Colmer TD

Islam AKMR

English

Sydney eScholarship

 1Attempts to transfer salt- and waterlogging-tolerances from Sea barleygrass (Hordeum marinum Huds.) to wheat  Islam, AKMR1,3 and Colmer, TD2,3 1School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Urrbrae, S.A. 5064, AUSTRALIA, 2School of Plant Biology and 3Future Farm Industries CRC, The University of Western Australia, 35 Stirling Highway, Crawley, W.A. 6009, AUSTRALIA   ABSTRACT  Wheat crops are adversely affected by salinity and water logging in areas of southern Australia. Sea barleygrass (Hordeum marinum), a wild distant relative of wheat inhabiting salt marshes, has a high degree of tolerance to both salinity and waterlogging. The initial aim of our work was to cross H. marinum and wheat and to produce the amphiploid from the hybrid.  The amphiploid showed improved salt- and waterlogging- tolerances than the wheat parent. Since the current amphiploids are all in H. marinum cytoplasm, they suffer a loss in fertility due to cytoplasmic male sterility induced by the H. marinum cytoplasm.  The cytoplasm of selected amphiploids, showing better tolerances, is currently being transferred back to the wheat cytoplasm to restore normal fertility.  The aim initially is to develop salt- and waterlogging-tolerant feed grain which will allow cropping to be extended onto mildly affected salt land.  Furthermore, in a parallel program, 6 out of the 7 possible disomic additions lines (1Hm, 2Hm, 4Hm, 5Hm, 6Hm and 7Hm) of individual H. marinum chromosome to CS wheat have been produced. These addition lines will be useful in determining the chromosomal controls of salt-and waterlogging-tolerance in H. marinum.  INTRODUCTION  Salinity is an increasing problem for crop production in many regions of the world11. In addition, many salt-affected areas are also prone to waterlogging thus making    these    soils    particularly       unproductive1. Improvement of salt tolerance in wheat can be achieved by introducing genes from salt-tolerant wild relatives3,10.  Among the halophytic wild relatives of wheat, tall wheat grass (Thinopyrum species) has received the earlier attention as donors of salt tolerance.  The amphiploid produced between these two showed higher salt tolerance6,9 but still lacked in waterlogging tolerance8. Sea barleygrass (Hordeum marinum), another halophytic wild relative that grows in salt marshes2 shows tolerance to waterlogging4 and salinity5.  Therefore, attempts were made to produce an amphiploid between wheat and H. marinum and then a set of H. marinum addition lines to wheat.   MATERIALS AND METHODS  Two accessions of Hordeum marinum Hudson subs. marinum namely H21 and H90 were imported from Sweden (courtesy of Dr Roland von Bothmer, Swedish University of Agricultural Sciences) and after being released from quarantine were grown in the greenhouse at the Waite Campus, Urrbrae, South Australia.  H21 was crossed with Chinese Spring (CS) wheat and H90 with commercial wheats.  Because of the small anther size, H. marinum had to be used as the female parent in the cross.  Beginning one day after pollination, florets were treated with gibberellic acid solution to promote embryonic growth.  Since the embryos do not mature on plants, they had to be dissected out under aseptic conditions and cultured on nutrient agar medium to produce F1 hybrid plants.  Potted seedlings at 3-4 tillering stage were uprooted from soil and after washing in water the root and crown region was treated in an aerated colchicine solution for chromosome doubling to produce amphiploids.  Chromosome counts of amphiploid, BC1 and BC2 plants were done following Feulgen staining procedure.  Alien chromosome addition lines were selected among BC2 progeny using representative RFLP probes previously mapped by others to each of the seven Triticeae homoeologous chromosome groups.  RESULTS AND DISCUSSION  F1 hybrids A total of 1340 florets of H. marinum H21(Fig 1a,b) were pollinated with CS wheat to give 49 seeds (3.6%). 10 small embryos were cultured on nutrient agar medium and 6 F1 hybrid plants were obtained. These plants were planted in pots and the hybrid status of some of these plants was determined from observing 28 somatic chromosomes in root tip cells which exhibited mostly 28 univalents (28’) at meiosis.  A small number of seed was produced in colchicine-doubled sectors of all F1 hybrid plants.  Similarly 1150 florets of H. marinum pollinated with commercial wheats (Westonia, Wyalkatchem, Camm) produced 28 (2.4%) seeds and 9 F1 hybrid plants were  2obtained.  These were all treated with colchicine as before and again seeds were obtained from them in colchicine-doubled sectors.  Amphiploids 56-chromosome amphiploid  plants (Figs 1c,d) were  selected from seeds obtained in doubled sectors and planted in large pots for seed increase.  The fertility of the amphiploid plants were low due to cytoplasmic male-sterility induced by the Hordeum cytoplasm.  This was particularly more noticeable in amphiploids with commercial wheats like Wyalkatchem.  This low fertility in amphiploids can be attributed to cytoplasmic male-sterility induced from interaction of Hordeum cytoplasm with the wheat genome.   First backcross (BC1) plants BC1 plants were obtained by pollinating wheat as the female parent with pollen from the amphiploid plants.  Several 49-chromosome BC1 plants were planted in large pots and their BC1 status was confirmed from observing 21” + 7’ at meiosis.  Since the BC1 plants are in wheat cytoplasm, these were, as expected, much more self fertile.  Second backcross (BC2) plants BC2 progeny was only produced from amphiploid involving CS wheat thus far.  The somatic chromosome constitution of 147 BC2 plants was determined from root tip chromosome counts in a search for putative 43-chromosome monosomic addition of individual H. marinum chromosomes to wheat.  Altogether 32 plants with 43 chromosomes were obtained.  These were planted in small pots and DNA from these plants was probed with RFLP markers mapping all seven H. marinum chromosomes. 1Hm, 2Hm, 4Hm, 5Hm, 6Hm and 7Hm monosomic additions were detected among these plants.    All of these monosomic additions were pollinated with maize pollen to produce haploids. These were planted in small pots and at 3-4 tillering stage were uprooted and root tip chromosome counts taken to select 22-chromosome aneuhaploids.  These aneuhaploids were treated with colchicine for chromosome doubling and disomic additions (1Hm, 2Hm, 4Hm, 5Hm, 6Hm and 7Hm) of the individual H. marinum chromosome to CS wheat were obtained.  Salinity and waterlogging tolerance Salt tolerance in the H. marinum-wheat (CS) amphiploid was intermediate to that of its parents7. The improved salt tolerance in the  amphiploid, as compared with wheat, was related to ‘exclusion’ of Na+ and Cl-. Waterlogging tolerance of the amphiploid will be reported in a future publication.  ACKNOWLEDGEMENTS  We thank the Grains Research and Development Corporation (GRDC) and the Plant-based Management of  Dryland Salinity for supporting this research.  REFERENCES 1. Barrett-Lennard, E.G. (2003). The interaction between waterlogging and salinity in higher plants: causes, consequences and implications. Plant and Soil 253: 35-54. 2. von Bothmer, R., Jacobsen, N., Baden, C., Jorgensen, R.B. and Linde-Laursen, I. (1995). An ecogeographical study of the genus Hordeum.  Systematic and Ecogeographic Studies on Crop Genepools.7. Int Board of Plant Genetic Resources, Rome. 129p. 3. Colmer, T.D., Flowers, T. J. and Munns, R. (2006).  Use of wild relatives to improve salt tolerance in wheat. J. Exp Bot 57: 1059-1078. 4. Garthwaite, A.J., von Bothmer, R. and Colmer, T.D. (2003). Diversity in root aeration traits associated with waterlogging tolerance in the genus Hordeum. Funct Plant Biol 30: 875-889. 5. Garthwaite, A.J., von Bothmer, R. and Colmer, T.D. (2005). Salt tolerance in wild Hordeum species is associated with restricted entry of Na+ and Cl- into the shoots. J Exp Bot 56: 2365-2378. 6. Gorham, J., Forster, B.P., Budrewicz, E., Wyn Jones, R.G., Miller, T.E. and Law, C.N. (1986). Salt tolerance in the Triticeae: solute accumulation and distribution in an amphiploid derived from Triticum aestivum cv. Chinese Spring and Thinopyrum bessarabicum.  J Exp Bot 37: 1435-1449 7. Islam, S., Malik, A.I., Islam, A.K.M.R. and Colmer, T.D. (2007). Salt tolerance in a Hordeum marinum-Triticum aestivum amphiploid and its parents. J Exp Bot 58: 1219-1229. 8. McDonald, M.P., Galwey, N.W., Ellneskog-Staam, P. and Colmer, T.D. (2001). Evaluation of Lophopyrum elongatum as a source of genetic diversity to increase the waterlogging tolerance of hexaploid wheat (Triticum aestivum). New Phytol 151: 369-380. 9. Omielan, J.A., Epstein, E. and Dvorak, J. (1991). Salt tolerance and ionic relations of wheat as affected by individual chromosomes of salt-tolerant Lophopyrum elongatum. Genome 34: 961-974. 10. Nevo, E., Krugman, T. and Beiles, A. (1993). Genetic Resources for salt tolerance in the wild progenitors of wheat (Triticum dicoccoides) and barley (Hordeum spontaneum) in Israel. Plant Breeding 110: 338-341. 11. Szabolcs, I. (1994). Soils and salinization. In: Pessarakali, M.ed. Handbook of plant and crop stress. New York: Marcel Dekker, pp3-11.   3      Figure 1.  (a) H. marinum plant, (b) H. marinum spike, (c) CS wheat plant (left) and H21xCS Amphiploid plant (right), (d) CS wheat spike (left) and amphiploid spike (right).  

Attempts to transfer salt- and waterlogging tolerances from Sea barleygrass (Hordeum marinum Huds.) to wheat

https://ses.library.usyd.edu.au/bitstream/2123/3438/1/P060.pdf

Attempts to transfer salt- and waterlogging tolerances from Sea barleygrass (Hordeum marinum Huds.) to wheat

Abstract

Similar works

Full text

Available Versions

Sydney eScholarship