Development Of A Hexaploid Wheat With Two HMW-GSs

It is generally accepted that the high molecular weight glutenin subunits (HMW-GSs) in hexaploid wheat varied from 3 to 5. To our knowledge, some wheat germplasms have more than five HMW-GSs in its background. Fox example, some Swedish wheat have 6 HMW-GSs. However, less study reports wheat lines expressing HMW-GS less than three. A synthetic wheat, expressing two HMW-GSs from Aegilops tauschii, was produced using Ttiticum turgidum ssp. dicoccum PI94668 (no HMW-GS) with Aegilops tauschii As60. The HMW-GS components of F2 and F3 seeds, the chromosome numbers of the root tip cells as well as the chromosome pairing configuration in the pollen mother cells at meiotic metaphase I were analyzed, the main results were as follows:1. Forty-five seeds of PI94668/As60 F2 had two HMW-GSs, by SDS-PAGE analysis, some other protein bands, specific for tetraploid wheat or Aegilops tauschii parents, were also detected. The chromosome numbers of 38 F2 were counted, of which,29 seeds had 42, while the chromosome numbers of remaining 9 seed varied from 34 to 42.2. The chromosome pairing configurations of pollen mother cells at meiotic metaphase I in 23 F2 were different from each other. Compared with other F2, Syn-G2-6 had less bivalent, with a mean of 0.59. Distinctively, Syn-G2-4 had more univalent than others, with a mean of 8.80. The plant of Syn-G2-4 was sterility, probably caused by the high frequency of univalent. Moreover, some lines had lagging chromosomes in the equatorial plate at meiosis metaphase I.3. Thirty F3 families of PI94668/As60 were detected for HMW-GS compositions. Among the 1000 grains,984 had the same HMW-GS patterns. The HMW-GS compositions of 28 in 30 family lines were the same exception that 16 seeds from Syn-G2-24 and Syn-G2-7 family lines were different from others. It was very interesting that 3 grains of Syn-G2-24 expression 3 HMW-GSs and the chromosome numbers of them were 42. However, no HMW-GS was detected in 13 grains of Syn-G2-7 and the chromosome numbers of them different from each other, ranged from 34-40. It was suggested that missing at least two 1D contained chromosomes probably resulted in failure of detecting HMW-GS in 13 seeds of Syn-G2-7.