Y. Nemoto¹, N. Nawakami²and T. Sasakuma¹ (¹Kihara Inst. Biol. Res., Yokohama City Univ., ²Meiji Univ.)

Novel salt stress responding genes isolated from common wheat.

We isolated five novel cDNAs that responded to 0.15M NaCI treatment from common wheat (Triticum aestivum L. cv Chinese Spring) by an improved differential display method. The clones were collectively named as WESR (wheat early salt-responding gene) since the clones were isolated from the salt treated seedlings only for 2 hours. They showed different patterns of transcript accumulation during exposure to salt stress. Analysis of nucleotide and deduced amino acid sequence indicated that WESR4 showed homology to a barley cDNA clone containing zinc finger motif, WESR5 was for glucose-6-phosphate dehydrogenase (G6PDH). Other clones did not show significant homology to known genes.


S. Tsvetanov¹, K Tsuda², S. Takumi², N. Mori² , A. Atanassov¹ and C. Nakamura² (¹Inst. Genet. Engineer., Bulgaria, ²Fac. Agr., Kobe Univ.)

Cloning and characterization of novel members of a cold-responsive gene family, Wcor, in wheat.

Five Wcor cDNAs were selected using a library constructed from a cold-acclimated Russian winter wheat cv. 'Mironovska 808'. The screening was based on the homology with three barley cold-responsive and/or ABA- responsive cDNAs. One novel clone Wcor35 was chimeric consisting of a 5'half region homologous with cold- and light-responsive barley T59 and wheat Wcs19 and a 3' half region homologous with a hedydrin group, Wcs66 and Wcs120. Wcor35 expression was specific to low temperature acclimation. Three other clones were homologous to several reported cold and/or ABA-responsive cDNAs.


M. N. Inagaki (Biol. Resour. Div., Japan Intern. Res. Cent. Agr. Sci. (JIRCAS))

Application of doubled haploids to wheat breeding programs

The breeding method using wheat doubled haploids (DHs) has advantages in reducing the time required to obtain recombinant inbred genotypes ready for yield evaluation.. Field experiments suggested that genetic advance obtained in DH method were comparable to that observed in the conventional methods. A methodology for producing wheat haploids using wide crosses followed by chromosome elimination has been developed over the last two decades. Significant technical advances on crossability have been made by using pollen donors selected from different subfamily species and by applying plant growth regulators. Efficient crossing techniques were developed using stored pollen and detached-tiller culture, resulting in considerable savings in terms of labor and space required for growing parent plants. Production efficiency of doubled haploid lines has been improved to a level allowing their utilization in breeding programs.

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