Relationship between Stalk and Cob Mechanical Strength during the Late Growth Stage of Maize (Zea mays L.)

Jun Xue,Keru Wang,Hongyan Li,Bo Ming,Ruizhi Xie,Peng Hou,Yinghu Fan,Shaokun Li,Qun Wang,Lulu Li

doi:10.3390/agronomy10101592

Abstract

The stalk strength of maize (Zea mays L.) has a significant effect on stalk lodging and harvesting loss, and the cob mechanical strength affects the grain broken rate in mechanical grain harvesting. Clarifying the relationship between maize stalk strength and cob mechanical strength could provide a theoretical basis for the selection of cultivars with high lodging resistance and high suitability for mechanical grain harvesting. In 2017 and 2018, 64 maize cultivars were planted in four locations to investigate the changes in the bending strength of stalks and cobs using the three-point bending method during the late growth stage. The results showed that, in the late growth stage, with increasing number of days after physiological maturity, the stalk bending strength (SBS) of the fifth internode above the soil gradually decreased, the cob bending strength (CBS) decreased first and then increased, and it was lowest at about six to eight days after physiological maturity. In the same experimental site and sampling period, there was no significant correlation between the SBS and the CBS of different maize cultivars. Cluster analysis showed that most of the investigated maize cultivars showed low stalk strength during the late growth stage. However, a few of the maize cultivars were suitable for mechanical grain harvesting due to their characteristics of high stalk bending strength and moderate cob bending strength during the late growth stage.

Highlights

Mechanical grain harvesting is the development direction of maize production in China [1].The mechanical harvesting of maize requires kernel moisture contents lower than 27% [2,3]
These sites results that there is no significantly correlated with the on any sampling dates. These results indicate that there is no correlation between the cob short-span bending strength (CBS) and the span bending strength (SBS) during the late growth stage in the studied maize cultivars
The slope of the fitting equation showed that the largest change in CBS with with SBS occurred for this cultivar

Summary

Introduction

The mechanical harvesting of maize requires kernel moisture contents lower than 27% [2,3]. Kernel dehydration via plant standing in the field after physiological maturity is an important measure to reduce kernel moisture content [4]. The plant height, ear height, internode length, and internode diameter does not change. The decomposition of carbohydrate and the decrease of moisture content causes the stalk mechanical strength to decrease, which increases the risk of lodging during the late growth stage of maize [5,6]. In addition to grain loss, lodging increases harvest costs and reduces grain quality. Maintaining high stalk strength during the late growth stage is important for ensuring in-field kernel dehydration in order to facilitate mechanical grain harvesting

Methods

Results

Discussion

Conclusion