HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Nishiyama, I. Articles by Shands, H. L. Search for Related Content PubMed Articles by Nishiyama, I. Articles by Shands, H. L. Agricola Articles by Nishiyama, I. Articles by Shands, H. L.

Twinning and Chromosome Anomalies in Kanota Oats¹

The frequency and chromosomec onstitution of twins in three Avena species (2n=42) were determined. A much higher frequency of twin seedlings was obtained from A. byzantina C. Koch var. ‘Kanota’ than from four other varieties of A. sativa L. and A. nuda L. Eighty-four percent of 44 Kanota twins observed in 1966-67 consisted of sister seedlings of different size. Seventeen of the 31 surviving smaller sisters and one of the larger ones had anomalous chromosome numbers, namely 63 (triploid) or Jess than 42. Of 86 pairs of Kanota twins in which both memberssu rvived, 36, 35, and 13 pairs were diplodiploid, diplo-triploid, and diplo-aneuploidty pes, respectively. One diplo-haploid twin and one diplo-diplo.triploid triplet were obtained.

Variable numberos f trivalents, bivalents, and univalents were observed at metaphase I in 63-chromosome plants (triploids). In each cell the number of bivalents and trivalents summedto 21, 22, or 23, which suggests that one or two bivalents were formed by autosyndesis. Twenty-four percent of the extra 21 chromosomes in triploids failed to pair at metaphase I. These T₁ plants had an average fertility of only 3.5%. Most of their T₂ and T₃ progenies still had more than 42 chromosomes but were markedly higher in fertility.

Hypothesesf or the induction of polyembryonic kernels, especially the anomalous twin sister, are presented.

Key Words: polyembryony • triploids • haploids • aneuploids • Avena • autosyndesis • chromosomal • chimeras • parthenogenesis • fertilization • cytology

² Formerly Visiting Professor, University of Wisconsin (now University of Missouri); Assistant Professor, Kyoto University, Kyoto, Japan; Assistant Professor and Professor of Agronomy, University of Wisconsin. Financial assistance from the Quaker Oats Company and from the Wisconsin Alumni Research Foundation through the University Research Committee is gratefully acknowledged by the senior author.

Received for publication March 21, 1968.