Identifying the Fertility Restorers and Maintainers from the Local Landraces in Sorghum - Abstract
Cytoplasmic male sterility system has been widely been used for increasing sorghum yield through heterosis exploitation. To effectively use male–sterility inducing cytoplasm, it is necessary to identify restorers and lines that are suitable for conversion to male sterility. The present study was undertaken to determine the fertility/sterility reactions of a subset of entries from a total of 1019 accessions of two collections (1976 and 2003) of landrace sorghums crossed onto two CMS lines NE223A and Tx623A. The male-sterile lines were Kafir-milo derivatives. Three hundred and forty test-crosses were generated and evaluated in two environments in Niger. Studies revealed four F1 test-crosses (NE223A x L95-1, NE223A x L95-3, NE223A x L119-2 and NE223A x L102- 1) with complete sterility across the two locations. The corresponding parental lines were therefore recommended for conversion to male sterile. However, forty (40) additional test-crosses showed male sterility at Maradi only and two others at Konni respectively, whereas 286 and 272 hybrids shed pollen. The pollen parents of the fertile test crosses were classified as fertility restorers. The male-sterility of female NE223A was maintained by more lines (42) than Tx623A (8) while, at the same time, there were more sterile crosses within the 2003 collection than within the 1976 collection. According to the classification of sorghum races, the sub-group guinea-margaritiferum had the highest number of lines without restorer genes.