ICE | The Israel Chemist and Engineer

The Israel Chemist and Chemical Engineer Issue 5 • November 2019 • Cheshvan 5780 29 History of Chemistry Articles experiments. I was tempted to hope that within this field of the new science I might find an opportunity ‘to satisfy my desire to do, as well as to learn.’ ’’ [1] Salaman became interested in genetics under the guidance of his friend William Bateson, founder of the science of Mendelian genetics. Bateson coined the term genetics in 1905. In 1906, Salaman started the first scientific breeding of potatoes along Mendelian lines. In 1908, he discovered what he called “genuine resistance” to late blight in the potato. He was the first to introduce the resistance of the wild potato Solanum demissum into the domesticated plant. All of the genetics work was carried privately in his garden at Barley. Salaman continued his “campaign against blight” at Barley until 1926, at which time the stocks were transferred to the newly founded Potato Virus Research Institute at Cambridge.The Institute was established at his initiative; he became its founding director and held the position until retirement in 1939. The results of Salaman’s work at Barley were published in a book in 1926, Potato Varieties . Salaman held the Chairmanship of the Potato SynonymCommittee from 1920, set up by the Royal Horticultural Society, later taken over by the National Institute of Agricultural Botany.The establishment of the committee was made essential by the need to test potato varieties for resistance to Wart Disease, which required clearing up the confusion existing among the names of the varieties. Together with this, another possible reason for the committee was the need for high yields from home-grown crops during WWI - which required clarity in the seed trade for the farmer. Salaman’s book lists about 500 distinct varieties grown in Britain and gives histories and descriptions of 89 varieties which were in general cultivation. The state of confusion in names can be appreciated by noting that the variety Up-to-Date had over 200 aliases or synonyms. Oddly enough, the overall confusion in the names of potato varieties played a key role in Salaman’s discovery of “genuine resistance” to blight, discussed later in this article. In 1949, Salaman published the monumental work The History and Social Influence of the Potato covering the history of the potato and its social implications [1, 2, 3]. During World War I, Salaman saw service in England from 1914 till 1917, at which time he volunteered and served in Egypt and Palestine as Medical Officer to the 38th and later the 39th Jewish Battalion of the Royal Fusiliers [4, 5, 6, 7, 8, 9]. The potato ( Solanum tuberosum ) Domestication of potatoes started about 9,000 years ago in the Andean region in what is today Bolivia and Peru, probably first by selection of tubers from natural variation and then later with further refinement by farmer selection and propagation. In the sixteenth century, the Spanish conquistadors brought potatoes back to Europe from the NewWorld. It was first used as food for the sailors on their journey home — sailors who ate potatoes did not get scurvy. It took another 200 years for the potato to take hold as a food source in Europe [10]. Salaman: “Although the potato, owing to its scanty pollen, its frequent sterility, and its delicate flower, is not an ideal subject for Mendelian research, it does offer to the experimentalist one redeeming character. An individual plant can always be ‘carried on’ by means of its tubers into the next season’s work, and whether it be for the sake of comparison or for the purposes of further fertilization this property is of the utmost service.” [11] Potato crops are usually grown by vegetative propagation. A small piece of a potato or sometimes a whole potato (called the seed potato ) containing at least one eye (a tuber bud) is planted. The next crop of potato is thus genetically identical to the potato chosen for propagation. The good traits of the selected potato are passed along to the next crop, which would not be the case if grown from seeds. On the other hand, growing crops by vegetative propagation results in genetic uniformity making the crop more susceptible to disease. Potato blight, Phytophthora infestans The causal agent of potato blight is the oomycete Phytophthora infestans , a fungus-like plant pathogen with a filamentous growth habit. Its name is derived from the Greek, meaning plant-decay (phyto-phthora) and the Latin, meaning to damage, to make unsafe (from the verb infestare). P. infestans is one of themost feared of plant pathogens. It has caused great death and destruction and continues today its ruthless devastation. The estimated annual loss of potatoes due to late blight could feed from 81 to 1,250 million people. Blight is responsible globally for 16% loss of potato yield. The pathogen is also destructive to the tomato and can attack other members of the Solanaceae plant family. Turner: “Readers familiar with the disease will know that late blight has re-emerged since the early 1990’s as a formidable threat to world agriculture, making the history of scientific efforts to cope with the disease, like the history of the disease itself, a matter of unexpected significance.”The title of a 2015 report by W. E. Fry et al . warns of the ongoing threat, Five reasons to consider Phytophthora infestans a reemerging pathogen [8, 12, 13, 14, 15]. The pathogen was listed by the Ad Hoc Group of the Biological Weapons Convention as a potential warfare agent. The French in 1939 discussed its use to attack German potato crops and in the 1950’s the Americans studied it as a strategic biological weapon [16].