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1.
The genotypes of Avena sativa were crossed to A. magna Murph. et Terrell, from the sterile pentapliod F1 amphiploids were successfully developed after colchicine treatment. The C1 plants were observed for their morphology, cytology and fertility. These plants were characterized by longer and broader glumes, swollen pedicel attachment, pubescent lemmas, bold seeds and persistent spikelets. Other characters, viz., final plant height, rachis length, peduncle length and spikelets per panicle were intermediate. All plants hail the chromosome number 2n = 70 or close to. 7C. Due to stickiness of chromosomes, meiosis of only two decaploid plants could be studied in detail. The average chromosome Association was 1.3 I + 28.56 II + 1.4 III + 1.77 IV + 0.07 VI and 0.13 I + 28.7 II + 0.14 III + 2.09 IV + 0.59 VI; but in some cells up to 35 bivalents were observed. Seed set as well as pollen fertility and size exhibited great variation.  相似文献   
2.
R. Simeone    D. Pignoni    A. Blanco  M. Attolico 《Plant Breeding》1989,103(3):189-195
Interspecific hybrids and amphiploids between Aegilops caudata L. (2n = 2x = 14, CC) and Triticum turgidum (L.) Thell. conv. durum Desf M. K. (2n = 4x = 28, AABB) were produced. Such hybrids can be used to introduce desirable traits such as disease resistance into cultivated durum wheats. One of the durum parents was a ph I mutation of the cv. ‘Cappelli’ used for testing the possibility of direct introduction of alien variation into cultivated species. The amphiploids were obtained both through colchicine chromosome doubling and as natural non-reductional mciosis products. In both hybrids and amphiploids, meiotic pairing and fertility were studied. Hybrids showed varying degrees of pairing and, in addition to the one involving the ph 1 mutant, one high pairing hybrid was found (Ae. caudata× cv. ‘Capinera’). Cytological examination of microsporogenesis in amphiploids revealed a high frequency of bivalent formation. Fertility proved to be a very variable character since some of the amphiploids were almost completely sterile. The use of amphiploids in breeding programmes is discussed in relation to meiotic and fertility data.  相似文献   
3.
Resistance to viruses such as wheat streak mosaic virus (WSMV) and barley yellow dwarf virus(BYDV) is lacking in the primary gene pool of wheat, and therefore resistance is being introgressed from wild relatives such as Thinopyrum species. Resistance to BYDV was found in partial amphiploids (2n = 8x = 56, consisting of 42 wheat and14 alien chromosomes) obtained in hybrids between wheat and both Th. intermedium and Th.ponticum. GISH analysis revealed that the alien genomes of all but one resistant partial amphiploid were heterogeneous consisting of different ratios of St, Js and J genome chromosomes obtained from theThinopyrum parent. Translocated chromosomes consisting of Robertsonian, interstitial and terminal translocations between the different genomes were also detected. The tissue blot immunoassay showed that partial amphiploids having resistance could be inoculated with the virus but both virus multiplication and spread were completely blocked. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
4.
Tolerance of wheat (Triticum aestivumL.) to high temperature might be improved by introducing alien genes from amphiploids. Our objectives were to determine responses of synthetic hexaploid and octaploid amphiploid wheats to high temperature and evaluate their potential usefulness for developing improved cultivars. Thirty synthetic hexaploids from durum wheat (T. turgidum L.) × Aegilops tauschii Cos. Accessions and four octaploid amphiploids from Chinese Spring wheat × different grasses were grown at 20/15 and 30/25 °C day/night during maturation. Tolerance was ascertained by two measures of senescence, leaf chlorophyll content and grain filling duration, plus grain yield and its components. Leaf chlorophyll was measured after 10 and 15 days of treatment, and grain yield was determined at maturity to calculate the heat susceptibility index(HSI), a gauge of the reduction in yield at high temperature of each line relative to all other lines. Chlorophyll content, grain filling duration, yield, and kernel weight were highly negatively correlated with HIS of the hexaploid amphiploids at30/25 °C, but grain yield was positively correlated with HSI at20/15 °C. The hexaploid lines might be useful for improving wheat for regions where stress from high temperature occurs frequently. Chlorophyll content and grain filling duration also were highly negatively correlated with HSI of the octaploid lines, but they would be less directly useful for improving wheat because the kernel number was reduced greatly due to unbalanced meiotic chromosomal segregation. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
5.
With the aim of widening the genetic variability of hexaploid tritorceum through the wheat parents, amphiploids between Hordeum chilense and Triticum turgidum ssp. dicoccoides, ssp. georgicum, and Cody, polonicum have been synthesized. The meiotic behaviour and the fertility were examined in these amphiploids. The morphology of the amphiploids in comparison to their wheat parents was described.  相似文献   
6.
The meiotic behaviour of the hybrid between Festuca gigantea (2n – 6x = 42) and Festuca gigantea (2n = 6x = 42) indicates distinct structural differences between the two species. These differences are also apparent in the degree of chromosome pairing observed in Lolium multiflorum×F. gigantea compared with previous reports on the L. multiflorum×F. arundinacea hybrids. Although the L. multiflorum×F. gigantea 8x amphiploid com Dines the complementary characters of the two species and is agronomically interesting, there are some irregularities in meiotic behaviour that could affect the stability of the amphiploid. Seed fertility in the amphiploid is high and preliminary studies show evidence of a high degree of self-fertility. The pentaploid hybrid between autotetraploid L. multiflorum×F. gigantea is sufficiently fertile to be used as the pollen plant in crosses with diploid L. multiflorum (BC1). Backcrossing the BC3 hybrid to L. multiflorum results in mainly diploid progeny. The possibilities, of using this crossing scheme to introgress F. gigantea characters into L. multiflorum is discussed as an alternative approach to amphiploid breeding as a means o: combining specific complementary characters of the two species.  相似文献   
7.
为了给小麦育种提供新的种质资源,对4份圆锥小麦-乌拉尔图小麦双二倍体(AABBA^uA^u)的农艺性状、染色体组成及高分子量谷蛋白亚基组成进行了鉴定。农艺性状调查结果表明,4份双二倍体的株高介于108.45~129.43 cm,分蘖数介于7.3~17.5个,穗长介于10.23~12.17 cm,小穗数介于16.26~22.06,自交结实率介于37.77%~70.46%;4份双二倍体对目前的流行条锈菌混合生理小种(条中31、条中32、条中33、条中34和水源11-4)均表现为高抗。利用寡核苷酸序列探针Oligo-pSc119.2-1、Oligo-pTa535-1、Oligo-pTa71-2、pTa-713和简单重复序列探针(AAC)5进行FISH分析,可区分出圆锥小麦-乌拉尔图小麦双二倍体的42条染色体。花粉母细胞染色体配对观察表明,在这些双二倍体的减数分裂中期I,染色体大多配对成二价体,仅有少量的单价体、三价体和四价体。SDS-PAGE分析表明,来自于乌拉尔图小麦TA#831的1Ay亚基在双二倍体Syn-TAU-2中得到了表达,但其迁移率发生了变化;来自于PI428270和PI428274的1Ax和1Ay亚基分别在双二倍体Syn-TAU-3和Syn-TAU-4中得到了表达。这些双二倍体可作为新的资源材料用于普通小麦的遗传改良。  相似文献   
8.
An introduction of genetic material from rye, Aegilops and Elymus into durum and common wheat by crossing the wheat species with different amphiploids, has been attempted. Meiotic studies of the hybrids demonstrated that the wheat Elymus sibiricus amphiploid contained several (two or three) genes suppressing the activity of the wheat homoeologous pairing control system. Somatic chromosome studies of the hybrids revealed that the distributions of the alien chromosomes transferred to the second hybrid generation did not correspond to random (0.5 + 0.5)2k and binomial (p + q)2k distributions. An essential amendment for gamete and zygote viability, allowing the approximation of distributions by binomial equation, is discussed. The preferential E. sibiricus chromosome transmission was observed. The first backcross was found to be a critical stage while using the Aegilops-rye amphiploids for production of wheat introgressive forms. Stabilisation of the somatic karyotype and improvement of the meiotic regularity was observed in a number of generations. The isolation of stable cytological lines in BC3 was found to be possible. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
9.
R.S. Chauhan  B.M. Singh 《Euphytica》1997,96(3):327-330
Reactions of Hordeum chilense accessions H1 and H7 and their amphiploids, HT8, HT9 and HT28 (named as tritordeum) alongwith wheat lines, T22, T24 and T59 used in their synthesis, were studied for resistance to the Karnal bunt pathogen (Tilletia indica) of wheat. Both the accessions of H. chilense and one tritordeum line, HT8, were rated as highly resistant with zero co-efficient of infection, whereas the other two tritordeum lines HT28 and HT9 were rated as moderately susceptible and susceptible with 5.2 and 10.5 co-efficients of infection, respectively, compared to reaction of the wheat lines involved in their synthesis. Karnal bunt infection was maximum on the susceptible wheat cultivar WL-711 with 24.3 co-efficient of infection. All the wheat lines involved in the synthesis of amphiploids were susceptible to Karnal bunt except, T59 (Triticum sphaerococcum) (6X), which showed a moderate level of resistance. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
10.
Tetraploid wheatgrass, Thinopyrum junceiforme(2n = 4x = 28; J1J1J2J2), a wild relative of wheat, is an excellent source of resistance to Fusarium head blight. Intergeneric F1 hybrids (2n = 4x = 28; ABJ1J2) between durum wheat (Triticum turgidum; 2n = 4x = 28; AABB) cultivars Lloyd or Langdon and Th. junceiforme were synthesized. Most of the pairing in F1 hybrids was between the J1- and J2-genome chromosomes. Some pairing occurred between wheat chromosomes and alien chromosomes, resulting in segmental exchange that was confirmed by fluorescent in situ hybridization (FISH). The F1hybrids were largely male-sterile and were backcrossed, as the female parent, to the respective durum cultivar. Backcrosses from Lloyd × Th. junceiforme hybrids yielded fertile partial amphiploids (2n = 6x = 42; AABBJ1J2) as a result of functioning of unreduced female gametes of the hybrid. Lloyd proved to be a more useful durum parent than Langdon in crosses with Th. junceiforme designed to transfer scab resistance genes. Pairing in the amphiploids was characterized by preferential pairing,which resulted in bivalent formation. However, some intergeneric pairing also occurred. Several fertile hybrid derivatives were produced by further backcrossing and selfing. The introduction of alien chromatin into the durum complement was confirmed by FISH. Hybrid derivative lines had significantly lower mean infection scores (p = 0.01), the best showing 10.93% infection, whereas the parental durum cultivars had 70.34% to 89.46% infection. Hybridization with wild relatives may offer an excellent means of introducing scab resistance into durum wheat. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
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