*Obituary* **Brief Biography of Professor Yingguo Zhu**

**Jun Hu <sup>1</sup> and Yuxian Zhu 1,2,\***


Professor Yingguo Zhu was born in November 1939 and grew up in a poor mountain village in Hubei Province, China. Since his early childhood was rooted in two major global wars, especially in China, his ordinary farmer parents had great difficulty raising him and their two other children. As the eldest son, he was used to the responsibility of caring for his little brother and sister at a very young age. He exhibited abundant talent as early as elementary school in Luotian village. In 1956, it was recommended that he study in Luotian's number one high school. Three years later, he was enrolled at Wuhan University after achieving excellent grades. During the "Three Years of Natural Disasters" (1959–1962), he witnessed a huge amount of death by hunger among his fellow peasants, friends and relatives. This horrible situation made him determined to devote his life to the field of global food security.

Prof. Yingguo Zhu studied and worked at Wuhan University for 58 years and contributed to enriching the diversity of hybrid rice. He pursued his dream of creating new rice germplasms by crossing different cultivar varieties with wild rice. Starting in 1964, he collected numerous rice varieties, and put all his time and energy into hybrid rice, including three-line and two-line breeding. He realized very early on that the creation of male sterile lines was a priority for hybrid rice. Owing to his great efforts, Honglian-type cytoplasmic male sterile (HL-CMS) lines were successfully bred in 1976, and Maxie-type cytoplasmic male sterile (MX-CMS) lines were bred in 1985. HL-CMS was derived from the crossing of wild rice and a cultivar rice, whereas MX-CMS was derived from the crossing of two cultivar rice varieties. From these data, Prof. Zhu suggested that CMS genes were widely spread in rice varieties. Subsequently, his team cloned the HL-CMS gene, *orfH79*, which is located downstream of *atp6* in the mitochondrial genome. They also cloned two fertility-restoration genes, *Rf5* and *Rf6*, for HL-CMS. These genes controlled HL-type rice hybridization with high efficiency. Meanwhile, his team also worked on two-line hybrid rice from 1986, and bred several thermo-sensitive male sterile lines. Many hybrid rice varieties bred by his team have been planted in China, and have also been released to several other countries in south-east Asia and Africa. Until 2021, it was estimated that those hybrid rice combinations have been planted in over 10 million hectares worldwide, and have made great contributions to improving food supply in relatively poor countries. The utilization of various rice hybrids has improved not only the yields of rice, but also the incomes of farmers. Thus, he realized his childhood wish, and the world will remember him for his contributions to food security.

Working as an ordinary teacher at Wuhan University, Prof. Zhu has taught many students in his 58-year career. He was modest, decent and polite, and always instructed his students through his words and deeds. He encouraged them to study new technologies with an open mind, and he wanted them to work hard to serve their motherland. His team has published more than 50 articles and made key contributions to hybrid rice research. He loved his family and his country deeply, and showed great passions for reading books and walking on the rice field banks. In 2015, he began to suffer from myelodysplastic

**Citation:** Hu, J.; Zhu, Y. Brief Biography of Professor Yingguo Zhu. *Agronomy* **2022**, *12*, 858. https:// doi.org/10.3390/agronomy12040858

Academic Editor: Xinghua Wei

Received: 15 March 2022 Accepted: 28 March 2022 Published: 31 March 2022

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syndrome, yet he persisted in working in the laboratory, as well as in the rice field. He finally succumbed to the disease on 9 August 2017, at the relatively young age of 79.

"Struggle and strive until you die" were among the last words he left to his students. As always, he insisted on encouraging people, especially his students, to work hard for food security around the world.

**Author Contributions:** Writing—original draft preparation, J.H.; writing—review and editing, Y.Z. All authors have read and agreed to the published version of the manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.
