Development and Cytogenetic Analysis of Perennial Wheat in Cold Region

Abstract

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.