INHERITANCE OF TILLER REGROWTH IN RATOONED SORGHUM

Abstract

Six populations (Psen, Pns, F1, F2, BCsen, BCns) were used to estimate genetic variances for ratoon tiller regrowth in sorghum (Sorghum bicolor (L.) Moench). All data involving progeny of senescent and nonsenescent crosses were pooled for analysis using the joint scaling test. Parental lines differed significantly in tiller production. Tiller production of a ratoon sorghum crop was used as a measure of nonsenescence and this character was quantitatively inherited with additive genetic effects, with no indication of significant dominance genetic effects. The large estimates for additive genetic variation indicated that some progress could be made in selecting for tillers in a ratoon sorghum crop. However, heritability estimates were low (0.18–0.28) for number of tillers in ratooned sorghum. The selection program would probably be most successful if it were based on tiller counts after 6 wk of regrowth. Estimates concerning the number of effective factors controlling tiller number in a ratoon crop indicated that this characteristic is under the control of one major factor or chromosome segment.