小麦-冰草附加系与小麦-杀配子染色体附加系杂交F_1的细胞学特性

Cytological Characteristics of F_1 Hybrids between Wheat-Agropyron Addition Lines and Wheat-Gametocidal Chromosome Addition Line

以小麦-冰草附加系与中国春-柱穗山羊草杀配子染色体2C附加系杂交,对杂交F1的形态学及细胞学特性进行了研究,为利用杀配子染色体诱导小麦ABD组和冰草P组染色体变异,创造小麦-冰草染色体易位系奠定基础。对8个小麦-冰草二体附加系同中国春-杀配子染色体附加系杂交F1的形态学、育性以及细胞学特性的观察结果表明,小麦-冰草不同附加系P染色体的传递能力存在差异。F1花粉母细胞减数分裂中存在染色体异常,平均35.3%的细胞含3个以上的单价体,74.0%的四分体含有微核,20.3%和23.8%的细胞含有染色体断片和桥,在某些组合中有多价体、四分体多裂和退化现象。杀配子染色体的诱变在配子形成的过程中已经开始发生作用。不同杂交组合之间F1植株自交结实率为51.67%-71.37%,反映出杀配子染色体2C在小麦-冰草不同附加系背景下对其育性的影响存在差异。

The basic genome of Agropyron spp. distributed in the cold and temperate plateau and sands of the Eurasia is the P genome. These species are not only adapted to abiotic stresses, such as drought, low temperature, and barren soils, but also resistant to powdery mildew, Barley dwarf virus, and the rusts in wheat. Moreover, Agropyron species produce multiple tillers, spikelets, and florets. The P genome of Agropyron can be a source of desirable genes for wheat improvement. In the 1990s, cross between wheat and Agropyron species was made, resulting in the development of a number of wheat-Agropyron chromosome addition lines, which made possible to transfer genes from the P genome into wheat by producing chromosome translocations between wheat and Agropyron. The gametocidal chromosome of Aegilops speicies, which is added to wheat genome, is able to induce various structural variations of chromosomes. Compared to the methods for inducing chromosome variations, such as irradiation, tissue culture and Ph mutant, gametocidal method is highly effective in inducing chromosome variations between wheat and relative species. This method has been used to produce chromosome translocations between wheat and Haynaldia villosa, Leymus racemosus, Elytrigia elongate, and Secale cereale, with a frequency of over 10%. However, no study has been reported on producing wheat-Agropyron chromosome translocation using gametocidal method. In the present study, eight wheat-Agropyron cristatum addition lines were crossed with Chinese Spring-Aegilops cylindrica （2C） addition lines and their morphological and cytological performances were investigated. The objective of this study was to lay a foundation on developing wheat-Agropyron chromosome translocations by inducing chromosome variations between wheat ABD genomes and Agropyron P genomes with gametocidal chromosome. The results showed that the chromosome addition lines Ⅱ -4-2, Ⅱ -21-6, Ⅱ -21-2, and Ⅱ -11-1 had transmission rate of 100% . The transmission rate was high in lines Ⅱ -5-1 and Ⅱ -9-3, but low in lines Ⅱ -29-2 and Ⅱ -5038. Chromosome abnormality was observed in F1 plants during meiosis. The frequency of pollen mother cells with over 3 univalents was 35.3 % . Micronuclei were observed in 74% of tetrads, and chromosome fragments and bridges appeared in 20.3% and 23.8% of cells. In certain crosses multivalents, multifid quadrants, and retrogression were observed. These aberrations of chromosome behaviors indicated that the gametocidal chromosome was effective during the formation of gametes. The percentage of seed setting in F1 plants varied from 51.67% to 71.37%, indicating that the gametocidal chromosome 2C had a different effect on various wheat- Agropyron chromosome addition lines.