GRAIN YIELD TRAITS OF SINGLE AND THREE-WAY SORGHUM HYBRIDS AND ITS PARENTAL LINES

Abstract

Reports of a grain yield improvement of single cross (SCSH) vs. three-way (TWSH) sorghum (Sorghum bicolor L. Moench) hybrids are scarce. The objective of this study was to compare midparent heterosis, high parent heterosis, and general and specific combining ability for yield traits (panicle length and width, grain yield/panicle, grains/panicle and 100-grains weight) of SCSH, TWSH and its parental lines. Irrigated and rainfed field trials were established in the Mexican Highlands (?2100 m altitude; 8 °C mean early morning temperature during the growing season). Both trials included five groups of genotypes (three or four pairs of ‘A’/‘B’ lines, four ‘R’ lines, 11 SCSH and 41 TWSH). Significant differences (p?0.05) were found for groups of genotypes (G) and environments (E) for most traits, but the G?E interaction was not significant (p?0.05). The TWSH group did not show significant differences (p?0.05) with that of the SCSH group for any trait. None significant differences (p?0.05) were found for grain yield/ panicle and grains/panicle between the group of ‘R’ lines, and those of SCSH and TWSH. High parent heterosis estimates were low due to the high expression of the ‘R’ lines. Estimates of general combining ability of female and male parents were significantly different (p?0.05), but not for specific combining ability in both hybrid types. Our ‘R’ lines can be sown as open pollinated varieties in the Mexican Highlands instead of sorghum hybrids.