STERILITY IN INTERCHANGE HETEROZYGOTES OF BARLEY

Abstract

Introduction In his paper proposinc the Oenothera method of establishing homoP zygous lines from promismg hybrids, Burnham (1946) suggested that the niethod may be applied to barley xvhere the chromosome number is small (211=14) and where interchange heterozygotes with 3 ring of four chromosomes are not accompanied b y an excessive decrease in fert~li ty. Various degrees of sterility have bcen reported in interchange heterozygotes of barley. These are summarized and prese~lted in Table I . As can be seen in the table, most of these studies dealt with simple interchanges. Relatively little work has bcen reported on the stcrility in plants heterozygous for interchanges at higher levels of chromosoine participation. T h e present study was conducted t o determine the effect of level of chromosonie interchange on sterility. Materials and Methods Thirty-one crosses werc made among 35 homozygous interchange stoclts of barley and 25 crosscs were inade between these stoclts and the normal R4ontcaln1, to produce hybrids heterozygous fo r interchanges of various cornbinations. T h e interchange stoclts wcre from four different sources. All C stoclts and the stoclt 4256-1 were f rom the Department of Agronomy and Plant Genetics, University of R4inncsota, E r t and X T stoclts were from the Swedish Seed Association. Svalijf. and stoclt 7031 was ~ r o d u c e d a t the Department of Field ~ u s b a n ' d r ~ , 1 , i v c r s i t ~ of ~asltatchex\;an. Roman numeral stocla are multiple interchange stoclts developed at the University of AjIanitoba b y crossing simple interchange stoclts. T h e designation of each stoclt and the interchanee cl~romosoiiies involved can bc found in Tablc 11. 0 Pollen niother cells f rom I;, plants were exalllined cytologically to confirm the presence of expected metapliase configurations. Sced set was determined fo r each I;, plant. Per cent sterility was calculated b y number of sterile s~il telets