紫花苜蓿品种间产量性状评价

连续4年对中国28个已通过审定的紫花苜蓿品种的产量及质量性状进行了研究。生育期测定结果表明：达初花期所需天数最少的品种有甘农3号、武功、蔚县、新牧1号、新牧2号、公农2号、甘农1号、准格尔、陇东、无棣和晋南。产量性状分析表明：总干物质产量最高和较高的品种为新疆大叶(35955．6kg／hm^2)、武功、甘农3号、公农2号、新牧2号、新牧1号、肇东、图牧2号、草原2号、龙牧801和龙牧803共11个品种(31088．3～33183．4kg／hm^2);叶茎比最高的品种为龙牧801和无棣。依据对4年总干物质产量、3龄总干物质产量、4年平均日增高、4龄叶面积、4龄总枝条数和叶茎比6个产量性状测定值的不加权平均进行生产性能的聚类分析,认为可将28个品种分为极强、较强、中等、较差和差5个类群。极强类群苜蓿生产能力最强,特征为生长迅速,干物质产量、日增高、枝条数均为最高,叶面积最高或较低;叶茎比为中等;达出花期所需天数为少或多。     

天津开发区滨海生态防护圈组成群落的生物量、物质和能量结构

构成天津开发区滨海生态防护圈的 4种群落的生物量和能量现存量分别为 ,乔 灌 草群落 2 8 5 5t·hm-2 、5 2 5 91× 10 9J·hm-2 ,灌木群落 2 8 11t·hm-2 、5 0 3 2 7× 10 9J·hm-2 ,草本群落 2 4 30t·hm-2 、35 5 6 8× 10 9J·hm-2 ,灌 草群落 4 2 1t·hm-2 、75 5 2× 10 9J·hm-2 ,都大大超过了原生植被碱蓬群落 ( 0 2 75t·hm-2 、3 6 1× 10 9J·hm-2 )。具有复层结构的乔 灌 草群落和灌 草群落在生物量和能量现存量的分配上 ,都是优势层占据绝对优势地位 ,而且在各群落中生物量和能量分配比例很接近 :乔 灌 草群落中乔木层占 84 34%和 84 4 3%、灌木层占14 89%和 14 84 %、草本层仅占 0 77%和 0 73% ;灌 草群落中灌木层占 80 0 8%和 80 5 1%、草本层占 19 95 %和 19 4 9%。 4种群落对N、P、K、Na、Ca、Mg、Cl- 7种元素的现存总量从大到小依次为草本群落 ( 2 4 81 87kg·hm-2 )、灌木群落 ( 5 18 16kg·hm-2 )、乔 灌 草群落 ( 4 99 4 9kg·hm-2 )、灌 草群落 ( 99 2 2kg·hm-2 ) ,大于原生碱蓬群落 ( 2 8 34kg·hm-2 )。草本群落对Na和Cl-有着极大的吸收和积累 ,分别达到 5 2 1 6 8kg·hm-2 和 14 2 9 15kg·hm-2 。元素现存量在复层结构的乔 灌 草群落和灌 草群落     

宿生陆地棉经济性状的研究

在引进抗虫陆地棉品种的基础上,对5个品种二年生及其一年生栽培的主要经济性状进行了比较研究。结果显示,二年生棉平均皮棉产量1510.56kg·hm-2,比其一年生棉平均增产14.57%;二年生棉的棉纤维品质性状与其一年生棉的基本一致,部分性状优于其一年生棉。在供试品种中,中928 F1和湘杂棉3号的二年生棉皮棉产量分别为1845.42kg·hm-2,1689.63kg·hm-2,棉纤维品质优良,产量构成因素匹配好,可在冬季无霜或轻霜地区进行二年生栽培并应用于生产。     

无芒雀麦种子产量因子与产量的相关和通径分析

采用多因素正交试验设计,通过大样本相关、通径和逐步回归分析后表明,无芒雀麦5个种子产量因子对种子产量的直接贡献大小排序为:生殖枝数/m 2＞种子粒数/小穗＞小花数/小穗＞单粒种子重＞小穗数/生殖枝;提高小花数/小穗和种子粒数/小穗可最有效提高无芒雀麦的种子产量,其次是提高生殖枝数/m2.     

中国主要苜蓿品种的产量性状及其多样性研究

对28个4龄苜蓿品种单株产量性状及其相关性和变异进行了研究．结果表明,品种间单株干物质产量及各产量性状存在显著差异,其中单株干物质产量最高和较高的分别是新疆大叶(452．8g·株^-1)和甘农3号(373．0g·株^-1);叶片最宽和最长者均为新疆大叶和甘农3号;单株枝条数增加最多是第3茬,3茬单株枝条数最高和较高的品种是新牧1号、图牧2号、肇东和北疆;苜蓿株高生长高峰期在第1茬,生长最快的品种为甘农3号和新疆大叶．相关分析表明,单株干物质产量与株高及枝条数等构成因素之间存在显著或极显著相关,其中1、3茬株高及3茬单株枝条数等性状相关最好,呈显著相关的品种达19～22个,且相关系数亦最高．产量性状变异分析表明,品种内变异大于品种间变异,前者占总变异的76．0％～93．8％,而后者仅占6．1％～24．0％．各性状变异程度表现依次为3茬单株枝条数>单株干物质产量>1茬单株枝条数>2茬单株枝条数>春季株高>3茬株高>2茬株高>叶宽>现蕾期株高>叶长>1茬株高．     

辽西褐土施肥及养分循环再利用中长期试验Ⅴ.不同降水年景作物产量对施肥的反应和水肥交互作用

通过比较平水年 ( 1996年 ,作物生长期降水 4 5 6mm)和丰水年 ( 1998年 ,作物生长期降水 5 98mm)作物对施肥的增产反应 ,初步估算了辽西半湿润 半干旱地区水肥交互作用对作物增产的贡献 .结果表明 ,施氮肥并增加水分供给 (降水增加 ) ,作物增产 (玉米、大豆 ) 30 5 6kg·hm-2 ,其中 1996kg·hm-2 来自水肥交互作用 ,占 6 5 .3% .施NP和堆肥并增加水分供给 ,作物增产 4 70 3kg·hm-2 ,其中 15 5 4kg·hm-2 来自水肥交互作用 ,占 33% .     

菜地和一般农田土壤主要养分累积的差异

选取不同类型菜地和一般农田 ,测定了 0～ 2 0 0cm土壤剖面的有机质、全氮、硝态氮、铵态氮、速效磷、速效钾等主要养分含量及其分布 .结果表明 ,菜地土壤中养分大量累积 ,其中硝态氮和速效磷累积程度较高 .大棚和露天菜地 0～ 2 0 0cm土层的硝态氮累积总量分别为 15 2 0 .9kg·hm-2 和 135 8.8kg·hm-2 ,比农田高出 5 .2和 4.5倍 ;速效磷分别为 978.1kg·hm-2 和 5 0 3.3kg·hm-2 ,比农田高出 6 .2和 2 .7倍 .而其它养分增加相对较少 .有机质累积总量分别为 2 80 .5Mg·hm-2 和 2 6 9.3Mg·hm-2 ,比一般农田高出 12 .5 %和 8.0 % ;全氮分别为 37.5Mg·hm-2 和 32 .7Mg·hm-2 ,比农田高出 36 .2 %和 18.6 % ;铵态氮分别为 2 11.5kg·hm-2 和 197.8kg·hm-2 ,比农田高出 2 9.6 %和 2 1.2 % ;速效钾分别为 6 5 6 7.8kg·hm-2 和 5 5 2 3 .6kg·hm-2 ,比农田高出 30 .6 %和 9.8% .此外 ,菜地土壤中累积的养分不仅分布在表层 ,在深层土壤也大量存在 ,说明菜地存在严重的养分淋溶现象 .     

长白山北坡苔藓红松暗针叶林倒木分解及其养分含量

对长白山北坡苔藓红松暗针叶林中云冷杉倒木的分解及其养分元素的含量进行了研究。研究表明 ,云冷杉倒木的腐烂分解过程符合单项指数衰减模型 ,冷杉倒木的分解常数为 0 .0 1 6 8/a( r2 =0 .94 83) ,云杉倒木为 0 .0 1 5 0 /a( r2 =0 .8895 )。对云冷杉倒木中养分含量进行测定可得 :C平均含量为 1 8876 .90 kg· hm- 2 ,N为 2 99.0 0 kg· hm- 2 ,P为2 .5 0 kg· hm- 2 ,K为 4 0 .4 9kg· hm- 2 ,Ca为 4 4.1 2 kg· hm- 2 ,Mg为 1 2 .5 0 kg· hm- 2 。在云冷杉倒木腐烂分解过程中 C的百分含量会逐渐下降 ,N和 P的含量会逐渐增高。K、Ca和 Mg的含量则没有明显的变化趋势。     

西双版纳热带季节雨林生态系统氮的生物地球化学循环研究

 用小流域集水区和物质平衡方法,于1999年对西双版纳热带季节雨林生态系统的氮素循环进行了初步研究。西双版纳季节雨林生态系统的氮库总储量为6 481.2 kg·hm-2,其中活体生物量、凋落物层和土壤（0～30 cm）中的氮储量分别为970.9、37.7、5 481.2 kg·hm-2。土壤中的氮占生态系统氮总储量的84.4%,活体生物量占15.0%,凋落物层仅占0.6%。结果表明季节雨林的氮主要分布在土壤中,而在生物量中只占很少部分。大气降水、林内穿透水、树干流及地表径流的氮含量分别为0.565、0.828、0.983和1.042 mg·dm-3,氮通量则分别为8.89、10.97、3.57、5.95 kg·hm-2·a-1。大气降水输入氮8.89 kg·hm-2·a-1,径流输出氮5.95 kg·hm-2·a-1, 收支平衡（输入—输出）为2.94 kg·hm-2·a-1。氮的生物循环：吸收为149.86 kg·hm-2·a-1,存留为69.30 kg·hm-2·a-1,归还为80.56 kg·hm-2·a-1,循环系数为0.54。结果表明未受干扰的季节雨林生态系统处于氮积累的状态,有利于该生态系统的稳定与持续发展。     

带距对小麦蛋白质产量的影响及边际效应分析

以冬小麦品种豫麦 34为材料 ,在不同带距条件下对小麦籽粒产量、蛋白质含量和蛋白质产量以及三者相互关系进行了研究。结果表明 :带距对蛋白质产量和籽粒产量有显著的影响 ,对籽粒蛋白质含量影响不明显 ;蛋白质产量与籽粒产量呈现极显著正相关 ,与籽粒蛋白质含量关系不密切 ;蛋白质产量与籽粒产量之间存在着直线回归关系 ,二者的模拟方程为 :Y =10 6 80 9+0 10 7X(kg·hm-2 ) ;2 0m带距条件下小麦籽粒产量最高 ;2 4米带距条件下 ,小麦边行优势总值最大 ,与其它作物套作 ,效益较好。     

Grain Yield in Two Contrasting Varieties of Spring Wheat

To investigate factors determining grain yield in spring wheattwo contrasting varieties of high (Jufy I) and low (Peko) yieldingcapacity were grown in field and glasshouse experiments. In a field trial Jufy I yielded approximately 14 per cent moregrain than Peko on both control and nitrogen-treated plots.In another field trial employing small plots, although for bothvarieties doubling the seed-rate did not affect grain yield,the two varieties differed in their response to the increasein density. In Peko the yield level remained unaffected becausedoubling the seed-rate halved the number of fertile tillersper plant, whereas for Jufy I in addition to a shift in tillernumber per plant there were changes in the number of grainsper ear. In both varieties the weight per seed remained constant. When the two varieties were grown alone or as a 1: 1 mixtureat the same seed-rate the grain yields were similar. In themixture, Peko, compared with Jufy I, produced a greater numberof fertile tillers and consequently a greater contribution tothe total grain yield. In glasshouse experiments the grain yield per tiller and theorder of leaf area duration per tiller for the period from earemergence to grain ripening were both higher for Jufy I. Onthe other hand, there was no varietal difference for the netassimilation rate estimated during the vegetative phase, butexcluding the roots. Additional nitrogen primarily stimulated tiller production inboth varieties. Shading either the upper or lower parts of the plant demonstratedthat the ear and flag leaf and its sheath are important sourcesof assimilates for grain formation, whereas the lower partsare relatively unimportant in this respect. There were indicationsthat the response between varieties differed.     

氮磷钾配比与用量对湘杂油763产量和经济效益的影响

为了筛选出冬油菜新品种"湘杂油763"在湖南油菜主产区推广的适宜氮磷钾配比及用量,于2008—2010年连续进行了2次该品种的氮磷钾配比及用量的大田小区试验,研究了不同氮磷钾配比及用量对其生物产量、籽粒产量、油分产量和经济效益的影响。结果表明:氮磷钾配比(N:P2O5:K2O)为1:0.50:0.50(处理B)和氮磷钾配比(N:P2O5:K2O)为1:0.43:0.57(处理G)的处理籽粒产量较高,分别达到2231和2065kg.hm-2,处理B显著高于除G外的其他处理;氮磷钾3种养分中,以氮肥对提高油菜籽粒产量的作用最大,其次为磷肥,作用最小者为钾肥;油分产量及植株生物产量变化规律与籽粒产量基本一致;按照处理B配比,籽粒产值为9816.97元.hm-2、施肥仅1641.23元.hm-2、施肥效益为6741.34元.hm-2,产投比达4.11;研究区域内N:P2O5:K2O=1:0.50:0.50,用量分别180(N)、90(P2O5)和90kg.hm-2(K2O)为较适宜施肥比例及用量。     

Mutations in Barley Row Type Genes Have Pleiotropic Effects on Shoot Branching

Cereal crop yield is determined by different yield components such as seed weight, seed number per spike and the tiller number and spikes. Negative correlations between these traits are often attributed to resource limitation. However, recent evidence suggests that the same genes or regulatory modules can regulate both inflorescence branching and tillering. It is therefore important to explore the role of genetic correlations between different yield components in small grain cereals. In this work, we studied pleiotropic effects of row type genes on seed size, seed number per spike, thousand grain weight, and tillering in barley to better understand the genetic correlations between individual yield components. Allelic mutants of nine different row type loci (36 mutants), in the original spring barley varieties Barke, Bonus and Foma and introgressed in the spring barley cultivar Bowman, were phenotyped under greenhouse and outdoor conditions. We identified two main mutant groups characterized by their relationships between seed and tillering parameters. The first group comprises all mutants with an increased number of seeds and significant change in tiller number at early development (group 1a) or reduced tillering only at full maturity (group 1b). Mutants in the second group are characterized by a reduction in seeds per spike and tiller number, thus exhibiting positive correlations between seed and tiller number. Reduced tillering at full maturity (group 1b) is likely due to resource limitations. In contrast, altered tillering at early development (groups 1a and 2) suggests that the same genes or regulatory modules affect inflorescence and shoot branching. Understanding the genetic bases of the trade-offs between these traits is important for the genetic manipulation of individual yield components.     

Heterosis breeding in rice (Oryza sativa L.)

Summary Studies conducted at the International Rice Research Institute (IRRI) during 1980 and 1981 have shown up to 73% heterosis, 59% heterobeltiosis and 34% standard heterosis for yield in rice. The latter was estimated in comparison to commercial varieties: IR36 and IR42 (yield 4–5 t/ha in wet season trials and 7–8 t/ha in dry season trials). Generally speaking, absolute yield was lower and extent of standard heterosis was higher in wet season than in dry season with some exception. Yields up to 5.9 t/ha (22% standard heterosis) in the wet season and 10.4 t/ha (34% standard heterosis) in the dry season were obtained. Most of the hybrids performed better in some season while some performed better in both seasons. Hybrids showed better lodging resistance although they were 5–10 cm taller. F₁ hybrids had significant positive correlations with the parental traits viz., yield (r = 0.446), tillering (r = 0.746), height (r = 0.810) and flowering (r = 0.843). Selection of parents among elite breeding lines on the basis of their per se yield performance, diverse origin and resistance to insects and diseases should give heterotic combination. Yield advantage of hybrids was due primarily to increase in number of spikelets per unit area even though tiller number was reduced. Grain weight was either the same or slightly higher. High yielding hybrids also showed significant heterosis and heterobeltiosis for total dry matter and harvest index. For commercial utilization of heterosis in rice, effective male sterility and fertility restoration systems are available and up to 45% natural outcrossing on male sterile lines has been observed. Consequently, F₁ rice hybrid have been successfully developed and used in China. Prospects of developing hybrid rice varieties elsewhere appear bright especially in countries that have organized seed production, certification and distribution programs and where hybrid seed can be produced at a reasonable cost.     

六个黄淮麦区优质小麦品种在晋中麦区晚播的产量与品质性状研究

目的：为拓宽山西优质小麦品种资源,采用田间试验,研究来自黄淮麦区的6个优质小麦品种在晋中晚熟冬麦区的籽粒产量及品质性状表现。方法：供试小麦品种分别是：来自河南省国家小麦工程中心的豫农416（编号Y-1）、豫麦34（Y-2）、豫麦70（Y-3）和豫麦18（Y-4）,来自山西省农科院棉花科学研究所的舜麦紫秆（S-1）和舜麦1718D（S-2）,以山西农业大学育成品种山农129为对照（CK）。试验于2010年10月15日在山西农业大学实验农场进行,收获后测定籽粒产量与产量结构及籽粒品质。结果：引进的6个黄淮麦区育成小麦品种在晋中晚熟冬麦区晚播种植,其籽粒品质均优于当地品种山农129,但产量不足。6个引进品种在晋中晚播种植后,其籽粒蛋白质含量、湿面筋含量等相关的籽粒品质亦明显高于原品种。相对而言,豫麦34、豫农416和舜麦紫秆均为高蛋白（〉17％）强筋（≥32％）品种,但前者高产（〉5800kg·hm-2）,后两者中产（〉4300kg·hm-2）;豫麦70和舜麦1718D均为高蛋白中筋（30％-32％）品种,但前者中产,后者低产（〈4000kg·hm-2）;豫麦18则为中等蛋白（〉16％）中筋的高产品种,当地品种山农129为低蛋白（〈16％）低湿面筋（〈30％）的高产品种。结论：豫麦34和豫麦18对改良山西小麦品种籽粒品质具有一定的意义。     

Tillering in grain sorghum over a wide range of population densities: identification of a common hierarchy for tiller emergence,leaf area development and fertility

Most studies of tiller development have not related the physiological and morphological features of each culm to its subsequent fertility. This introduces problems when trying to account for the effects of tillering on yield in crop models. The objective of this study was to detect the most likely early determinants of tiller fertility in sorghum by identifying hierarchies for emergence, fertility and grain number of tillers over a wide range of assimilate availabilities. Emergence, phenology, leaf area development and dry weight partitioning were quantified weekly for individual tillers and main culms of tillering and uniculm plants grown at one of four densities, from two to 16 plants m(-2). For a given plant in any given density, the same tiller hierarchy applied for emergence of tillers, fertility of the emerged tillers and their subsequent grain number. These results were observed over a range of tiller fertility rates (from 7 to 91%), fertile tiller number per plant at maturity (from 0.2 to 4.7), and tiller contribution to grain yield (from 5 to 78 %). Tiller emergence was most probably related to assimilate supply and light quality. Development, fertility and contribution to yield of a specific tiller were highly dependent on growing conditions at the time of tiller emergence, particularly via early leaf area development of the tiller, which affected its subsequent leaf area accumulation. Assimilate availability in the main culm at the time of tiller emergence was the most likely early determinant of subsequent tiller fertility in this study.     

Genetic variability and association of characters in linseed (Linum usitatissimum L.) plant grown in central Ethiopia region

Linseed is one of the most important oil seed crop in the central highlands of Ethiopia for which yield enhancement is the major breeding purposes and genotypic variability is important for selection in any breeding programs. However, shortage of improved varieties’ that provides optimum seed yield is one of the major constraints of the crop. Therefore, this study was carried out to assess the genetic variability and association among quantitative traits of 36 linseed genotypes. The experiment was conducted in 2018 main cropping season by using simple lattice design. The analysis of variances reveled highly significant difference among the genotype for most of traits considered in present study. High phenotypic and genotypic coefficient of variation was recorded for tiller per plant, harvest index, oil yield (kg ha⁻¹), and seed yield (ton ha-1) number of capsules per plant. High heritability along with genetic advance was observed for seed yield (tones ha-¹), oil yield (kg ha-¹) harvest index which indicates selection of these traits at early generation would be effective. Oil yield (kg ha⁻¹) harvest index and number of capsules plant ⁻¹ showed highly significant positive with seed yield (ton ha⁻¹). Cluster analysis revealed that 36 linseed genotypes were grouped into two clusters and four genotypes remain ungrouped. The maximum inter clusters distance was observed between clusters II and the local check. The data set was reduced into four significant principal components (PCs) that comprise (80%) of the variance. The first PC accounted for 34% of the variances that implies greater proportion of variable information explained by PC1. The traits, which contributed more to PC1, were seed yield per plant, primary branches per plant, secondary branches per plant and plant height showed positive association and had positive direct effect on seed yield. This indicates that any improvement of oil yield and harvest index would result in substantial increase on seed.     

“Ecological Armageddon” – more evidence for the drastic decline in insect numbers

The efficient use of nitrogen by crops can minimise environmental risks and maximise returns to farmers. Under organic farming systems, this can be achieved by adjusting the fertilisation management and/or using genetic variability. Seven durum wheat (Triticum durum) cultivars and three emmer (Triticum dicoccum) cultivars were assessed under an organic farming system over a non‐consecutive 4‐year period (2005–11) in Foggia (southern Italy). The objectives were to investigate the agronomic and qualitative characteristics, and to evaluate the agronomic efficiency and adaptability according to three N fertilisation levels (0, 40, 80 kg N ha^?1). A split‐plot design was used, with three replications in each year. Nine traits were investigated: heading time, plant height, seed yield, number of spikes m^?2, harvest index, specific weight, 1000‐seed weight, and protein and gluten contents. Increasing N to 80 kg ha^?1 increased plant height (+7.3%), seed yield (+22.1%), spike density (+16.6%), and protein (+9.8%) and gluten (+2.1%) contents. The emmer genotypes and the oldest durum wheat ‘Cappelli’ showed the highest protein and gluten contents (mean, 13.9%, 11.2%, respectively). The maximum N agronomic efficiency [AE(N)] and N recovery efficiency [RE(N)] were seen for the modern durum wheat cultivars under 40 kg ha^?1 N treatment: ‘Duilio’, ‘Iride’ and ‘Varano’. The significant correlation between AE(N) and RE(N) and the year of release of the durum wheat cultivars (r = 0.53, P < 0.05, F = 4.7 for AE(N) and r = 0.57, P < 0.01, F = 5.7 for RE(N), respectively; n = 14) showed that the genetic breeding of this species for high grain yield is associated with an increase in the efficiency of N fertiliser use under organic farming. The highly significant effect for the Genotype × Environment interaction (F = 18.1, P < 0.001) of seed yield indicate the possibility to select for stable genotypes across environments. Based on the additive main effects and multiplicative interaction analysis, and the yield stability index, the varieties ‘Iride’ and ‘Varano’ show high‐stability responses and good seed yields under all N fertiliser treatments. Therefore, these varieties can be recommended for organic farming systems in Mediterranean areas.     

Tillering in grain sorghum over a wiide range of population densities: modelling dynamics of tiller fertility

The prediction of tillering is poor or absent in existing sorghum crop models even though fertile tillers contribute significantly to grain yield. The objective of this study was to identify general quantitative relationships underpinning tiller dynamics of sorghum for a broad range of assimilate availabilities. Emergence, phenology, leaf area development and fertility of individual main culms and tillers were quantified weekly in plants grown at one of four plant densities ranging from two to 16 plants m(-2). On any given day, a tiller was considered potentially fertile (a posteriori) if its number of leaves continued to increase thereafter. The dynamics of potentially fertile tiller number per plant varied greatly with plant density, but could generally be described by three determinants, stable across plant densities: tiller emergence rate aligned with leaf ligule appearance rate; cessation of tiller emergence occurred at a stable leaf area index; and rate of decrease in potentially fertile tillers was linearly related to the ratio of realized to potential leaf area growth. Realized leaf area growth is the measured increase in leaf area, whereas potential leaf area growth is the estimated increase in leaf area if all potentially fertile tillers were to continue to develop. Procedures to predict this ratio, by estimating realized leaf area per plant from intercepted radiation and potential leaf area per plant from the number and type of developing axes, are presented. While it is suitable for modelling tiller dynamics in grain sorghum, this general framework needs to be validated by testing it in different environments and for other cultivars.