Modern trends in breeding and genetic improvement of sunflower varieties and hybrids at VNIIMK

Modern sunflower breeding is significantly diversified due to the different needs of agricultural production. The breeding of sunflower varieties and hybrids is carried out at V.S. Pustovoit All-Russian Research Institute of Oil Crops (VNIIMK) in all areas in demand on the market and is based on fundamental biological research. In the field of breeding for faster maturing, the following commercial cultivars were obtained: very early maturing, cv. Skormas and the three-way hybrid Achilles, early maturing cvs. Varyag and Uspekh, medium maturing cvs. Amelie, Aris and Aurus. Within the framework of breeding for immunity, eight hybrids and one variety have been produced. So at the Don experimental station (Rostov region), productive hybrids were bred, resistant to the virulent broomrape of the G race due to the presence of the Or7 gene: ‘Gorstar’, ‘Gorfild’, ‘Grant’, ‘Status’, ‘Fogor’ and the three-way hybrid Nika. On the central experimental base, the following were obtained: the mid-early hybrid Typhoon and the earlymaturing variety Platonych with resistance to common races of downy mildew and a high oil content of achenes (up to 53 %) as well as the mid-early hybrid Tayzar, which is simultaneously resistant to virulent races of broomrape and to the causative agent of downy mildew. The early maturing large-fruited sunflower variety Belochka was included in the “Russian State Register of Selection Achievements…”, and the large-fruited varieties Karavan, Konditer and Kalibr are currently undergoing state tests. The breeding use of germplasm with genes for herbicide resistance was accompanied by their extensive genetic study. A practical recommendation for all three alleles of the ALS gene (Imr, CLHA-Plus, Sur) was the need to create homozygous hybrids for their reliable use in appropriate production systems. For Clearfield technology, the hybrids Imidzh, Arimi and Immi have been developed; for Clearfield Plus, the hybrid Klip; and for Express Sun (or SUMO), the hybrid Surus. Klip and Surus are mid-oleic. All newly developed fertile ornamental sunflower varieties – Aurelia, Fizalia, Zhemchuzhny, Rumyanets, Agat and Mazhor – were transferred for practical use to a sterile CMS RIG basis. Thus, new achievements have been attained across the entire spectrum of modern trends in sunflower breeding.

Pest management via endophytic colonization of tobacco seedlings by the insect fungal pathogen Beauveria bassiana

BACKGROUND

It has been suggested that entomopathogenic fungi can be introduced into plants as endophytes potentially leading to insect control. Here, we sought to identify specific strains of the insect pathogenic fungus, Beauveria bassiana that would form endophytic associations with tobacco (Nicotiana benthamiana) benefitting host plant growth and/or resistance against insect pests and pathogens.

RESULTS

Tobacco seeds were inoculated with six different B. bassiana strains and entophytic colonization, plant growth, and resistance to pathogens and insect pests were evaluated over a 50 day-period. Although all the strains could colonize seedlings, 90% seedling colonization was seen for four strains. Fungal cells could be detected in stems more readily than in leaf and root tissues. Colonization by B. bassiana boosted plant growth with an increased photosynthetic rate, chlorophyll content, and stomatal and trichome density seen in fungal treated plants. Tobacco seedlings colonized by specific B. bassiana strains displayed significantly increased tolerance/resistance against bacterial and fungal pathogens. B. bassiana-colonized seedlings also displayed higher resistance to aphids (Myzus persicae) as compared to untreated controls. Colonization by B. bassiana was shown to trigger both of the salicylic acid (SA) and jasmonate acid (JA) defense pathways, but SA pathway was upregulated much more than JA pathway for some of the tested strains.

CONCLUSION

Specific strains of B. bassiana can be introduced into host plants as endophytes, resulting in promotion of host plant growth, increased resistance to microbial pathogens, and/or increased resistance to insect pests. © 2020 Society of Chemical Industry.

High-throughput genomics enhances tomato breeding efficiency

Tomato (Solanum lycopersicum) is considered a model plant species for a group of economically important crops, such as potato, pepper, eggplant, since it exhibits a reduced genomic size (950 Mb), a short generation time, and routine transformation technologies. Moreover, it shares with the other Solanaceous plants the same haploid chromosome number and a high level of conserved genomic organization. Finally, many genomic and genetic resources are actually available for tomato, and the sequencing of its genome is in progress. These features make tomato an ideal species for theoretical studies and practical applications in the genomics field. The present review describes how structural genomics assist the selection of new varieties resistant to pathogens that cause damage to this crop. Many molecular markers highly linked to resistance genes and cloned resistance genes are available and could be used for a high-throughput screening of multiresistant varieties. Moreover, a new genomics-assisted breeding approach for improving fruit quality is presented and discussed. It relies on the identification of genetic mechanisms controlling the trait of interest through functional genomics tools. Following this approach, polymorphisms in major gene sequences responsible for variability in the expression of the trait under study are then exploited for tracking simultaneously favourable allele combinations in breeding programs using high-throughput genomic technologies. This aims at pyramiding in the genetic background of commercial cultivars alleles that increase their performances. In conclusion, tomato breeding strategies supported by advanced technologies are expected to target increased productivity and lower costs of improved genotypes even for complex traits.