Molecular Cytogenetic Characterization Of A Small Segment Translocation Line From Wheat-Psathyrostachys Huashanica Amphiploid

With the development of modern agriculture technology and farming system, genetic variation of wheat varieties decreased sharply and it restricted to improve yield and quality of wheat, as a result of the long term oriented use of high yield, quality and resistance to parents, appearance of new pathological races, as well as scarce resource. These become the major obstacles for wheat breeding. Therefore, one of the purpose is to improve wheat cultivars by constantly tapping new sources of resistance and transferring excellent exogenous genes. Psathyrostachys huashanica Keng ex Kuo (2n=2x=14, NsNs) is a perennial grass of Psathyrostachys Nevski in the tribe Triticeae, which not only possesses characteristics of early maturity, high quality, tolerance to cold, drought and barren, but also has high resistance to wheat stripe rust. Therefore, it is an important gene resource for wheat genetic improvement. Much effort has been made to transfer beneficial genes of P. huashanica into common wheat by chromosome manipulation, which created a series of wheat-P. huashanica intermediate materials, such as amphidiploid, alien addition, substitution and translocation lines. The creation of these materials improves the resistance and quality of common wheat to a certain extent. In our previous study, the F1 hybrids between wheat-P. huashanica (PHW-SA,2n=8x=56, AABBDDNsNs) and chuannong 16 (CN16) were backcrossed with CN16, and then the superior individuals of high stripe rust resistance from selfed progeny were selected. In the present study, we successfully screened and identified a novel small segment translocation line K-13-835-3 of wheat-P. huashanica from the BC1F4, which revealed high resistance to stripe rust and grains per spike type by using GISH, FISH, SDS-PAGE and other methods, combining of agronomic evaluation. The translocation line will be used as a new germplasm resource for breeding of high-yield, disease resistant wheat varieties. The main results were shown as follows:(1) The chromosome number of K-13-835-3 was 2n= 42 and the average chromosome pairing configuration consisted of 0.1 univalents,19.45 ring bivalents, and 1.5 rod bivalents, suggesting that K-13-835-3 is cytologically stable.(2) The results showed that K-13-835-3 occurred among middle of small fragment of wheat-P. huashanica translocation by genomic in situ hybridization (GISH) analysis using P. huashanica DNA as probe. Fluorescence in situ hybridization (FISH) with the pSc119.2, pTa535 or pAs1 revealed that a pair of small P. huashanica fragments was inserted into the 5DS arm substituting for wheat fragments.(3) Compared with its parents, the number of spikelets per spike was not significantly different in K-13-835-3 and PHW-SA, whereas it was significantly higher than Chuannong16. Its kernels per spike were significantly higher than its parents. In addition, K-13-835-3 had high level of resistance to stripe rust. These suggested that chromosome of P. huashanica may carry resistance genes and increasing spikelets per spike related genes.(4) SDS-PAGE analysis showed that the HMW-GS region of K-13-835-3 derived all of its glutenins from CN16, including the Glu-A1 subunit 1, quality Glu-D1 subunits (5+ 10), and inferior Glu-B1 subunit 20.