740 EXPERIMENT STATION RECORD. [Vol.43 



to the determination of the most productive size of seed piece and the best 

 spacing within tlie row. The observations may be summarized as follows : 



Plants from whole tubers sprouted and emerged more quickly than those 

 from cut tubers, and sets from whole potatoes produced a more luxuriant vine 

 growth than cut tuber sets, the plant vigor increasing in proportion to the size 

 of the set. The average loss of stand ranged from less than 1 per cent for 

 whole and halved tubers to 12 per cent with quartered tubers. The number of 

 stalks per hill increased directly as the size of the set increased. It was noted 

 that the earlier sprouting bud-eye of the Idaho Rural potato did not grow to 

 the exclusion of the growth of the other eyes. 



Although whole tubers produced 1.1.4 per cent greater total yield than cut 

 seed, the cut tubers yielded 18 per cent more marketable potatoes per aci'e, 

 the percentage of marketable stock increasing as the size of set decreased. The 

 larger sets produced greater numbers of tubers but with a smaller average 

 weight per tuber. When yield and amount of seed used were considered, the 

 o oz.-halved and 4 oz. -quartered seed rendered the most economical returns. 



Results of spacing studies indicated that the largest percentage of marketable 

 tubers, together witli the greatest weight per tuber, were obtained from the 

 greater distances between hills in the row. On good alfalfa land, plantings 

 from 24 to 28 in. in the row gave the best yields, while spacing 16 in. or less 

 did not prove to be economical. On the other hand, the most profitable yields 

 for seed-stock purposes were obtained from 8 to 12 in. spacing in the row, as 

 the close plantings reduced the size of the tubers and produced large numbers 

 of potatoes of seed size. The main essentials in seed-stock selection are held 

 to be health and trueness to type and variety, regai-dless of whether grown on 

 irrigated or dry land. 



Late-planted potatoes produce good seed, .1. B. Keil (Mo. Bui. Ohio Sta., 

 5 (1920), No. 6, p. 119). — The practice of planting potatoes during the last week 

 in June is recommended, as the plants set tubers early in September or October, 

 generally receive more rainfall, return higher yields, and produce more seed of 

 good vitality than early potatoes which set their crop in August. Seed for this 

 planting is frequently prepared by sun-sprouting, a procedure consisting essen- 

 tially of removing the long sprouts from the stored potatoes and spreading the 

 tubers out on a floor exposed to light until planting time. It is said that only 

 small green sprouts develop under this treatment, and that the potatoes grow 

 very rapidly after planting. 



Growing late potatoes, J. T. Rosa, .tr. {Missouri Sta. Circ. 95 {1920), pp. 

 Jf). — Brief popular instructions on the culture of the fall crop in Missouri, 

 including notes on seed, preparation of land, and pests. 



HORTICULTURE. 



[Report of the horticulturist], F. J. Cuider {Arizona Sta. Rpt. 1918, pp. 

 303-310, 311-313). — The condition of the date orchards at Tempe and Yuma is 

 briefly noted and varietal yields for the 1917 season ai'e tabulated. Studies in 

 the culture and management of date orchards and of cultural methods with 

 citrus fruits here outlined were begun in 1918. 



The method of propagating dates in a propagating house covered with canvas 

 and with no ventilation (E. S. R., 36, p. 142) gave poor results in 1917, but was 

 giving much better results in 1918 than propagation in the open after the propa- 

 gating house had been removed from a location where the soil is heavy and 

 poorly drained to a location where the soil is sandy and well drained. A careful 

 examination in the latter part of November showed that out of 237 offshoots 

 placed in the house, only 37 failed to show evidence of growth. Several indi- 



