Genetic variation in Isozyme patterns in the genus Amaranthus

Abstract

six cultivars of five species of grain amaranth were used to study electrophoretic differences for six isozyme markers namely, :- esterase (Est.), peroxidase (Per.), phosphoglucoisomerase (Pgi), 6-phosphogluconate dehydrogenase (6-Pgd), malate dehydrogenase (Mdh) and phosphoglucomutase (Pgm). The plants were grown in the glasshouse at Kabete Field Station, University of Nairobi, Kenya and the Institute of Agronomy and plant Breeding I, University of Giessen, Germany. The glasshouse temperature range in Kabete was 17 37 degrees o 0 Celsius ( C) while in Giessen, 14 - 20 C with relative humidity between 40 - 90%. starch gel electrophoresis was performed on leaf extracts beginning with 2-week old plants for a period of 2 1/2 months in ~ach trial. Best isozyme zymograms were obtained with plants between 60 - 70 days of age. Esterase isozyme identified ~ caudatus because at 64 days stage, band A 1 was specific to it and band A 2 was missing in it. b.hypochondriacus was identified due to early activity of the enzyme ( 14 - 32 days old). Cultivars Jumla and 1023 of ~ hypochondriacus were distinguished using bands A , A 3 4 and A . 5 F Jumla was distinguished from Jumla parent because its bands 1 were less conspicous. - 2 - Peroxidase zymograIo identified ~ hypochondriacus because at 64 days, band A was missing in it. ~ tricolor was identified 3 because band A was only present in it. ~ cruentus was identi- 1 fied because it lacked band C present in other species. ~ hybr- 1 idus was identified because all its bands were light stained. Phosphoglucoisomerase isozyme identified ~ cruentus because at 64 days, band A was only specific to it. 1 Phosphoglucomutase zymogram, at 70 days, identified ~ and A were specific to it. cultivars 4 cruentus because bands A 2 1023 and Jumla of ~ hypochondriacus were distinguished using band A which stained light in 1023 and medium in Jumla. F was 4 1 distinguished from Jumla parent because its bands were generally lighter stained.