Radiation effects on potential number of grains per spike and biomass partitioning in two- and six-rowed near isogenic barley lines

The critical period for yield determination in barley (Hordeum vulgare L.) is situated in the pre-heading phases. During the latest part of the critical period one of the most important yield components (i.e. the number of grains per spike) is set in two- and six-rowed barley. In wheat, much is known about the role of the spike in assimilate acquisition for the establishment of grains per spike, but not in barley. This paper evaluates how biomass partitioning between vegetative and reproductive organs impacts floret development and primordia survival in response to radiation during different periods in the crop cycle, in barley lines. Field experiments were carried out using two- and six-rowed near isogenic barley lines differing only in spike type. Shading treatments were applied at different periods during the crop cycle (from 60 to 15 days before and after heading) reducing the intercepted radiation (ca. 70%). Dynamics of floret primordia initiation and mortality and of floret development for different spikelet positions along the spike were measured, and biomass partitioning between vegetative and reproductive structures was calculated.

Pre-heading shading reduced fertile florets per spike (P < 0.001). In the immediate pre-heading treatment, distal floret primordia could not reach a fertile floret stage due to a low rate of floral development.

The amount of assimilates partitioned to the spike at heading affected the number of fertile florets per spike in both barley types. However, when spike biomass at heading was corrected by nitrogen concentration, the fitness of the relationship did not improve in relation to the first one. In relative terms, radiation restrictions during the immediate pre-heading phase increased the amount of biomass partitioned to the growing spike.     

二棱大麦与六棱大麦籽粒性状的差异性及其相关性

为了解不同棱型大麦籽粒性状的差异性及其千粒重与粒型性状的相关性,对98份二棱大麦和89份六棱大麦品种(系)在不同试点的千粒重、粒长、粒宽进行测定和分析。结果表明,二棱大麦千粒重、粒长和粒宽普遍高于六棱大麦,不同棱型大麦千粒重、粒长和粒宽在基因型间及环境间差异均达到显著或极显著水平。经过聚类分析,依据千粒重将二棱大麦和六棱大麦聚为高、中、低粒重3类。随着千粒重的减小,二棱大麦千粒重与粒长之间由显著正相关变为不显著负相关,六棱大麦则由不显著正相关变为显著正相关。二棱大麦和六棱大麦各类品种(系)的平均千粒重与粒宽均呈极显著正相关,而且相关系数均高于千粒重与粒长的相关系数。     

大麦籽粒大小的遗传多样性与稳定性评价

为了解大麦籽粒大小的遗传多样性与稳定性,以185份大麦种质资源为材料,测定了7个试验环境下籽粒的长度、宽度、长宽比及千粒重等性状,对其遗传多样性和稳定性进行了分析评价。结果表明,所有试验环境下二棱大麦粒长、粒宽及千粒重均值均大于六棱大麦,籽粒长宽比均值均小于六棱大麦;二棱大麦与六棱大麦千粒重、粒长、粒宽及籽粒长宽比在品种(系)间及环境间差异均极显著,且品种(系)与环境之间存在极显著的互作效应,籽粒大小在环境间差异程度因性状而异,其中以千粒重的差异程度最大。依据10级分类分布频次法则,千粒重和粒宽分布比较集中,六棱大麦集中分布在3、4等级,二棱大麦集中分布在7、8等级;粒长和籽粒长宽比分布比较分散,六棱大麦粒长和籽粒长宽比分别分布在1~10等级和2~10等级范围内,二棱大麦粒长和长宽比分别集中分布在4~8等级和2~7等级范围内。千粒重与粒长、粒宽及粒长与籽粒长宽比呈极显著正相关,粒宽与籽粒长宽比呈极显著负相关;粒长与粒宽及千粒重与籽粒长宽比的相关性因棱型不同而异。二棱大麦千粒重的稳定性小于六棱大麦,而粒长和籽粒长宽比的稳定性恰好相反,粒宽的稳定性与棱型无关;皮大麦千粒重稳定性小于裸大麦,其余籽粒大小性状的稳定性与皮裸无关。通过熵权法TOPSIS对大麦籽粒大小进行综合评价,筛选出籽粒饱满且稳定的品种川52209,其可作为大麦籽粒性状改良的优异种质。     

大麦主茎穗与分蘖穗出穗差异及其对穗型的影响

为明确大麦主茎穗与分蘖穗出穗差异及其对穗型的影响,以1个二棱大麦和1个六棱大麦品种为材料,考察大麦主茎穗和不同分蘖穗的出穗顺序及其穗部性状。结果表明:供试品种主茎和分蘖的出穗期不一致,随出穗期延迟,穗长、每穗粒数和千粒质量呈下降趋势,主茎穗与分蘖穗1和分蘖穗2之间的差异较小。因此,大麦高产栽培应控制合理的基本苗和2个左右的分蘖穗。     

Pearling Quality of Canadian Barley Varieties and their Potential Use as Rice Extenders*

Barley can be used as an extender of rice to increase the nutritive value of the end-product. Specific quality barley is required if the processed barley is to resemble cooked white rice in colour and shape. The barley must pearl and split without the production of broken kernels or fines and yet produce desired end use quality. Barley endosperm texture and colour are key to determining these processing characteristics. Testing of Canadian barley types indicated the waxy type was most appropriate for pearling and processing as rice extender. It had a firm endosperm texture that was not steely and yet processed into a white product with few broken grains. Covered barley was of better quality than hull-less, as the former generally had fewer steely kernels as well as firmer endosperm texture. Differences observed between two- and six-rowed type were related to grain size and could be overcome by proper adjustments to processing conditions. Growing conditions affected kernel size and barley protein contents but to a lesser extent than barley type. L* brightness values, Particle Size Index and kernel size were found to be important predictors of barley quality for pearling and as rice extender.     

不同分类大麦籽粒大小及粒重的差异分析

为改良大麦籽粒性状,依据棱型、皮裸及选育水平对125份大麦材料按3种不同分类方式进行分组,比较了组别间的粒重、粒长、粒宽及粒厚的差异及各性状间的相关性。结果表明,大麦粒重与棱型相关,与皮、裸无相关性,二棱大麦粒重(46.89mg)显著高于六棱大麦(35.71mg)。就籽粒长而言,皮大麦长于裸大麦,二棱大麦长于六棱大麦,以野生大麦最长,为13.19mm;人工驯化和品种选育使大麦粒长有所变短。二棱大麦的粒宽(3.55mm)显著大于六棱大麦(3.26mm);粒宽在皮、裸大麦间无显著差异。粒厚变异与粒宽类似,野生大麦的粒厚最小(1.69mm)。相关分析表明,大麦粒重主要由粒宽、粒厚决定,且后两者呈极显著正相关。     

黎巴嫩引进大麦种质的黄花叶病抗性及农艺性状评价

为了丰富国内大麦育种的种质资源,从黎巴嫩引进了365份大麦种质资源并对其黄花叶病抗性及农艺性状进行了调查分析。结果表明,引进种质中二棱品种（系）占46.03%、六棱品种（系）占53.97%,大部分品种生育期适宜,表现为弱春性。株高为矮秆和中秆类型,平均穗长较当地推广品种长,且穗粒数多。引进品种（系）对大麦黄花叶病的抗性存在显著差异,其中有7份高抗大麦黄花叶病且综合农艺性状优良,分别为INBON-HI-33、GSBSN-9、GSBSN-13、GSBSN-19、IBON-HI-28、IBON-HI-33、IBON-HI-74。     

不同播栽方式下杂交籼稻茎秆生长和穗粒形成特点及与气象因子的关系

为探明不同播栽方式下杂交籼稻幼穗分化期茎秆和幼穗生长的规律及差异以进一步明确不同播栽方式穗粒形成特点,于2014年采用两因素裂区试验设计,研究了机直播、机插和手插3种播栽方式下2个不同穗粒型杂交籼稻组合[宜香优2115(中穗型)和F优498(大穗型)]的穗分化期茎秆和幼穗生长规律和穗粒形成特点,并分析了幼穗分化期气象因素与幼穗和茎秆生长的关系。结果表明:1)基部向上第1至第3伸长节间长度分别在抽穗前20d、16d、12d后趋于稳定,故基部第1、2节间的降长增粗应在抽穗前16d之前;穗干质量和穗茎比在抽穗前12d后迅速增加。2)从抽穗前16d开始至抽穗期,穗茎干重比与多数枝梗和颖花性状呈显著或极显著正相关,穗与茎秆竞争同化物的能力直接影响到穗粒形成。3)机插穗分化中后期穗茎干质量比较高,且抽穗期穗干质量显著高于手插和机直播,有利于提高其每穗粒数,且机插拔节后群体生长率及单茎和群体干物质积累量较高,抽穗期叶面积指数较高,粒叶比高于机直播,较机直播更利于粒重的提高和穗长及着粒数的增加;大穗型品种F优498抽穗期穗干质量显著高于中穗型品种宜香优2115,且穗分化后期穗茎干质量比高于宜香优2115,是其每穗粒数高的重要原因;F优498穗部着粒较密,较大的叶面积指数及粒叶比利于大穗的形成。4)机插全生育期最长,机直播最短,且机插穗分化期历时较长,穗分化期积温和日照时数较高,为穗粒形成提供了较好的温光条件;茎秆长度和干质量及穗长受气象因子影响较大,孕穗前适宜的温度和一定的积温有利于茎秆和幼穗伸长及茎秆的物质充实。生产上应针对不同播栽方式及品种的生育进程差异,适时采取措施调节茎秆和幼穗生长及物质分配,在培育壮秆的基础上提高穗分化期穗茎比以达到增粒增产的目的。     

大麦籽粒中γ 氨基丁酸、总黄酮和生物碱含量在发芽过程中的变化

为了解大麦发芽过程中功能成分的变化,用分光光度计测定了28份大麦籽粒发芽前(无菌水浸泡24h,记作发芽0d)及发芽1～9d的γ-氨基丁酸(GABA)、总黄酮和生物碱的含量差异,结果表明:(1)大麦籽粒中的GABA和生物碱含量均为发芽0d高于发芽1～2d,而明显低于发芽3～9d的相应含量;发芽前后GABA累积最大均值是最小均值的2.1倍,生物碱累积最大均值是最小均值的11.6倍。(2)大麦籽粒发芽前总黄酮含量最高,发芽后相对较低;而发芽4～8d期间的GABA和生物碱含量相对较高。(3)不同大麦品系间籽粒GABA和生物碱含量在发芽4～6d差异明显,且达到峰值的频率较高;籽粒总黄酮含量在发芽8～9d差异明显,发芽前总黄酮含量达到峰值的频率最高。     

Effects of Cultivar and Environment on β-(1,3)-(1,4)-D-glucan Content and Acid Extract Viscosity of Spanish Barleys

The acid extract viscosities and β-glucan contents of ten two- and six-rowed barley cultivars grown at seven locations in three consecutive years in Spain were studied in the present work. The viscosities varied from 2·4 to 24·8 centistokes (cSt) and the mean value was 6·4 cSt. The average β-glucan content of barleys determined by HPLC was 3·5% with a range of 1·9–5·5%. Significant differences were found in both β-glucan content and acid extract viscosity between different cultivars, locations and years. The β-glucan contents and viscosities of winter cultivars were higher than those of spring. Cvs. Barbarrosa and Hatif de Grignon were the genotypes with the highest values for both parameters, while cv. Beka had the lowest viscosity and β-glucan content. Environmental factors influenced both parameters. The acid extract viscosities of barleys were correlated negatively with the amount of precipitation (r=−0·754;P<0·05). Barleys grown in wet and rainy areas (Girona and La Coruña) had lower viscosity values.     

密度和肥料运筹对青稞秸秆产量及品质的影响

为探究二棱青稞在藏区的应用潜力及关键栽培技术,以二棱型青稞品系14-3492为材料,以六棱品种藏青3000为对照,设置不同种植密度、肥料运筹处理,研究了种植密度和肥料运筹对青稞秸秆产量及品质的影响。结果表明,秸秆产量和蛋白质含量在不同材料间差异显著;六棱品种藏青3000秸秆产量和蛋白质含量受密度影响较大,二棱品系14-3492的秸秆产量和蛋白质含量受肥料运筹影响较大。施用拔节肥青稞秸秆蛋白质含量最高,穗肥次之;相同施肥量,施用拔节肥+穗肥处理的秸秆产量显著高于单次施肥处理。从协同秸秆产量与蛋白质含量角度,低密度时,基肥+拔节肥的施肥模式可以同时提高分蘖成穗数及穗粒数;高密度时,基肥+拔节肥+穗肥的施肥模式可以保证青稞的稳健生长;二棱青稞品系14-3492的秸秆产量和品质总体优于六棱品种藏青3000。     

留桩高度对再生稻源库性状与物质运转的影响

 以8个水稻品种(组合)为材料,研究了留桩高度对再生稻源库流特性的影响。根据不同留桩高度下再生稻产量,将供试品种分为3种再生类型：高桩再生型、低桩再生型和中高桩再生型。留桩高度降低,再生稻有效穗数减少而每穗粒数增加,而低桩再生型品种每穗粒数增幅更大;高桩与中高桩再生型品种再生稻叶面积指数以高桩处理最大,而低桩再生型品种随留桩高度下降而增大;高桩再生型品种灌浆期光合速率以中、高桩处理较大,中高桩与低桩再生型品种齐穗期以高桩处理最大,齐穗后10 d和20 d以中低桩处理较大;高桩再生型品种再生稻作物生长率以高桩处理最高,而中高桩、低桩再生型品种以低桩或中桩处理最高;中高桩与低桩再生型品种再生稻枝梗过氧化氢酶活性随留桩高度下降而增强,而高桩再生型品种表现相反;高桩再生型品种茎鞘碳水化合物转运率以高桩处理较高,而低桩再生型品种以中、低桩处理较高。可见,留桩高度对再生稻源库流特性的影响与品种的再生类型密切相关。     

Critical competition period of parthenium weed (Parthenium hysterophorus L.) in maize

For minimizing yield losses due to infestation of a weed, it is essential to know about its critical period of competition in a specific crop. The yield response of maize (Zea mays L.) to different competition periods (0, 35, 42, 49 and 56 days after crop emergence (DAE), and competition throughout growing season) of the invasive weed Parthenium hysterophorus L. was tested during autumn seasons of two consecutive years 2012 and 2013. Increasing parthenium competition period increased its dry weight up to 448% and relative competition index up to 52%. The corresponding increases in the uptake of N (up to 581%), P (up to 700%) and K (up to 669%) were also recorded. Parthenium weed competition period of 35 DAE decreased grain yield and harvest index of maize. However, number of grains and grain weight per cob, and 100-grain weight of maize were reduced at parthenium weed competition period beyond 42 and 56 DAE, respectively. Maize grain yield losses varied between 21 and 53% with parthenium competition period ranging from 35 DAE to full growing season. Maximum N, P, and K uptake by parthenium was 18.4, 2.4 and 17.7 kg ha⁻¹, respectively. A three parameter logistic model was fitted to yield data in response to increasing durations of weed infestation. The critical timing of parthenium weed removal to avoid 5% and 10% maize grain yield loss was 8 and 17, and 13 and 23 DAE during year 2012 and 2013, respectively. Relatively shorter critical period of parthenium weed competition in maize crop suggested this weed to be highly allelopathic in addition to its competitive behavior.     

Triticale and other small grain cereals for forage and grain in Mediterranean conditions

In field experiments conducted over 2 years, triticale was compared with barley, bread wheat and oats for its dual-purpose (forage and grain) capability.
The effect of spring forage removal on grain yield ranged from small yield increases (in the triticale and barley genotypes that otherwise lodged) to a 53% decrease, and was dependent on species, genotype, stage of development when cut, and time for recovery before grain harvest. A key factor influencing grain yield after early cutting was the number of spikes that developed.
The complete types of triticale were better than the one substituted type tested for dual purpose but, as there is variability among them, selection for good mixed aptitude is possible.
The production of the best triticale averaged over 2 years 3 t of forage DM ha^-1 (with 684 kg of crude protein ha^-1) and then 4–3 t of grain ha^-1. In this instance, neither the grain yield nor the number of spikes per plant were reduced after clipping, in spite of the fact that the shoot apices were removed.
Plant height and lodging were reduced by a forage cut. In triticale, the number of days to heading was increased even more when the cut was late, but no effect was observed in barley.     

Effects of Cultivar and Environment on β-(1,3)-(1,4)- -glucan Content and Acid Extract Viscosity of Spanish Barleys

The acid extract viscosities and β-glucan contents of ten two- and six-rowed barley cultivars grown at seven locations in three consecutive years in Spain were studied in the present work. The viscosities varied from 2·4 to 24·8 centistokes (cSt) and the mean value was 6·4 cSt. The average β-glucan content of barleys determined by HPLC was 3·5% with a range of 1·9–5·5%. Significant differences were found in both β-glucan content and acid extract viscosity between different cultivars, locations and years. The β-glucan contents and viscosities of winter cultivars were higher than those of spring. Cvs. Barbarrosa and Hatif de Grignon were the genotypes with the highest values for both parameters, while cv. Beka had the lowest viscosity and β-glucan content. Environmental factors influenced both parameters. The acid extract viscosities of barleys were correlated negatively with the amount of precipitation (r=−0·754;P<0·05). Barleys grown in wet and rainy areas (Girona and La Coruña) had lower viscosity values.     

Is barley yield in the UK sink limited?: II. Factors affecting potential grain size

In the absence of serious post-anthesis stress, the potential supply of assimilates for grain filling in barley appears to exceed the storage (sink) capacity of the grains. The sink capacity is a function of the number of grains per unit land area and their potential size. In order to investigate the contribution of pre and early post-anthesis factors in the control of potential grain weight, regression analysis has been used to analyse data from field experiments conducted on winter barley crops cv. Pearl grown at six sites across the UK between 2002 and 2004. Crops were grown under a comparable husbandry regime with a full crop protection, growth regulator and fertilizer programme. The mean grain weight (MGW) varied from 35 to 46 mg at 100% dry matter over 17 site/year combinations. The variation in MGW between site/years was associated with differences in the rate rather than the duration of grain filling. MGW did not relate well to any measure of above ground growth or crop structure at ear emergence (Zadoks GS59). There was a significant positive linear relationship between MGW and the amount of radiation (PAR) intercepted per unit grain number between ear emergence and the start of rapid grain filling (r² = 0.32, P = 0.023), but not over the whole grain filling period. This is consistent with the view that MGW is determined by potential grain size. A multiple regression model comprising five explanatory variables accounted for a much larger proportion of the total variation in MGW (r² = 0.72, P = 0.013) than PAR interception on its own. There were significant positive associations of MGW with post-anthesis radiation use efficiency and PAR intercepted from GS59 to the start of rapid grain growth (RGG), and significant negative associations with the shoot number per plant, mean air temperature from GS39–59 and mean daily rainfall from GS59-RGG. The results suggest that both pre and post-anthesis conditions operate in concert to determine the potential grain weight of barley in temperate climates. The dry weight and water content of grains and ears followed a common pattern during grain growth for all site/years when the percentage moisture content was used as an index to normalise different rates of development. Use of the above data for predicting potential grain weight of barley prior to harvest is discussed.     

大麦冠层性状与穗部经济性状的遗传相关分析

通过对20个大麦品种（系）（16个二棱、4个多棱）的冠层性状及穗部经济性状的差异性及遗传相关分析，结果表明：1）除倒二叶、倒三叶叶面积及单株有效穗数的品种间差异不显著外，其余各研究性状在品种间的差异均达极显著水平。2）株高、穗长、每穗粒数的遗传力较高（＞0．80），其余各性状的遗传力相对较低，3）二棱大麦每穗粒重与千粒重、每穗粒数间正相关极显著，而千粒重无明显相关。4）二棱大麦上三叶面积与穗长正相关达显著或极显著水平，而多棱大麦只有倒三叶面积与穗长正相关达显著水平。     

Grain weight changes over time in ancient cereal crops: Potential roles of climate and genetic improvement

Inferences of grain weight (GW) for cereals cultivated in the past could be useful to track early agronomic improvements. Though strongly genetically determined, GW also depends on environmental conditions, such as water availability. In the archaeological context, we can estimate GW and plant water status from grain dimensions and carbon isotope discrimination (Δ¹³C), respectively. In this study we attempted to determine the role of environmental changes on the evolution of GW of naked wheat (Triticum aestivum/durum) and hulled barley (Hordeum vulgare) in the Ebro Depression (NE Spain) during the last four millennia. To that end, we examined charred grains from nine archaeological sites, from the Bronze Age (ca. 1950 BCE) to the end of the Middle Ages (XVth century). Estimated GW in archaeological grains (averaging ca. 19.5 mg for both species) was significantly lower than in present rainfed cereals in the area (ca. 35 mg). In contrast, for both species mean Δ¹³C values in archaeological grains were similar to or even greater than in modern material (16.3‰ and 15.5‰, respectively). Accordingly, we conclude that the most recent increase in GW cannot be attributed to increased water availability, but probably to empirical breeding efforts which would have started not before the beginning of the CE.