| Frequencies of Ne1 and Ne2 genes in Emmer
and common wheats K. TSUNEWAKI and K. NISHIKAWA National Institute of Genetics, Misima, Japan Three complementary genes, Ne1, Ne2 and Ne3, cause in combination a progressive necrosis in common wheat. Ne1 gene is located in B, Ne2 in A and Ne3 in D genome Among them Ne1 and Ne2 were extensively investigated by CALDWEL and COMPTON (1943), HEYNE, WIEBE and PAINTER (1943) HERMSEN (1957, '59, '62, '63,), SCHMALZ (1959) TSUNEWAKI (1960) and TSUNEWAKI and KIHARA (1962). The number of examined varieties amounts to 520. For 4 of them, a contradictory result was reported by different authors. Those two genes are also found in Emmer wheat and their distribution among 41 varieties was investigated by TSUNEWAKI and KIHARA (1962) and NISHIKAWA (1962a, b). Excluding the contradictory cases, frequencies of 4 possible genotypes in two groups of wheat are summarized in Table 1. From these results, frequencies of individual alleles were calculated and are listed in the same table. In Emmer wheat, frequencies of 4 genotypes are in good agreement with those expected from random assortment between two pairs of alleles. Concerning each allelic pair, the dominant allele predominates in the Ne1 series, while the recessive is prevalent in the Ne2. In common wheat, frequencies of 4 genotypes deviate from those expected from random assortment. Frequencies of Ne1Ne1ne2ne2 and ne1ne1Ne2Ne2 are much higher than the expected ones from randomness. In this group of wheat, the recessive allele is predominating in the Ne1 allelic pair, while the frequencies of the 2 alleles of the other pair were not markedly different from each other. Those results clearly indicate that: (1) two genotypes, Ne1Ne1ne2ne2 and ne1ne1Ne2Ne2, are preferentially selected in common wheat against the two others, and (2) a shift in the gene frequencies must have occurred at the hexaploid level in favor to Ne2 and especially ne1. |