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Reference -
wwC.O.882/12
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PUBLIC RACORD OFFICE, LONDON
ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC-
COPYRIGHT PHOTOGRAPH-NOT TO
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F. S. Earle, a well-known authority on the varieties, cultivation and diseases of sugar-cane, has made the following statement concerning White Tanna (under the synonym Yellow Caledonia ") in his book Sugar Cane and its Cultivation published in 1928.
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"Ten years ago the planting of this cane was probably being extended more rapidly in all parts of the world than that of any other variety. To-day it is every- where losing ground, being crowded out by better sucrose canes, notably by H. 109 in Hawaii and by B.H. 10 (12) and S.C. 12/4 in the West Indies. It is quite im- probable that it will ever again become as popular as in the past."
This statement is subject to the qualification that Yellow Caledonia is still the dominant variety grown under direct rainfall in the Hawaiian Islands, H. 109 having displaced it on irrigated lands. The choice of varieties in those Islands was restricted, however, by a total exclusion of all foreign kinds for some 20 years and reintroduction has begun only recently under very strict quarantine conditions. The policy of exclusion doubtless kept out Gumming Disease (to which H. 109 is quite susceptible), Leaf Scald, Sereh, Fiji Disease, and Leaf Stripe (Downy Mildew).
M.P. 131. This dark purple, rather slender cane is one of the very few survivors of the many seedlings raised by Perromat in the early 'Nineties. It occupied about 8 per cent. of the total area of estate cane in 1925, rather more than it did in 1915. It is a mid-season kind, resistant to dry weather and to Gumming Disease, Leaf Scald, and Red Rot, but not a high yielder. It was introduced into Australia about 1900 as Innes 131" where it has been recognised as highly resistant to Leaf Scald and moderately resistant to Gumming Disease. Smut is liable to attack the young growth in dry localities during dry weather.
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M.P. 55. This is a dark purple, thick-stalked Perromat seedling. It is a mid-season, high sucrose, and heavy yielding kind. The secondary leaf stripe infections of Gumming Disease are frequently noticeable on the standing cane, but appreciable stem infections (ooze of gum) are rare. It appears to be highly resistant to Leaf Scald and Red Rot, but is rather unreliable, being subject to Root Disease and occupied about 8 per cent. of the estate area in 1925 as against 14 per cent. in 1915.
D.K. 74. This Demerara seedling (D. 74) was introduced from Barbados in 1905. It is an early, high sucrose, and high yielding cane, resistant to Gumming Disease and Leaf Scald, but quite susceptible to Red Rot as it matures. Unless cut early the tonnage reaped may fall considerably short of the estimate owing to the amount of dead cane left in the field. Owing to partial inversion of the sucrose, It is also the most the reaped infected cane is liable to give an inferior juice. susceptible to Smut of all the varieties in general cultivation. It occupied about 9 per cent. of the estate area in 1925 as against 5 per cent. in 1915. An early maturing, high sucrose, good ratooning seedling is needed to replace this variety. In the two drier northern lowland districts, where the diversity of varieties is greater, D. 130, introduced in 1901, dominated (18 per cent. of the estate area) in 1915 the four kinds mentioned, while in 1925, D. 109, introduced by the Depart- ment in 1914, took the first place (15 per cent. of the estate area).
The interest in new varieties.
In the course of my tour of the estates I was much impressed by evidence of the renewed interest everywhere in a number of the more recently introduced and locally produced seedlings, which the Department, after repeated careful plot tests, had been able to recommend for more extended trials on the estates. Even on estates where the great bulk of the cultivation is in White Tanna, trial plots of many of these seedlings have been started during the last two years. The low price of sugar and the marked increase in output effected during recent years in Java by means of the newer seedlings raised there (E.K. 28 followed by the new P.O.J. kinds, especially P.O.J. 2878) without any appreciable increase in acreage planted or in factory extraction, have doubtless been the two main factors in arousing this interest in Mauritius which shared the Indian market for so many years with Java. In 1927 a Sugar Industry Conference was held and an added stimulus was given to the interest aroused by an address before the "Société des Chimistes July, by the then Director of Agriculture, summarizing the results of the work with seedling canes since the Department's inception in 1913 (published in the Revue Agricole No. 37, 1927); and by his address to the " Chambre d'Agriculture in December, presenting the results of the surveys of the incidence of diseases in
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1925-27; a Standing Committee of the Technical Conference was appointed by Government in 1928, which has received reports from sub-committees of which the Director is Chairman, on these and kindred subjects.
The earlier plot trials of new canes on the estates, carried on in conjunction with trials at the Department's own stations at Pamplemousse and Reduit, havo-- suffered somewhat in reliability from the fact that they were not wholly under the control of the Department. This difficulty has been remedied now by the acquiring of land on a number of estates where the trials are fully under the control of the Department. These sections have been located in several instances adjacent to main roads so that they serve also as demonstration plots of seedlings both under trial and those which can be definitely recommended, on the basis of past trials, for extended estate planting. Many of the estates have, in addition set out their own plots with recommended seedlings and with newer seedlings selected from the Department's plots at Pamplemousse and Reduit; it is hoped in this way to pick out sooner those which appear to suit local conditions. It is desirable, however, that the Department release only seedlings for planters' trials which have shown satisfactory resistance to Gumming Disease, Leaf Scald, and Red Rot. New seedlings also are like foreign introductions; they have to adapt themselves and may show to advantage only after several years of trial, and so may run the risk of being rejected too soon.
Of recent years, the two seedlings R.P. 8 and R.P. 6, produced at Providence Estate, British Guiana, and introduced by the Department in 1915 and tested and recommended by it, have grown in favour. R.P. 8 is proving a promising disease- resistant cane in the low country and at medium elevations. It is the only existing variety which shows occasional symptoms of Streak. There is no evidence of secondary transmission (the South African vector Balclutha nobila has not been found in Mauritius), all cases being apparently due to sett infection, which makes eradication a simple matter of taking out infected stools. In the experiments at Reduit with three successive crops grown from diseased and healthy setts, the stools from the diseased setts were always fully infected while those from un- infected setts were uniformly healthy, indicating no transmission. The diseased mature canes were stunted and showed a reduction of 30-40 per cent. in tonnage and a reduction of sucrose in the juice. Streak has not been detected on Uba cane in the Island.
R.P. 6. is promising well in the up country, being resistant to Gumming Disease and Leaf Scald, but of lower resistance to Red Rot. I saw the same dis- coloration adjacent to the pith in some instances which occurs in White Tanna. It is low in fibre and cannot, on that account, form a high proportion of the crop.
B.H. 10 (12) was introduced by the Department in 1920, and, after trial, recommended for estate cultivation. It is highly resistant to Gumming Disease and has remained hitherto free from Leaf Scald. At Labourdonnais in the northern lowlands with a rainfall of 50-60 inches, this cane is receiving a thorough trial in test plots with White Tanna, R.P. 8, D. 109, and the local seedling M. 2316. The plots are well laid out (ten rows of each variety repeated three times on uniform land), and may well serve as a model for estate trials. It has done well and there has been a keen demand for setts by other estates. This seedling has such a high reputation in the West Indies (Earle considers it one of the best seedlings ever produced) that it is sure to do well in many localities in Mauritius wherever the top soil is fairly deep and fertile. It is not a cane for shallow and poor lands.
P.O.J. 213 was introduced by the Department from Java in 1914 and again in 1915. It has shown itself highly resistant to diseases and is undergoing extended field trials on the estates both in the lowlands and uplands. It frequently yields better as ratoons than as virgins, but being a relatively thin variety costs rather more than the thicker canes to cut and transport.
In addition to the introduced seedlings, a number of seedlings produced by the Department during and since 1916 and now well tested and recommended, are being grown widely in trial plots on the estates, and some have already gone into field cultivation; among these M. 2316, M. 2716, and M. 2916 may be mentioned as especially promising. The local seedling 55/1182 has also gone into field cultiva tion but is showing such marked susceptibility to Gumming Disease that further planting cannot be advised.
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