed for partitioning of cultigens into two distinct groups [Group 1 and Group II (Node 1); bootstrap = 100%] after cluster analysis. With rare exception, cultigens grouped with respect to geographical region, where cultigens within a group and subgroups possessed high degrees of genetic similarity. The relatively high marker indices (6.2 to 19.4), polymorphic information content of the markers employed (0.20 to 0.25), and multiplex ratios (28.9 to 77.4), collectively indicate that the AFLP markers employed are discriminatory in bitter gourd, and that the analysis of the broad-based cultigens described provides valuable baseline information for advancing initial breeding strategies for this crop species.