Infection processes and soft wheat response to root rot and crown rot caused by Fusarium culmorum

An isolate of the fungus Fusarium culmorum constitutively expressing green fluorescent protein was used to investigate the infection process and host response of primary seedling roots and stem base leaf sheaths of soft wheat cv. Genio. Disease progress was assessed macroscopically by visual symptoms, microscopically by confocal laser scanning microscopy (CLSM) and via gene expression analysis of fungal and wheat genes by real‐time quantitative RT‐PCR. In the roots, CLSM investigations revealed an initial intercellular and subsequent intracellular colonization by fungal hyphae. The fungus invaded the rhizodermal layer and cortex but was not seen to colonize the stele. The fungus consistently expressed TRI5 (24, 48 and 96 h post‐inoculation), indicating that trichothecenes were being synthesized throughout this phase of infection and colonization. The expression of the six host defence‐associated genes (Wheatwin 1‐2, PR1, Chitinase, PAL, WIR1 and LOX) increased early in infection and decreased during later stages. In the stem base, CLSM observations revealed the fungus sequentially penetrating though the first, second and third basal leaf sheaths. Expression of TRI5 was initiated early in the infection of each leaf sheath. The expression of the host defence‐associated genes varied over time and across leaf sheaths, and all were also expressed in leaf sheaths which had not yet been in contact with the fungus. Expression of LOX and WIR1 were particularly enhanced in the third leaf sheath.     

Wheat Seed Presoaking for Improved Germination

Seed presoaking improves wheat germination under marginal moisture conditions. The duration of seed presoaking was studied at The University of Arid Agriculture, Rawalpindi, using 10 wheat varieties. Seed presoaking beyond 12 h does not improve germination further, and beyond 21 h, germination rate is drastically reduced.     

湖北省小麦区域试验回顾

回顾了2001—2015年的15年时间内,湖北省小麦(Triticum aestivum L.)区域试验的基本情况和工作进展,指出按照目前的区域试验思路和方法可能影响到结果科学性的部分问题,并有针对性地提出了按水地和旱地小麦设置试验组别、结合相应对照品种评价参试品种、小麦区域试验应与小麦生产机械化接轨、加强区域试验人员的业务技能培训等建议,旨在进一步规范和完善湖北省小麦区域试验。     

油菜和小麦种苗根系对乙草胺的耐性差异分析

为揭示油菜和小麦根系对乙草胺耐药性差异的原因,采用水培法研究了梯度浓度乙草胺对油菜和小麦种苗根系形态、根尖生理代谢和解剖结构的影响。结果表明,1 mg/L乙草胺对油菜根长抑制率为33.63%,而对小麦根长抑制率可达55.22%;100 mg/L乙草胺对油菜侧根抑制率为63.03%,而对小麦侧根抑制率达100.00%;经0.01 mg/L乙草胺处理后的油菜根尖细胞膜透性高于小麦,当乙草胺浓度高于0.1 mg/L后,小麦根尖细胞膜透性剧烈增加且高于油菜;在较高浓度乙草胺胁迫下,小麦根尖抗氧化酶活性均低于油菜;10 mg/L乙草胺处理下,小麦根尖的解剖结构变异较油菜明显,表现为细胞排列松散、混乱,根冠变形,分生组织细胞染色程度变浅,伸长区细胞分化提前,中柱鞘细胞木质化。研究表明,小麦的根系建成比油菜更容易受乙草胺抑制,且侧根数比根长更敏感;油菜和小麦对乙草胺耐药性差异可能与细胞膜透性、抗氧化酶活性以及根尖细胞组织分化等差异有关。     

优质高产小麦新品种襄麦25的选育及应用

襄麦25是襄樊市农业科学院以矮败Tai1062为杂交平台与鄂麦19杂交后用系谱法选育而成的中筋、早中熟小麦新品种,2008年通过湖北省农作物品种审定委员会审定,适宜湖北省各麦区种植.该品种在产量、品质和抗性上都全面超过了郑麦9023,具有良好的开发应用前景.     

八倍体小滨麦与硬粒小麦杂交F1的细胞遗传学研究

八倍体小滨麦(OctoploidTritileymus)与硬粒小麦(Triticumdurum)的杂交研究结果表明以八倍体小滨麦作母本,硬粒小麦作父本时,杂交结实率较高,平均为28.47%,而其反交结实率较低,平均仅为5.84%。杂种F1自交结实率极低,平均为1.11%;F1形态兼具硬粒小麦、普通小麦(Triticumaestivum)和滨麦(L.mollis)特性;杂种F1PMCMI染色体构型主要是14 14 ,平均为13.51 13.82 0.14 0.10 0.02 ,普通小麦D染色体组与滨麦J、N染色体组配对频率分别为3.02%和3.57%,说明D组与J、N组间基本无同源关系。同时杂种F1PMC后期有落后染色体排列在赤道板上,末期和末期出现大量二分孢子、四分孢子带微核现象。     

四川和黄淮生态区小麦品种(系)主要产量性状比较

采用来自四川和河南两地区的主栽小麦(Triticum aestivum Linn.)品种和2012年两地部分区试小麦品系共27个材料,在河南辉县地区种植,随机区组法2次重复,生长期间和收获后调查产量结构性状,研究南方和北方生态区小麦品种产量构成的差异.比较分析结果表明:①四川品种在北方种植,其产量明显低于北方品种;②四川品种的穗粒数高于北方品种,但穗数和粒重低于北方品种;③北方的多穗型品种在北方生态区种植易获得高产,大穗型品种在产量结构合理的条件下也能获得较高产量;④单位面积穗数是北方冬麦区构成小麦产量的第一因素;⑤大穗型品种播量对单位面积穗数调节效果不明显.上述结果说明,不同类型生态区小麦最佳产量结构差异较大,北方品种高产主导因素是单位面积穗数,南方品种优势倾向于穗粒数.     

干旱条件下绵阳26小麦籽粒灌浆特性分析

[目的]探讨大田干旱情况下绵阳26及其姊妹系小麦籽粒灌浆过程及其影响因素。[方法]在大田持续干旱条件下,以绵阳26及其姊妹系共10个小麦品种(系)为试验材料,用Logistic方程对籽粒灌浆过程拟合,并推导出一系列次级参数,用相关、逐步回归与通径分析方法对不同灌浆参数与粒重关系进行分析。[结果]在干旱条件下,绵阳26及其姊妹系小麦的平均灌浆时间相对缩短;籽粒灌浆速率对小麦粒重形成作用明显,而灌浆持续时间与粒重形成无明显的相关关系;逐步回归分析和通径分析表明,灌浆持续期对千粒重可通过间接作用产生影响。[结论]在大田持续干旱条件下,绵阳26及其姊妹系小麦可通过不同的策略达到较高的千粒重。     

小麦BES1转录因子基因 TaBEH3的克隆及表达分析

BES1(油菜素内酯不敏感1-甲磺酸乙酯-抑制剂1)是一类植物特有的转录因子家族, TaBEH3基因是小麦 BES1基因家族成员之一,为进一步了解该基因的功能,以中国春为材料,克隆了 TaBEH3基因,将其3个同源基因分别命名为 TaBEH3-A、 TaBEH3-B和 TaBEH3-D。序列分析显示,3个同源基因均包含2个外显子,分别编码356、354和358个氨基酸,启动子区含有大量与植物生长发育、激素响应相关的顺式作用元件,其中,分生组织表达元件（CAT-box）和脱落酸响应元件（ABRE）在3个基因中普遍存在。系统进化树分析显示, TaBEH3基因在麦类作物中具有更近的亲缘关系。基于qRT-PCR进行的时空表达分析显示, TaBEH3基因在不同组织和不同器官间均有组成性表达,表明 TaBEH3基因在植物生长发育（特别是花器官的发育和形成）过程中具有重要的作用。 TaBEH3-A、 TaBEH3-B和 TaBEH3-D基因响应ABA激素胁迫处理,且3个基因的表达量变化趋势一致。     

Yield and water-production functions of two durum wheat cultivars grown under different irrigation and nitrogen regimes

Wheat (Triticum durum L.) yields in the semi-arid regions are limited by inadequate water supply late in the cropping season. Planning suitable irrigation strategy and nitrogen fertilization with the appropriate crop phenology will produce optimum grain yields. A 3-year experiment was conducted on deep, fairly drained clay soil, at Tal Amara Research Station in the central Bekaa Valley of Lebanon to investigate the response of durum wheat to supplemental irrigation (IRR) and nitrogen rate (NR). Three water supply levels (rainfed and two treatments irrigated at half and full soil water deficit) were coupled with three N fertilization rates (100, 150 and 200 kg N ha⁻¹) and two cultivars (Waha and Haurani) under the same cropping practices (sowing date, seeding rate, row space and seeding depth). Averaged across N treatments and years, rainfed treatment yielded 3.49 Mg ha⁻¹ and it was 25% and 28% less than half and full irrigation treatments, respectively, for Waha, while for Haurani the rainfed treatment yielded 3.21 Mg ha⁻¹, and it was 18% and 22% less than half and full irrigation, respectively. On the other hand, N fertilization of 150 and 200 kg N ha⁻¹ increased grain yield in Waha by 12% and 16%, respectively, in comparison with N fertilization of 100 kg N ha⁻¹, while for cultivar Haurani the increases were 24% and 38%, respectively. Regardless of cultivar, results showed that supplemental irrigation significantly increased grain number per square meter and grain weight with respect to the rainfed treatment, while nitrogen fertilization was observed to have significant effects only on grain number per square meter. Moreover, results showed that grain yield for cultivar Haurani was less affected by supplemental irrigation and more affected by nitrogen fertilization than cultivar Waha in all years. However, cultivar effects were of lower magnitude compared with those of irrigation and nitrogen. We conclude that optimum yield was produced for both cultivars at 50% of soil water deficit as supplemental irrigation and N rate of 150 kg N ha⁻¹. However, Harvest index (HI) and water use efficiency (WUE) in both cultivars were not significantly affected neither by supplemental irrigation nor by nitrogen rate. Evapotranspiration (ET) of rainfed wheat ranged from 300 to 400 mm, while irrigated wheat had seasonal ET ranging from 450 to 650 mm. On the other hand, irrigation treatments significantly affected ET after normalizing for vapor pressure deficit (ET/VPD) during the growing season. Supplemental irrigation at 50% and 100% of soil water deficit had approximately 26 and 52 mm mbar⁻¹ more ET/VPD, respectively, than those grown under rainfed conditions.