Volume 41, Issue 68 -

Dr Chao-Chien Jan, Research Geneticist with the USDA-Agricultural Research Service (USDA-ARS), Red River Valley Agricultural Research Center, Northern Crop Science Laboratory, Sunflower and Plant Biology Research Unit, Fargo, ND retired January, 2017 after 35 years of dedicated service. He began his research career in 1974 after receiving his Ph.D. in genetics from the University of California, Davis, CA, working with wheat. He was a postdoctoral Research Biologist at the Cancer Research Institute, University of California, San Francisco in 1975. From 1976 to 1981 he was a postdoctoral Research Agronomist, Department of Agronomy and Range Science, UC, Davis, CA. working on wheat. In 1981, Dr Jan joined the U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS) as a Research Geneticist at the Rice and Oilseed Unit at Davis, CA with an emphasis on cytogenetics, working on sunflower ( Helianthus annuus ) crop wild relatives (CWR) for the improvement of the sunflower crop. The sunflower program at Davis, CA was closed in 1984, and he was transferred to the USDA-ARS Sunflower Unit in Fargo, ND where he spent the rest of his career working on sunflower CWR. Dr Jan’ research contributed significantly to the ability to utilize the genetic diversity of the 53 species of wild sunflowers, especially in the areas of germination, use of embryo culture and chromosome doubling to overcome embryo abortion and fertility problems. His pioneering research in interspecific hybridization, cytoplasmic male sterility and fertility restoration, cytogenetic stocks, disease resistance and mutation opened doors to genetic diversity never before available for utilization by the sunflower industry. This led to his global stature with invitations to serve as a visiting scientist and fellowships in Australia, Serbia, Spain, Romania, and China. He has hosted over 20 scientists from 15 countries, as well as countless students during his career. Due to his stature, he has been invited to present several invited plenary talks, both national and international, and in 2012 he was presented the prestigious Pustovoit Award, the highest award in the sunflower industry given by the International Sunflower Association for his contribution to sunflower science and technology.

Helianthus porteri , a sunflower endemic to drought prone granite outcrops, has been hypothesized to be drought resistant. We compared H. porteri to three Helianthus species ( H. annuus, H. agrestis, H. carnosus ) from less drought prone habitats for traits associated with drought avoidance and tolerance in greenhouse experiments. Under well-watered conditions, H. porteri had high specific root length suggestive of high capacity for water uptake, but intermediate root mass ratio (RMR) and shallow rooting inconsistent with enhanced capacity for drought avoidance. In response to mild drought, none of the species exhibited osmotic adjustment, and H. porteri had no change in RMR and no greater capacity to increase water-use efficiency, again, inconsistent with greater drought avoidance. In response to cessation of watering, H. porteri wilted at a leaf water potential similar to a wet habitat species, inconsistent with greater drought tolerance. Overall, under the conditions assessed, we found no evidence that H. porteri possesses traits that confer a unique ability to avoid or tolerate drought as compared to congeners.

The investigation was carried out at Dobrudzha Agricultural Institute – General Toshevo, Bulgaria, and encompassed the period 2009–2010. The experiment involved four double haploid fertility restorer lines (DH-R-2, DH-R-7, DH-R-116 and DH-R-128), which have shown in our previous studies various degree of resistance to Sclerotinia sclerotiorum de Bary under artificial infection conditions. Ten plants from each investigated line were inoculated by the Straw-method at stage 5-6th pair of leaves. The plants were self-pollinated and the seeds obtained from them, as well as the seeds from the check plants (not infected), were analyzed for the traits 1000 seed weight, % of kernel, oil in kernel and protein content in kernel. Variations in the quality characteristics of the sunflower seeds were found in all investigated lines, the degree of quality “deterioration” having different expression according to the tolerance of the line to the pathogen. Lines DH-R-2 and DH-R-7 formed seeds with lower seed weight and percent of kernel. These seeds had lower oil and protein content. The established variations in the quality of the seeds between lines DH-R-116 and DH-R-128 and the check variants were not statistically significant.

Orobanche cumana Wallr. is a holoparasitic plant for only sunflower, hence it is called as sunflower broomrape. Yield loss created by O. cumana which is generally 50 % can reach to 100 %. In this study, it was planned to perform molecular characterization of O. cumana germplasm as nine locations of Thrace region obtained from Trakya Agricultural Research Institute by using Single Nucleotide Polymorphism (SNP) markers, widely used in plant breeding programs, in Competitive Allele Specific PCR (KASP) assay which is a fluorescent tagged allele specific PCR method based, economic, reliable and easily repeatable genotyping technology. Databases and literature were scanned to spot variations on O. cumana genome which is not known clearly. So far, four SSR (Simple Sequence Repeat) marker ( Ocum-197, Ocum-006, Ocum-023 and Ocum-151 ) regions showing polymorphic pattern were used for searching possible SNPs. Primer pairs were designed for amplification of the regions possibly having SNPs and PCR amplifications with these primer pairs were performed and 1 candidate deletion was detected on the amplicon which was amplified by Ocum-197 SSR marker. Following, the deletion was converted to KASP primers and KASP assay was performed. The deletion marker, Del-197 , has grouped the samples from nine locations in the resulting allelic discrimination plot and infestation was performed according to this grouping, As a conclusion, Del-197 is considered as a selective marker for the ability to rapidly assay allelic variation at DNA markers for O. cumana populations that have effects on infestation results were evaluated as races, F, G, H and I in Thrace region.

Simple sequence repeats (SSR) polymorphism of 34 microsatellite loci (LG1, 8 and 13) was studied in lines carrying the downy mildew resistance genes Pl and lines with no Pl . The microsatellite loci ORS328 and ORS781 were selected as markers for genes Pl6 and Pl8 in lines HA 335 and QHP-1, respectively. Markers were identified for gene Pl ARG in RHA 419 and some accessions of H. argophyllus . The SSR markers ORS509, ORS605, ORS610, ORS1182 and ORS1039 were proven to reliably identify the parental line carrying Pl ARG gene, control and select the heterozygous F 1 hybrids and identify homozygous genotypes in F 2 generations. Obtained results indicate the necessity of validation of the markers in various germplasm pools and breeding collections. The SSR markers that are tightly linked to Pl 6 , Pl 8 , Pl ARG would be useful in the sunflower breeding. Pl ARG homozygous F 2 segregants, developed and identified with marker assisted selection in this study, are recommended for further breeding as a new source of genetically determined resistance to downy mildew.

Abiotic stresses including drought are major crop production constraints. However, specific functional phenotypic markers induce resistance against these stresses. Therefore, a study was initiated to study the variability, inheritance and selection of epicuticular waxes (EW) and leaf hairiness (LH) along with low cell membrane injuries (CMI) within F 2 populations derived by crossing H. annuus × H. argophyllus lines. These traits have been shown to be associated with drought tolerance of Helianthus argophyllus and thus study aims to introgress these traits in Helinathus annuus . The studied parent populations showed contrasting values of the traits. The drought susceptible line CMS-14 and CMS-20 showed lower epicuticular waxes (0.79, 0.69 mg g −1 ), leaf hairiness (0.75, 1.53) and higher cell membrane injury (40.90, 55.76 %) respectively while drought resistant line Argo 1802 and 1806 showed higher epicuticular waxes (2.28, 3.18), leaf hairiness (3.71, 3.80) and lower cell membrane injury (14.22, 21.54 %) respectively. The F 1 hybrids had mean values of the three studied parameters i. e. epicuticular waxes (1.50 mg g −1 ), cell membrance injury (32.54 %) and leaf hairiness (2.74) in the range of parent lines, but some of F 2 individuals extend beyond this range (Parents and F 1 s). The two-step selections maintained high variability especially of LH for set of F 2 individuals ( H. annuus CMS-20× H. argophyllus 1806). Simultaneous selection of F 2 individuals with high values of LH or EW with low CMI was possible. The selected plants were further studied for narrow leaf, high fertility and silver canopy color. Selected material was promoted as the candidate of inbred line. Plant (F 4 ) having introgressed traits (silver canopy) showed lower yield (19 %) than green leafed plants (53 %) and commercial hybrids under drought stress (63 % and 53 %). The study could help to increase the abiotic stress tolerance, minimize the yield losses under drought stress and increase functional diversity within sunflower.

Collection of sunflower lines of the Institute of Oilseed Crops was studied based on its branching. Ten lines with the basal branching trait were identified. It was established that the inheritance of the basal branching is due to the recessive alleles of the genes. For lines InLD1240, Z1064, LD835, KG13, VIR130, KG13, LD4, basal branching trait is due to the recessive homozygote of one gene b2 . In lines LD72/3, LD156, KG16, I2K2218, basal branching trait is due to the recessive homozygote of two genes b3 and b4 . It was established that the genes determining basal branching are distributed in the offspring independently of the genes controlling the top branching.

The genus and species composition of the micromycete complex in the root zone (rhizoplane, rhizosphere and edaphosphere) of sunflower at the beginning of flowering and full maturity stages during its cultivation on leached chernozem was studied. It was established that representatives of the genera Aspergillus, Botrytis, Gliocladium, Fusarium, Paecilomyces, Penicillium, Rhizopus and Trichoderma formed the complex of typical fungi of the rhizoplane and rhizosphere. At the stage of flowering in the mycocenosis, the species Paecilomyces lilacinus, Paecilomyces variotii and Trichoderma viride dominated, and in the maturity stage Rhizopus nigricans, Penicillium nigricans, Botrytis cinerea and Fusarium moniliforme var . subglutinans prevailed. The phytopathogenic complex at the flowering stage formed the species of the genera Fusarium and Rhizopus , and by the end of the vegetation the variety of potential pathogens was expanded by representatives of the genera Alternaria, Botrytis and Gliocladium . A comparative analysis of the micromycete complex revealed a similarity of the dominant species of the rhizoplane and rhizosphere in different stages of sunflower development. However, by the end of the vegetation in the rhizosphere, compared to rhizoplane, the abundance of fungi of the species Fusarium moniliforme var. subglutinans and Penicillium nigricans increased significantly. As for edaphosphere, Rhizopus nigricans, Trichoderma viride and Penicillium nigricans dominated during sunflower flowering, and by the end of the crop vegetation the number of micromycetes of the genus Fusarium was reduced while the proportion of micromycetes of the genus Rhizopus increased significantly.

Wild Helianthus species should have be a main interest sunflower breeding for the introgressing elite genes for biotic and abiotic stress. The future use of wild sunflower in development of drought resistance cytoplasmic sources should be expanded to the wide range of wild species as compared to conventional sources. The objective of this study was to evaluate different parental lines for their water-use efficiency and seed yield performance under two environments for two years. ARG-2A received from H. argophyllus , 234A and 38A from H. petiolaris were found to be the most susceptible genotypes, whereas, 42A, 42B from H. petiolaris and ARG-6A ( H. argophyllus) were found to be tolerant to drought stress. CMS-XA, RCR-8297, E002-91A, NC-41B and P124R were observed to be well adapted to stress environments. ARG-3A from H. argophyllus had a stable performance over the environments, which may be useful to develop water use efficient hybrids having diversified cytoplasmic backgrounds in sunflower breeding.