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Breeding Winter Wheat for Improved Powdery Mildew Resistance and Weed Suppressive Ability against Italian Ryegrass.

机译:选育冬小麦,以增强抗白粉病和抗意大利黑麦草的杂草抑制能力。

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摘要

Interest in breeding wheat (Triticum aestivum L.) cultivars adapted to organic production systems is growing in response to rapidly expanding market opportunities in the southeastern United States. Breeding for resistance to biotic stresses is a major focus of the North Carolina State University small grains breeding program. Resistance to these pests and diseases is particularly important in organic systems, where the use of synthetic fungicides and insecticides is prohibited. Resistance to powdery mildew (Blumeria graminis DC f. sp. tritici) and weed suppressive ability against Italian ryegrass ( Lolium perenne L. ssp. multiflorum (Lam.) Husnot) are considered high priority traits for organic wheat producers in North Carolina. Emphasis on breeding for novel sources of powdery mildew resistance is essential because of the rapid evolutionary potential of the pathogen. Italian ryegrass, a major weed in small grain crops, has been identified as a major limitation to organic wheat production in the region. Although Italian ryegrass is controlled with herbicides in conventional production, the efficacies of popular chemical herbicide classes are threatened by the rapid expansion of resistant biotypes. T herefore breeders in the region are increasingly interested in developing weed suppressive wheat cultivars that suppress Italian ryegrass growth and reproduction and complement chemical herbicide options. The wheat germplasm line NC09BGTUM15 (NC-UM15) possesses the first form of powdery mildew resistance introgressed from Aegilops neglecta Req. ex Bertol. Evaluations of F 2:3 families derived from the cross NC-UM15 x 'Saluda' indicated that a single dominant gene, MlUM15, conferred disease resistance. Molecular markers specific to chromosome 7AL segregated with the resistance gene. The multi-allelic Pm1 locus also maps to this distal region of chromosome 7AL. Detached leaf tests revealed that NC-UM15 had a different disease response pattern from lines possessing alleles of the Pm1 complex. Allelism tests with Pm1 will be required to elucidate the relationship between MlUM15 and other Pm loci on 7AL. Research was conducted to identify indirect methods of selection for weed suppressive ability of winter wheat cultivars that correlate well with Italian ryegrass to wheat biomass ratios. Italian ryegrass seed head density and visual estimates of Italian ryegrass biomass during grain fill were highly correlated with Italian ryegrass to wheat biomass ratios and are considered appropriate indirect methods of selection for weed suppressive ability. Fifty-three entries from the North Carolina Official Variety Test (NC OVT) were evaluated for weed suppressive ability against Italian ryegrass in order to identify wheat morphological traits and molecular markers that could facilitate indirect selection for weed suppression. Weed suppressive ability was correlated (P < 0.05) with high early vigor (Zadoks GS 25 and 29), erect growth habit (Zadoks GS 29), high leaf area index (LAI) (Zadoks GS 31), high vigor rating (Zadoks GS 55), and height throughout the growing season in three of four sites. The winter-type short vernalization allele vrn-B1a-in1 was found more commonly than expected by chance among highly weed suppressive lines at both sites in 2012. Research was also conducted to test the relative importance of allelopathy and competitive ability on weed suppression outcomes in the field. Fifty-eight wheat lines from the NC OVT were screened for allelopathic activity against Italian ryegrass in a seedling bioassay. Eight strongly and weakly allelopathic lines with varying final height were then evaluated for weed suppressive ability in the field. Although the allelopathic activity of genotypes differed significantly in the seedling bioassay, no correlations between allelopathy and weed suppression outcomes were found in any of the field sites. Therefore, breeders in the southeastern United States should focus their efforts on improving competitive traits within adapted germplasm in order to achieve maximum gains in weed suppressive ability.
机译:响应于美国东南部迅速扩大的市场机会,对适合有机生产系统的小麦育种品种的兴趣正在增长。对生物胁迫的抗性育种是北卡罗来纳州立大学小谷物育种计划的主要重点。对这些害虫和疾病的抵抗力在有机系统中尤其重要,在有机系统中,禁止使用合成杀真菌剂和杀虫剂。对北卡罗莱纳州有机小麦生产者而言,对白粉病的抗性(Blumeria graminis DC f。sp。tritici)和对意大利黑麦草(Lolium perenne L. ssp。multiflorum(Lam。Husnot))的杂草抑制能力被认为是高度优先的性状。由于病原体具有快速进化的潜力,因此必须重视新品种的白粉病抗性的育种。意大利黑麦草是小谷物作物中的主要杂草,已被确定为该地区有机小麦生产的主要限制。尽管意大利黑麦草在常规生产中受除草剂控制,但抗药性生物型的迅速扩展威胁了流行的化学除草剂类别的功效。因此,该地区的育种者对开发能抑制意大利黑麦草生​​长和繁殖并补充化学除草剂选择的抑草小麦品种越来越感兴趣。小麦种质系NC09BGTUM15(NC-UM15)具有从Aegilops neglecta Req渗入的白粉病抗性的第一种形式。前Bertol。对来自交叉NC-UM15 x'Saluda'的F 2:3家族的评估表明,单个显性基因MlUM15赋予了抗病性。特异于7AL染色体的分子标记与抗性基因隔离。多等位基因Pm1基因座也映射到染色体7AL的这个远端区域。分离的叶片测试表明,NC-UM15与拥有Pm1复合体等位基因的品系具有不同的疾病反应模式。需要使用Pm1进行等位基因检测,以阐明MlUM15与7AL上其他Pm基因座之间的关系。进行了研究以确定间接选择的冬小麦品种的杂草抑制能力选择方法,这些方法与意大利黑麦草对小麦生物量的比率具有很好的相关性。意大利黑麦草种子头密度和灌浆过程中意大利黑麦草生​​物量的目测估计与意大利黑麦草与小麦生物量的比率高度相关,被认为是抑制杂草能力的合适间接方法。对北卡罗来纳州官方品种测试(NC OVT)的53个条目进行了针对意大利黑麦草的杂草抑制能力的评估,以鉴定可促进间接选择以抑制杂草的小麦形态特征和分子标记。杂草抑制能力与高早期活力(Zadoks GS 25和29),直立的生长习性(Zadoks GS 29),高叶面积指数(LAI)(Zadoks GS 31),高活力等级(Zadoks GS)相关(P <0.05)。 55),以及整个生长季节中四个地点中的三个地点的高度。在2012年两个地点的高杂草抑制系中,偶然发现冬季型短春化等位基因vrn-B1a-in1的发生率高于预期。还进行了研究,以检验化感作用和竞争能力对杂草抑制结果的相对重要性。场。在幼苗生物测定中,筛选了来自NC OVT的58个小麦品系对意大利黑麦草的化感活性。然后评估了八种具有不同最终高度的强和弱化感作用系,用于野外抑制杂草的能力。尽管基因型的化感活性在幼苗生物测定中存在显着差异,但在任何田间地点均未发现化感作用与杂草抑制结果之间的相关性。因此,美国东南部的育种者应集中精力改善适应种质内的竞争性状,以最大程度地提高杂草抑制能力。

著录项

  • 作者单位

    North Carolina State University.;

  • 授予单位 North Carolina State University.;
  • 学科 Agriculture General.;Biology Genetics.;Agriculture Agronomy.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 272 p.
  • 总页数 272
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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