SILAGE AND MILK PRODUCTION. A COMPARISON BETWEEN A DIPLOID AND A TETRAPLOID RYEGRASS

Two grass silages made in May and two made in August were compared in a 16-week winter-feediag experiment with 12 Ayrshire cows. The silages were fed ad lib. with a supplement of barley and groundnut cake. One of the silages made ia May and one made in August consisted of S24, a diploid variety of perennial ryegrass, and the other two of Reveille, a tetraploid variety of the same species. The silages made from Reveille had a higher content of lactic acid and a lower pH than those made from S24. The contents of digestihie organic matter in the silage DM made in May and August were 71.9 and 63.2%, respectively, for RevelUe and 68.7 and 60.9% for S24. Silage and total DM intakes were higher in the treatments where Reveille silages rather than S24 silages were fed. The mean daily milk yields from cows fed on the silages made in May and August were 39.6 and 34.5 lb (18.0 and 15.7 kg), respectively, for Reveille, and 38.0 and 34.1 lb (17.3 and 15.5 kg) for S24. The solids-not-fat (S.N.F.) and the crude protein contents of the milk averaged 8.64 and 3.29%, respectively, for Reveille, and 8.56 and 3.22% for S24. It is concluded (hat the silages made from Reveille were superior to those made from S24 as a feed for dairy cows.     

A LINEAR PROGRAMMING MODEL OF A HIGH-TEMPERATURE GRASS-DRYING ENTERPRISE

A linear programming model of a high-temperature grass-drying enterprise is described. From information about seasonal crop response, area of crop available and management constraints, the model determines the harvesting schedules which give greatest returns, less costs, from the enterprise over the season. This information can be used to examine the effects of long-term strategic decisions or to evaluate economically data on new crops from field experiments. For example, assuming a fixed cost of λ70,000/year for a high-temperature grass-drying installation and what is considered to be reliable input data for 1972, the returns less costs for optimum harvest schedules from different areas or crop varieties are:

A MANAGEMENT STUDY OF A BIRDSFOOT TREFOIL STRAIN TRIAL

A study of birdsfoot trefoil ( Lotus corniculatus L.) variety trial management was conducted with three variables, variety, stubble height and harvest date. The range in maturity for the three varieties used was 12-14 days. All plots were harvested thrice per season. The harvest dates for the two management regimes imposed differed by about two weeks for the first cut, by about one week for the second and were identical for the third cut. Stubble heights were two and six inches (5.08 and 15.24 cm).
Late-cut material outyielded that cut early, but suffered more winter damage. Material cut at a stubble height of two inches (5.08 cm) outyielded that cut at six inches (15.24 cm), but it also suffered more winter-killing. The ranking of varieties varied with management.
Alternative management schemes, designed to provide maximum yields and survival consistent with good-quality forage, are proposed and discussed.     

Development of A dormancy release technology: A review

Tuber dormancy can be released immediately in many commercially important potato cultivars by brief treatment (1-2 days) with bromoethane (BE) vapor at room temperature. The development of a large scale technology for BE application and safe removal through a capturing technique is necessary for successful application of this dormancy release method. Ideally, BE treatment of seed tubers would occur in a closed environment that would capture BE vapor in an unaltered form and allow controlled release for treatment of subsequent tuber lots. Results of screening studies for adsorbents indicate that the medium capacity activated carbon adsorbent, YAO has: i) a high capacity for BE; ii) a low capacity for water; and, iii) adsorbs and de-adsorbs BE quickly and easily. A plausible design of a large scale, dormancy release facility is presented. The proposed facility should meet present goals of the seed potato industry in an environmentally responsible manner.     

A COMPARISON BETWEEN A PADDOCK SYSTEM AND A 'WYE COLLEGE' SYSTEM OF GRAZING FOR MILK PRODUCTION

Two grazing systems, a paddock system and a ‘Wye College’ system, were compared in two 20-week experiments nsing 16 and 20 spring-calved Ayrshire cows in 1970 and 1971, respectively. A sward of S23 perennial ryegrass was used, and an average of 342 kg N/ha (305 lb N/ ac) was applied per annum. The paddock system had 28 separate paddocks; one paddock was grazed each day in rotation and occasionally topped in mid-season. The Wye College system had 4 plots of equal size and the cows were offered 1/7 of one plot each day; no back fence was used and surplus herbage was neither cut nor topped. The stocking rate on hoth systems was 1 cow per 0.20 ha (0.49 ac) in 1970 and per 0.16 ha (0.40 ac) in 1971. The mean daily milk yields per cow on the paddock and the Wye College systems were 16.2 and 15.3 kg (35.7 and 33.7 lb), respectively, in 1970; and 18.1 and 18.4 kg (39.9 and 40.6 lb) in 1971. The average annual output of milk was 13,500 and 13,150 kg/ha (1200 and 1170 gal/ac) on the paddock and Wye College systems, respectively. The fat and solids-not-fat (S.N.F.) contents of the milk were not significantly affected by the grazing system. It is concluded that the Wye College system was as effective as the paddock system in producing a high output of mUk per ha, but at a lower cost and with far fewer management decisions.     

广东育成无垩白软型优质籼稻不育系粤丰A

粤丰Ａ是由广东省农科院水稻研究所于1998年育成的国内第一个无垩白、低直链淀粉含量(14.3%)、软胶稠度(92ｍｍ)、低糊化温度(碱消值7.0)和香味浓的特优籼型三系不育系。该不育系千株群体不育株率为100%,花粉不育度为99.99%,柱头外露率达88.1%,稻瘟病全群抗性比达中抗水平。2000年10月在广州通过了由来自扬州大学、国家水稻改良中心、国家杂交水稻工程技术研究中心等单位著名专家的技术鉴定。专家组一致认为该不育系综合性状优良、不育性稳定、配合力强、异交结实率高、品质改良有重大突破,研究成果达国内外领先水平;其投入生产应用对推动我…     

A Rice Reference

Rice quality:A guide to rice properties and analysis reviews variability in rice characteristics and their effects on rice quality in great detail.After an introduction on rice quality that also explores paradoxes associated with the crop,the book goes on to examine rice physical properties and milling quality.This leads to a discussion of the effects that the degree of milling has on rice quality.The ageing of rice and its cooking and eating quality are comprehensively investigated in the following chap...     

A系较B系早始穗的野败型不育系095A育成

目前生产上应用的野败型三系不育系均具有保持系 (B)较不育系 (A)早始穗的特性 ,随种植季节的不同 ,保持系一般较不育系早 1～ 3d始穗。迄今 ,尚未见有A系较B系早始穗的报道。最近 ,我们转育定型的野败型不育系 0 95A则具有此特性。在同期播种、同期移栽的情况下 ,海南春季、嘉兴早季及翻秋三季 ,0 95A分别较 0 95B早始穗 4,3 ,5d。而对照珍汕 97B较珍汕 97A分别早始穗 2 ,3 ,3d。由于在不同的季节A系较B系早始穗的趋势一致 ,因此推断 0 95A表现的该特性应为遗传决定 ,而非环境条件影响所致。对A系较B系早始穗的现象在生产应用上的积…     

COMPETITION FOR PHOSPHATE BETWEEN A DIPLOID AND A TETRAPLOID PERENNIAL RYEGRASS

The relative uptake of P was measured in two varieties of Lolium perenne using radioactive tracer techniques. The diploid cv. Hora and the tetraploid cv. Terhoy were sown as pure stands and as 50:50 mixtures at both high and low density. Uptake from four depths 10, 20, 30 and 40 cm was examined. The results showed that: in pure stands the diploid uptake at 10 cm exceeded that of the tetraploid although at deeper levels the uptake pattern was similar; in mixtures the uptake of the tetraploid variety increased markedly at 10 cm while that of the diploid variety decreased. The diploid compensated for its decreased uptake at 10 cm by a substantial increase in uptake at 20 cm; overall the tetraploid variety had a deeper pattern of uptake than the diploid; in general, uptake at high density was greater than that at low density; the mixture showed a greater degree of P utilization than pure stands in the upper layers of the soil; when these two varieties are grown together in 50:50 mixtures the tetraploid is relatively more efficient in taking up.     

Action et rôle probable de certaines gibbérellines (A1, A3, A4, A5, A7, A9 et A13) sur la croissance des stolons et la tubérisation de la Pomme de terre (Solanum tuberosum L.)

Résumé Les différentes gibbérellines étudiées (A1, A3, A4, A5, A7, A9), sauf la gibbérelline A13, provoquent des retards sur la tubérisation des germes de pomme de terre cultivésin vitro et de boutures feuillées. Il existe une corrélation étroite entre les retards qu’elles provoquent et la stimulation qu’elles exercent sur la croissance du système stolonifère. L’action retardatrice semble être liée à certaines particularités de la structure de la molécule (double liaison dans le noyau A; carbone 7 substitué; présence d’une structure lactonique). On démontre que la tubérisation ne se produit pas à la suite de phénomènes d’antagonisme par compétition entre les différentes gibbérellines étudiées et l’acide gibbérellique (gibbérelline A3). On discute l’influence des gibbérellines endogènes et d’autres facteurs internes sur le contr?le de la tubérisation et sur la croissance des stolons, et ses rapports avec les conditions externes qui stimulent la tubérisation.

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Summary The various gibberellins used in this trial, with the exception of A13, delayed the tuberization of shoot pieces taken from tubers and aerial parts of super eliteBintje and culturedin vitro. The techniques used were those described by Gregory and Tizio, respectively. White’s culture solution, with the addition of Nitsch’s microelements, was used forin vitro cultures. Each variant in this case consisted of 24 test tubes which were exposed after culturing to continuous darkness at a temperature of 20–21°C. In the trials carried out according to Gregory’s method, each variant consisted of 10–12 cuttings. These were planted in a vermiculite soil mixture and placed in a glasshouse (16–20°C.) under short day conditions (8–9 h). A direct correlation was established between delayed tuberization caused by gibberellins (Tables 1–5) and similarly induced stolon growth and extension of stem axes. Gibberellins A3 and A5 proved to be the most active. Such activity seems to correlate with certain peculiarities of molecular structure (existence of a double bond in the A-ring; substitution of carbon 7 by a hydroxyl group; presence of lactone structure). It was shown that tuberization does not occur as a consequence of antagonism through competition between the different gibberellins and gibberellic acid (gibberellin A3). It is deduced that the endogenous gibberellins, the concentration of which is stimulated by thermal and photoperiodic conditions non-inductive to tuberization, could act in the control of such a mechanism and upon stolon growth, possibly in connection with other factors, especially inhibitor-like substances. It is believed that the method of action could be connected with changes in the mode of growth of the sub-apical meristem induced by these factors and which affects both stolon growth and tuber initiation.

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Zusammenfassung Die verschiedenen im gegenw?rtigen Versuch benutzten Gibberelline (A1, A3, A4, A5, A7, A9) verursachen mit Ausnahme der Gibberelline A13-eine Verz?gerung der Knollenbildung bei denin vitro kultivierten und aus Kartoffelknollen der SorteBintje Super Elite wachsenden Sprossfragmenten sowie eine Verz?gerung des Blattwachstums der Augenstecklinge bei der gleichen Sorte (hergestellt nach der Technik, die von Tizio bzw. von Gregory empfohlen wird). In den in virto angestellten Versuchen wurden das Kulturmedium von White und zus?tzlich Spurenelemente von Nitsch benutzt. Jede Variante bestand aus 20–24 Prüfgl?sern, die nach dem Kultivieren dauernder Dunkelheit bei einer Temperatur von 20–21°C ausgesetzt wurden. In den nach der von Gregory empfohlenen Technik angestellten Versuchen wurden 10 bis 12 Stecklinge verwendet. Nach dem Auspflanzen der Stecklinge in ein Gemisch von Vermikulit und Kulturerde wurden sie im Treibhaus bei 16–20°C unter natürlichen Kurztagbedingungen (8–9 Stunden) gehalten. Zwischen der von den Gibberellinen verursachten Verz?gerung (Tabellen 1–5) und der Anregung, die das Wachstum des stolonischen Systems und der Stengelachsen erfuhr, wurde eine direkte Wechselwirkung festgestellt. Die Gibberelline A3 und A5 waren am aktivsten. Ihre Wirkung scheint in Beziehung zu gewissen Eigenschaften der molekul?ren Struktur (Vorhandensein einer doppelten Verbindung im A-Ring der Moleküle, Ersetzung in der Stellung des Kohlenstoffs 7 durch eine OH-Gruppe, Vorhandensein einer lactonischen Struktur) zu stehen. Es wird bewiesen, dass die Knollenbildung nicht als Folge eines Konkurrenz-Antagonismus zwischen den verschiedenen Gibberellinen und der Gibberellins?ure (A3) stattfindet. Daraus wird gefolgert, dass die endogenen gibberelline, deren Konzentration durch thermische und photoperiodische, jedoch nicht für die Knollenbildung induktive Bedingungen gef?rdet wird, an der Kontrolle des erw?hnten Mechanismus teilnehmen und einen Einfluss auf das Wachstum des stolonischen Systems, m?glicherweise in Verbindung mit anderen, haupts?chlich hemmenden, Faktoren des natürlichen Wachstums ausüben k?nnten. Man glaubt, dass die Wirkungsart Ver?nderungen der Wachstumsweise hervorrufen k?nnte, die die genannten Faktoren im subapikalen Meristem der Stolonen bewirken; dies würde sich auf ihr Wachstum und auf den Beginn der Knollenbildung beziehen.

     

一个新的大豆细胞质黄化突变体的初步研究

用一个大豆叶片黄化突变体与6个带有不同标记基因的基因型杂交配制了8个杂交组合(包括两组正反交组合)。根据杂交后代的表现对该突变体进行了遗传分析并测定了亲本和F_1植株的叶绿素含量。结果表明该突变体的叶绿素缺失性状呈母体遗传。当以黄化突变体为母本时,杂交F_1和F_2单株都表现为黄化,当用正常的非黄化基因型作为母本时,所有的F_1和F_2植株都不黄化。在自然光照条件下,突变体的叶绿素a、叶绿素b和总叶绿素含量约是正常基因型的47.4、40.4和43.7％。突变体新生叶片的叶绿素含量很低,随着叶片的发育成熟,叶绿素含量逐渐接近正常基因型。根据大豆遗传委员会的有关规定和惯例,建议将该突变体定名为Cyt—Y_4。     

红花含油率选择方法的研究

我们选用9个栽培红花品种为试验材料,进行含油率选择方法的研究。结果表明:诸性状中,对含油率的影响以种壳率最大,其次是分枝高和株高。通过种壳率进行间接选择,可有效提高含油率。这3性状综合选择,对提高含油率的效果大于单性状相关选择的作用。采用分枝高、百粒体积、始花开花天数、种壳率4性状构成的选择指数对含油率进行选择时的效果最好。用该选择指数对9个参试品种评审结果表明,油酸李德是综合性状优良的最佳油用型品种,夫里奥和AC—1次之。UC—26和张掖无刺是综合性状最差的低含油率品种。     

A specific gravity calculator

A low cost, pocket size, specific gravity calculator has been developed that will convert weight in air and weight in water values directly to specific gravity. This calculator is eminently suitable for use in the field and has been developed for use by potato growers in a research project involving specific gravity determinations of developing tubers.