Cytomorphological investigations in Oxyria digyna Hill. from the Kashmir Himalaya, India

In the present paper, detailed cytomorphological investigations in Oxyria digyna Hill. from Kashmir Himalaya—India have been reported for the first time. All the 14 investigated populations of O. digyna are diploid based on x = 7. Out of these in two populations 0–2B chromosomes have been recorded for the first time while 6 populations differed significantly in their meiotic characteristics. Meiotic abnormalities during male meiosis observed include inter PMC chromatin transfer (cytomixis). Non-synchronous disjunction of some bivalents, laggards and bridges at anaphases and telophases. Consequent to these meiotic anomalies, microsporogenesis in meiocytes is abnormal resulting in to dyads, triads and polyads with or without micronuclei. The overall effect is seen in reduced pollen fertility. Unreduced pollen grains were observed in some populations, which differed significantly in their size compared to the normal (reduced) pollen grains. It is observed that a smaller frequency of pollen grains differed morphologically in Aharbal and Yosmarg populations. The remaining eight populations showed regular meiotic course, normal microsporogenesis and high percentage of pollen fertility (95.09–99.09 %).Приводятся детальные цитоморфологические ис-следования Oxyria digyna Hill из Кашмира (Гималаи, Индия). Все 14 изученных популяций являются диплоидными, где x = 7. Из них в двух популяциях впервые описаны 0–2B хромосомы, тогда как шесть популяций сильно различались по своим мейотическим характеристикам. Аномалии мейоза при микроспорогенезе включали цитомиксис, несинхронное расхождение некоторых бивалентов, задержки и мосты в анафазах и телофазах. Возникающий в связи с этим аномальный микроспорогенез приводит к формированию диад, триад и полиад как с микроядрами, так и без них. Общим эффектом является снижение фертильности пыльцы. В некоторых популяциях наблюдали нередуцированные пыльцевые зерна, которые по величине значительно отличались от нормальных. В популяциях Aharbal и Yosmarg некоторые пыльцевые зерна отличались морфологи-чески. Оставшиеся восемь популяций проявляли нормальный ход мейоза, нормальный микроспорогенез и высокий процент фертильности пыльцы (95,09–99,09 %).The authors are grateful to the University Grants Commission, New Delhi for providing financial assistance under the DRS SAP III and DST programmes. Thanks are also due to the Head, Department of Botany, Punjabi University, Patiala for necessary laboratory facilities

Meiosis in elephant grass (Pennisetum purpureum), pearl millet (Pennisetum glaucum) (Poaceae, Poales) and their interspecific hybrids

The cultivated and sexually compatible species Pennisetum purpureum (elephant grass, 2n = 4x = 28) and Pennisetum glaucum (pearl millet, 2n = 2x = 14) can undergo hybridization which favors the amplification of their genetic background and the introgression of favorable alleles into breeding programs. The main problem with interspecific hybrids of these species is infertility due to triploidy (2n = 3x = 21). This study describes meiosis in elephant grass x pearl millet hybrids and their progenitors. Panicles were prepared according to the conventional protocol for meiotic studies and Alexander’s stain was used for assessing pollen viability. Pearl millet accessions presented regular meiosis with seven bivalents and high pollen viability. For elephant grass, 14 bivalents in diakinesis and metaphase I were observed. The BAG 63 elephant grass accession, derived from tissue culture, presented a high frequency of meiotic abnormalities. The three hybrid accessions presented a high frequency of abnormalities characterized by irregular chromosomal segregation which resulted in the formation of sterile pollen