Non-destructive and Quantitative Evaluation Method for Root Lodging Resistance by Measurement of Horizontal Pulling Resistance in Maize

Abstract

There has been need for a precise technique for evaluating root lodging resistance in maize breeding, because natural lodging is accidental and unreliable. The present study was conducted to develop a new method for evaluating root lodging resistance of maize by measurement of horizontal pulling resistance. Ten inbreds selected for root lodging resistance in the previous experiments, 44 single cross hybrids among them and three commercial hybrids were used and their horizontal pulling resistance was determined about 20 days after silking. Since root lodging resistance is closely related to root strength and plant size, horizontal pulling resistance-value (HPR-value) was calculated using the following formula. [numerical formula] Two years mean of HPR-value and that of discriminant function value of root lodging resistance (DF-value) by ISHIGE et al. (1983) were compared for correlation with the three years mean of rate of root lodged plants. The correlation coefficients of HPR-value (r=0.631 in hybrids, r=0.564 in inbreds) were higher than those of DF-value (r=0.277 in hybrids, r=0.382 in inbreds). However, the correlations were not significant in inbreds. The results indicated that HPR-value is non-destructively measurable and efficient for quantitative evaluation of root lodging resistance of hybrids.