COMPARISON OF THE CROSSABILITY OF RYE (SECALE CEREALE) AND HORDEUM BULBOSUM ONTO WHEAT (TRITICUM AESTIVUM)

Abstract

Fifty-six wheat (T. aestivum L.) lines representing a wide diversity of germ plasm were screened for crossability with rye. Seed set values ranged 0.0-95.4% of the florets pollinated. Twenty-eight of these wheat lines representing the range of crossability with rye were then pollinated with tetraploid H. bulbosum L. Seed set ranged 0.0-32.2%. Those wheats giving seed set with H. bulbosum generally had medium to high crossability with rye. A high correlation (r = 0.75) was obtained for crossability or rye and H. bulbosum on wheat, indicating that the main genetic system (Kr1 and Kr2) governing crossability with rye is also the main system operating in crosses with H. bulbosum. Evidence for additional factors influencing crossability and for differences between rye and H. bulbosum is provided. Hybrids between wheats having different crossability levels exhibited intermediate crossability levels with rye but very low crossability with H. bulbosum. H. bulbosum genotypes differ in their ability to effect seed set.