Abstract
Natural cross-fertilization of single plants of sesame with recessive characters grown in a matrix of a cultivar with the corresponding dominant characters amounted to 2·67 ± l·94 per cent for 'Majaza light', 9·02 ± 5·76 for 'X 30/115' and 51·72 ± 21 ·04 for ' 1argo'. Pericentral guard rows of sesame and maize reduced intervarietal cross-fertilization for 'X 30/115' on an average from 2·5 and 3·7 per cent to 2·25 and 1·6 per cent respectively. Two-thirds of the research stations in different countries maintained sesame germplasm under open pollination. A general formula is proposed by the author to estimate genetic impurity resulting from open pollination. It is concluded that controlled self-pollination is advisable for the maintenance of germplasm collections. Natural cross-pollination has its uses for population improvement through recurrent selection.
