The Chromosome Structure Identification Of Four Hybrid Progeny Stable Lines Between Common Wheat And Thinopyrum Intermedium

Wheat (Triticum aestivum L.) is one of the most important crops and it is widely grown in the world. Development of new cultivars provides an effective approach for easing the contradiction between the world population growth and food production reduction. So researching and cultivating high-yield, high-quality wheat varieties is the major objective of wheat breeding. However, with increasing of wheat breeding levels, the genetic diversity of wheat has become increasingly narrow and the resistance to biotic and abiotic stress capability has become increasingly weak. It is urgent to develop and utilize new germplasm resource to broaden the genetic background of wheat. There is a systematic study of the application of Thinopyrum intermedium. Domestic and foreign scholars have developed a great deal of partial amphidiploids, additional lines, substitution lines and translocation lines related with Thinopyrum intermedium.In this study, the chromosome structure of four stable lines (line 13-388,13-420,13-455,14-493) derived from hybrid progeny between partial amphidiploid TAI7047 of Th. intermedium and common wheat Chuanmai 107 were identified using cytological methods and molecular technique. The results are as following:1. The cytogenetic identification of line 13-388The somatic chromosome number per cell of line 13-388 was 2n=42.21 bivalents and no univalent or multivalent were observed at meiotic metaphase I of pollen mother cells (PMCs). The average height of line 13-388 is about 8.5cm higher than the parent chuanmai 107. The average spikelet number per panicle is more than the parent chuanmai 107. GISH and FISH analysis on the mitotic metaphase of root tip cells indicated that a pair of wheat chromosome has been substituted by a pair of St genome chromosome from Th. intermedium in line 13-388. Meanwhile a chromosomal fragment of Th. intermedium was found to be transferred into another pair of wheat chromosomes on its short arms with an interstitial translocation. The length of translocation fragment is about 80% of the short chromosome arm. However, which wheat chromosome pair substuted and translocated by Th. Intermedium chromosome were formerly researched.2. The cytogenetic identification of line 13-420The somatic chromosome number per cell of line 13-420 was 2n=42. It was observed to have 21 bivalents and no univalent or multivalent at meiotic metaphase I of pollen mother cells (PMCs). Agronomic traits investigation showed that line 13-420 was susceptible with powdery mildew and stripe rust and its average height was 15cm than present Chuanmai 107. The average spike of line 13-420 is about two more than the present Chuanmai 107. These results suggested that line 13-420 was cytologically stable. GISH analysis showed that a pair of wheat chromosomes was replaced by a pair St chromosomes of Th. intermedium in line 13-420.3. The molecular cytogenetic identification of line 13-455The somatic chromosome number per cell of 13-455 was 2n=42 and it formed 21 bivalents at meiotic metaphase I of pollen mother cells (PMCs). Agronomic traits investigation showed that line 13-455 was susceptible with powdery mildew and stripe rust and its average height is about 5cm than present Chuanmai 107. The average spike of line 13-455 is less than the present Chuanmai 107. Giemsa C-banding analysis revealed that no apparent change of chromosome constitution was observed. The sequential GISH and FISH analysis indicated that a small segment translocation closed to the top of wheat IBS satellite was found in line 13-455.PLUG analysis showed that PLUG primer TNAC1001 located on 1BS1BS.sat18-0.50-1.00 could amplify two bands as the same bands as nuli-tetrasomic N1A-T1B. It means that line 13-455 has missed part of IBS satellite. PLUG primer TNAC1001 also amplified an about 750bp band in Line 13-455, Th. intermedium and Ps. spicata. This result furtherly indicated that line 13-455 may contain chromatin of Th. intermedium.4. Chromosome structure identification of Line 14-493The somatic chromosome number per cell of 13-493 was 2n=42. It was observed to produce 21 bivalents and no univalent or multivalent were found at meiotic metaphase I of pollen mother cells (PMCs). GISH and FISH analysis indicated that the chromosome constitution of line 14-493 consisted of 19 pairs of wheat chromosomes. One pair chromosomes was a segmental translocation between Th. intermedium and wheat, and the translocation breakpoint was closed to the telomere of wheat 3DS. Another pair of chromosome 4D were substituted by a pair of Th. intermedium chromosomes from St genome.PLUG analysis showed that primers TNAC1403 located on 4AS3-0.76-1.00, 4BL5-0.86-0.95,4DL12-0.71-0.86, could amplify the same bands between nuli-tetrasomics N4D-T4B and lines 14-493. All these results showed that line 14-493 was not only a wheat-Th. intermedium 4D/4J substitution line and but also a 3D translocation line.