, biotic and abiotic stresses have negative effect on tomato production. Rootstock potentials of some interspecifichybrids derived from S. habrochaites were studied ( Rivard et al., 2010 ). As a result, the interspecifichybrids were found to be
Venskutonis, P. R. (2002): Chemical composition of the essential oil of an interspecifichybrid of thyme (Thymus × oblongifolius Opiz) growing wild in Lithuania. —
J. Essent. Oil Res. 14
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.
The aim of the programme started at ARDI-Fundulea in 1999 is to improve the pest and disease resistance of cultivated barley (H. vulgare L.) by introgressing valuable genes from the wild species H. bulbosum L. The paper presents results on the development and cytogenetical characterization of primary genetic stocks represented by diploid, triploid and tetraploid interspecific hybrids and first backcrossed generation descendants. several sterile diploid hybrids were found during the phenotypic screening and cytological analysis of haploid progeny from H. vulgare 2x × H. bulbosum 2x crosses. These hybrids were treated with colchicine and fertile tetraploid hybrids were obtained. Significant improvements in the seed setting and in vitro triploid hybrid regeneration were obtained using doubled haploid lines (DHLs), previously selected for high interspecific crossability, in crosses with a tetraploid cytotype of H. bulbosum. Meiosis analysis of triploid hybrids provided compelling evidence that relatively high intergenomic allosyndetic pairing had occurred in some of the triploids with increased potential for crossing over and genetic recombination. High mean values for hybrid stability, multivalent associations in MI, higher chiasma frequency per PMC and partial pollen fertility were considered by far the most important criteria in the cytogenetic selection of triploid hybrids. Selected triploids were backcrossed to barley DHLs. Among the in vitro regenerated backcrossed progeny several putative substitution lines (SLs) were identified by preliminary cytological screening. The complete phenotypic and cytogenetic characterization and disease resistance tests of tetraploid hybrids and putative SLs or RLs are now in progress.
The new stem rust strain, Puccinia graminis f. sp. tritici — Ug99, has been a rising threat since the alarm was rung in Uganda in 1998. The genetic and breeding dimensions of research against this disease include the development of vigorous molecular markers, the identification and introgression of multiple resistance genes, the translocation of alien chromosomes, the enrichment of breeding lines with crossability alleles and the development of interspecific hybrids. Resistance genes have been identified in the primary wheat gene pool and in alien sources such as Aegilops spp., Dasypyrum villosum, Secale cereale, Hordeum vulgare and Oryza spp. and some of these sources have been used to confer resistance as a function of single or multiple gene effects. Realizing the potential disaster if Ug99 and related variants break out in other regions, wheat-producing countries are characterizing their germplasm and improving their stem rust race tracking systems. Equally important is “appropriate genetic management”, i.e. the use of currently effective resistance genes in such a way that the evolution and adaptation of new virulence will be deterred. This review will summarize the recent research advances and future perspectives in setting effective genetic barriers vis-à-vis the seemingly intractable spread and evolution of Ug99.
Some wild species of the genus Oryza such as O. rufipogon and O. longistaminata show a high level of resistance to pests and diseases including rice blast (caused by Magnaporthe grisea). To transfer blast resistance from wild species into cultivatedvarieties (O. sativa), interspecific hybrids were produced and anther culture was used toaccelerate the procedure of resistance breeding. Anther culture efficiency depended onboth the medium and the genotype of the cultivated varieties and the wild species. Afterinoculation with a mixture of six strains with wide spectrum virulence, all the F1 hybridswere resistant to blast; the F2 plants segregated, from high resistance to susceptibility, anda similar result was obtained for the H1 and H2 plants. At the H3 stage, blast resistancetended to be stable and almost 100% of inoculated H5 plants were highly resistant to riceblast. For agronomic characteristics, the F2 and H1 showed segregation, but no significantdifferences were seen between the cultivated parents and the H2 to H5 generations. Theresults demonstrate that blast resistance genes can be transferred from wild rice speciesinto cultivated varieties through crossing and anther culture, and the H5 can be used asstable lines in future breeding programmes.
Pál Kozma, a scientist famous throughout Europe for his work on vines, was born into a poor peasant family in the small village of Gyulaháza in Szabolcs-Szatmár-Bereg County in Eastern Hungary on 11 July 1920. Despite his thirst for knowledge, he was obliged to interrupt his studies on several occasions due to the poverty of his family, and it was not until 1947 that he finally graduated from the University of Agriculture with a first class honours degree in agriculture, specialising in horticulture and vine-growing. The following year he obtained his teaching diploma, again with first-class honours. In 1947 he started work as an assistant inspector of viticulture in Tarcal, later moving to the Technical College for Horticulture and Viticulture in Miklóstelep, where he was employed as a teacher and viticulture inspector. From 1949 onwards he worked in the Department of Viticulture at the Faculty of Horticulture and Viticulture of the University of Agricultural Sciences, filling the post of Head of Department from 1960 until he retired in 1990. From 1962-1965 he was Vice-Rector of the University, followed by six years as Rector from 1965-1971. The basic and applied research he carried out from 1948 onwards gave a new direction to viticulture. His field of research included the flowering biology of the vine (flower morphology, histology, divergence and evolution of flower types, special types of fertilisation and grape formation in various flower types, light and electron microscope studies on morphological traits), vine breeding through selection and crossing (intra- and interspecific hybrids of white and red wine grapes and table grape varieties), leaf analysis for the study of the organic and mineral metabolism of vines and the diagnosis of optimum nutrient supplies, transpiration, the physiological effects of cultivation and pruning methods, the physiology of vine branches, improved technologies for the cultivation of table grapes, and the history of viticulture. In addition to the success he achieved in scientific research, he was also an excellent teacher. His students left the university with a high standard of knowledge and many of them distinguished themselves in later life. In recognition of his achievements he was given many awards, including the State Prize in 1975 and the Order of the Hungarian Republic in 1990. He received a prize from the publishers for his books entitled "Table Grapes" in 1962 and "Vines and Their Cultivation I-II" in 1994. He also received a number of international awards, including the OIV Prize (1964, 1994), the Humboldt Memorial Plaque (1968) and the Hegel Medal, Berlin (1970). He was a member of the Editorial Committee of Acta Agronomica Hungarica from 1967 to 1994 and Chief Editor from 1995 to 2000. Those who were privileged to know Pál Kozma found him to be a good-humoured and extremely well-informed man, with an enormous thirst for new knowledge and the determination which had stood him in good stead in his rise from the depths of poverty to the heights of an academic career. He was not only highly intelligent, but also extremely hard-working, never allowing difficulties to hinder him in his quest for knowledge. He will be sadly missed, but his influence will remain with us in his books and in the work of the experts he trained so well.