Impact of Reciprocal Translocations and Non-Synchronous Disjunction of Chromosomes on Pollen Fertility in <i>Astragalus chlorostachys</i> from the Northwest Himalayas (India)

Abstract

Summary Cytological investigations carried out on a population basis in Astragalus chlorostachysLindl. which exists at diploid level (n=8) revealed the presence of quadrivalents, the late disjunction of 1-4 bivalents and some pollen sterility (34%) in 1 accession collected from Koksar, at 3140 m in the Lahaul Valley (Lahaul-Spiti, Himachal Pradesh). The presence of quadrivalents in this diploid species seems to be a consequence of reciprocal translocations. The occurrence of structural heterozygosity in the species has been reported here for the first time. All of the other populations showed normal bivalent formation and regular sporad generation and 100% pollen fertility. The paper here discusses in detail the course of meiosis and the effect of multivalent formation and non-synchronous disjunction of bivalents on meiotic course and pollen fertility.

Structural Heterozygosity for Reciprocal Translocations Affecting Chiasma Frequency and Pollen Fertility of a Natural Tetraploid of <i>Anthoxanthum odoratum</i> L. from Northwest Himalayas

“…In the species, there seems to be a direct correlation of pollen sterility with structural heterozygosity. Similar effects of structural heterozygosity resulting in non-viable pollen grains has been reported in a number of plants, namely, Chrysanthemum zawadskii (Kim et al 2008), Artemisia parviflora (Gupta et al 2010), Astragalus chlorostachys (Rana et al 2012), Saxifraga diversifolia (Kumar and Singhal 2013), Achillea millefolium (Singhal et al 2014) and Anemone rivularis (Kumar et al 2015). Gohil and Koul (1978) and Sharma and Gohil (2003) have reported that structural heterozygotes of Allium consanguineum and A. roylei depicted complete gametic sterility due to reciprocal translocations, respectively.…”

Structural Heterozygosity for Reciprocal Translocation in <i>Tanacetum artemisioides</i> Sch. Bip. ex Hook. f. from Ladakh Division of Jammu and Kashmir

“…In the presently studied accession of Tanacetum artemisioides, the majority of the PMCs showed the adjacent type of orientation of quadrivalents/hexavalents (ring or chain) and the alternate (zigzag) orientation was seen in only one PMC, resulting in a considerable amount of pollen sterility (30-35%), which appears to be the result of duplications and deficiencies of genes as mentioned by Ghosh and Datta (2006) in Nigella damascene. Similar effects of structural heterozygosity leading to nonviable pollen grains have been reported in a number of plants, namely, Citrus jambhiri (Singhal and Gill 1981), Chrysanthemum zawadskii (Kim et al 2008), Artemisia parviflora (Gupta et al 2010), Astragalus chlorostachys (Rana et al 2012), Saxifraga diversifolia (Kumar and Singhal 2013), Tradescantia spathacea (Koul et al 2013), Achillea millefolium (Singhal et al 2014), and Anemone rivularis (Kumar et al 2015). Gohil and Koul (1978) and Sharma and Gohil (2003) have reported that structural heterozygotes of Allium consanguineum and A. roylei depict complete gametic sterility due to reciprocal translocations.…”

“…From this laboratory, the naturally occurring reciprocal translocations have been reported in individuals of Artimisia parviflora (Gupta et al 2010), Astragalus chlorostachys (Rana et al 2012), Saxifraga diversifolia (Kumar and Singhal 2013), Achillea millefolium (Singhal et al 2014), and Anemone rivularis (Kumar et al 2015). Kaul (1977) opined that breakage and exchange of heterologous chromosomes in a structural heterozygote are genetically conditioned and controlled, thereby eliminating the chance factor operating for the predominance of either ring or chain or both types of multiple associations of chromosomes.…”

Multiple Associations of Chromosomes Due to Structural Heterozygosity in the Wild Plants of <i>Achillea millefolium </i>L. from Northwest Himalayas (India)

“…Partial homology resulted as a consequence of such exchanges between more than two nonhomologous chromosomes, leading to the pairing of non-homologous chromosomes in a diploid taxon, which is attributed either to the hybrid nature of the taxon or heterozygosity for reciprocal translocations (Singhal 1982). Since the first report of reciprocal translocations in the Stizolobium deeringianum by Belling (1914), their occurrence and consequences have been reported in a number of plants by various workers (Gohil and Koul 1978, Singhal and Gill 1981, Sharma and Gohil 2003, 2008, Talukdar 2008, 2010, 2013, Gupta et al 2010, Kohli and Gohil 2011, Rana et al 2012, Kumar and Singhal 2013. Here, we report the existence of structural heterozygosity due to reciprocal translocations in the species for the first time.…”

“…However, the PMCs having univalent chromosomes tend to have decreased the value of chiasma frequency. Pollen sterility in a translocation heterozygote largely depends upon whether the orientation of multivalents is of the adjacent or alternate type at M-I (Ghaffari et al 2009, Gupta et al 2010, Rana et al 2012, Kumar and Singhal 2013. In the present case, pollen fertility is high, so the orientation of multivalents at M-I seems to be of the alternate type in a majority of the cases.…”