农药使用与植保技术问与答

<正>问:小麦品种选择不当怎么办?答:中、早茬地块播种春性及弱冬性品种,会导致麦苗冬前旺长,不利于安全越冬。在及早划锄、镇压的基础上,冬前壅土围根,或盖施"蒙头粪",保护麦苗安全越冬。     

普通小麦及其不同品种生态型生育期的地理变化

用普通小麦的春型强春性、春型春性、春型弱春性、过渡型4个品种生态型在我国纬度和海拔各不相同的10个试验点进行多年度同日春播试验；还用过渡型、冬型弱冬性、冬型冬性、冬型强冬性、冬型超强冬性5个品种生态型在纬度和海拔各不相同并且有小麦越冬期的10—12个试验点进行同日秋播试验。包括各个品种生态型在内的普通小麦，其播种至成熟的生育期天数与纬度和海拔皆呈正相关。在春播条件下。海拔不变时，纬度北移1度，生育期延长3—4天；纬度不变时，海拔每升高100米，生育期延长2—3天。在秋播条件下，海拔不变时，纬度北移1度，过渡型和冬型超强冬性品种生态型生育期延长2天左右；纬度不变时，海拔每升高100米，生育期也延长2天左右。无论春播或秋播，各型小麦品种的生育期皆与“生态高度”呈极显著正相关。生态高度每增加10000度米，生育期延长4—5天。试验研究有助于最终揭示普通小麦生育期的地理变化律。     

不同生态型小麦品种生长发育特性的研究

通过７个不同生态型的小麦品种在郑州４ａ１６个春、秋播期中的生育表现,提出了不同生态型品种在不同播期中的主茎叶片数,主茎叶龄等指标。如在秋播条件下的主茎叶片数春性品种为１２片,半冬性品种１３片,冬性品种１４片;主茎生长锥伸长时叶龄春性品种为３片左右,半冬性品种为４片左右,冬性品种为５片左右。     

内蒙古平原灌区“春麦冬播”种植效应及品种适应性

针对内蒙古春播小麦生育期短、干热风、高温逼熟等因素制约产量提高,且收获后光温资源极大浪费的现状,以及试种冬小麦发现的冬季冻害、春季干旱或"倒春寒"影响返青率及前茬限制等问题,本研究以"春麦冬播"种植模式为切入点,采用不同春化类型小麦品种,通过连续2年的田间试验,系统研究了不同小麦品种越冬出苗、叶片生理、根系性状及产量形成的差异,以期筛选适宜冬播的小麦品种。结果表明:供试的全部春性小麦品种及部分冬性品种可以以种子形式完成春化作用,第2年正常抽穗成熟。冬播条件下春季田间出苗率较春播小麦有所降低,但根系发达,对低温及干旱的适应性强。通过系统聚类筛选出适宜内蒙古平原灌区冬播的3个小麦品种,包括春性品种永良4号、冬性品种宁冬11号和半冬性品种河农7106,其共同特征为越冬出苗率高、抗逆性强、根系发达、产量表现较高,其中永良4号产量可达到与春播相同的水平。     

冬小麦播后管理技术问答

1．品种选择不当怎么办？ 中、早茬地块播种春性及弱冬性冬小麦品种，会导致麦苗冬前旺长，不利于安全越冬。对策：在及早划锄、镇压的基础上，冬前壅土围根，或盖施“蒙头粪”，保护麦苗安全越冬。     

陕西关中川水地小麦新品种筛选试验初报

为筛选出适宜关中灌区种植的最佳小麦品种,征集了陕西近年审定的一批川水地小麦新品种进行比较试验。结果表明,西农136、西农119、武农981丰产性优于对照西农822;西农136、西农119冬季抗寒性较好,分蘖力较强,成穗率较高,灌浆速度快,熟相好,穗粒数及千粒重较高,三要素协调,株高适宜,综合抗性好,次年可大面积推广;武农981大穗大粒,春性较强,抗寒能力较差,可适期晚播并适当增加播量;武农6号产量与对照相当,但其抗性较好,生育期最短,较对照早熟5 d,建议在复种区域种植。     

河南省彩色小麦品种冬春性鉴定研究

为了探索冬春性鉴定指标在彩色小麦上的应用效果,进一步明确新育成小麦品种的春化特性,准确鉴定小麦品种的冬春性类型,防范因品种定性不准造成小麦冬春冻害风险,以冬春性类型不同的小麦品种为试验材料,通过连续3年的春播试验,对彩色小麦冬春性鉴定应用情况进行汇总分析。由试验结果可知,春播二期条件下的抽穗率是评价小麦品种冬春性的根本指标,是彩色小麦冬春性鉴定的最佳指标。     

越冬期抗寒性不同冬小麦品种间生理指标的比较

以抗寒性不同的4个冬小麦品种为材料,对其在越冬期间叶鞘内丙二醛、可溶性蛋白和脯氨酸生理指标的含量进行测定,以分析高寒地区冬小麦抗寒性的遗传改良潜力.越冬期间,抗寒性强的品种(系)的丙二醛含量较低,可溶性蛋白含量较高；在低温驯化期抗寒性强的品种脯氨酸含量迅速增加,在越冬期各品种脯氨酸含量均保持较高水平.     

白菜型冬油菜叶片结构和光合特性对冬前低温的响应

为明确白菜型冬油菜在冬前低温下叶片结构特征、光合作用特性及其抗寒性,本研究在0℃和–7.6℃自然低温条件下,选用白菜型冬油菜品种陇油7号(超强抗寒)和天油4号(弱抗寒),测定并比较其叶片气孔性状、解剖结构和光合、荧光参数的日变化等指标。结果表明,随着冬前温度下降,2个白菜型冬油菜叶片气孔密度、气孔面积、气孔周长、栅栏组织和海绵组织厚度均变小,细胞间隙变大,叶片变薄;P_n日变化呈"单峰"型曲线,无光合"午休"现象;叶片的P_n、G_s、T_r和CE均降低,而C_i均升高,说明是非气孔限制引起P_n降低。白菜型冬油菜在冬前低温条件下发生了光抑制现象,表现为F_m和F_v/F_m下降,F_o上升。与超强抗寒品种陇油7号相比,弱抗寒品种天油4号叶片气孔密度和气孔面积均较大,气孔总周长较长,叶片较厚,P_n、F_m和F_v/F_m均较高,说明冬前低温条件下,天油4号光合能力较强,光抑制程度较弱。白菜型冬油菜在冬前低温条件下的叶片气孔密度越大、气孔面积越大、气孔周长越长、叶片及栅栏组织和海绵组织越厚,光合能力越强,地上部生长越旺盛,品种抗寒性越差。本研究为冬油菜抗寒种质创新和育种提供了部分理论支撑。     

中国主要小麦品种春化基因的STS标记鉴定

本文选取来自中国各麦区的260份小麦品种,用STS标记对其Vrn-A1、Vrn-B1、Vrn-D1和Vrn-B3四个春化基因位点进行检测,并结合小麦田间生长情况记录,探讨春化基因的4个位点显隐性情况对品种冬春性的影响.结果表明,各位点显性基因频率以Vrn-D1位点最高,而Vrn-A1和Vrn-B1显性等位基因对品种冬春性的影响高于Vrn-D1和Vrn-B3基因,且所含显性春化基因越多的品种生长习性越偏向春性.另发现,Vrn-A1仅存在于春性品种中;而对于冬性品种来说,各位点均不含显性春化基因.本文标记鉴定结果与田间冬春性观察具有较高的一致性,在小麦育种及品种推广中具有较高的指导意义和应用价值.     

Genetic variation for resistance to Fusarium head blight in bread wheat

Summary During a four year period, a total of 258 winter and spring wheat genotypes were evaluated for resistance to head blight after inoculation with Fusarium culmorum strain IPO 39-01. It was concluded that genetic variation for resistance is very large. Spring wheat genotypes which had been reported to be resistant to head blight caused by Fusarium graminearum were also resistant to F. culmorum. The resistant germplasm was divided into three gene pools: winter wheats from Eastern Europe, spring wheats from China/Japan and spring wheats from Brazil. In 32 winter wheat genotypes in 1987, and 54 winter wheat genotypes in 1989, the percentage yield reduction depended on the square root of percentage head blight with an average regression coefficient of 6.6. Heritability estimates indicated that for selection for Fusarium head blight resistance, visually assessed head blight was a better selection criterion than yield reduction.     

Abortion of infection structures of wheat leaf rust in susceptible and partially resistant wheat genotypes

Summary Arrest of the growth of wheat leaf rust infection structures was studied with fluorescence microscopy in seedling leaves and flag leaves of the susceptible spring wheat genotypes Morocco and Kaspar and the partially resistant genotypes Westphal 12A and Akabozu. The percentages non-penetrants and substomatal vesicle abortion were low in all genotypes. In the partially resistant genotypes the percentage abortion of infection structures was higher than in the susceptible genotype Morocco. Aborted infection structures had formed one or two haustorial mother cells. In adult plants differences in the percentage aborted infection structures between susceptible and partially resistant genotypes were more pronounced than in seedlings. The so-called late abortion was not observed.     

Influence of winter and spring wheat genetic backgrounds on haploid induction parameters and trait correlations in the wheat × maize system

The interactive influence of winter and/or spring wheat genetic background on haploid induction parameters and trait correlation was studied by hybridizing five elite and diverse genotypes each of winter and spring wheat and their F₁s (winter × winter, spring × spring, and winter × spring, generated in a diallel design excluding reciprocals) with a single genotype of maize. Data were recorded with respect to per cent seed formation, embryo formation, and regeneration. High genetic variability was present among the wheat genotypes (parents + F₁s) for the three haploid induction parameters. Significant differences were obtained within and between different groups viz., spring wheats, winter wheats, spring × spring wheats, winter × winter wheats, and winter × spring wheats with respect to the three haploid induction parameters based on ANOVA. The winter genotypes (winter parents and winter × winter wheat hybrids) responded better than the spring groups (spring wheat parents, spring × spring and winter × spring wheat hybrids) with respect to embryo formation and winter × spring wheat hybrids yielded significantly the highest numbers of regenerants. Correlation studies amongst the haploid induction parameters indicated that the genes controlling seed formation and haploid plantlet regeneration are negatively correlated when the genetic backgrounds of both ecotypes are combined in winter × spring hybrids. Haploid embryo formation had no association with seed formation and regeneration in all genetic backgrounds, suggesting independent inheritance.     

高寒地区冬小麦东农冬麦1号越冬前的生理生化特性

在北方寒地田间自然条件下,于越冬前不同时期(不同气温)分别对抗寒冬小麦品种东农冬麦1号(返青率大于85%)和非抗寒品种济麦22(返青率小于1%)的叶片、分蘖节和根取样,测定其与抗寒相关的一些生理生化指标。结果表明,东农冬麦1号的可溶性糖、可溶性蛋白、脯氨酸、叶绿素含量,以及超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均高于济麦22;组织含水量、相对电导率均低于济麦22,说明东农冬麦1号的抗寒适应性强于济麦22。分蘖节储备抗寒物质的能力最强,是小麦安全越冬中起重要作用的器官。     

Variation of PGM and IDH isozymes for identification of alfalfa varieties

Growth habit, heading date and Vrn genotypewere examined for wheat landraces cultivated in China,Korea and Japan, to study their ecogeographicaldifferentiation in east Asia. Spring type landracesaccounted for 43.6% of the whole, and the frequencyvaried between the localities, being closely relatedto the degree of winter coldness. Spring typelandraces mainly adapted to north and south Chinawhere average January temperature is under –7 ^°Cand over 4 ^°C, respectively. On the contrary,winter type adapted to areas of average Januarytemperature from –7 ^°C to 4 ^°C. As toheading date, significant difference was not observedbetween spring and winter type landraces but betweenlocalities, and those cultivated in north China weresignificantly later in heading. It is thereforeindicated that spring type mainly adapts to areaswhere wheat is sown in spring to avoid frost injury,and where winter temperature is not low enough tovernalize winter type wheat. Genetic analysis forspring type landraces showed that the relativefrequency of four Vrn genes was different witheach other. Vrn3 was most widely and frequentlyfound among the four genes, followed by Vrn1 andVrn2. Only seven landraces proved to be thecarrier of Vrn4. The frequency was alsodifferent between localities. Genotype with Vrn1plus other dominant gene(s) adapted to spring sowingto avoid severely cold winter in north China, whilegenotype with only Vrn3 adapted to winter sowingin south China and southwest Japan. It is thereforeconcluded that at least three ecotypes, differing ingrowth habit and Vrn genotype, areallopatrically distributed in east Asia, as a resultof adaptation to winter coldness in each locality.     

Iron and zinc grain density in common wheat grown in Central Asia

Sixty-six spring and winter common wheat genotypes from Central Asian breeding programs were evaluated for grain concentrations of iron (Fe) and zinc (Zn). Iron showed large variation among genotypes, ranging from 25 mg kg⁻¹ to 56 mg kg⁻¹ (mean 38 mg kg⁻¹). Similarly, Zn concentration varied among genotypes, ranging between 20 mg kg⁻¹ and 39 mg kg⁻¹ (mean 28 mg kg⁻¹). Spring wheat cultivars possessed higher Fe-grain concentrations than winter wheats. By contrast, winter wheats showed higher Zn-grain concentrations than spring genotypes. Within spring wheat, a strongly significant positive correlation was found between Fe and Zn. Grain protein content was also significantly (P < 0.001) correlated with grain Zn and Fe content. There were strong significantly negative correlations between Fe and plant height, and Fe and glutenin content. Similar correlation coefficients were found for Zn. In winter wheat, significant positive correlations were found between Fe and Zn, and between Zn and sulfur (S). Manganese (Mn) and phosphorus (P) were negatively correlated with both Fe and Zn. The additive main effects and multiplicative interactions (AMMI) analysis of genotype × environment interactions for grain Fe and Zn concentrations showed that genotype effects largely controlled Fe concentration, whereas Zn concentration was almost totally dependent on location effects. Spring wheat genotypes Lutescens 574, and Eritrospermum 78; and winter wheat genotypes Navruz, NA160/HEINEVII/BUC/3/F59.71//GHK, Tacika, DUCULA//VEE/MYNA, and JUP/4/CLLF/3/II14.53/ODIN//CI13431/WA00477, are promising materials for increasing Fe and Zn concentrations in the grain, as well as enhancing the concentration of promoters of Zn bioavailability, such as S-containing amino acids.     

Shortening generation times for winter cereals by vernalizing seedlings from young embryos at 10 degree Celsius

Methods allowing quick generation cycles are available for various crop species but are limited to spring genotypes. However, winter types predominate in many crops including wheat and barley. Different from spring ones, winter genotypes need to be treated in low temperature for extended periods to accelerate flowering. Combined with known factors that reduce generation cycles for spring wheat and barley, the generation cycle effects of vernalizing seedlings from young embryos of winter types at 10°C of several crop species were studied. Here, we described how to obtain up to seven generations of winter barley, six generations for winter wheat or five generations for both winter oat and triticale genotypes per annum. This procedure should find wide applications in breeding and other biological studies.     

Adaptation and ecological differentiation in wheat with special reference to geographical variation of growth habit and Vrn genotype

Geographical variation of growth habit was studied for 749 landraces from various parts of the world, with special reference to their adaptation and ecogeographical differentiation. The total frequency of spring‐type landraces was 49.9%, and varied between localities. Spring‐type landraces were frequent in two distinct areas where the average January temperature was either below ‐7°C or above 4°C, with winter‐type landraces in areas from ‐7°C to 4°C. These results indicated that geographical variation of growth habit is closely related to the degree of winter coldness. An analysis of the Vrn genotype for 216 spring‐type landraces demonstrated the uneven distribution of four Vrn genes, with Vrn4 being the least frequent. The adaptive Vrn genotype was different between localities. Genotypes carrying Vrn‐A1 and additional Vrn gene(s) were frequent in two distinct areas where the average January temperature was either below ‐7°C or over 10°C, while genotypes with any of three Vrn genes, except Vrn‐A1, adapted to areas with temperatures from 4°C to 10°C. Therefore, it was concluded that the adaptability of wheat landraces differed depending on their growth habit and Vrn genotype, and that ecotypes with different Vrn genotypes were allopatrically distributed as a result of adaptation to different winter temperature. However, the differential distribution of Vrn‐B1, Vrn‐D1 and Vrn4 could not be explained by their adaptability, and might reflect the polyphyletic origin of common wheat.     

Spring Freeze Effect on Wheat Yield is Modulated by Winter Temperature Fluctuations: Evidence from Meta‐Analysis and Simulating Experiment

Increasing climatic variability is projected to affect large‐scale atmospheric circulation, triggers and exacerbates more extreme weather events, including winter warming and more frequent extreme low temperatures in spring. Historical data from 1961–2000 indicate these temperature fluctuations may seriously affect grain yield of winter wheat crops. In this study, a field air temperature control system (FATC) was used to simulate the winter warming, spring cold and freezing events in the field experiment in 2010–2011 to explore their impacts on growth and yield of winter wheat. Eight elite wheat varieties released during 1961–2000 were included and four temperature scenarios were applied, including late spring freeze alone, winter warming + late spring freeze, early spring cold + late spring freeze and the normal temperature condition as control. Winter warming combined with late spring freeze significantly decreased tiller survival rate, leaf photosynthetic rate and leaf growth in wheat plants, and reduced the spike number and kernel number per spike, and the final grain yield. In contrast, the wheat plants experienced early spring cold had higher tiller survival rate, leaf photosynthetic capacity and sugar accumulation and improved tolerance to the late spring freeze, resulting in less yield loss, as compared with those without experiencing early spring cold. Both the meta‐analyses and the field experimental data demonstrated that the effects of later spring freeze stress on wheat yield were exacerbated by winter warming but were extenuated by early spring cold events. Therefore, it is important to consider the characteristics of temperature fluctuations during winter to spring for precise evaluation of climate change effects on wheat production.     

Resistance to multiple leaf spot diseases in wheat

Tan spot (TS), Stagonospora nodorum blotch (SNB), and Septoria tritici blotch (STB) are three major leaf spot diseases of wheat worldwide. Host plant resistance (HPR) is one of the main components in the management of these diseases in wheat. The objective of this study was to identify new sources of resistance to TS (races 1 and 5), SNB, and STB. A total of 164 wheat genotypes developed by the International Maize and Wheat Improvement Center (CIMMYT), Mexico were individually evaluated for TS, SNB and STB in spring and fall of 2006 in the greenhouse. Two experiments were conducted in a randomized complete block design with three replicates. Each replicate consisted of 164 wheat genotypes planted in cones with three seedlings/genotype in each cone and disease reaction was assessed for each race or pathogen at the two- to three-leaf stage. Based on the disease reactions, three wheat genotypes were resistant to both TS and SNB, while 13 genotypes were resistant to TS and STB. Similarly, 13 genotypes were resistant to both SNB and STB. In addition, four wheat genotypes were highly resistant to TS, SNB, and STB. These results suggest that the resistant genotypes identified in this study possess high levels of resistance to multiple leaf spot diseases and could be valuable sources for wheat improvement programs.