Intercropped wheat (Triticum aestivum L.) and bean (Vicia faba L.) as a whole-crop forage: effect of harvest time on forage yield and quality

Abstract Sole crops and intercrops of wheat (Triticum aestivum L.) and bean (Vicia faba L.), at three harvest dates, representing successive growth stages, were evaluated for biomass production of whole‐crop forage and quality characteristics of crude protein (CP), neutral‐detergent fibre (NDF), acid‐detergent fibre (ADF), water‐soluble carbohydrate (WSC) concentrations and ash content. These tests were carried out for two field experiments, respectively, drilled during the spring of 1997 and autumn of 1997 on Imperial College Farm, Wye, UK. Results indicated that optimum forage yield and quality were obtained from the second to third harvest dates for the spring‐drilled experiment and the second harvest for the autumn‐drilled experiment. Wheat and bean intercrops were higher in total forage dry matter (DM) yield than either wheat or bean grown as sole crops. Field bean intercropped with wheat led to increased forage quality (CP and NDF concentrations) compared with sole wheat, and higher WSC concentrations compared with sole bean. Intercrops also enhanced weed suppression compared with sole bean. It is suggested that winter wheat–bean intercrops may have considerable potential as a moderate‐yielding, relatively high‐quality, low‐input and environmentally benign forage crop with considerable potential with regard to yield and quality and warrant further study.     

Growth Analysis, Herbage and Seed Yield of Certain Forage Legume Species Under Rainfed Conditions

The need to increase forage production for the growing livestock population in the Mediterranean region necessitates the evaluation of various promising forage species with respect to maximum herbage yield, optimum time for harvest and seed yield. Seven forage legumes, woolly pod vetch ( Vicia villosa subsp. dasycarpa accession 683), narbon vetch (V. narbonensis accession 67), common vetch ( V. sativa selections 2541, 2037, 2020), common chickling ( Lathyrus sativus selection 439) and ochrus chickling ( L. ochrus selection 104) were compared over two years with contrasting rainfall. In both years the entries were sown in November and their primary growths sampled periodically during growth. For each sample, phenology, total dry matter, leaf area index (LAI) and, at maturity, total dry matter, seed yield and harvest index, were recorded.
In both seasons, narbon vetch attained the highest dry matter and seed yields, and there was very limited variability in the maximum dry matter yield of the other entries. In general, the maximum dry matter occurred at 20–50 % podding in woolly pod vetch, 100 % podding in common vetch selection 2541 (local), narbon vetch and common chickling and at maturity in common vetch selection 2037, selection 2020 and ochrus chickling.
Throughout the vegetative to early flowering stages, woolly pod vetch had the highest dry matter yield and LAI. Possible uses of each species as animal feed are discussed.     

Agronomic Potential of Three Vetches (Vicia spp.) Under Rainfed Conditions

The major limiting factor to livestock production in West Asia and North Africa is the inadequate feed supply. The introduction of leguminous forage species into fallow lands represents a means of increasing feed supplies for the rapidly growing livestock population.
Twenty five lines each of common vetch ( Vicia sativa L.) wooly-pod vetch ( Vicia villosa ssp. dasycarpa Ten.), and bitter vetch ( Vicia ervilia L.) were tested over three seasons with contrasting rainfalls and winter temperatures. For each species, seedling vigour, winter growth, cold effect, spring growth, leafiness, herbage yield at 100 % flowering, grain yield, harvest index and aspects of herbage quality were recorded. There were considerable variation among entries with the same species, entries of V. ervilia were the earlier in flowering and maturity, and V. villosa ssp. dasycarpa almost the latest by 45 days. V. sativa , was the most affected by frost whilst both V. villosa ssp. dasycarpa and V. ervilia proved to be cold tolerant.
Although V. villosa ssp. dasycarpa produced high herbage yield in springs its grain yield is low resulting in a low harvest index. Both V. ervilia and V. sativa produced high grain yield with high harvest index. Seed yield was negatively correlated (P < 0.01) with days to flowering and maturity indicating the need of earlier types.
Quality of the herbage in term of digestibility was far lower (46 % IVDMD) in V. villosa ssp. dasycarpa than the other two species (69 % and 72 %).
The possible niches and utilization of each species as animal feed in the prevailing farming systems are discussed.     

多效唑处理对直播油菜机械收获相关性状及产量的影响

以阳光2009与沣油520为材料,于封行期及蕾薹初期喷施不同浓度多效唑,测定倒伏、角果抗裂性及产量相关指标,研究多效唑对油菜产量和机械收获相关性状的影响,为高产及机械收获条件下油菜的多效唑调控提供技术支撑及理论依据。结果表明,不同时期多效唑处理均显著提高2个油菜品种的抗倒性、抗裂角性及产量,蕾薹初期喷施300 mg L–1多效唑后油菜抗倒与抗裂角指数增量大,封行期喷施150 mg L–1多效唑则后产量的增量大。多效唑处理降低每角果粒数,但增加油菜品种的单株角果数及千粒重,故而增加产量;且可通过增加油菜根颈粗、鲜重根冠比及抗折力降低株高和倒伏指数,提高油菜抗根倒与抗茎倒能力;通过增加角果含水量、延缓角果成熟度、增加角果皮干重提高油菜角果抗裂性。本研究认为封行期喷施150 mg L–1的多效唑是最佳喷施时期与喷施浓度,既可显著增强易倒伏而减产油菜田块的抗倒与抗裂角能力,最大幅度地提高产量,又可满足油菜机械化生产模式所需的高产、抗倒及抗裂角要求。     

红菜苔种株采收适期的研究

该试验分析了红菜苔（Brassicacampestuisvarpurpurea）种株不同采收期对种子产量和种子质量的影响。种子质量是以种子活力、种子发芽力和种子大小进行评价的。结果显示，红菜苔十月红一号品种在种株最老熟荚果内籽粒变色后13天为最佳采收期。     

Transgressive segregation in inter and intraspecific crosses of barley

Summary Six populations of F₂-derived lines of barley and their parents were evaluated for heading date, plant height, grain yield, bundle weight, and harvest index in a replicated experiment in the field. These data were used to estimate the minimum number of effective factor pairs segregating for each trait, the number of favorable factors contributed by each parent in a cross, and the frequencies and magnitudes of transgressive segregates.Heading date, plant height, and harvest index were controlled by three to four effective factor pairs, whereas grain yield and bundle weight were controlled by five or more.All three H. spontaneum strains used in our study contributed one or more useful genes for each of the traits, grain yield, heading date, plant height, bundle weight, and harvest index. Therefore, it seems that H. spontaneum can be a useful source of favorable genes for quantitative traits, especially for grain yield, which could be incorporated into barley varieties readily by backcrossing. Transgressive segregates for grain yield in the interspecific crosses may provide the basic materials for improving the productivity of cultivated barley varieties.Journal Paper No. J-9760 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA 50011. Project 2227. Supported in part by a grant from the Science and Education Administration-Cooperative Research, United States Department of Agriculture.     

Genetic improvement in wheat yield and associated traits. A re-examination of previous results and the latest trends

Two field experiments were carried out with seven wheat cultivars (three of them, including a commercial hybrid, released during the last 10 years) representing different eras of plant breeding, to evaluate genetic improvement over the last century in grain yield, height, biomass, harvest index and grain yield components. Plots were fertilized and irrigated, and lodging and diseases were prevented. Main culm height was negatively correlated with the year of release of the cultivars, probably as a consequence of selection for increased lodging resistance. There was no significant association between total above-ground biomass and year of release of the cultivars. On the other hand, grain yield increased as newer cultivars were released. Results indicate that during recent years harvest index has been kept as the main attribute responsible for increases in grain yield. In general, number of grains/m² was associated with increases in grain yield during the century. However, the newest cultivars showed an increased grain weight. In both growing seasons, cultivars released before 1980 showed a trend towards reduced grain weight, but cultivars released after 1987 had a similar number of grains per m² with a higher grain weight than their predecessors. This was probably because the most modern cultivars have a longer grain-filling duration with a similar length of growth cycle.     

Carbon Isotope Discrimination and Productivity in Field-Grown Barley Genotypes

Five barley genotypes of different origins were used to examine the relationships between carbon isotope discrimination (Δ) and grain yield, yield components, dry aerial biomass and harvest index under rainfed and irrigated Mediterranean conditions. High positive correlations were found between Δ and grain yield and harvest index under both water conditions, suggesting that Δ may represent efficiency of dry matter partitioning to the grain. This hypothesis was also supported by the positive correlation found between Δ and thousand-grain weight when all the data were considered. The two drought-tolerant genotypes LM2887 and Tadmor presented the smallest difference between the two treatments for traits related to productivity as well as the highest Δ values. These results highlight the potential of Δ as a selection criterion in barley breeding in Mediterranean regions. They also encourage the study of the genetics of Δ and the identification of molecular markers linked to its variation in available progenies derived from crosses between the genotypes used in the present paper.     

小麦-玉米轮作耕作方式对玉米灌浆成熟期叶片衰老生理特性的影响

为了进一步探索适宜山东省半湿润易干旱地区夏玉米高产、稳产的耕作措施,本试验研究小麦、玉米轮作下免耕、深松、深耕两季的耕作方式(7个)对夏玉米穗位叶片衰老特性、灌浆期干物质积累、转运及籽粒产量的影响.结果表明(定位试验第3年):小麦深松+玉米免耕直播+秸秆还田(W3 M2)可显著提高夏玉米叶片生育后期SOD活性、叶片可溶性蛋白含量,而MDA含量增加缓慢,显著延缓穗位叶衰老;在吐丝至成熟期间干物质生产量上,W4M4(小麦深耕+玉米隔年深耕+秸秆还田)和W1M1(小麦旋耕+玉米隔年旋耕+秸秆还田)最高,W3M2和W3M3(小麦深松+玉米隔年深松+秸秆还田)次之,均显著高于CK和W1M2(小麦旋耕+玉米免耕直播+秸秆还田);W3M2干物质向籽粒运转比例即收获指数最高,W4M4最低;各耕作方式下W3M2和W1M1籽粒产量最高,分别比对照增加23.90％和9.87％.因此在本试验条件下小麦深松+玉米免耕直播+秸秆还田(W3M2)耕作方式下更有效延长叶片功能期,提高后期叶片生理活性,促进干物质向籽粒运转,增产效果显著.本研究可为华北麦-玉两熟农区合理安排周年耕作措施提供理论依据.