Inter- and intra-population genetic variation for leaf:stem ratio in landraces and varieties of lucerne

A comparison was made of landrace vs. variety inter‐ and intra‐population genetic variation for leaf:stem ratio in lucerne and investigated its relationship with forage yield and other characters. Very early‐flowering genotypes were excluded from the assessment to limit the impact of maturity stage on the variation in leaf:stem ratio. The evaluation was performed on a summer harvest of 390 genotypes belonging to ten landraces from northern Italy and to six well‐performing varieties, and on nineteen clones of a single genotype which were used to estimate the environmental variance. Landrace and variety groups did not differ in mean leaf:stem ratio. Variation for this trait was significant among varieties (P < 0·05) but not among landraces. Within‐population variation was significant for both germplasm groups (P < 0·01), being somewhat larger in landraces. The estimated within‐population variance component largely exceeded the among‐population variance component within varieties. Higher leaf:stem ratios were mainly associated with shorter and thinner main stems in genotypes and populations, and showed a modest inverse correlation with forage yield. The results highlight the importance of landrace germplasm and the paramount importance of selection within populations to identify parent material with a high leaf:stem ratio.     

The effect of row spacing on alfalfa seed and forage production under irrigated Mediterranean agricultural conditions

We evaluated the effect of row spacing on seed and forage yields in alfalfa (Medicago sativa L.) using combined seed and forage production plots, in an irrigated Mediterranean agricultural environment. We compared three row distances (20, 40 and 60 cm) in two cultivars at a seed rate of 25 kg ha^?1 over a period of 4 years. We measured the seed yield and yield components as well as forage production. The 4‐year average revealed an overall clean seed yield of 367 kg ha^?1 declining over time, without significant differences in row distances. The number of shoots per square metre differed significantly as a function of row spacing, with averages of 357, 226 and 172 shoots m^?2 for row widths of 20, 40 and 60 cm respectively. The row spacing did not affect the number of racemes per shoot (23·1), the number of pods per raceme (7·2), the number of seeds per pod (6·5) or the thousand seed weight (1·667 g). The average forage production was 20·1, 18·5 and 17·9 Mg DM ha^?1 for row distances of 20, 40 and 60 cm, respectively, with higher yields associated with smaller row distances. Our data demonstrate that row spacing >20 cm does not confer any advantage to the production of alfalfa seed under irrigated Mediterranean agricultural conditions and that close spacing can significantly increase forage yields in the same environment.     

Selection of grazing-tolerant lucerne cultivars

Improvement of grazing-tolerance in lucerne ( Medicago sativa L.) is an objective of interest worldwide for the acknowledged potential of this species in pastures. A breeding programme applied standard methods of the selection for this trait, which implies continuous stocking and intensive grazing, to germplasm preliminarily selected for reportedly positive morphological attributes (large and deep crowns; non-erect growth habit). In this study six experimental cultivars, originating from this programme, and three check varieties were evaluated. Grazing tolerance was assessed under continuous sheep stocking for 2 years. Herbage yield in 3 years and seed yield (in the second year) were also evaluated in distinct and contiguous sub-experiments. One experimental cultivar had a prostrate habit, two were semi-prostrate, and three were semi-erect. Under grazing, five of them showed final persistence similar to, or better than, that of the tolerant check variety adopted in the standard test. In particular, the prostrate experimental cultivar (termed Camporegio) had remarkable persistence, although associated with low vigour, associated with the introgression of M. sativa ssp. falcata into its parentage. A semi-erect cultivar (termed Verbena) possessed a good balance between grazing tolerance, potential dry-matter yield and seed yield.     

Thermal time approach to predicting seedling emergence dates of red clover,white clover and lucerne in farm fields

A practical method for predicting seedling emergence dates of red and white clovers, and lucerne is proposed. The germination response at seven different constant temperatures ranging from 5 to 35°C was examined. Germination rate, which is a reciprocal of the duration for 50% germination of seeds, was linearly regressed against temperature to calculate the base temperature and thermal constant of seed germination. The calculated values were 3·9°C and 15·8 degree days for red clover, 4·2°C and 13·6 degree days for white clover, and 2·9°C and 17·7 degree days for lucerne. Using the base temperatures, thermal constants, and the daily mean air temperatures at the study site, the seedling emergence dates of the three forage legumes were predicted. At the same time, in an outdoor pot experiment, seeds of these legumes were sown approximately every 3 weeks and seedling emergence dates were determined. The predicted dates of seedling emergence generally fitted the observed dates. Another prediction was attempted using the base temperatures, thermal constants, and normal daily mean air temperatures recorded over more than 30 years in the study site. This prediction showed that the seedlings of the three forage legumes began to emerge at the beginning of April and could continue to emerge until the beginning of November when their non‐dormant seeds were present in the site, and that when the seeds were sown from mid‐November of one year to late March of the next year, the emergence of seedlings was delayed until the beginning of April.     

Differences in the crude protein fractions of lucerne leaves and stems under different stand structures

Protein degradability in forage legumes is of global importance because utilization efficiency of forage has economic and environmental consequences. However, there are no published studies on the effect of legume stand structure on differences in crude protein (CP) fractions. The main objective of the present research was therefore to investigate differences in CP fractions in leaves and stems of lucerne (Medicago sativa L.) during the growing season. Stand traits were measured over 2 years, and forage was sampled at the early bud and early flower stages in the first, second and third cuts. Stems had significantly higher concentrations (in g kg^?1 CP) of non‐protein (fraction A: 430 g kg^?1 CP) and indigestible nitrogen (fraction C: 92 g kg^?1 CP) than leaves and had lower relative content of true protein (fraction B: 478 g kg^?1 CP). In the total forage (stems and leaves combined), about 80% of the variation in CP fractions was explained by year, cut and maturity. Year was the most important factor, particularly for the B fractions. Cut was the second‐most important factor; its main effect was that the relative abundance of fraction A declined from 394 g kg^?1 CP in the first cut to 293 in g kg^?1 CP the third cut. Maturity increased the amounts of indigestible fraction C and protein fractions B₁ and B₃. This was associated with the leaf weight ratio, which had an inverse relationship with maximal stem length and dry matter yield. Variation partitioning showed that 75% of CP fraction variability associated with cut, maturity and year could be explained by the evaluated stand traits. This research has highlighted the need to consider plant morphological traits when legume CP fractions are evaluated.     

Agronomic value and adaptation across climatically contrasting environments of Italian red clover landraces and natural populations

This study aimed to support red clover (Trifolium pratense L.) breeding programmes by investigating germplasm adaptive variation. Four landraces representative of the former commercial ecotypes from northern and central Italy, thirteen natural populations collected in Italy across a wide latitudinal and altitudinal range in exploited or abandoned old natural grasslands, natural pastures or in the wild, and the varieties Perseo and Divin were evaluated for 2‐year forage yield, for plant survival and for some morphophysiological traits. Evaluations were made at two sites, one with a subcontinental climate (Lodi) and the other with a Mediterranean climate (Viterbo). Specific adaptation was particularly large in natural populations, whose interaction with location implied a widespread inversion of population ranks across sites for forage yield depending on their geographical origin. Forage yield and persistence of the populations were not correlated, owing to the trend of landrace and variety germplasm towards high yield but poor persistence. At Lodi, forage yield was associated with winter hardiness and was maximized by landrace germplasm, whereas persistence depended on various factors and was high only in a set of natural populations collected from pastures. At Viterbo, natural populations that evolved under severe summer drought stress tended towards high yield and persistence, showing no yield disadvantage relative to the best‐performing landrace or variety germplasm.     

Effects of tractor wheeling on root morphology and yield of lucerne (Medicago sativa L.)

The purpose of this study was to determine the effect of soil compaction on the herbage yield and root growth of lucerne ( Medicago sativa L.). A field experiment was conducted on a silty loam Mollic Fluvisols soil in 2003–2006. Herbage yield and root morphology, in terms of root length density, mean root diameter, specific root length and distribution of dry matter (DM) in roots, were measured. Four compaction treatments were applied three times annually by tractor using the following number of passes: control without experimental traffic, two passes, four passes and six passes. The tractor traffic changed the physical properties of the soil by increasing bulk density and penetration resistance. Soil compaction also improved its water retention properties. These changes were associated with changes in root morphology and distribution of the DM in roots. Soil compaction resulted in higher proportions of the DM in roots, especially in the upper, 0–10 cm, soil horizon. Decreases in the root length density were observed in a root diameter range of 0·1–1·0 mm. It was also found that roots in a more compacted soil were significantly thicker. An effect of the root system of lucerne on soil compaction was observed. The root system of lucerne decreased the effects of soil compaction that had been recorded in the first and the second year of the experiment. An increase in the number of passes resulted in a decrease in the DM yield of herbage in the second and third harvests each year.     

The use of a rising plate meter to evaluate lucerne (Medicago sativa L.) height as an important agronomic trait enabling yield estimation

A rising plate meter (RPM) is an instrument used for the measurement of compressed sward height and estimation of yield on grasslands. The aim of this study was to investigate the use of an RPM to evaluate lucerne height as an agronomic trait enabling yield estimation. Compressed height (CH), stem length, plant and stem density and yield measurements were recorded from the late‐vegetative stage to flowering in the first cut and from the late‐bud stage to flowering in the second and third cuts, during three successive years. For lucerne maximal stem‐length prediction, CH could be used successfully (with R ² over 0·90) in developmental stages before flowering and for stem lengths up to 80 cm, irrespective of stand density or order of cut. The dry‐matter yield of lucerne was better predicted using CH (R ² = 0·72) than maximal stem length (MSL) (R ² = 0·53). The recommended number of observations was 7–9 per treatment in the first cut and twice this in subsequent cuts because of higher variability in stand structure. The use of RPM to measure CH of lucerne is not recommended when MSL exceeds 80 cm, or in the case of lodging. RPM may also be suitable for similar forage crops with erect or semi‐erect stems, subject to consideration of disc weight and diameter. Heavy discs are unsuitable for lucerne height prediction but could be more suitable for yield prediction.     

刈割对干热河谷地区紫花苜蓿种子生产的影响

通过对干热河谷地区10个紫花苜蓿品种在孕蕾初期进行刈割1茬和不刈割处理后,从其种子成熟时间、产量方面,研究刈割对该区引种的紫花苜蓿品种种子生产的影响,以提高其种子生产性能。结果表明:在干热河谷地区,在紫花苜蓿孕蕾初期刈割1茬后,种子产量平均提高14.933 g/m2,并促使种子主要集中在播种次年的5月份成熟采收;10个参试紫花苜蓿品种中,猎人河(74-55)的种子平均产量显著高于其他品种,可达36.401 g/m2,其次是萨兰纳斯(75-43)和德宝,其种子平均产量分别为31.727 g/m2和30.060 g/m2。     

引发提高水稻劣变种子发芽率的蛋白质组学分析

引发处理是目前简便有效的提升种子发芽率和整齐度的方法,但引发提高水稻劣变种子发芽能力的机理并不清楚。利用蛋白质组学方法,分析清水引发和藤茶提取物二氢杨梅素引发2种处理方法与对照的差异蛋白,初步揭示引发提升种子发芽能力的机制。分析双向电泳图谱差异获得2倍以上显著差异蛋白点79个,通过MALDI TOF/TOF MS质谱分析鉴定出74个蛋白,其中2种引发处理与未引发对照相比同步上调或下调的共有蛋白,即引发相关蛋白有57个。分析引发相关蛋白可知,绝大多数的逆境防御蛋白类、能量相关蛋白类以及蛋白质合成和目标类蛋白丰度在引发处理中显著增加,推测引发提高种子发芽率的原因与逆境记忆、能量代谢活动和蛋白质合成能力增强等密切相关。     

Estimation of lucerne yield stability for enabling effective cultivar selection under rainfed conditions

Evaluation of crop and forage yield stability is of increasing relevance in the context of current and recent environmental changes but, in contrast to other field crops, there are no published systematic analyses among forage crops in Europe. A study of stability performance was conducted with 13 Czech cultivars of lucerne at four locations over a 2‐year period with the following aims: (a) to evaluate yield stability of varieties across different environments and (b) to calculate measurable benefits of variety selection in relation to the specific environment. The cultivar Vlasta was identified as the highest yielding cultivar (annual yield 16.0 t DM/ha), whereas the lowest yielding cv. Magda, Tereza and Oslava averaged around 14.9 t DM/ha. Effect of genotype × environment interaction (G × E) was two times higher than for genotype alone. Additive main effects and the multiplicative interaction (AMMI) model showed that the highest yielding cultivars may not be stable across environments. This study demonstrated further that significant yield improvement could be detected, even among a relatively homogenous group of domestic cultivars, and this was driven mainly by site productivity: the improvement was +10% in low‐yielding sites, compared with +3% in high‐yielding sites. Results highlight that advanced agronomy should also consider stability parameters such as AMMI stability value or superiority measures for forage crops in response to the challenges associated with climate change.     

Production, survival and nutritive value of the perennial legumes Dorycnium hirsutum and D. rectum subjected to different cutting heights

Dorycnium hirsutum and D. rectum are perennial legumes which may have potential for use as pastures for the control of groundwater recharge in southern Australia. Little is known about the quality of the forage of Dorycnium species for grazing livestock or how these species respond to cutting. The effect of cutting height on plant survival, production of dry matter (DM), the proportion of leaf, edible stem (approximately <5 mm diameter) and woody stem in the DM and the nutritive value of the edible components was investigated. Biomass above five cutting‐height treatments (uncut, ground level, 5–8 cm, 10–15 cm and 15–30 cm above ground level) was removed at 8‐week intervals from plots of D. hirsutum and D. rectum from September 2002 to July 2003. In both species, plants subjected to lower cutting height treatments produced less DM above the height of the cut than those cut at higher heights. DM production declined over time in all treatments. Plants cut to ground level failed to regrow after the second harvest in D. hirsutum and the fourth harvest in D. rectum. Thus, these Dorycnium species were susceptible to high severity defoliations at 8‐week intervals. Negligible inedible woody stem was present in regrowth of both species after 8 weeks but D. hirsutum regrowth had a higher proportion of leaf (0·72) than D. rectum (0·56). Plants left uncut accumulated a large proportion of inedible woody stem in the DM (0·69 in both species) by July 2003, particularly at the base of the plant. Edible DM from regrowth of D. hirsutum and D. rectum had crude protein (CP) concentrations of 120 and 150 g kg^?1 DM; dry matter digestibility (DMD) values of 0·45 and 0·58; organic matter digestibility (OMD) values of 0·50 and 0·64; neutral‐detergent fibre (NDF) concentrations of 370 and 290 g kg^?1 DM; and acid‐detergent fibre (ADF) concentrations of 260 and 210 g kg^?1 DM, respectively. Medicago sativa, grown under similar conditions, had higher digestibility values (0·63 DMD and 0·66 OMD) and similar CP concentrations to D. rectum (140 g kg^?1 DM), but higher concentrations of NDF and ADF (410 and 290 g kg^?1 DM). Leaf material from both Dorycnium species had a higher nutritive value than edible stems, with DMD and OMD values of leaf of D. rectum being 0·68 and 0·74 respectively. Uncut plants had a much lower nutritive value of edible DM than the regrowth from cut treatments; older material was also of a lower nutritive value. The relatively low nutritive value of even the young regrowth of Dorycnium species suggests that forage quality is a major limitation to its use. Forage of Dorycnium species could be used during periods when other sources of forage are in short supply but infrequent grazing it is likely to produce forage of a low nutritive value.     

Efficacy of zinc phosphide baits to control voles in alfalfa - an enclosure study

The efficacy of broadcasting zinc phosphide (Zn₃P₂) grain baits as an acute rodenticide to control graytailed voles (Microtus canicaudus) in alfalfa (Medicago sativa) was assessed. A total of 428 voles was distributed within 18, 0.2-ha enclosures having a 2+ year stand of plants. Single, pre-bait (0.0% Zn₃P₂) and test-/control-(2.0/0.0% Zn₃P₂) bait broadcasts (11.2 kg ha⁻¹) were applied within enclosures 18 and 20 days following final vole distribution. At 14 days later, a trap-out of the surviving voles was conducted. Only 5.6% of those distributed in Zn₃P₂-baited enclosures were recaptured; whereas, 70.1% of those placed in control-baited enclosures were retrapped. Analyses of variance for proportions of voles and total voles captured within enclosures yielded significant main effects for rodenticide. Program CAPTURE estimates also confirmed significant decreases in vole populations in Zn₃P₂-baited enclosures. Daily carcass searches yielded 25 and 5 vole carcasses, respectively, in the Zn₃P₂ and control enclosures during the bait-exposure period. Three non-target carcasses were found within enclosures during this period: one Savannah sparrow (Passerculus sandwichensis) and two vagrant shrews (Sorex vagrans). Results demonstrate the efficacy and low hazards to non-target passerines of a single Zn₃P₂ baiting to control vole populations in alfalfa.     

Genetic Diversity of Seed Storage Proteins in Different Ecotype Varieties of japonica Rice and Its Application

Plant endosperm storage proteins are coded by a group of enormous gene families, and a sub-family genes code a kind of protein respectively. These proteins are deposited in one kind of protein body and cannot be denatured during seed is formed. Thus, storage proteins as direct, stable products of genes can reflect DNA diversity of plants. The kind of diversity can be easily detected by various electrophoresis. So far, the polymorphism of seed storage proteins has already widely applied in pl…     

工业大麻种衣剂的筛选

用4个大麻专用种衣剂扣6个其它作物种衣剂对云南推广使用的工业大麻品种“云麻1号”种子进行包衣，经筛选对比试验，结果表明：不同类的种衣剂或药种配比量，对出苗有影响。各种衣剂处理对植株生长及经济性状无不良影响。试验优选出了3个种衣剂及其相应的药种比，红种子大麻种衣剂1#（药种比1：50）、12％甲硫悬浮液（药种比1：50）、中国农大大麻种衣剂（药种比1：80），它们时“云麻1号”安全、有效，有显著保苗扣增产作用。     

硫酸锌浸种对马铃薯生长发育及产量的影响

采用大田试验,研究硫酸锌浸种对马铃薯脱毒种薯生长发育以及产量的影响,硫酸锌设为4个水平,0.05%、0.10%、0.15%、0.20%,以清水为对照,结果表明：在适宜的浓度范围内,硫酸锌浸种对马铃薯的生长发育有促进作用,能显著提高株高、叶面积以及根冠比,延长生育时期,提高马铃薯的产量,增加经济效益,硫酸锌浓度过高或过低,效果都不佳,最终确定0.10%硫酸锌浓度为最佳的马铃薯浸种浓度。     

杂交水稻制种群体结构研究

通过杂交水稻制种父母本基本苗、厢宽和母本栽插规格对制种产量的影响的试验分析，指出各因子中以父母本基本苗对产量的影响最大，必须采用适当行比，同时增加父母本基本苗数，才能达到制种高产的要求．     

The influence of trichome density on the drying rate of alfalfa forage

Trichomes decrease water loss in some plant species, but their influence on water loss from alfalfa ( Medicago sativa L.) forage is unknown. A study was conducted which measured the water loss from field-grown, harvested forage of three erect, glandular-haired alfalfa germplasms, KS161, KS210 and KS224, the eglandular 'Arc' cultivar and the 'Kenland' cultivar of red clover ( Trifolium pratense L.). Harvests were taken once in 1995 and 1997, and four times in 1996. Plant height, phenological stage, upper and lower stem diameters, leaf:stem ratio and apical stem densities of simple, procumbent glandular and erect glandular trichomes were determined. The drying rate constants of the forage were calculated by a combination of parametric and non-parametric modelling techniques. The harvest × germplasm interaction was significant for all parameters measured. The density of erect glandular hairs varied among entries for all harvests, while the drying rate of harvested forage differed among entries for three of the six harvests. Correlations between densities of erect glandular hairs and drying rate constants were generally low and non-significant, except for one harvest. Erect glandular hairs, at the densities measured in this study, generally did not influence drying rates of alfalfa forage. However, density of total trichomes was significantly and negatively correlated with drying rate for all alfalfa entries. The diameter of the stem had the greatest negative impact on drying rate.     

不同生态类型大麻品种在南京引种的生育表现

从欧洲和东北、西北、华北、西南、华东等生态类型地区引种的26个品种和南京本地品种进行比较,分析了其在南京种植后生育期、经济性状、形态特征等方面的变化特点。结果表明,27个大麻品种的干茎和纤维产量与生育期长短、株高、茎粗、平均节间长度呈极显著的直线相关关系;北方和欧洲品种引种南京后,生育期缩短,植株生殖生长早,株高、茎基粗、总叶片数等大大减少,节间短,叶片小,干物质积累量小,茎杆产量和纤维产量都很低;南方品种表现相反,生育期延长,植株营养生长茂盛,下部分枝少,节间长度增加,快速增长时期的出叶速度和干物质积累速度显著大于北方和欧洲品种。欧洲、东北和西北的品种雄株生长过小,无纤维利用价值;南方及江苏、山东、河南的品种,雄株生长速度快于雌株,纤维利用价值高于雌株。     

Use of regrowth for forage in crops of timothy (Phleum pratense L.) cv. Grindstad grown for seed in Norway

Six experiments were carried out in two climatically different regions in south‐east Norway in order to compare different procedures for autumn management and use of regrowth in seed crops of timothy (Phleum pratense L.) cv. Grindstad. The experiments were laid out after seed harvest in mid‐August in crops with a stubble height of 5 cm (two experiments) or 12–15 cm (four experiments). Cutting to 5 cm on 15 September or 15 October, with or without an application of 50 kg N ha^?1 immediately after seed harvest, and with or without an additional application of 30 kg N ha^?1 after cutting, were compared with an uncut and unfertilized control treatment. As a main effect,autumn cutting increased seed yield in the subsequent year in only one experiment; this was laid out in a 13 cm stubble on a fertile soil near the coast. In the remaining five experiments seed yields were unaffected byautumn management regardless of climate or stubble height. Autumn cutting and N application increased the number of seedheads in two experiments, but this was offset by a drop in other seed yield components. On average for two cutting dates and for plots receiving an application of 50 kg N ha^?1 after seed harvest, the dry matter (DM) was 1430 kg ha^?1 on an inland site with 12–15 cm stubble, 1400 kg ha^?1 on a coastal site with 5 cm stubble and 2460 kg ha^?1 for two coastal sites with 12–15 cm stubble. Whereas forage yield and quality were fairly stable from the first to the second cut at the inland site, the yield of DM increased, but the crude protein and energy concentrations decreased from 15 September to 15 October at the coastal sites. It is concluded that the stubble and regrowth in seed crops of timothy cv. Grindstad can be harvested for forage without any effect on seed yield in the next year.