On January 20, 2026, Reverend Dr. died at the age of 93. Leo D’Souza, a Jesuit scholar based in Mangaluru. Dr. D’Souza, affectionately known as Fr Leo, trained at the Max Planck Institute for Plant Breeding Research in Cologne in the 1960s, working alongside industry stalwarts such as Ing.
In 1975, he established one of India’s first tissue culture laboratories, where his female-led team of PhD students slowly and steadily made a number of breakthroughs – including the world’s first-ever test-tube cashew tree that was transplanted into soil.
“P. D’Souza was among the early pioneers of plant tissue culture research in India and made significant contributions at a time when the discipline was still in its formative stages,” said Pramod Tandon, a leading plant biotechnologist and Padma Shri awardee.
In 1970, when Leo D’Souza was called back to India after his scientific studies, his PhD advisor Joseph Straub suggested that he meet his friend to guide him on a suitable research topic. The friend turned out to be MS Swaminathan, who was in New Delhi at the time. When Dr. Swaminathan discovered that the young priest’s hometown was Mangalore, he recommended Anacardium occidentale, the cashew nut plant, as a research topic.
Tissue culture
The cashew tree is not native to India. It was brought to the coastal area by the Portuguese from Brazil in the 16th century to prevent erosion of the laterite soil found there. Once people recognized the commercial value of its nuts and fruits, it proved to be an important cash crop. By the 1980sCashew was grown on nearly 5,000,000 ha of land in the country, although net production remained well below what was optimal for the processing industry.
Article noted in a 1982 issue of Manushi magazine that women constituted more than 80% of the workers employed in the cashew industry. They were usually illiterate and commonly underpaid. P. Leo personally visited many cashew processing plants in and around Mangalore and was impressed by the plight of workers and small farmers in cashew plantations. He realized that relying on seed propagation, grafting and cuttings was not enough and that the solution might be tissue culture – a relatively new technology in which he was an expert. He embarked on a mission to develop high yielding cashew varieties to benefit these sections of society.
Photograph from the P. Leo collection showing women working in a cashew processing factory. | Photo credit: Special arrangement
At that time there was already a cashew research station at Ullal, near Mangalore, but Fr Leo was told that the scientists assigned there were desperate to be relocated as they were not used to the intense rains and high humidity of the seaside town. Dr. Swaminathan also believed that as a Jesuit priest unfettered by aspirations for promotion and transfer, Fr. Leo was uniquely positioned to do justice to this overlooked area of research.
Convinced, Fr. Leo founded his Laboratory of Applied Biology at the Jesuit College of St. Joseph’s College in Bangalore. It was almost a decade before the Department of Biotechnology (DBT) was established. Five years later, however, he was appointed director of another Jesuit college, St. Aloysius in Mangalore. While Mangalore was his hometown and St Aloysius was where he did all his schooling, he dreaded the idea of sidelining research for administration. Fortunately, there was a room available for him to move his lab to.
His lab has been operating there ever since, and today it is headed by his former PhD student Shashikiran Nivas.
Top of his mind
Although a reluctant headmaster, Fr Leo managed the college efficiently. Right from the beginning, he advocated for the inclusion of women in the college, which had been exclusively for boys since its foundation in 1880. Not only did he have to convince skeptical management and staff, but he also had to ensure that the college’s infrastructure adequately served the needs of this new demographic. In 1986, the school finally began admitting women; today they make up more than 50% of the staff and students there.
Of the many responsibilities he undertook during his career, one in particular was close to his heart: the establishment and operation of the Aloysians Home for Boys, a rehabilitation center and home for abandoned, traumatized and orphaned children, many of whom were in prison. He was proud of the lives the boys who grew up there built.
In one of his essays, he wrote about how driving a bus was a dream for many boys and how he was encouraged that so many of them fulfilled it by becoming bus drivers in Mangalore. He recalled another example of a former home resident named Nelson who completed a vocational training course and secured a position as an air conditioning and refrigeration training officer at a technical institute.
Although he struggled with administrative problems and was involved in many other activities, his laboratory was always at the top of P. Leo’s mind. He received approval from Mangalore University to start a PhD program, which was (and remains) an unconventional and remarkable achievement for a college of higher education. His first PhD student was a young woman from a village in Kundapura, Udupi district, named Icy D’Silva.
Together, they began attempts to grow cashew tissue culture plants that would allow the trees to be rapidly propagated on a large scale.
From the laboratory to the soil
Conventional breeding techniques such as seed propagation and cross-breeding can help improve plant varieties and yield, but are time-consuming and difficult to maintain quality. On the other hand, tissue culture, or micropropagation, allows the development of an entire cashew plant from a small sample of tissue. Controlled conditions in the laboratory allow mass use of this technique with the guarantee that the resulting plants will be genetically identical to the original plant.
Several scientists in tropical countries, including India, have attempted to revolutionize the cashew industry with a reliable tissue culture protocol, but this has proven extremely difficult. Compared to related species such as mango and pistachio, cashew is resistant to tissue culture, probably because it releases phenolic compounds into the culture medium and eventually kills the developing cells. In the few cases where researchers have succeeded in creating plantlets in the laboratory, the plants die soon after being transferred to soil.
It took almost 10 years, but in 1990, under the guidance of Don Leo, D’Silva accomplished her goal. In an article published in a journal Plant cell, tissue and organ culture in 1992, the couple described how they created cashew plantlets, successfully transplanted them into soil, and established them in a field.
One of P. Leo’s regrets was that he could not secure the cooperation of the scientists at the Ullal Cashew Nut Research Station in continuing the work. He believed that this led to science fulfilling its potential with regard to the improvement of cashews as well as the livelihoods of the people who grew and processed them.
Although P. Leo taught at St. Joseph’s College in Bengaluru for a relatively short time, his students still remember him. | Photo credit: Special arrangement
‘International quality’
Over the years, the laboratory of P. Leo also he did an important job with coconuts, ferns, algae, ragi and ornamental and medicinal plants. In addition to cashew, the team succeeded in micropropagating a number of other trees. Part of P. Leo’s legacy is the avenue of tissue trees growing on today’s St. Aloysius (now considered a university).
Many of his students have gone on to do research in academia and industry, both in India and abroad. One of them is Smitha Hegde, a leading pteridologist (pteridology is the science of ferns) and currently Director of Research at the Center for Advanced Education in Mangaluru. Dr. Hegde pointed out that Fr Leo provided every opportunity for his students to present and share their work at foreign conferences. She herself was given the opportunity to present her work on ferns at the Royal Botanic Gardens, Kew in 1995.
“These experiences helped us to realize that our work has an international quality.” She fondly recalled their small group of researchers wandering around campus feeling like “little Einsteins.”
Dr. Hegde also recalled that Fr Leo was a champion of women’s empowerment.
“If he saw only men on stage, even for a simple function, he would ask ‘where is the representation of the woman?’ Not only did he want women to get a chance to work, he was also very happy to make our work visible,” she said.
Used to explaining himself
Although he taught at St. Joseph’s College in Bengaluru for a relatively short time, his students still remember him. Notable among them is Jyotsna Dhawan, a leading cell biologist and Scientist Emeritus at the CSIR-Centre for Cellular and Molecular Biology in Hyderabad.
“It strikes me now that there was no dichotomy in his teaching of a scientific discipline rooted in the principles of evolutionary theory and his identity as a man of the cloth,” she wrote to this reporter upon learning of P. Leo’s death. “Along with Fra Cecil Saldanha, these. Jesuit botanists He gave us a solid foundation in plant science, for which I am forever grateful.”
Reconciling these two identities came effortlessly to Fr. Leo, but he constantly encountered raised eyebrows along the way.
“People stared at me when I first entered the Max Planck Institute in Cologne,” he told this reporter in an interview a few months before he died. “I thought they were staring at my brown skin, but it was my clerk’s collar.
So Don Leo was used to explaining himself.
“A priest should not only work in the church. His work must have value for other people, especially the poor,” he confirmed in the same interview.
When one of his colleagues in Germany asked him why he did not stick to the altar and the pulpit, Fr. Leo replied: “If Gregor Mendel (an Austrian monk, often known as the father of genetics) had followed this principle, then the scientific world would have lost an important scientist who discovered the basics of genetics and plant breeding.”
Nandita Jayaraj is a freelance science journalist and co-founder of the feminist science media project Labhopping.
