A high-throughput method for precise phenotyping sugarcane stalk mechanical strength using near-infrared spectroscopy

Abstract

Background: Sugarcane (Saccharum officinarum L.) is the core crop for sugar and bioethanol production over the world. A major problem in sugarcane production is stalk lodging due to weak mechanical strength. Since there are no efficient methods for determining stalk mechanical strength in sugarcane, genetic approaches for improving stalk lodging resistance are largely limited. This study was designed to use near-infrared spectroscopy (NIRS) calibration assay to accurately assess mechanical strength on a high-throughput basis for the first time. Results: Hundreds of sugarcane germplasms were harvested at the mature stage in the year of 2019 and 2020. In terms of determining rind penetrometer resistance (RPR) and breaking force, large variations of mechanical strength were found in the sugarcane stalk internodes, based on well-established laboratory measurements. Through partial least square regression analysis, two online NIRS models were established with a high coefficient of determination (R2) and the ratio of prediction to deviation (RPD) values during calibration, internal cross-validation, and external validation. Remarkably, the equation for RPR exhibited R2 and RPD values as high as 1.00 and 17.7, as well as showing relatively low root mean square error values at 0.44 N mm-2 during global modeling, demonstrating excellent predictive performance. Conclusions: This study delivered a successful attempt for rapid and precise prediction of mechanical strength in sugarcane stalk by NIRS assay. By using these established models, genetic improvements could be made to phenotyping jobs for large-scale sugarcane germplasm.

A high-throughput phenotyping assay for precisely determining stalk crushing strength in large-scale sugarcane germplasm

“…This suggests that sugarcane crushing strength is a complex trait that is closely related to the biological properties of sugarcane stalks. This is different from the pattern of rind penetrometer resistance (RPR) and breaking force that characterized in our previous study ( Shen et al., 2022 ). It implies that the application of a single indicator in assessing the mechanical strength of sugarcane stalks to determine the lodging resistant is not desirable.…”

“…In spite of this, it remains a serious problem that there is currently no method of measuring mechanical strength in crops that is both accurate and high-throughput. In our latest study, a precise and high-throughput mechanical strength characterization assay was developed in terms of measuring rind penetrometer resistance (RPR) and breaking force by NIRS modeling in sugarcane ( Shen et al., 2022 ), providing a framework for high-throughput phenotyping of crop stalk mechanical properties. Through a combination of complementary explorations, this study aimed to establish high-throughput phenotyping methods for sugarcane crushing strength.…”

“…It implies that the application of a single indicator in assessing the mechanical strength of sugarcane stalks to determine the lodging resistant is not desirable. Therefore, the high-throughput phenotypic analysis assay for sugarcane crushing strength determination established in this study, combined with our previously established rapid assays for sugarcane rind penetrometer resistance (RPR) and breaking force characterization ( Shen et al., 2021 ; Shen et al., 2022 ), can provide a more comprehensive and systematic technical support for lodging resistance targeted sugarcane breeding and beyond.…”

“…In our previous studies, the NIRS has been successfully applied for stalk quality determination ( Wang et al., 2021 ), cell wall features and lignocellulose digestibility characterization in sugarcane ( Li et al., 2021 ; Adnan et al., 2022 ). Notably, in a recent study, we have also successfully implemented the NIRS for assessing the mechanical strength of sugarcane stalks by measuring the rind penetrometer resistance (RPR) and breaking force ( Shen et al., 2022 ).…”