David Mackill grew up in San Diego, California, in the 1960s and early ‘70s, enjoying the life of a beach bum and surfer on the nearby Pacific coast. “I spent a lot of time on the waves and quite a bit of time being ‘submerged’ by the waves,” he said, fondly recalling his surfer days. “And, I sometimes thought, ‘it’s too bad there isn’t a career in this.’” Little did he know then, that—using the operational word “submerged”—he indeed would end up in a profession that would ultimately enable him to improve the lives of millions of rice farmers in Asia and beyond!
Father of the SUB1 gene
Flash forward about 40 years to Tilaktajpur (photo right) and Samauta villages in Bihar State situated in northeasternIndia. In this region, vast expanses of rice fields are annually prone to total crop losses due to serious flooding or “submergence” of the plants. When farmers from these areas heard that Dr. Mackill was in India, they invited the former principal scientist and plant breeder for the International Rice Research Institute (IRRI) to visit them in their fields. When he arrived in Samauta village, many hailed him as their “messiah” and the “father” of the SUB1 gene.
These farmers had started growing Swarna-Sub1, a new submergence-tolerant rice variety, during the 2009-10 growing season. They had received the seeds through Rajendra Agricultural University in Pusa, Bihar, under IRRI’s Stress-Tolerant Rice for Poor Farmers in Africa and South Asia (STRASA) project.
During that cropping season, many rice fields around the villages were flooded for 8 to 12 days and the crop failed completely. However, some farmers who had planted Swarna-Sub1 in the same areas and experienced the same submergence were surprised to see the rice plants in their fields rapidly regenerate after the water receded. The farmers harvested 5–6 tons per hectare from their fields and found the new submergence-tolerant rice to have good cooking quality as well. They called it a “miracle variety”—a variety that Dr. Mackill and his colleagues at IRRI were responsible for developing.
Swarna-Sub1 and other submergence-tolerant varieties now being deployed across South and Southeast Asia have been dubbed “scuba rice” and characterized by “Scubie.”
“The farmers also shared their experiences and concerns with me,” Dr. Mackill recalled. “Many of the farmers in Samauta village were excited about growing Swarna-Sub1 in the forthcoming season, which has started in June 2011. I thanked them for their invitation to visit them and promised that their feedback will help in our further research to improve rice.”
Later, upon hearing about Dr. Mackill’s interactions with the Bihar farmers, IRRI Director General Robert Zeigler commented: “The gratitude of the farmers expressed towards Dave is a profound reminder and endorsement of what IRRI is all about.”
Those particular encounters also fulfilled a young surfer’s dream to do something one day that would have a lot of impact and help people. As he planned his university studies back in 1972 to achieve that dream, Dr. Mackill began to look into agriculture and the agricultural sciences. “Coming from a completely nonfarm background, it was new to me, but I found it quite fascinating,” he said.
Rice by chance
He started college at UC San Diego, but then switched to the large agricultural college at UC Davis, the University of California campus just west of the state capital of Sacramento. “I was always interested in genetics, which was one of my best subjects in the biological sciences,” Dr. Mackill said. “Fortuitously, I put genetics and agriculture together and came up with plant breeding. One thing I liked about plant breeding is that it is kind of an art. It is not just confined to analyzing data; you never really know what is going to come out of your efforts.”
During the time he was an undergraduate in college (1972-76), the international agricultural research centers were becoming well known for their work on the hunger problem in the world. IRRI, of course, was at the forefront of the Green Revolution in Asia. So, this came to his attention early on.
“More or less by chance, I ended up getting a job working as an undergraduate in a rice research project involving genetics at UC Davis,” recalled Dr. Mackill. “That was in 1975 and, basically, I have spent my entire career since then working with rice except for a brief stint at the International Crops Research Institute for the Semi-Arid-Tropics (ICRISAT) in India.”
While at UC Davis working on rice, the budding plant breeder got to know some of the people who occasionally visited from IRRI, including Gurdev Khush, future World Food Prize Laureate and IRRI rice breeder and principal scientist, 1967-2001; and Ronnie Coffman, IRRI plant breeder, 1971-81, and currently chair of Cornell University’s Department of Plant Breeding and Genetics, and director of International Programs. Soon, he would be a colleague of both.
“I became aware of a project of the Rockefeller Foundation that gave students fellowships to work overseas at one of the international centers,” said Dr. Mackill. “So, in 1978, Ronnie Coffman helped me set up my thesis research on heat tolerance in rice at IRRI.”
After obtaining his PhD in genetics in 1981, he went job hunting still very interested in agriculture. He got an opportunity to work on sorghum as an international intern at ICRISAT. “I found that dealing with sorghum was quite different from working on rice and I missed IRRI,” he said. “So, about a year later, when IRRI expressed an interest that I come back to the Philippines, I jumped at the opportunity to join IRRI’s Plant Breeding Department as a breeder working on rice improvement for rainfed lowland conditions and the genetics of resistance to rice blast and tolerance for drought, problem soils—and submergence.”
Bringing the Green Revolution to more farmers
His new job at IRRI was to try to bring the Green Revolution to probably more than half of the world’s rice farmers who, as of the early 1980s, had not yet benefited from the new short-statured rice plants. The new varieties were not suited to the field-submergence conditions that prevailed in the densely populated deltas, estuaries, and river valleys of India, Bangladesh, Myanmar, Thailand, Cambodia, Vietnam, and Indonesia. There were other rice farmers in these same countries whose crops suffered due to drought and poor soils as well.
On the submergence front, Dr. Mackill pointed out that scientists had long known that an Indian rice variety, called FR13A, could survive a week or more of complete submergence, but conventional breeding methods were not successful in developing varieties popular with the farmers. So, he and his colleagues at IRRI and UC Davis—during his 1991-2001 stint there—began using marker-assisted selection (MAS) to transfer the FR13A submergence-tolerance trait to modern rice varieties. It turned out to be nearly a 30-year odyssey of ups and downs to achieve what now has farmers like those in Bihar so excited and grateful. The scuba rice saga is aptly told in the 2009 article Scuba rice: stemming the tide in flood-prone Asia.
When the article SUB1A is an ethylene-response-factor-like gene that confers submergence tolerance to rice was published in Nature (442:705-708, 10 August 2006), there was really tremendous excitement among the California and IRRI groups. “I was really pleased that this reflected the basic work that I started at UC Davis with Pamela Ronald and Kenong Xu in the Department of Plant Pathology there, and other colleagues at UC Davis and Riverside,” said Dr. Mackill. “But it also included the work done at IRRI. That paper essentially recorded the development of Swarna-Sub1 and everyone’s contributions. At that time, Swarna-Sub1 was so new that we didn’t know how it would perform. But, since then, it has done rather well as, for example, the Tilaktajpur and Samauta village farmers can attest to.”
Dr. Mackill thinks that, over the last several years, IRRI has been able to push the MAS technology to develop varieties that give farmers a better chance to have a decent crop when their fields are threatened by not only submergence but also other abiotic stresses such as drought and salinity. “These three stresses are the main focus of IRRI’s breeding program and the STRASA project,” he said. “I’m quite pleased that we’ve made really good progress in all of them. Up until a few years ago, there was very little impact from the stress work in terms of actual varieties adopted by farmers. So, seeing tolerant rice varieties now becoming available to farmers in India, Bangladesh, and elsewhere has been really rewarding.”
IRRI researchers haven’t found any single gene like the SUB1 gene that bestows the same level of tolerance for other stresses, but they have, for example, found multiple genes that impart a significant drought tolerance. “By combining several of them,” explained Dr. Mackill, “we can transfer a pretty good degree of multiple stress tolerance, for both submergence and drought, into a given popular variety that is already being used by farmers. Instead of introducing only the SUB1 gene, a variety can now have two or three drought-tolerance genes in it as well.”
Onward to Mars
After nearly 20 years combined over two assignments at IRRI, Dr. Mackill has decided to try something new back home in California. “I don’t know any scientist who has left IRRI previously that can say that he or she went to ‘Mars’ next, but that is where I’ve been since February,” he smiled. “Mars Incorporated is a private company that owns, among many other enterprises, “Uncle Ben’s Rice.”
Dr. Mackill’s principal focus at Mars is to establish a global network of rice researchers, research institutions, and government agencies that can be mobilized to generate groundbreaking new research to support improved rice production and breeding programs. In a press release, Marc Turcan, Mars Food’s vice president of R&D and supply, stated, “David will be the bridge between the company and the scientific community, initiating new research to advance global understanding as well as channeling the world’s leading scientific expertise into Mars, to help us continually improve our sustainability and nutritional performance.”
“I probably am not going to do any breeding myself, but I’ll be working with partners who are based at different institutions,” said Dr. Mackill. “I’ll be looking for others who have an interest and expertise in rice. Mars’s-preferred methodology is to establish partnerships with other organizations. Usually, it is with USDA, a university, or another company. So, I’ll be working on those kinds of projects in the future and I think there are solid opportunities to work with IRRI. At the same time, I am based at UC Davis, where I still have a part-time opportunity to work in academia.”
His future collaboration with IRRI was cemented with the announcement on 1 April that he had been appointed as a consultant to the Plant Breeding, Genetics, and Biotechnology Division at the Institute to assist in planning STRASA’s Phase 2 work as well as to advise the Eastern India Rainfed Lowland Shuttle Breeding Network. The odyssey continues.
Mr. Hettel is the editor-in-chief of Rice Today