The use of Sorghum propinquum to enhance agronomic traits in Sorghum

Abstract

Introgression of desirable alleles into elite germplasm pools is needed to maintain genetic diversity and genetic improvement rates. The objective of the current study is to determine if agronomically useful alleles are present in an exotic source of sorghum (S. propinquum) by introgressing them into an elite genetic background of common sorghum through backcrossing. A total of 93 BC₄ S. propinquum-derived A-lines and 74 hybrids (BC₄ equivalents) were tested in College Station, Texas in 1998 and 1999 and compared with recurrent parent checks (or equivalent) of ATx623 and ATx623*RTx430. In the two-year combined analysis, 30 S. propinquum-derived lines (SPDLs) were significantly (p<0.05) earlier than ATx623, while 17 S. propinquum-derived hybrids (SPDHs) were significantly earlier than ATx623*RTx430. Only one SPDL had significantly higher yield than the check, while 36 were significantly lower yielding. However, four SPDHs were significantly higher yielding than the check, while seven were significantly lower yielding. In general, the SPDLs were earlier, taller, lower yielding, with greater panicle exsertion and test weight than ATx623. The SPDHs generally were earlier, taller, and higher yielding than ATx623*RTx430. Both SPDLs and SPDHs showed a strong positive correlation between height and yield. SPDL height and maturity correlated (r>0.55) with SPDH height and maturities, respectively. SPDL exsertion and test weight also correlated (r>0.27) with SPDH exsertion and test weight, respectively. SPDL yield did not correlate with SPDH yield. The results indicate that S. propinquum-derived germplasm contains agronomically desirable alleles for grain yield and maturity. Correlation of these results with previous RFLP analysis could provide an excellent tool for identifying agronomically desirable S propinquum QTLs and for breeding program utilization.