Cook Douglas D, de la Chapelle Witold, Lin Ting-Che, Lee Shien Yang, Sun Wenhuan, Robertson Daniel J
1Mechanical Engineering, Brigham Young University, Provo, USA.
2Division of Engineering, New York University Abu Dhabi, Abu Dhabi, UAE.
Plant Methods. 2019 Sep 3;15:102. doi: 10.1186/s13007-019-0488-7. eCollection 2019.
Stalk lodging (breakage of plant stems prior to harvest) is a major problem for both farmers and plant breeders. A limiting factor in addressing this problem is the lack of a reliable method for phenotyping stalk strength. Previous methods of phenotyping stalk strength induce failure patterns different from those observed in natural lodging events. This paper describes a new device for field-based phenotyping of stalk strength called "DARLING" (device for assessing resistance to lodging in grains). The DARLING apparatus consists of a vertical arm which is connected to a horizontal footplate by a hinge. The operator places the device next to a stalk, aligns the stalk with a force sensor, steps on the footplate, and then pushes the vertical arm forward until the stalk breaks. Force and rotation are continuously recorded during the test and these quantities are used to calculate two quantities: stalk flexural stiffness and stalk bending strength.
Field testing of DARLING was performed at multiple sites. Validation was based upon several factors. First, the device induces the characteristic "crease" or Brazier buckling failure patterns observed in naturally lodged stalks. Second, in agreement with prior research, flexural rigidity values attained using the DARLING apparatus are strongly correlated with bending strength measurements. Third, flexural stiffness and bending strength values obtained with DARLING are in agreement with laboratory-based stiffness and strength values for corn stalks. Finally, a paired specimen experimental design was used to determine that the flexural data obtained with DARLING is in agreement with laboratory-based flexural testing results of the same specimens. DARLING was also deployed in the field to assess phenotyping throughput (# of stalks phenotyped per hour). Over approximately 5000 tests, the average testing rate was found to be 210 stalks/h.
The DARLING apparatus provides a quantitative assessment of stalk strength in a field setting. It induces the same failure patterns observed in natural lodging events. DARLING can also be used to perform non-destructive flexural tests. This technology has many applications, including breeding, genetic studies on stalk strength, longitudinal studies of stalk flexural stiffness, and risk assessment of lodging propensity.
茎倒伏（收获前植物茎杆折断）对于农民和植物育种者来说都是一个主要问题。解决这一问题的一个限制因素是缺乏一种可靠的茎杆强度表型分析方法。以前的茎杆强度表型分析方法所导致的破坏模式与自然倒伏事件中观察到的不同。本文描述了一种名为“DARLING”（谷物抗倒伏评估装置）的用于田间茎杆强度表型分析的新装置。DARLING仪器由一个垂直臂组成，该垂直臂通过铰链连接到一个水平踏板。操作人员将该装置放置在茎杆旁边，使茎杆与力传感器对齐，踩在踏板上，然后向前推垂直臂，直到茎杆折断。测试过程中持续记录力和旋转情况，这些量用于计算两个量：茎杆弯曲刚度和茎杆弯曲强度。
在多个地点对DARLING进行了田间测试。验证基于几个因素。首先，该装置会导致在自然倒伏茎杆中观察到的特征性“折痕”或布雷斯纳屈曲破坏模式。其次，与先前的研究一致，使用DARLING仪器获得的弯曲刚度值与弯曲强度测量值高度相关。第三，用DARLING获得的弯曲刚度和弯曲强度值与玉米茎杆基于实验室的刚度和强度值一致。最后，采用配对样本实验设计来确定用DARLING获得的弯曲数据与相同样本基于实验室的弯曲测试结果一致。DARLING还被部署到田间以评估表型分析通量（每小时表型分析的茎杆数量）。在大约5000次测试中，发现平均测试速率为210茎杆/小时。
DARLING仪器在田间环境中提供了对茎杆强度的定量评估。它会导致在自然倒伏事件中观察到的相同破坏模式。DARLING还可用于进行无损弯曲测试。这项技术有许多应用，包括育种、茎杆强度的遗传研究、茎杆弯曲刚度的纵向研究以及倒伏倾向的风险评估。
