Modern breeding of sunflower (Helianthus annuus L.), which started 100 years ago, increased the number and the diversity of cultivated forms. In addition, for more than 50 years, wild sunflower and other Helianthus species have been collected in North America where they all originated. Collections of both cultivated and wild forms are maintained in gene banks in many countries where sunflower is an important crop, with some specificity according to the availability of germplasm and to local research and breeding programmes. Cultivated material includes land races, open pollinated varieties, synthetics and inbred lines. The majority of wild accessions are ecotypes of wild Helianthus annuus, but also 52 other species of Helianthus and a few related genera. The activities of three gene banks, in USA, France and Serbia, are described in detail, supplemented by data from seven other countries. Past and future uses of the genetic resources for environmental adaptation and breeding are discussed in relation to genomic and improved phenotypic knowledge of the cultivated and wild accessions available in the gene banks.
The study represents a review of the evolution of the parasitic plant Orobanche cumana Wallr. and current racial status in some sunflower cultivating countries. Identification of racial status of broomrape populations belonging to eight sunflower cultivating countries from Europe and Asia (Republic of Moldova, Romania, Bulgaria, Ukraine, Spain, Turkey, Serbia and China) revealed the presence of high virulent races G and H in the majority of countries, except Serbia, where accessions belonging to race E or less virulent than E were found. The most virulent race H was identified particularly in the Black Sea area (Romania, Ukraine and Turkey). Additionally, the emergence of new biotypes characterized by high virulence, overcoming the resistance genes to race H was observed in some areas of the Republic of Moldova, Romania and Turkey, which signifies the importance of periodic evaluations of racial status for the prevention of occurrence and dissemination of new races. Analyzing the occurrence chronology of broomrape races in different countries we conclude that by the mid-1990s, the state of play was relatively stable, the most aggressive race being E. After this period the process of O. cumana development and appearance of new more aggressive and virulent biotypes became faster, which may be explained by the intensification of sunflower breeding activities and, respectively by the selection pressure exerted on the parasite by new resistant hybrids.
The emergence of new broomrape populations (races) has been observed in the past 20 years in several countries (Romania, Moldova, Ukraine, Russia, Turkey, Bulgaria, Spain, Serbia, and China) where sunflower is frequently grown in the same sites without applying traditional crop rotations. Differential lines for sunflower broomrape races A to F have been secured. The new broomrape races have been identified by researchers as races G and H. The question of whether the same broomrape mutations can occur in one year and affect the same countries remains unsolved. Several results of new broоmrape population emergences in some of the affected will be presented in the paper. A total of 390 genotypes were studied at four Romanian localities (Cuza Voda, Crucea-Stupina, Braila-Valea Canepii, and Tulcea-Agighiol) in 2014. At all four localities, a certain degree of sunflower broomrape infestation was observed in control hybrids and lines (Performer, LC-1093, LG-5661, and PR64LE20), which indicated the emergence of new populations higher than race H. The 390 studied genotypes had different reactions in all four localities. In 2015, 10 hybrids and controls were studied at five Romanian localities (Ciresu-Braila, Iazu-Ialomita, Stupina-Constanta, Topolog-Tulcea, and Viziru-Braila) and, according to the results, only hybrid Hy-7 was resistant in all localities. The results obtained from the three studied localities showed the emergence of new sunflower broomrape populations not controlled by gene for race H. Self-fertilization of hybrid Hy-7 produced the F2 generation in 2016. In 2017, broomrape resistance was studied at the infested (contaminated) plot at the All-Russian Research Institute of Oil Crops by the name of Pustovoit V.S. – VNIIMK in Rostov on Don. The plot was found to be infested by new broomrape populations originating from Russia, Ukraine, Romania, Turkey, and Spain. The obtained results showed an infestation degree in 17.1% plants of hybrid Hy-7, 35% in the F2 generation of Hy-7, control hybrids PR64LE25, LG-5580 and Donskoy-22 showed 19.4, 23, and 100% broomrape infestation, respectively. In conclusion, the plot contained broomrape populations which cannot be controlled by race H gene. According to the obtained results, a permanent change in variability of broomrape populations can be confirmed practically year after year. At present, new broomrape populations found at several localities are locally dispersed. Geneticists and breeders have to make joint efforts in further detailed studies of broomrape variability.
Genetic resources in sunflower, which could to be used as base of creating new inbred lines or as donor sources for genes controlling different characteristics in the inbred lines breeding, are made up of old or new varieties, hybrids and inbred lines, induced mutations, synthetic populations, as well as sunflower wild species. For improving sunflower resistance to the main diseases all these genetic resources can be used. In the sunflower breeding program of the National Agricultural Research & Development Institute (NARDI) Fundulea, Romania, we have used especially varieties, hybrids, inbred lines and sunflower wild species. The varieties and inbred lines were used for creating synthetic populations, which formed the base of obtaining new inbred lines resistant to Plasmopara halstedii (genes for resistance to different races of this pathogen). Sunflower wild species have been used for crossing with cultivated sunflower, obtaining interspecific hybrids, which allowed creating different donor sources of genes for resistance to Plasmopara halstedii, as well as to Sclerotinia sclerotiorum. We obtained some populations which are still in the breeding process for creating inbred lines with high resistance to Phoma macdonaldii and Phomopsis helianthi pathogens. We improved the resistance of some lines with good agronomic traits, to different diseases. The new inbred lines obtained by using different genetic resources were studied as general and specific combining ability for the seed yield and for oil content. Most of them were significantly superior as general combining ability for the seed yield or for oil content, or for both of them.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.