寒地多年生小麦的选育与细胞遗传学分析

通过杂交方法获得八倍体小偃麦与中间偃麦草杂种后代，对该杂交后代进行了形态学观察和细胞遗传学分析。杂交当代结实率为10%~39%；F₁表现为两亲中间型，多年生，抗小麦多种病害，生长的第2和第3年结少量种子，结实率为2%~3%；F₂分离复杂，出现八倍体小偃麦类型和中间偃麦草类型的多年生材料；F₃和F₄代出现一些普通小麦类型的多年生小麦,表现多分蘖、多小穗、抗病、抗寒。F₁根尖减数分裂中发现49条染色体，在减数分裂中期I形成14~17个二价体和4~21个单价体；而F₂和F₃代减数分裂时形成14~21个二价体和9~17个单价体。杂种后代结实率逐代恢复。F₁植株已在田间自然条件下生长5年。从F₄代中获得了4个植株高大(140 cm)、分蘖丰富(60个以上)、小穗多(25~30个)的饲草型多年生小麦株系，它们不仅具有良好的刈割再生能力，而且兼抗多种病害，抗寒性好，草质与中间偃麦草相似。还获得了一些普通小麦类型的多年生株系，有待进一步改良。这些结果为多年生小麦的遗传研究和利用提供了信息和材料基础。

Development and Cytogenetic Analysis of Perennial Wheat in Cold Region

The morphology of the progenies from octoploid Trititrigia Thinopyrum intermedim and their chromosomal behaviours during meiosis were observed to provide therotical and material bases for developing perennial wheat.The seed-setting rate of contemporary hybrid was 10-39%,and the F1 plants showed an intermediate type of parents with perennial characteristic and resistance to multiple diseases.During the second and third growing year,the F1 plants produced a small amount of seeds with setting rate of 2-3%.The F2 plants separated complexly,which involved the types of Tritielytrigia and Thinopyrum intermedium.The F3 and F4 generations tended to produce some types of common wheat but with perennial characteristics,such as rich tillers,prolific spikelets,and resistances to diseases and coldness.In F1 generation,49 chromosomes were observed in root tip cells,which formed 14-17 bivalents and 4-21 univalents at metaphase of meiosis I.In F2 and F3 generations,the numbers of bivalent and univalent at meiosis were 14-21 and 9-17,respectively.Seed-setting rate of the perennial hybrids was recovered with the increase of generation,and the F1 plants could survive in natural environment for five years.We have obtained four perennial wheat lines in forage type from the F4 generation.These lines showed tall plant height(140 cm),abundant tillers(more than 60),rich spikelets(25-30),resistance to multiple diseases,tolerance to coldness,and high regenerative capability after harvest.Besides,some common wheat-type perennial lines were also attractive,which requires further improvement.