Changes in Several Traits of Oats Caused by Selection for Vegetative Growth Rate*

Growth rate and harvest index are the primary components that cause variation in gram yield or oats it growth duration of the crop is fixed as it is in mid western USA. Because harvest index for oats in that region has been optimized 45 %, growth rate is the only remaining trait for improving grain yield. F₂ derived oat lines from inter- (Avena sativa L. ×A. Sterilis L.) and intraspecific mating (among A. sativa cultivars) in F₃ were selected for vegetative growth rate at maturity (GRM) with an intensity of 8.3%. Predicted genetic gain was 21.5% for GRM, and actual gain was 7%. Changes in grain, biological, and straw yields were higher than gains in GRM when expressed as percentages of the oat population means. Predicted genetic gains were very low for traits unrelated or negatively associated with GRM such as heading data and harvest index. This study suggests that indirect improvement can be made for gain, biological, and straw yields by selecting for GRM.     

Responses in Agronomic Traits Associated with Three Recurrent Selection Regimes for Groat-Oil Content in Oat*

Crop strains with high values for the selected trait but unacceptable agronomic characteristics are not useful as varieties. In this study, we determined whether selection for groat-oil content in oat (Avena sativa L.) via three recurrent selection regimes caused associated changes in 10 agronomic traits. Random lines of each cycle of selection of each regime were evaluated in a replicated field experiment at two locations. Biomass, grain yield, groat yield, and test weight decreased in all three regimes. Seed weight and plant height decreased in two regimes, and groat fraction in one. Oil yield increased in two regimes and decreased in the other. Plants headed earlier in one and later in another regime over cycles of selection. No changes in harvest index occurred. Heritabilities and genetic variances were relatively high for all traits in each regime. Factor analysis of the phenotypic correlation matrices indicated that simultaneous increases in grain yield and in groat-oil content are possible, that continuous selection for groat-oil content decreases groat fraction and test weight, and that seed weight is strongly and negatively associated with groat-oil content. A new recurrent selection regime for increasing groat-oil content of oat that may overcome the negative responses of agronomic traits was proposed.     

Agronomic and Bioenergetic Consequences of Selection for High Groat-Oil Content and High Protein Yield in Oat*

Few studies have examined the effects of selection for high oil or protein content on the chemical composition of cereal seeds. This study was conducted to examine agronomic and bioenergetic consequences that result with changes in the chemical composition of groats of oat (Avena sativa L.). Oat lines with low and high groat-oil content (GO) and with low and high groat-protein content (GP) were chosen from each of five cycles of a recurrent selection program for increasing GO and from each of four cycles of a recurrent selection program for increasing protein yield via elevating GP, respectively. These lines were evaluated at three Iowa locations in 1988. The results indicated that GP was not significantly affected by selection for high GO and that GO significantly increased during selection for high protein yield via elevating GP. Both selection procedures resulted in oat lines with higher groat-energy contents. A bioenergetic cost analysis showed that for GO in the oil population and GP in the protein population to be increased, additional photosynthate needed to be available.     

Physiological Evaluation of Drought Resistance in Oats

Twelve varieties of Oat ( Avena sativa L.) were screened for relative drought tolerance based on the magnitude of chlorophyll stability index (CSI), relative water content (RWC) and free proline accumulation. IGFR1-2670, IGFRI-3021, IGFRI-2688 and IGO-8 showed a lower magnitude of CSI under stress condition in comparison to other tested varieties whereas the values of RWC and tree proline accumulation were higher. Based on the observations of this study it is concluded that, of the varieties tested, IGFRI-2670, 3021 2688 and IGO-8 are relatively more drought tolerant than the other genotypes tested. A close agreement was also noticed amongst the trends of CSI and proline accumulation, and per cent reduction in yield in rainfed over irrigated conditions.     

High Phytomass Producing Oats for Cultivation in Northern Growing Conditions

It has been argued that the breeding of cultivars with higher weight per panicle but constant phytomass (i.e., improved harvest index) is unlikely to improve grain yield of cereals in the future. To examine this question in oats, this study observed relationships between above-ground phytomass production and grain yield as well as 18 morphological and physiological traits representing maturity class and architecture of oat stand. The study was conducted in two dissimilar growing seasons. Material consisted of 29 Finnish and Scandinavian oat cultivars and breeding lines. Correlations between phytomass and other traits were evaluated by linear regression analysis. The study revealed that there has already been a trend toward improving the above-ground phytomass production in cereal breeding in Finland. The phytomass elevation can be attributed to both higher panicle weight as well as increased above-ground vegetative phytomass. Thus, improved grain yield of oats is not merely a consequence of increased harvest index, as is often mentioned, but is also a result of higher phytomass as such. The weight of the above-ground phytomass did not correlate with undesirable traits such as plant height or susceptibility to lodging, but it did have a positive relationship with days to yellow ripening. The applicability of phytomass weight in indirect yield breeding of oats in the northern growing conditions is discussed.     

Competition and Productivity in Mixture of Oats and Wheat

The research assesses the productivity of mixture of oats (Avena sativa) and wheat (Triticum aestivum), and compares two different approaches used in plant competition studies: replacement (substitutive) designs and additive designs. The experiment was carried out on sandy loam soil at the Experimental Station of Agricultural University of Wrocław (Poland). Oats and wheat were grown for grain as sole crops and in 1 : 1 replacement mixtures at three rates of seeding: 150, 300 and 600 viable seeds m⁻². These designs allowed mixtures seeded at a rate of 300 and 600 seeds m⁻² to be analysed according to either a replacement or an additive approach. In 1999, pure stand wheat and oats–wheat mixture yielded significantly more grain than oats grown alone but in 2000 there was no difference in yield. Wheat outcompeted oats in mixture but the relative competitive ability of the two species changed little with increasing seeding density. Relative yield total (RYT) for grain was significantly >1.0 (RYT = 1.07) in 1999 for the lowest seeding density, showing partial complementarity in use of limiting resources by the species in mixture. Based on grain yields, the results obtained from substitutive and additive mixtures were similar with respect to the relative yields and relative competitive ability of the two species concerned.     

不同药剂浸种对燕麦种子发芽特性的影响

利用不同化学药剂处理燕麦种子对提高燕麦的出苗率、燕麦产量具有显著效果。本试验采用生化黄腐酸、氯化钙、赤霉素、乙酰水杨酸对燕麦种子进行浸种处理24h,然后在15%PEG渗透胁迫液(模拟干旱)中进行萌发试验,探讨化学药剂处理对燕麦种子发芽势、发芽率和物质转换率的影响。结果表明,赤霉素、生化黄腐酸和氯化钙溶液浸种可提高燕麦种子在干旱条件下的发芽率、发芽势和物质转换率;而乙酰水杨酸溶液浸种对燕麦种子萌发有抑制作用。综合效果来看,0.025%的赤霉素处理燕麦种子效果最佳,0.10%～0.15%生化黄腐酸和0.15%～0.20%氯化钙处理燕麦种子效果次之。     

Direct and Correlated Responses to Four Cycles of Divergent Selection for Heading Date in Barley*

In order to investigate the direct and correlated responses to selection for heading date in barley, two F₂ populations were subjected to four cycles of divergent selection. For each cross, eight populations selected for earliness (from 1E to 4E) and for lateness, (from 1L to 4L) and four unselected populations (1, 2, 3 and 4 SSD) were obtained and than compared together with parental lines. Selection caused a change greater than one day/cycle in Doth directions, and the cumulative responses were -5.4 and -5,9 days in the direction of earliness, 7.7 and 7,1 days in the opposite direction. Such results suggest that in the two base populations the heading, date is under the control of a polygenic system with prevailing additive effects and a slight directional dominance toward earliness. Early populations showed a reduction of ear moisture and an increase of plant height, ear extrusion, kernel weight and harvest index, whereas late populations showed the opposite changes. Grain yield was linearly reduced by selection for lateness, whereas no substantial change was evidenced in the opposite direction, so that 4E significantly out-yielded 4L in both crosses.     

低温胁迫对燕麦种子萌发期蛋白质组影响的研究

为探析燕麦种子萌发时蛋白质的差异表达及其相关蛋白的生理功能,采用室内生测法比较了不同温度下种子萌发力和幼苗的生长能力,同时采用双向电泳(2-DE)结合基质辅助激光解析飞行时间质谱的方法,比较低温条件下(5℃)吸胀25 h和128 h(萌发)与正常温度下吸胀25 h(萌发)时种子蛋白质组的差异表达.结果表明,随着温度的降低,燕麦种子的萌发活力降低.燕麦种子蛋白质组在低温胁迫下萌发时,有7个蛋白质点发生了变化,其中5℃低温吸胀25h时,有3个蛋白质点的表达量降低;5℃低温吸胀萌发128h时,有5个蛋白质点表达发生了改变,其中3个蛋白质点的表达量增加.经MALDI-TOF质谱鉴定分析和Mascot搜索NCBI非冗余数据库,确定了4个蛋白质,分别为燕麦蛋白、燕麦蛋白N9和丝氨酸蛋白酶抑制剂等.这些蛋白质的质量变化与燕麦种子萌发时的低温胁迫可能有关联.     

陆地棉超高产轮回选择群体创建及其选择

构建陆地棉超高产轮回选择群体基础群体的亲本材料包括皖杂40的亲本I40006和I40007、湘杂棉2号的亲本I40001和I40005、中杂028的亲本中4133以及优良种质中棉所23和苏棉12。将源于长江流域的材料和源于黄河流域的材料分别互交,其后代自交后分别再在长江流域材料和黄河流域的材料内进行株与株间的选择交配,得基础群体一（Q10     

Recurrent Selection for Increased Grain Yield and Resistance to Downy Mildew in Pearl Millet*

Six pearl millet (Pennisetum glaucum [L.] R. Br.) composites were subjected to three or more cycles of selection in multilocational yield trials and downy mildew disease nurseries in India. The base and selected populations were tested (a) over four years at three locations in India (11° to 29°N), (b) under terminal-drought and optimal moisture conditions for two years, and (c) under induced downy mildew infections to determine the impacts of selection on grain yield, agronomic traits, and resistance to downy mildew (Sclerospora graminicola Sacc. Schroet.). Mean grain yield increases for four composites undergoing three to six cycles of selection ranged between 23 to 94 kg ha^-1 cycle^-1 (0.9 to 4.9 % cycle^-1) which, averaged over composites, amounted to 3.3 % cycle^-1. Yield gains were generally expressed at all test locations and under both terminal-drought and optimal moisture environments. The gains in grain yield were associated with increases of both biomass and harvest index without extending the growth duration except in the earliest composite. Susceptibility to downy mildew remained below 10 % in all selected populations. Thus, the effectiveness of recurrent selection for increasing yield and yield stability of pearl millet is clearly demonstrated.     

大棚内麻地膜覆盖栽培下辣椒的营养生长和产量研究

为明确大棚内麻地膜覆盖对辣椒营养生长的影响,测量不同覆盖处理下辣椒主要营养生长时期的株高和分枝级数,开花初期的开花率,结果初期的结果率,结果期辣椒的总产量,拔棵期辣椒的营养器官干物质积累及养分积累。结果表明,白色麻地膜覆盖下辣椒的株高一直最高,除5月2日取样外,其余时期分枝级数也最多;白色麻地膜覆盖下辣椒营养器官干物质积累和养分积累最高;白色麻地膜覆盖辣椒开花率比无覆盖高53.34%,结果率同样为白色麻地膜覆盖最高;白色麻地膜覆盖产量比无覆盖高31.20%。研究表明,麻地膜覆盖促进辣椒营养生长,同时没有对生殖生长造成不利影响,可以增加辣椒产量。     

Change of Expected Response to Multitrait Selection in a Synthetic Population of Perennial Ryegrass Through Recurrent Selection

The changes in genetic parameters, variances, covariances and heritabilities, caused by the Bulmer effect have been predicted for an artificial breeding population of perennial ryegrass using recursion formulae. This enabled anticipation of the decrease in the expected response to multitrait index selection, using two different sets of economic weights. This theoretical decrease in selection efficiency was found to be quite substantial; it is approximately halved after 4 cycles of individual recurrent selection with a fairly high selection intensity of 5 %. However the synthetic population is improved for 4 out of 5 agronomic traits and could theoretically reach quite a high level of performance after 5 cyles. The choice of economic weights has relatively little influence on the expected genetic progress of each trait.     

云南稻种资源胚乳蛋白质的变异

本文报道了对云南省100个水稻样品, 其中包括81个地方种、 10个改良种和9个低 直 链淀粉含量突变体进行十二烷硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)分析的结果。 从电泳 带谱上可以看出： 高分子蛋白质(第10条和第11条带), 谷朊α-3亚基及低分子蛋白质( 第 56条和第57条带)均有变异。 根据电泳带谱变异, 可将水稻样品分成7     

不同生态型芸芥响应盐胁迫的有机物质初步研究

为了探明有机渗透调节剂在耐盐性中的作用,本研究以芸芥耐盐生态型和不耐盐生态型为试材,测定了盐胁迫下芸芥叶片可溶性蛋白、脯氨酸、可溶性糖含量等。结果表明,渗透势和可溶性蛋白含量在两种生态型间均无明显差异;叶片渗透势和有机渗透调节剂之间没有呈现一致性的变化趋势;不同盐胁迫下,耐盐生态型较不耐盐生态型含有较多的脯氨酸,而在高盐胁迫下,在耐盐生态型中还检测到了高浓度的可溶性糖和游离氨基酸。随着盐浓度的升高,耐盐生态型中可溶性蛋白的总量缓慢增加,但当盐浓度大于200 mmol L_-1时,可溶性蛋白的含量下降。这些结果初步证明,脯氨酸、可溶性糖和游离氨基酸在盐胁迫应答中起关键作用,可作为选择耐盐芸芥的标准。     

Response to Mass Selection for Plant Height and Grain Yield in Amaranth (Amaranthus spp.)

Two landrace accessions of amaranth, UCC 192 (Amaranthus cruentus) and UCH 213 (A. hypochondriacus), were used in a mass selection experiment; five per cent of the tallest and highest yielding plants in both populations were selected for three cycles. Selection gain was largest in the first cycle for both traits. Realized heritability estimates for plant height were C.22 in the UCC 192 population and 0.49 in UCH 213, and 0.09 in both populations for yield. The results supported earlier findings for the existence of genetic variability within amaranth landrace populations.     

Chromosomal location of genes for resistance to powdery mildew in cultivated oat (Avena sativa L.). 1. Gene Eg-3 in the cultivar 'Mostyn'

The cultivar 'Mostyn' of hexaploid oat ( Avena sativa L.) possesses a dominant gene conferring resistance to powdery mildew caused by Erysiphe graminis avenae. The resistance gene, designated Eg -3, was derived from the wild oat Avena sterilis L. var. ludoviciana. Monosomic analysis revealed that this gene was located on chromosome 17, which corresponds to the missing chromosome in the 'Kanota' monosomic line Kl1. This chromosome is associated with the homoeologous group 1 of the Triticeae.     

Leaf Area Duration of Oat at High Latitudes

Contribution of leaf area duration (LAD) to grain yield during the short growing season characteristic of northern latitudes may differ from the marked impact it has at lower latitudes. Three experiments (exps) were carried out at Viikki Experimental Farm, University of Helsinki, Finland (60° 13′N) to compare associations between main shoot and tiller LAD with grain yield, yield components and morpho-physiological traits characterizing plant stand structure. This was done using correlation analysis and principal component analysis (PCA) for data from trials conducted during 1993–1995. Exp I included three N fertilizer rates (80, 120, 160 kg N ha^?1), three seeding rates (250, 500, and 750 seeds m^?2), and tall, moderate, semi-dwarf, and dwarf oat lines. Exp II incorporated two N fertilizer rates (80 and 120 kg ha^?1), three seeding rates (400, 600, and 800 seeds m^?2), and naked and hulled oat lines, and exp III, foliar applications of plant growth regulators [control, chlormequat chloride (CCC), and ethephon], and dwarf, naked, and conventional oat lines. LAD for main shoots and tillers [calculated as ∫ LAI d T, where T is cumulated degree days from seedling emergence to yellow ripening (dd °C)] and 12 morpho-physiological traits were measured. Oat was not able to benefit from high main shoot LAD if drought occurred at grain-fill, but in the absence of severe drought or if it occurred at pre-anthesis, high LAD favoured yield formation. Tiller LAD had a negative impact, if any, on grain yield in cases of an inverse relationship between tiller LAD and yield components on main shoots was recorded. Use of low seeding rates resulted in improved ability of total LAD to contribute to dry-matter production, but was not associated with grain yield. Low seeding rates enhanced formation of high tiller LAD, which was not able to compensate for grain yield reduction caused by fewer main shoots. Foliar application of CCC and ethephon tended to increase the proportion of LAD production by tillers at the expense of grain yield, which can be attributed to lower post-anthesis precipitation. Oat types differed in main shoot and tiller LAD. Disadvantageous characteristics of naked oat, such as low single groat weight, were not associated with insufficient main shoot LAD. High tiller LAD in naked lines and the Minnesota-adapted dwarf line that was not associated with high tiller grain yield in naked lines, in particular, indicates that tiller growth was enhanced at the expense of grain yield production. Application of N fertilizer at various rates did not have any effect on LAD.     

大豆籽粒蛋白质含量早世代选择效果及其对产量和脂肪含量的影响

随着科学技术的发展及人民生活水平提高,选育优质农作物品种已成为我国农作物育种的重要任务。提高大豆籽粒蛋白质含量则是优质大豆新品种选育的主要目标之一。因此,探讨提高蛋白质含量的选择方法及其对产量和脂肪含量的影响具有重要的意义。本试验利用3个杂交组合早世代以蛋白质含量高、中、低3组进行选择,分析蛋白质含量选     

轮回选择对豫综5号玉米群体产量性状配合力的改良效果

玉米群体遗传基础广泛、遗传变异丰富,是培育优良玉米自交系的源泉。玉米群体的改良研究对玉米种质资源创新、优良自交系选育具有重要的指导意义。本研究采用NC II遗传交配设计,以豫综5号5个轮次改良群体为父本,以黄早四、丹340、中综5号、齐319、掖478、Mo17为测验种配制成30个测交组合,通过一年两点的产量性状及其配合力评价试验,研究轮回选择对豫综5号群体的改良效果。结果表明,轮回选择对群体单株产量的改良是有效的,群体与各测验种间的杂交后代产量平均每轮提高3.57%。半姊妹轮回选择和相互半姊妹轮回选择在改良群体产量一般配合力方面, 均得到显著提高,呈逐轮上升的趋势;采用半姊妹轮回选择对豫综5号群体3轮的选择后,C₃群体与C₀相比,一般配合力效应值从–11.63增长到5.57,差异极显著;经1轮相互半姊妹轮回选择后,群体的一般配合力效应值从C₃的5.57增加到C₄的9.75。豫综5号改良群体与黄早四的特殊配合力得到一定的提高,逐轮朝着Reid×唐四平头杂优模式水平提高的方向稳定发展。