232 EXPEEIMENT STATION RECOED. [Vol.35 



Sweet potato culture for the southern planter, C. Ckow and C. W. Waughtel 

 (Seville, Ga.: Crotc d Brogdon, 1915, pp. 103, pis. 12, fig. 1).—A popular treatise 

 on sweet potato culture, including descriptions of the various phases of the 

 worlj and devoting a chapter to commercial sweet potato plant growing in 

 Florida. 



Timothy: Its history, culture, and variability, and breeding work carried 

 on with the plant at Svalof, H. Witte {Sveriges Vtsddesfdr. Tidskr., 25 {1915), 

 Nos. 1, pp. 23-U; 4< PP- U3-182; 5, pp. 199-221, figs. 26).— This article pre- 

 sents historical and cultural notes regarding timothy, reviews breeding work 

 with the plant carried on in different countries, discusses its different forms, 

 describes the technique and the method employed at Svalof in breeding peren- 

 nial grasses, particularly timothy, and reports results secured together with 

 deductions drawn from them. It is pointed out that since timothy is cross- 

 fertilized and is also very variable, it is impracticable to base its improve- 

 ment on the selection of homozygous individuals. 



In the breeding work it was found that in length of stem the plants varied 

 from 20 cm. to over 100 cm. The heritability of the length of stem was indi- 

 cated by the experimental results. The number of internodes varied only from 

 5 to 7 but in length the internodes showed great variations. In some forms 

 the upper internode constituted more than half and in others only one-fourth 

 of the stem length. The lower internodes were quite short in some cases and 

 in others comparatively long. The thickness of stem varied for the different 

 forms but no correlation with the length of stem was established. The shape 

 or form of the stem was found to vary to a considerable extent and appeared 

 to be a heritable character. 



Most forms showed a habit of stooling densely, but some stooled quite loosely 

 due to the development of culms from the leaf axils of the preceding generation 

 of sprouts. The leaves varied in length and width and also in shape, some 

 forms having soft and pendant blades while in others the blades were stiff and 

 erect. 



The spike in the different strains ranged in length from about 2 to 15 cm. 

 and in thickness from approximately 4 to 10 mm. Correlation between length 

 and width of spike and between length of spike and stem was not established. 

 The spike was generally cylindrical but forms with the greatest diameter either 

 at the ba.se, the point, or the middle were found. In some forms the spike was 

 loose and pendant, while in most cases it was stiff and erect with the spikelets 

 densely set. The spikelets in certain strains were not entirely united with 

 the central axis of the spike, which gave to the head a rough or minutely 

 , branched appearance. This also proved to be a heritable character, but the 

 author points out that from a practical standpoint the length and density of 

 the spike are mainly of value. 



The floral parts and the fruit also presented many variations. At Svalof 

 no differences in winter resistance were observed but in the extreme northern 

 part of Sweden marked differences in this respect were found to exist. 

 Variations were also determined in regard to sprouting, time of blossoming, 

 strength of culm, time of withering of leaves, quantity and quality of second 

 growth, rust and drought resistance, and the length of the period of productive- 

 ness. The degree of adherence of the glumes to the ripe seed varied with the 

 different forms and the practical bearing of this character is dwelt upon. The 

 characters of strains of timothy requisite for profitable temporary and perma- 

 nent meadows, and for satisfactory seed and forage production, are enumerated. 



The results of tests with new strains of timothy showed that No. 237a, or 

 Primus, produced a yield 16.7 per cent greater than commercial sorts, while 

 No. 217 yielded 6.7 per cent more than Primus. 



