不同倍性麦类作物HI和NHI的杂种优势及其与产量的关系

本研究利用冬性和春性四倍体硬粒小麦(Triticum durum,AABB)、普通小麦(T.aestivum,AABBDD),春性和冬性六倍体小黑麦(AABBRR)及春性八倍体小黑麦(AABBD-DRR)等三种倍性六套材料,分别在每套材料中选取亲本并配成双列杂交以研究倍性与杂种优势的关系。结果表明:①冬性倍性材料间一致地表现出单株经济产量具有最高的杂种优势,单株经济产量优势高的主要原因在于生物产量的优势较高,收获指数一般优势较小。②不同倍性间亲本产量水平与杂种优势幅度表现出不同关系。冬性硬粒小麦产量水平与杂种优势幅度呈显著正相关,而普通小麦和八倍体小黑麦这种相关不显著。③倍性间杂种优势的比较表明普通小麦产量杂种优势略高于硬粒小麦,超亲优势无差异,表明在 AABB 内增加 D 染色体组似乎不会影响杂种优势的幅度。但小黑麦杂种优势和超亲优势明显低于硬粒小麦和普通小麦,似乎在 AABB 或 AABBDD 中增加 R 染色体组降低了杂种优势的幅度。     

调制方法对多花黑麦草干燥特性及干草质量的影响

研究6种调制方法对多花黑麦草干燥特性及干草质量的研究,结果表明：（1）与自然晒干相比,烘干、压扁茎秆、压扁茎秆＋喷碳酸钾3种调制方法可显著缩短多花黑麦草干燥所需时间,提高多花黑麦草干草质量,而喷碳酸钾溶液和风干处理在缩短多花黑麦草干燥时间及提高其干草质量上效果不显著;（2）灰色关联综合评价结果表明,与自然晒干相比,烘干...     

Ammonia, pH and volatile fatty acids in the bovine rumen after feeding with hay.

The effect of feeding level and interval between feedings on the fermentation pattern in the bovine rumen have been investigated in experiments with hay. The animals were completely adapted heifers fitted with rumen cannulas, and the parameters measured were ammonia, pH, volatile fatty acids (VFA) and non-glucogenic/glucogenic ratio (NGGR) in the VFA mixture.Increasing feeding levels, ranging from 2/3 to 4/3 of maintenance level, resulted in higher average concentrations of VFA and lower pH in the rumen fluid. Further the highest level of intake caused a considerable diurnal variation in the pH and the concentration of total VFA, and increased the variation in the molar composition of the VFA mixture.Three feeding intervals ranging from 8 to 16 hrs., with hay administered at maintenance level, caused no changes in the fermentation pattern.Typical variations in the concentrations of ammonia and valeric acid as related to time after feeding were demonstrated, but the concentrations of the branched-chain fatty acids in the rumen fluid were found to be quite constant.It may be concluded that a representative mean value of the parameters measured, except for ammonia and valeric acid, may be based on relatively few samples when feed intake does not exceed maintenance level, whereas sampling every hour is required at higher feeding levels.     

Einfluß eines variierten N-Angebots auf α-Amylase-Aktivität, primäre Dormanz und Auswuchsresistenz von Weichweizen (Triticum aestivum L.), Roggen (Secale cereale L.) und Triticale (X Triticosecale Wittmack)

Influence of Varying N-Fertilization Rates on α-Amylase Activity, Primary Dormancy and Resistance to Pre-Harvest Sprouting in Wheat ( Triticum aestivum L.), Rye ( Secale cereale L.) and Triticale (X Triticosecale Wittmack)
Pre-harvest sprouting, induced by unfavourable ecological conditions, can affect the grain growers success considerably. Positive correlations are reported between resistance to pre-harvest sprouting and primary dormancy. Genotypes with a short dormancy period have a high pre-harvest sprouting risk. In the case of a premature germination of caryopses in the head of grain a hydrolysis of intact starch granules caused by the endoenzyme α-amylase takes place in the endosperm.
Negative correlations between falling number and protein content are reported, however, it is unknown, if a varying N-application influences pre-harvest sprouting rates, dormancy periods and amylase activity. For this reason, both greenhouse and field trials were conducted with different N-fertilization rates and (additional in the greenhouse) a rain simulation treatment.
High amounts of α-amylase a few days post anthesis are opposed to small enzyme activities in mature kernels. Stratificating temperatures and germination inducing precipitations at the same time are inducing pre-harvest sprouting and a high α-amylase activity especially in rye and triticale. It seems as if N-deficiency reduces the possibility of pre-harvest sprouting, on the other hand high N-rates increase the enzymes' activity and promote germination processes in the kernel. Effects of N-fertilization on dormancy are not known.
In the discussion of reasons for an increase of α-amylase activity in sprouted grain caryopses, changes in the relation of the phytohormones gibberellic acid (promoter of enzyme activities) and abscisine acid are mainly presumed.     

Indigestion in Young Calves. II. The Influence Of Ground Barley,Coarse and Fine Hay

Four experiments comprising 86 calves have been carried out in order to examine the influence of ground barley, coarse and fine hay, when raising young calves on a high lactose milk replacer causing diarrhoea. The frequency of diarrhoea decreased when feeding barley (P < 0.01) or fine hay (P < 0.001), but increased when feeding coarse hay (P<0.01). Barley increased (P < 0.01) live weight gain and carcass weight, reduced (P < 0.001) rumen pH, favoured gram-positive cocci and rods in the rumen, caused hyperkeratosis and gave increased (P < 0.01) empty reticulo-rumen weights, the latter being supposed to be enhanced by hyperkeratosis. The calves ate more (P < 0.001) fine than coarse hay, fine hay being superior (P < 0.01) in promoting growth of the rumen. All hay maintained a predominantly gram-negative rumen flora, but somewhat different from that on the milk replacer, and counteracted (P < 0.01) low pH in the rumen and apparently also hyperkeratosis due to barley. The results with barley indicated no relationship between diarrhoea and hyperkeratosis.     

Influence of grain type on the insecticidal efficacy of two diatomaceous earth formulations against Rhyzopertha dominica (F) (Coleoptera: Bostrychidae)

Laboratory bioassays were carried out in order to evaluate the effectiveness of two diatomaceous earth (DE) formulations, Insecto and SilicoSec, against adults of Rhyzopertha dominica (F) in eight different grain commodities. The adherence of the two DEs to each grain was also measured. The eight grains tested were wheat, whole barley, peeled barley, oats, rye, triticale, rice and maize. These commodities were treated with the DEs at three rates, 0.75, 1.0 and 1.5 g DE kg(-1) grain. The mortality of R dominica adults was measured after 24 h, 48 h, 7 days and 14 days of exposure in the treated grains at 26 degrees C and 55% RH. After the 14-day mortality count, all adults were removed and the treated grains retained under the same conditions for a further 60 days. The treated grains were subsequently examined for F1 progeny. Significant differences were recorded among the eight grain types as well as between the DE formulations tested. After 14 days of exposure, even at the lowest DE rate for both formulations, adult mortality was high (>90%) in wheat and triticale. In contrast, adult mortality was significantly lower in peeled barley. Increasing the rate improved the efficacy of the DEs significantly in only some of the grains tested. Reproductive capacity in all the treated grains was significantly suppressed when compared with untreated grains. Generally, more F1 individuals of R dominica were noted in the treated peeled barley than in the other commodities. Significant differences in the percentage of DE retention were noted among the eight grains. The highest retention level was noted in rice (>87%) and the lowest in maize (<6%). However, the degree of DE adherence to a given grain was not always indicative of the effectiveness of DE against R dominica.     

河西地区几种多年生栽培牧草的产量比较

通过对几种栽培饲草盛产期生产力水平试验,筛选出适宜河西地区高水肥条件下栽培的多年生饲草种类为松香草Silphium perfoliatum、紫花苜蓿Medicago sativa、百脉根Lotus corniculatus、无芒雀麦Bro-mus inermis,干草产量依次达到30 120、21 179、20 679和25 024 kg/hm2;粗蛋白产量分别达到6 174.6、5 083.4、4 756.2和2 628.0 kg/hm2,无氮浸出物达到8 478.4~11 911.4 kg/hm2。在河西地区每年刈割3茬产量最高,干草产量比刈割2茬提高7.4%~20.6%。鲁梅克斯Rumex acetosa、披碱草Elymus dahuricus高感白粉病和黑粉病,大面积栽培需要加强病害防治或更新抗病品种。     

日粮中使用低纤维饲料对奶牛消化情况影响的研究

【目的】研究在日粮中使用10 kg饲用甜菜替代3 kg玉米青贮、在日粮中使用1/3开花期和现蕾期苜蓿干草对奶牛消化情况的影响。【方法】试验采用单因素设计。根据泌乳天数、胎次、年龄、产奶量相近的原则,选取荷斯坦奶牛51头,随机分为3组,分别饲喂对照组(甜菜粕+玉米青贮+1/3开花期苜蓿干草)、试验1组(饲用甜菜+玉米青贮+1/3开花期苜蓿干草)、试验2组(饲用甜菜+玉米青贮+现蕾期苜蓿干草)3种粗饲料组合的日粮,每组混合精料相同。试验预饲期7 d,正式期43 d。【结果】日粮中使用饲用甜菜和现蕾期苜蓿干草饲喂奶牛可以提高有机物、粗蛋白、粗脂肪和无氮浸出物的消化情况,但差异不显著(P>0.05)。【结论】现蕾期苜蓿干草的品质优于1/3开花期苜蓿干草,饲用甜菜是一种低纤维多汁饲料,日粮中使用饲用甜菜和现蕾期苜蓿干草可以提高奶牛的消化情况。     

应用模糊综合评判法评价小黑麦的抗旱性

运用模糊综合评判法对19个小黑麦(Triticosecale wittmack)品种(系)与抗旱性相关的性状进行了综合评价.结果表明,08草鉴15、07草品11、05草鉴2、08草鉴13和06草鉴5的抗旱性较强.参试大部分品种(系)经干旱胁迫处理后综合性状优于对照品种新小黑麦3号,表明大部分参试高世代品种(系)的抗旱性较强.