Rit Landbúnaðardeildar : A-flokkur - 01.10.1954, Blaðsíða 23

21
Mælt var sterkju- og þurrefnismagn afbrigðanna, og reyndust
mönd'ukartöflurnar vera beztar. Væri hins vegar reiknað sterkju- og
þurrefnismagn af hektara, gaf Sequoia mesta uppskeru, en Kennebec
nokkru minni.
Frostþol kartaflna var skráð haustið 1952, þegar lítils háttar frost
hafði fellt grös sumra afbrigðanna. Rejmdust afbrigðin Eyvindur, Sequoia,
Rauðar íslenzkar og Furore vera þolnastar, en Red Warba þolminnst.
Að lokum er bent á nokkur afbrigði sem góðar matarkartöflur og mælt
með afbrigðunum Sequoia og Kennebec til ræklunar í stórum stíl.
Summary.
During the years from 1948 to 1953 inclusive comparative trials with 142
potato varieties were performed at the University Research Station near Reykjavík,
in order to find a more productive variety suitable for the harsh climatic conditions
of Iceland.
A good deal of the material for study was kindly donated by Statens Frökon-
trollanstalt, Stockholm, Sweden, and these given the trial numbers 1 to 92. Varieties
obtained from F. H. Woodruff & Sons, Inc., Milford, Conn., U. S. A. were given nos.
93 to 97 and those kindly supplied by U.S.D.A., Beltsville, Maryland, U.S.A., got
the trial numbers 98 to 133. Numbers 135 to 137 were brought back from Tierra del
Fuego by the author in 1950, but the rest of the varieties had been cultivated in
Iceland for some time and were either obtained from local growers or the state
market.
The varieties were arranged in randomized blocks, checked and weighed.
Cold and comparatively dry growing periods had great effect on decreasing the
yield of all varieties as can be seen by comparison of tables 1 and 2, the crops of the
cold and dry years of 1951 and 1952 being by far the poorest. Analysis of variance
of the yield was calculated for each separate year and the varieties compared to Iíerrs
Pink, no. 10, which is a common variety in the country. In table 2 the significantly
better yiekls than that of Kerrs Pink are printed in italics. In order to find out
Avhich varieties were significantly better than Kerrs Pink during several years, the
yields of the 27 best varieties from 1950 to 1953 were analysed, the last steps in this
calculation being given in table 3. The mean squares of the varieties being higher than
those of years times varieties indicates that some varieties are better yielders than others
in all years. Compared to Kerrs Pink the varieties Kennebec, no. 120, and Sequoia,
no. 131, were significantly better at the 1% level.
In the last column of table 2 are given figures of % small potatoes, i. e. those
that fall through 3 cm2 mesh. Here again Sequoia and Kennebec are low, having their
tubers of quite an even size.
The amount of starch was then measured by a Z. W. G. starch scale and dry
matter content found after drying in oven at 80° C for 24 hours. The resultant figures
given in table 4 show a high correlation between the measurements as would be
expected. The average starcli content was 13.4% and dry matter 19.2%, with the
lowest and highest figures for starch respectively 9.9% in Konsuragis, no. 49 and
21.2% in no. 87. As the great diversity in starch content highly affects the total
nutritive value of the crop, starch and dry matter production of each variety per hectare
was calculated. The 17 best yielding varieties are shown in table 5, Sequoia still
ranking highest with Kennebec second in rate.