Pollen viability and meiotic behaviour in intraspecific hybrids of Hydrangea aspera subsp. aspera Kawakami group x subsp. sargentiana |
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| Authors: | Laurent Crespel Philippe Morel |
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| Institution: | 1. Agrocampus‐Ouest, Institut de Recherche en Horticulture et Semences (INRA Agrocampus‐Ouest Université d'Angers), , F‐49045 Angers, France;2. INRA, Institut de Recherche en Horticulture et Semences (INRA Agrocampus Ouest Université d'Angers), , F‐49071 Beaucouzé, France |
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| Abstract: | Pollen viability and male meiosis in intraspecific hybrids of Hydrangea aspera subsp. aspera Kawakami group (2n = 2x = 36) and subsp. sargentiana (2n = 2x = 34) were investigated. Although it had been assumed that they were sterile, pollen viability was observed; it varied from 2.5% to 12.1%. The production of gametes with different chromosome numbers was implied by the analysis of the dispersion of the diameter distribution of pollen grains. Analysis of male meiosis made it possible to identify the origins with two major categories of meiotic aberrations: abnormal chromosome distribution (early chromosome migration at metaphase, lagging chromosomes at anaphase, micronuclei at telophase), leading to the formation of unbalanced tetrads and/or ones with supernumerary microspores; and abnormal spindle orientation in metaphase II (tripolar, fused and parallel spindles), leading to the formation of dyads or triads. The mode of 2n pollen formation is of the First Division Restitution type. The high level of parental heterozygosity that is normally associated with them should facilitate the transfer of a polygenic trait in breeding programme. |
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| Keywords: | pollen diameter abnormal chromosome distribution disoriented metaphase II spindles 2n pollen grain first division restitution |
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