Abstract
BackgroundStalk fracture caused by strong wind can severely reduce yields in maize. Stalks with higher stiffness and flexibility will exhibit stronger lodging resistance. However, stalk flexibility is rarely studied in maize. Stalk fracture of the internode above the ear before tasseling will result in the lack of tassel and pollen, which is devastating for pollination in seed production. In this study, we focused on stalk lodging before tasseling in two maize inbred lines, JING724 and its improved line JING724A1 and their F2:3 population.ResultsJING724A1 showed a larger stalk fracture angle than JING724, indicating higher flexibility. In addition, compared to JING724, JING724A1 also had longer and thicker stalks, with a conical, frustum-shaped internode above the ear. Microscopy and X-ray microcomputed tomography of the internal stalk architecture revealed that JING724A1 had more vascular bundles and thicker sclerenchyma tissue. Furthermore, total soluble sugar content of JING724A1, especially the glucose component, was substantially higher than in JING724. Using an F2:3 population derived from a JING724 and JING724A1 cross, we performed bulk segregant analysis for stalk fracture angle and detected one QTL located on Chr3: 14.00–19.28 Mb. Through transcriptome data analysis and ∆ (SNP-index), we identified two candidate genes significantly associated with high stalk fracture angle, which encode a RING/U-box superfamily protein (Zm00001d039769) and a MADS-box transcription factor 54 (Zm00001d039913), respectively. Two KASP markers designed from these two candidate genes also showed significant correlations with stalk fracture angle.ConclusionsThe internode shape and glucose content are possibly correlated with stalk flexibility in maize. Two genes in the detected QTL are potentially associated with stalk fracture angle. These novel phenotypes and associated loci will provide a theoretical foundation for understanding the genetic mechanisms of lodging, and facilitate the selection of maize varieties with improved flexibility and robust lodging resistance.
Highlights
Stalk fracture caused by strong wind can severely reduce yields in maize
Among the total soluble sugars, we found that glucose content contributed the largest difference in cell wall composition between lines, and JING724 had less glucose than JING724A1, which was in agreement with the maize brittle stalk bk4 in which the glucose content was significantly lower than that in wild type [8]
(3) One QTL region located on chr3:14.00–19.28 Mb was detected for stalk fracture angle
Summary
Stalk fracture caused by strong wind can severely reduce yields in maize. We focused on stalk lodging before tasseling in two maize inbred lines, JING724 and its improved line JING724A1 and their F2:3 population. In grain crops such as maize, lodging disrupts the optimal spatial distribution of the plants, resulting in interference with water and nutrient transport, and leading to less efficient mechanical harvesting and reduced yields [1]. Root lodging and stalk fracture are two major types of lodging [2], with stalk fracture in the early stage of tasseling causing devastating effects to the tassel and/or the ear, and resulting in significant yield loss. A number of fragile stalk mutants have been reported [3,4,5,6,7,8], and they share similar phenotypes in the stalk architecture, vascular bundles, and cell wall composition
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
