Authors:I. Bellil, O. Hamdi, A. Benbelkacem, and D. Khelifi
Wheat endosperm storage proteins are the major components of gluten. They play an important role in dough properties and in bread making quality in various wheat varieties. In the present study, the different alleles encoded at the 5 glutenin loci were identified from a set of 38 tetraploid wheat germplasm obtained from interspecific crosses between durum wheats (Triticum turgidum L. ssp. durum (Desf.) Husn.) and their relatives (T. dicoccum Schübl. and T. polonicum L.) using SDS-PAGE. At Glu-A1 and Glu-B1, encoding high molecular weight glutenin subunits (HMW-GS), 2 and 4 alleles were observed, respectively. Low molecular weight glutenin subunits (LMW-GS) displayed similar polymorphism, as 3, 5 and 3 alleles were identified at loci Glu-A3, Glu-B3 and Glu-B2, respectively. One new allele was detected at Glu-B3 locus and appeared in nine accessions obtained from five crosses. This allele codes for five subunits (2 + 8 + 9 + 13 + 18), encoded by the Glu-B3b without subunit 16 plus subunits 2 and 18. A total of 38 patterns resulted from the genetic combination of the alleles encoding at the five glutenin loci. This led to a significantly higher Nei coefficient of genetic variation in Glu-1, Glu-3 and Glu-B2 loci (0.54). The germplasm analyzed exhibited allelic variation in HMW and LMW glutenin subunit composition and the variation differed from that of tetraploid wheats of other countries. The presence of high quality alleles in glutenin loci have led the accessions to be considered as an asset in breeding programs aimed for wheat quality.
Hordeum vulgare L. (2 n = 14) x Hordeum bulbosum L. (2 n = 14 and 2 n = 28) interspecificcrosses. In: COST 824, "Wide crosses in cereals - problems and applications". Krakow, Poland, pp. 21-22.
Mihãilescu, A., Giura, A
Authors:Hongmei Jia, David Livingston, J. Murphy, and David Porter
is a perennial, autotetraploid oat. In its natural habitat it has a high degree of winter hardiness. The objective of this experiment was to screen 53 backcross progenies of an interspecific cross between the cultivar Brooks (
using a controlled freezing test. No entry tested was more freezing tolerant than the recurrent parent Brooks. These results indicated that freeze tolerance from
had not been introgressed into the progeny. It was suggested that the mechanism for winter hardiness in
is different from that in
and may involve an escape mechanism rather than a genetically controlled freezing resistance mechanism.
The Capsicum genus, which originates from the American continent, contains species with a chromosome number of n=12. The plants have white, lilac or purple flowers, and hollow fruit of very varied shape and size, containing glands alongside the veins that produce a pungent alkaloid known as capsaicin. The majority of varieties in the species C. annuum, grown in the largest volume throughout the world and consumed as fresh vegetables or ground spices, are non-pungent. Interspecific crosses are often possible between C. annuum and related, white-flowered species, thus facilitating breeding for resistance against various diseases and pests and the search for new, valuable traits. Species with lilac and purple flowers can be crossed with each other, but direct crosses with white-flowered species are unsuccessful.
Colchicine is a plant alkaloid, known for thousands of years and currently used widely for the doubling of the genome in plant and animal cells due to its antimitotic effect. The aim of the present experiments was to develop stable autodiploid pollen grains in vitro in diploid lines of rye (Secale cereale L.) and barley (Hordeum vulgare L.) and to use these in intra- and interspecific crosses. Spikelet cultures of one rye and one barley variety were subjected to colchicine treatment in different stages of development and under differing in vitro conditions. Exposure to colchicine led to a drastic reduction both in the number of fertile pollen grains and in the percentage seed-setting, which was only observed in cultures inoculated in the early binuclear microspore stage. On medium containing colchicine the seed-setting percentage was 1.6% for barley and 0.1% for rye. Flow cytometry and root tip analysis revealed that all the progeny barley plants were diploid, while in the case of rye one was tetraploid, indicating that the egg cell may also be diploidised by colchicine treatment.
The virulence frequency of 750 wheat powdery mildew isolates of wheat genotypes, carrying 23 Pm-genes and gene combinations, was studied over ten consecutive years from 2004 to 2013. Seventy-eight previously known and 39 new pathotypes were identified during this period. The results indicate that the majority of Pm-genes have high level of virulence. Sixty to ninety percent of the isolates were virulent to Pm6, Pm8, Pm8+11, Pm2+4b+8, Pm3g, Pm10+15, Pm10+14+15. The virulence frequency was variable for Pm1a, Pm2, Pm3a, Pm3b, Pm3c, Pm5, Pm7 genes and reached high level in certain years. The virulence frequency to genes Pm20, Pm37, Pm4a+ and to gene combination with Pm3c+5a+35 and breeding lines CN240/06, CN98/06 and CN158/06 ranged from 1 to 8%. Bread wheat lines CN240/06, CN98/06 and CN158/06, derived from interspecific crosses, proved to be highly resistant to powdery mildew.
. 1995. Interspecificcrosses: Hybrid production and utilization. In: Mujeeb-Kazi, A., Hettel, G.P. (eds), Utilizing Wild Grass Biodiversity in Wheat Improvement: 15 Years of Wide Cross Research at CIMMYT, CIMMYT Research Report No. 2, Mexico, D. F., pp