Items from Italy.

ITEMS FROM ITALY

 

EXPERIMENTAL INSITUTUE FOR CEREAL RESEARCH

via Mulino, 3 - 26866 S. Angelo Lodigiano (LO), Italy.

 

Bread wheat genotypes for sustainable-cropping systems. [p. 59]

M. Perenzin, M. Corbellini, and G. Boggini.

The long-term history of wheat breeding has been characterized in Italy and elsewhere by the constant release of leading cultivars that in turn became progenitors of new cultivars, selected to perform well under intensive crop management. In the present economic and political context where farmers are forced to optimize and reduce inputs, there is a need to release genotypes characterized by high nitrogen-use efficiency.

Our recent data confirm that modern cultivars do not perform well when the nitrogen supply is reduced. On the other hand, the reintroduction of old cultivars is not realistic mainly because of their low harvest index and very poor bread-making quality. In order to meet the farmer's needs, a breeding strategy based on selection under low-input management was used, and five lines with stable yield and quality have been selected. All lines appeared different from Donald's wheat ideotype at least in terms of plant height, but highly efficient for dry matter and nitrogen accumulation in the grain. Further studies are needed to establish if they really represent an example of high nitrogen use efficiency.

 

Allelic variability at the waxy loci in Italian wheat germ plasm. [p. 59-60]

G. Boggini, M. Cattaneo, S. Empilli, and P. Vaccino.

G. Boggini, M. Cattaneo, P. Vaccino, and C. Concaro.

Waxy wheats, characterized by reduction or absence of amylose in the starch, may find a use in the production of modified food starch and their flour may be used to extend the shelf life of baked products. The primary enzyme responsible for the synthesis of amylose in amyloplast, granule-bound starch synthase (GBSS), is present in bread wheat in three isoforms encoded by the structural genes Wx-A1, Wx-B1, and Wx-D1.

We have analyzed 288 cultivars of bread wheat, 139 cultivars of durum wheat, and about 200 accessions from other Triticum species in order to find genetic variability for the waxy trait. Electrophoretic separation of GBSS allowed the identification of 63 bread wheats deficient in Wx-B1, one in Wx-A1, and one in Wx-D1 protein isoforms. The wheat accessions with Wx mutations were evaluated with a Rapid Visco Analyser to investigate starch properties. All the analyzed cultivars showed peak and final viscosities different from normal wheat.

Analyses made in order to evaluate the amylose:amylopectin ratio and the rheological characteristics of the partial-waxy genotypes have been completed. The results suggest that the loss of one of the three Wx-protein isoforms is not sufficient for a significant reduction of amylose content, and the variation in the gelatinization profiles is probably due to the dimension or molecular weight of starch granules.

A crossing program to select double and null waxy-wheat mutants is in progress; double mutants have been selected by means of electrophoretic analysis.

 

Puroindoline and kernel hardness in Triticum aestivum and Triticum monococcum. [p. 60]

N.E. Pogna, L. Gazza, G. Boggini, M. Corbellini, P. Vaccino, and E. Ponzoni.

Puroindolines a (pin a) and b (pin b), two lipid-binding proteins affecting grain texture, were investigated in diploid and hexaploid wheat species by A-PAGE fractionating and PCR amplification. A-PAGE provided a clear separation of pin a and pin b, which occurred as two or four major bands in T. aestivum and T. monococcum, respectively. Using A-PAGE analyses, four different puroindoline patterns were identified among 67 diploid wheat accessions, all of them exhibiting a very soft grain texture as determined by the Single Kernel Characterization System. Among the 66 bread wheat cultivars analyzed, four A-PAGE patterns, two alleles coding for pina, and four alleles coding for pinb were identified. Grain softness proved to be associated with the presence of alleles pina-D1a, and pinb-D1a, coding for wild-type pin a and pin b, respectively. On the other hand, medium-to-hard grain texture was associated with either the absence of pin a (allele pina-D1b) or the occurrence of a single amino-acid substitution in wild-type pin b (alleles pinb-D1b, and pinb-D1d). Pin b alleles have been sequenced and Southern analyses are in progress in order to investigate the structures of the genes.

 

Breeding for resistance to powdery mildew. [p. 60]

A. Brandolini, M. Corbellini, and G. Reffo.

A breeding program based on backcrossing and MAS selection and aimed at the introgression of powdery mildew resistance gene Pm13, derived from Ae. longissima, in bread wheat cultivars is currently at the BC5 stage. To fix the gene, a cycle of selfing will be made this season. Evaluation of lines for similarity to the recurrent parents also is under way.

 

Genetic analysis of einkorn wheat quality traits. [p. 60]

A. Brandolini, P. Vaccino, G. Bruschi, and M. Corbellini.

A consensus map of einkorn wheat, obtained in collaboration with the Max-Planck Institut of Cologne, is completed and published. The map was used to localize QTL for quality and agronomic traits. A major QTL for bread-making quality was detected on chromosome 1S, and the gene responsible for free threshing was positioned on 2S in a position compatible with Tg genes of polyploid wheats.

Progenies of two-, three-, and four-way crosses of lines with good agronomic and quality traits (earliness, free-threshing, short straw, gluten quality, and large kernel) are ongoing and at different stages of evaluation.

 

Publications. [p. 61]

  • Cavallero A, Empilli S, Brighenti F, and Stanca AM. 2002. High (1-3, 1-4)-b-glucan barley fractions in bread making and their effects on human glycemic response. J Cereal Sci 36:59-66.
  • Corbellini M, Perenzin M, Accerbi M, Vaccino P, and Borghi B. 2002. Genetic diversity in bread wheat, as revealed by coefficient of parentage and molecular markers, and its relationship to hybrid performance. Euphytica 123:273-285.
  • Ozkan H, Brandolini A, Schafer-Pregl R, and Salamini F. 2002. AFLP analysis of a collection of tetraploid wheats indicates the origin of emmer and hard wheat domestication in southeast Turkey. Mol Biol Evol 19(10):1797-1801.
  • Palumbo M, Spina A, and Boggini G. 2002. Bread-making quality of Italian durum wheat (Triticum durum Desf.) cultivars. Ital J Food Sci 2(14):123-133.
  • Pogna NE, Gazza L, Corona V, Zanier R, Niglio A, Mei M, Palumbo M, and Boggini G. 2002. Puroindolines and kernel hardness in wheat species. In: Wheat quality elucidation: the Bushuk legacy (Ng PKW and Wrigley CW eds).
  • Salamini F, Ozkan H, Brandolini A, Schafer-Pregl R, and Martin W. 2002. Genetics and geography of wild cereal domestication in the near east. Nature Rev Genet 3(6):429-441.
  • Taenzler B, Esposti RF, Vaccino P, Brandolini A, Effgen S, Heun M, Schafer-Pregl R, Borghi B, and Salamini F. 2002. Molecular linkage map of einkorn wheat: mapping of storage-protein and soft-glume genes and bread-making quality QTLs. Genet Res Camb 80:131-143.
  • Vaccino P, Redaelli R, Metakovsky EV, Borghi B, Corbellini M, and Pogna NE. 2002. Identification of novel low Mr glutenin subunits in the high quality bread wheat cv Salmone and their effects on gluten quality. Theor Appl Genet 105:43-49.