Effectiveness of R1-nj Anthocyanin Marker in the Identification of In Vivo Induced Maize Haploid Embryos

• Published in: Plants (Basel) Vol. 12; no. 12; p. 2314
• Main Authors: Lopez, Luis Antonio, Ochieng, John, Pacheco, Mario, Martinez, Leocadio, Omar, Hamilton Amoshe, Gowda, Manje, Prasanna, Boddupalli M, Dhugga, Kanwarpal S, Chaikam, Vijay
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14.06.2023; MDPI
• Subjects: Anthocyanins; Breeding; Chromosomes; Corn; Cost control; Crop production; Diploids; doubled haploids; Efficiency; embryo rescue; Embryos; false detection rate; false negative rate; false positives; Fertility; Germplasm; Identification; In vitro methods and tests; In vivo methods and tests; Inbreeding; Light; Plant breeding; Plant species; Production methods; R1-nj marker; Seedlings; Seeds; Sucrose; embryo rescue; false detection rate; doubled haploids; false negative rate; R1-nj marker; false positives
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants12122314

Doubled haploid (DH) technology has become integral to maize breeding programs to expedite inbred line development and increase the efficiency of breeding operations. Unlike many other plant species that use in vitro methods, DH production in maize uses a relatively simple and efficient in vivo haploid induction method. However, it takes two complete crop cycles for DH line generation, one for haploid induction and the other one for chromosome doubling and seed production. Rescuing in vivo induced haploid embryos has the potential to reduce the time for DH line development and improve the efficiency of DH line production. However, the identification of a few haploid embryos (~10%) resulting from an induction cross from the rest of the diploid embryos is a challenge. In this study, we demonstrated that an anthocyanin marker, namely , which is integrated into most haploid inducers, can aid in distinguishing haploid and diploid embryos. Further, we tested conditions that enhance anthocyanin marker expression in embryos and found that light and sucrose enhance anthocyanin expression, while phosphorous deprivation in the media had no affect. Validating the use of the marker for haploid and diploid embryo identification using a gold standard classification based on visual differences among haploids and diploids for characteristics such as seedling vigor, erectness of leaves, tassel fertility, etc., indicated that the marker could lead to significantly high false positives, necessitating the use of additional markers for increased accuracy and reliability of haploid embryo identification.