TAHANI ELAGIB, HEIKO K. PARZIES, H. H. GEIGER
University of Hohenheim, Institute for Plant Breeding, Seed Science and Population Genetics, Germany
Sorghum (Sorghum bicolor) is the most important grain crop in the Sudanese economy and diet. The Sudan and the adjacent areas in Eritrea and Ethiopia are considered as centres of diversity of sorghum. In Sudan sorghum ranks first in terms of cultivated area (6.4 mill.ha) and production (5 mill. metric tons). However, average yield per unit area is very low (kgha) in comparison to the world average (kgha). The only released sorghum hybrid variety is sensitive to drought and the parasitic weed Striga hermonthica. The aim of this study therefore is to characterise the pattern of genetic diversity in a representative samples of Sudanese sorghum landraces and to determine genetically distinct pools which shall serve as base materials for hybrid breeding. Seed samples of 52 landraces from a broad range of the sorghum growing area in Sudan were provided by ARC. Most of the landraces belong to the races durra and caudatum. For comparison, a world-wide collection of 25 inbred lines and 2 wild sorghums (S. arundinaceum) were included.
A total of 30 Simple Sequence Repeat markers were employed to establish clusters of potentially heterotic groups. A UPGMA-dendrogram was generated from distance-matrix data using modified Roger's distance. The results show that Sudanese sorghum landraces are highly variable providing abundant diversity for the development of hybrids and open-pollinated varieties. SSR-clustering revealed distinct sorghum landrace groups which are considered as promising base materials for building up heterotic gene pools for the development of high-yielding hybrid varieties. Presently, all landraces and inbred lines will be testcrossed with two Cytoplasmatic Male Sterility lines derived from different gene pools. Individuals of differential clusters will be manually crossed in a diallel manner. The landraces, inbred lines, test crosses and diallel crosses will be evaluated in regular yield trials at three sites in Sudan in 2005 and 2007. Final clustering will be based on molecular markers as well as field data.
Keywords: Heterotic grouping, plant breeding, sorghum, SSR, Sudan