Identification Of High Scab Resistance Germplasm S42 By Molecular Cytogenetics In Wheat

Wheat Fusairum head blight (FHB) is one of the most disastrous diseases in the world and increasing with the development of greenhouse effect and some other reasons. In China, heavy epidemics mainly caused by Fusarium graminearum Schwabe. Apart from direct yield losses, the most serious concern is the contamination of the crop with mycotoxins. Wheat seeds contaminated with deoxynivalenol (DON) may be rejected by the malting and brewing industry. Wild relatives of wheat in Triticeae are of a great number of potentially valuable genes resources. Introduction of alien genetic germplasm from related species was an important method for improving genetic basis of wheat. Rye (Secale cereale L.) is an important source of alien genes because of its considerable tolerance to a series of biotic and abiotic stresses, and has been extensively used in worldwide wheat breeding program.S42 was a high scab resistance germplasm of common wheat, which was brought from Nanping of Fujian province by agriculture scientific institute of Yangzhou, Jiangsu province. In this research, we used the means of morphological character recognition, cytogenetic analysis and molecular marker test including chromosome Giemsa C-banding, GISH and simple sequence repeats (SSR). Some common cultivars wheat, Alondra(1RS/1BL) and Chinese cultivar rye Jingzhouheimai was used as control in the research. The results are as following:S42 had a chromosome number of 2n=42 in somatic cell. The result of C-banding showed that its chromosome composition was 40 normal wheat chromosomes and one pair of short arms of the translocation chromosome. Compared with the common wheat standard C-bands and rye standard C-bands, it revealed the translocation chromosome of S42 derived from 1RS. GISH analysis indicated that translocation chromosome was really chromosome arms 1RS in S42 background, and the rye translocation position was on the terminal of one chromosome of wheat. Using rye specific SSR markers scm9 (located in 1RS) to do PCR for S42 and control materials, the results suggested that S42 had the same special band as Alondra (1RS/1BL) and rye about 220bp. The PCR amplification by rye specific SSR markers scm39 (located in 1RL) indicated only in rye with the special band about 280bp. In addition, the result of PCR with the specific SSR markers wmc49 (located in 1BS) displayed only a special band about 300bp in common wheat. However, there was not this special band in S42. Those results indicated S42 with 1RS and 1BS deletion.All of the results suggested that S42 was an alien translocation line of 1RS/1BL. On the other hand, the results of scab resistance identification in Nanjing, China from 2006 to 2008, showed scab resistance genes expressed stably in S42, and with the same phenotype of scab resistance as to cultivar rye Jingzhouheimai. S42 could be used as a novel scab resistance germplasm in wheat breeding program.