COMPARISON OF 2 RIND PENETROMETERS FOR MEASUREMENT OF STALK STRENGTH IN MAIZE

Efforts to increase grain yield of maize (Zea mays L.) by breeding high-yielding cultivars, improving soil fertility, and/or increasing plant density have often resulted in increased stalk lodging. Selection for mechanical stalk strength may improve lodging resistance, but to be of practical value, the procedure needs to be simple to enable screening of many genotypes. The objective of this study was to evaluate two different rind penetrometers by using two synthetic maize populations, MoSQA and MoSQB, that had been selected for high stalk crushing strength. Selection for high stalk crushing strength improved stalk strength per se in MoSQA and MoSQB. Manual and modified electronic rind penetrometer measurements were significantly correlated (r = 0.98) and rind penetrometer resistance showed 2.9%/cycle increase as measured by both the manual and electronic rind penetrometer in MoSQA. In MoSQB, rind penetrometer resistance increased 2.6 and 2.2%/cycle as measured by the manual and electronic penetrometers, respectively. The modified electronic rind penetrometer can be considered for application as a simpler and more rapid device to aid in selection of superior stalk strength.