CHARACTERIZATION OF WINGED BEAN (PSOPHOCARPUS TETRAGONOLOBUS (L.) DC.) ACCESSIONS USING ISOENZYME PROFILES AND MORPHOLOGICAL CHARACTERISTICS (ELECTROPHORESIS, STARCH GEL, DICHOTOMOUS KEY).

摘要

The winged bean, a tropical legume, is rich in protein, minerals, vitamins, and carbohydrates. It is unique among leguminous plant kinds in that every part of the plant except the roots can be eaten. There are over a thousand accessions and cultivars of winged bean. Therefore, the use of classical methods of describing and identifying genotypes based on morphological characteristics has become increasingly difficult.; A two-part experiment was conducted to characterize 42 accessions collected from nine countries. The first part of the experiment was done in Sri Lanka, at the Dodangolla Experimental Station of the University of Peradeniya. During this period, nine qualitative and five quantitative morphological characteristics were observed on plants and seeds of the 42 accessions. The second part of the experiment was carried out at the Pennsylvania State University. At this time, seedling leaf tissue was extracted and separated via horizontal starch gel electrophoresis. Of 26 isoenzymes tested in preliminary studies, five (diaphorase, phosphoglucoisomerase, glutamate oxaloacetate transaminase, triose phosphate isomerase, and methylumbelliferyl esterase) were useful to help characterize accessions. Compared to other qualitative morphological characteristics, seed color was the most useful to help separate accessions; five groups were found for seed color. Flower color, hilum color, leaf shape, and seed shape had three groups each, while stem color, pod color, pod shape, and seedcoat mottling had two groups each. Five quantitative characteristics (leaflet number per plant, internodal length, stem diameter, days to flower, and pod length) also were variable and of use to help characterize winged bean accessions. By combining morphological data most accessions could be separated. For example, a combination of nine qualitative characteristics separated 22 of 42 accessions. Combinations of nine qualitative and five quantitative characteristics separated 38 of 42 accessions.; Combining data of banding patterns from five isoenzyme systems 19 of 42 accessions were separated. Morphological and isoenzyme characteristics together separated all accessions, except two from Nigeria (TPT 1 and TPT 2). These two accessions probably were closely related or perhaps even duplicate samples of the same genotype. Electrophoresis was repeatable, quick, and inexpensive to perform compared to morphological tests.