STUDIES ON THE EXTENSION OE THE GRAZING SEASON I.

Plots were sown broadcast with ryegrass, cocksfoot or timothy and were strip-grazed at various times during three successive winters by store cattle maintained almost entirely on foggage. In the first winter the plots were rested from 2 September. Each was sampled when required for grazing and the mean organic-matter yield was 2020 Ib. per acre containing 17.5% crude protein. In the two following years, when rested from 15 July and 10 August, November yields were 4340 Ib. (11.8% crude protein) and 3003 Ib. (16.0% crude protein), respectively. Ryegrass yields were 15–30% higher than timothy and 25–50% higher than cocksfoot. Losses during winter due to rotting were related to botanical characteristics and were 40% for ryegrass, 30% for timothy and 10–20% for cocksfoot. Cocksfoot was the most suitable for winter-grazing since it had the highest stock-carrying capacity at all times. This was due mainly to high consumption of ryegrass and timothy, not affecting live-weights, and increasingly poor utilization of the ryegrass produced. It is emphasized that grazing animals should be used when evaluating pastures. Foggage production is considered as a method of herbage conservation and in relation to whole-year pasture output.     

INTERNATIONAL EXCHANGE OF HERBAGE SEEDS AND THE O.E.C.D. HERBAGE SEED SCHEME

The use of the correct variety has an important influence on the economic use of sown grassland. The production of seed must be done in such a way that the essential characters of varieties are preserved. The O.E.C.D. Herbage Seed Scheme provides a sound basis for seed production, and has made possible the wider exploitation of good seed growing areas. The technical basis for some of the rules is discussed. It is concluded that in the 8 years in which the Scheme has been operating there has been a significant change in the pattern of seed use with a greater emphasis on the better varieties.     

PANICLE DEVELOPMENT AND PLANT VIGOUR IN DACTYLIS GLOMERATA L. IN RELATION TO DATE OF SOWING AND PLANTING

Cocksfoot sown late in summer or early in autumn to provide a seed crop the following year generally produces a disappointing yield. The experiments described were set up to study this problem. Seeds of four varieties, American, Danish and two British cocksfoots, were sown at fortnightly intervals during the spring and summer of 1956. The sowings were repeated in 1957 with the addition of Potomac, a bred variety from USA, and an ecotype from Israel.
Plants sown after mid-May showed a diminishing capacity to produce panicles the following summer. The last sowing in 1957 caused the weight of green hay per plant in 1958 to be at least 50% below that of the spring-sown plants, and panicle number to drop 60–80%. Sowing after mid-May affected panicle development in the autumn and in the following hay crop. Date of sowing had no effect on mean date of panicle emergence in the following summer. In the populations as a whole, neither the presence nor the number of panicles in the first autumn was related to productivity in the hay stand.     

大豆抗感病毒病品种过氧化物酶同工酶的初步比较研究

利用垂直板聚丙烯酰胺凝胶电脉研究了10个抗、感病毒病(SMV)大豆品种和5个品种各自健株与病株过氧化物酶同工酶的变化。结果表明,感病品种比抗病品种的过氧化物酶同工酶活性明显加强,且增加一条酶带。同一品种病株也比健株过氧化物酶同工酶活性强。可见,大豆抗、感病毒病不同的品种与过氧化物酶同工酶有密切关系。     

高异黄酮含量大豆新品种中豆27

大豆新品种中豆27（原名中作91K12）是中国农业科学院作物育种栽培研究所利用高产，抗花叶病毒病品种中豆19号作母本，美国引进材料威廉姆斯（Williams)的近等基因系P.I.L81-4590作父本进行有性杂交，采用高效液相色谱（HPLC）技术，对杂种后代的异黄酮含量进行检测及多年辅助选择育成，其突出特点为抗癌物质（异黄酮）含量高，高产，优质（蛋白质，脂肪双高），抗病，综合性状优异，并对中豆27的栽培技术进行了探讨。