Preliminary results about experimental sunflower hybrids resistant to both sulfonylurea and imidazolinone herbicide

It is important to choose what herbicide we want to use depending on degree of weed infestation and what type of sunflower hybrid resistant at sulfonylurea or imidizalinone herbicide. Some farmers who cultivated sunflower in SouthEast of Romania where broomrape is present with the most virulent races, use IMI sunflower hybrids and spray with a IMI herbicide for a better control. Other farmers, prefers SU sunflower hybrids especially in field without broomrape. At NARDI Fundulea, we created sunflower hybrids resistant at sulfonylurea herbicide and sunflower hybrids resistant at imidazolinone herbicide but also we created experimental sunflower hybrids resistant to booth sulfonylurea and imidazolinone herbicide. In year 2018, at NARDI Fundulea, we tested, four experimental sunflower hybrids SU-IMI Plus, H1 SU-IMI Plus, H2 SU-IMI Plus, H3 SU-IMI Plus and H4 SU-IMI Plus, for resistance at sulfonylurea herbicide in Express Sun™ system and imidazolinone herbicide in Clearfield® system. These four experimental sunflower hybrids were full resistant in booth systems, in Express Sun™ and Clearfield®

Sunflower downy mildew, in year 2021, in East of the Romanian plain

Seed yield decrease at sunflower genotypes infected with pathogen Plasmopara halstedii because the plants remain small and the seeds are dry. In last years, sunflower downy mildew has developed new races and it is important to identifying which races is present. In year 2021, in Fundulea location we tested a differential set for sunflower downy mildew and identified 12 races of pathogen Plasmopara halstedii: 300, 304, 310, 314, 330, 334, 700, 703, 704, 710, 714, 731. New races present in Fundulea location, in year 2021 are 703, 704 and 731

Sunflower genotypes from NARDI Fundulea in field infestation with broomrape in Braila area, in year 2019

In south-east of Romania is present the most dangerous races of parasite Orobanche cumana and because of that, who want to cultivated sunflower hybrids, has low seed yield do to broomrape attack. In year 2019, in Braila area, in sunflower fields natural infested with the new races of broomrape from Romania, we tested many sunflower genotypes for resistance/tolerance to this parasite. We want to identifying sunflower genotypes who are resistant/tolerant to broomrape present in Brăila area and from 20 sunflower experimental hybrids tested in natural infested field in three epochs, no one was resistant at broomrape attack. The highest intensity of broomrape attack was in epoch I who was sowing on date May 3, 2019 and sunflower hybrid H2 has 520 broomrape\44 sunflower plants. The lowest intensity of broomrape attack was in epoch II who was sowing on date May 17, 2019 and sunflower hybrid H19 has 40 sunflower plants\13 broomrapes. Sunflower hybrid H17 has a better tolerance at broomrape then other 19 sunflower hybrids tested in field with natural infestation with parasite Orobanche cumana, from Brăila area, Romania where is present races G and H. Regarding plant height of sunflower hybrids tested, was between 90 cm (H10) and 135 cm (H6) in first epoch and between 145 cm (H2) and 200 cm (H9) in the second epoch

OIL CONTENT OF SUNFLOWER GENOTYPES IN YEARS 2020 AND 2021 IN FUNDULEA LOCATION

At NARDI Fundulea, sunflower breeding program is focused for developing sunflower hybrids with high seed oil content, with resistance at main pathogens such as Plasmoparahalstedii, Sclerotiniasclerotiorum, Phomopsishelianthi and with resistance at sulfonylurea herbicides (SU) and to imidazolinone (CL Plus) herbicides. Temperature and precipitation influence seed oil content of sunflower genotypes in booth years 2020 and 2021, in Fundulea location. The amount of precipitation during the sunflower vegetation period from April to September, in both years 2020 (248.6 mm) and 2021 (273.2 mm), was lower than the 60-year average amount (351.8mm). Average seed oil content, in year 2020, was included in the values of 48.63% at sunflower experimental hybrid H54CLP in Clearfield Plus system and 51.79% at sunflower experimental hybrid H87SU in Express Sun system and in year 2021, was included in the values of 41.69% at H54CLP and 50.56% at H87SU. Agricultural year (2020, 2021), sunflower hybrid and their interaction, influence significant positive the oil content of seed. In year 2020 in Fundulea location, pathogen Plasmoparahalstedii has an attack degree between 3% at H76SU, H50CLP and 17% at H54CLP and in year 2021, between 6% at H76SU, H50CLP and 23% at H54CLP

The Resistance of Sunflower to the Attack of Some Pathogenic Agents in the Climate Conditions of the Northeast Baragan

Due to its national economic importance, the sunflower crop has established itself as the main oleaginous crop cultivated in Romania. It faces several diseases that are difficult to fight chemically. The creation of hybrids resistant to the attack of pathogens has proven to be an effective, safe, and environmentally friendly solution. This paper aims to examine the resistance of some biological sunflower creations created in Romania, to the attack of Phomopsis helianthi and Phoma macdonaldi fungi, in 2021. The experiment was placed in field conditions with a natural infestation, at A.R.D.S. Braila. The used biological material was represented by nine new sunflower hybrids. Two problem pathogens were studied: Phomopsis helianthi (perfect stage Diaporthe helianthi) and Phoma macdonaldi (perfect stage Leptosphaeria lindquistii). The climatic conditions of 2021 were favorable for the growth of the pathogens. Phoma macdonaldi had an average attack frequency of 38.8% and an average attack intensity of 1.71%, while Phomopsis helianthi recorded average values of 67.8% and 3.08%, respectively. The lowest attack degree of the Phoma macdonaldi pathogen was found in H3 (0.35%). Regarding the pathogen Phomopsis helianthi, the hybrid H3 showed good resistance, with an attack degree of 1.64%

Active collection of sunflower wild helianthus species from NARDI Fundulea and their use for the introgression of resistance genes to the races of broomrape present in Romania in cultivated sunflower

Annual wild and perennial sunflower species are used in sunflower breeding programs for resistance to various biotic and abiotic factors. For increase the variability inside sunflower must use this species who represent a valuable gene pool. The parasite broomrape (Orobanche cumana Wallr) is a danger to the sunflower culture in Romania, especially in the southeastern part of the country where the most virulent races are present. The identification of new sources of resistance to the attack of this parasite is a priority in the sunflower breeding program from NARDI Fundulea. We have in our collection at NARDI Fundulea, mine perennial wild species and six annual wild species of sunflower and we cross gene from this species in elite line for improving resistance at parasite broomrape and other diseases of sunflower. By crossing the wild sunflower species with different cultivated sunflower genotypes, we obtained interspecific hybrids that are tolerant to more than race G and H of broomrape from area Braila in year 2017. These interspecific hybrids are sources of resistance to the races of broomrape present in Romania and can be used in breeding programs to obtain commercial hybrids of sunflower

The improvement of oil quality and resistance to broomrape in sunflower genotypes resistant to herbicides

Sunflower crop has an important place in the word agriculture, due to many advantages, as the capacity to release high seed yield and good oil content. For improving different characteristics, by breeding methods, we need sources as genes donors. 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. Herbicide resistant crops are becoming increasingly common in agricultural production. A wild population of annual Helianthus annuus was the source for developing cultivated sunflower genotypes resistant to imidazolinone and sulfonylurea herbicides. There have been created inbred lines as sources for the genes transferring in the elite lines. The quality of sunflower oil can be modified by means of induced and spontaneous mutations. The sunflower lines, sources for high oleic acid content, there have been obtained from a Russian variety, created by chemical mutation. Using these sources we transferred genes for improving the oil quality, in our elite lines, resistant to herbicides. Broomrape, caused by Orobanche cumana Wallr. is a parasitic weed which infests sunflower roots, causing severe crop losses. Since broomrape is a highly variable parasite, the breakdown of resistance is a frequent phenomenon and multiple sources of resistance are needed. Genetic resistance to broomrape it was introduced in the sunflower crop from the wild relatives (H. tuberosus, H. maximiliani, H. debilis). The inbred lines created by interspecific hybridization have been used for the improvement of resistance to this parasite, of the lines resistant to imidazolinone and sulfonylurea herbicides

Sunflower genotypes with high tolerance to drought and extreme temperatures, having good resistance to some specific diseases

Sunflower is considered to be moderately resistant to drought, but in hot conditions, the plants suffer reduction in fertility, yield performance and quality of products. In literature there are mentioned some adoptive mechanisms of plants to drought: escape, avoidance and tolerance, as well as their genetic variability. For sunflower it is very important to increase the cold resistance in early development stages, at stage of germination, emergence and the stage of 2-3 leaves, in order to facilitate an early sowing. Wild Helianthus species are a very valuable source of resistance in increasing drought resistance as well as resistance to low temperatures in sunflower. Some of our best elite lines have been introduced in a process of improvement of resistance to drought, using recurrent selection. Also it has been transfered some genes for controling the attack of some important pathogenes. In this process of selection, we obtained inbred lines (CMS and pollen fertility restorer lines) having very good tolerance to drought as well as resistance to low temperatures

Broomrape (Orobanche cumana wallr.) control, by developing genetic resistant genotypes in sunflower

Sunflower broomrape (Orobanche cumana Wallr.) is a parasitic plant which has a significant negative impact on seed yield. The parasite is spread in large areas of Europe, Asia and it has identified recently, in North Africa. Breeding for resistance is regarded as the most effective, feasible and environmentally friendly solution to control sunflower broomrape. However, breeding for resistance is challenging as new races of the parasite have evolved. The use of resistant hybrids of monogenic resistance type, is followed by the appearance of new more virulent races that overcome the existing resistance genes. So, it is necessary to develop sunflower hybrids which can accumulate qualitative and quantitative resistance in a single one, in order to have a durable resistance. Among this, by developing Clearfield Production System in sunflower it could have an important control strategy and complemented the genetic resistance against the parasite