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Critical Discussion on Abortive Interspecific Crosses in Brassica
Author(s) -
Nishiyama I.,
Sarashima M.,
Matsuzawa Y.
Publication year - 1991
Publication title -
plant breeding
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.583
H-Index - 71
eISSN - 1439-0523
pISSN - 0179-9541
DOI - 10.1111/j.1439-0523.1991.tb00552.x
Subject(s) - ploidy , biology , interspecific competition , brassica , botany , hybrid , sexual reproduction , human fertilization , interspecific hybridization , reciprocal cross , polar body , reproduction , polar , pollination , meiosis , genetics , pollen , gene , physics , astronomy
Abstract In most interspecific hybridization among diploid Brassica species (n = 8, 9, 10), few or no hybrids are obtained, and the three crosses of tetraploid (n = 17, 18, 19) by diploid species are usually only partially successful, especially in one of the reciprocal crosses. Such a cross‐incompatibility complex is explained in this paper by a polar‐nuclei activation (PNA) hypothesis which proposes two reversible functions, a normal reproduction and a sexual barrier, of double fertilization in higher plants. The first, i.e. the relative activating value (AV) of diploid species, was estimated as 1.0–3.5, whereas that of tetraploid species was 2.7–5.2. In addition, crosses with a polar nuclei activation index (AI) of about 15–87 % were compatible but those beyond the two limits were incompatible, 50 % of those showing normal seed development after self‐pollination.