PIvANT BREEDING 965 



magnesium and residual magnesium on the other, it is found that the 

 absolute weight of organic magnesium increases from April to May in 

 chestnut and lilac leaves. The maximum is reached on the 4th May in the 

 former case, and on the 3rd in the latter. Beyond those dates this weight 

 decreases almost regularly. With regard to the leaves of the chestnut tree 

 the maximum weight of magnesium is reached on the 26th April. Taking 

 on the other hand the ratio between the weights of organic and those of 

 residual magnesium, this ratio is found to reach its maximum on the 26th 

 ^lay in the leaves of the horse-chestnut, on the 3rd May in those of the 

 lilac, and not until the 14th June in those of the common chestnut. As- 

 suming that the time when this ratio reaches its maximum corresponds, at 

 any rate in the year under consideration, to the maximum activity of 

 a.ssimilation, it must be concluded that this process is most active during 

 I he whole of May in the horse-chestnut, at the beginning of May in the li- 

 lac, and between the end of May and the middle of June in the ordinary 



chestnut. On the other hand, on comparing the and 



residual phosphonis 



organic magnesium .■ r . 4. -u j. .1.1 • r -1 



—- — , T— a satisfactory agreement between the maxima of these 



residual magnesium -^ '^ 



two ratios is found in the horse-chestnut leaves. Although this agreement 

 is less marked in the other two species of leaves studied, it is reasonable 

 to assume that the maximum of vegetative activity is at the same time 

 manifested by the elaboration of carbohydrates and the concurrent pro- 

 duction of the organo-phosphoric compounds the existence of which is 

 unquestionably bound up with the chlorophyll synthesis. 



These experiments should be resumed subsequently on other plant 

 species. 



746 - Comparative Tests of 4 Varieties of Barley at Torestorp, Sweden. — hjalmar von plant 



Feilitzen, in Svenska Mosskultur/dn-ni7i:^s Tuiskriii XXXth Year ; No. i, pp. 57-60. BREEDING 



Jonkoping, 191 6. 



Tests covering a period of 6 years (1009 to 1914) at the Station of 

 Torestorp. Manure : superphosphate, 178 lb per acre (in the last years 267 

 lb.), potash salts of 37 % strength 178 (267) lb. per acre. The varieties test- 

 ed were always sown at the same time, the time of sowing varying from the 

 7th to the 15th May in different years. The crops were more or less damag- 

 ed by spring frosts. This was the case in 1909 and 1913. In 1910 the 

 r)-rowed barley, an early variety, was the otdy one to suffer from the low- 

 temperatures. 



As appears from the Table, the annual fluctuations of yield are very 

 great. The best results were in 1911. In that year the " Svanhals " variety 

 .2;a ve a yield of about 23 cwt. per acre. The same was the case in 1914, 

 in which year the 6-rowed barley furnished a yield of about 23 14 cwt. per 

 acre. The worst years were 1909 and 1913, with yields of 31 cwt. and 24 

 cwt., owing to the spring frosts which in those regions form the most f re- 

 fluent weather fealure, and the f)ne which does nicest injur}- to the coreaj 

 in. question. 



As regards the yield (if grain, tlic " IMymage " variety furnishes the 



