Date of this Version
Maydica 44 (1999): 155-158
Resistance to lodging is critical in sorghum [Sorghum bicolor (L.) Moench] grown for grain, yet adequate tools for plant breeders to assess this character at or before anthesis have not been developed. The objective of this study was to evaluate whether an electronic penetrometer previously shown to be an effective tool for measuring stalk strength in maize (Zea mays L.) could be usedd to differentiate among grain sorghum hybrids. Entries in three commercial grain sorghum hybrid trials were evaluated for rind penetrometer resistance (RPR) of the peduncle, the lower stalk anthesis and the lower stalk at maturity. Actual lodging counts were also taken immediately prior to harvest. Significant differences were detected among hybrids for RPR of the peduncle and lower stalk at antesis and for actual lodging percentages in all three experiments. Rind penetrometer resistance of lower stalks at maturity differed significantly among hybrids in only one of the three experiments. Coefficients of variation (CVs) ranged from 8.9 to 11.2% for peduncle RPR at anthesis. 6.3 to 7.8% for lower stalk RPR at anthesis 10.4 to 14.0% for lower stalk RPR at maturity, and 85.4 to 116.0% for actual lodging percentages. Rind penetrometer resistance measurements allowed better separation of hybrids into groups with high or low RPR than did actual lodging scores. Correlation of RPR values with actual lodging scores was extremely low and were usually non-significant. Based on these results, RPR of penduncles and lower stalks at anthesis may have utility as a selection tool for direct improvement of sorghum stalk strength.