Sunflower Genetics from Ancestors to Modern Hybrids-A Review

Domestication and the first steps of sunflower breeding date back more than 4000 years. As an interesting crop to humans, sunflower underwent significant changes in the past to finally find its place as one of the most significant oil crops today. Substantial progress has already been made in understanding how sunflower was domesticated. Recent advances in molecular techniques with improved experimental designs contributed to further understanding of the genetic and molecular basis underlying the architectural and phenotypic changes that occurred during domestication and improvements in sunflower breeding. Understanding the domestication process and assessing the current situation concerning available genotypic variations are essential in order for breeders to face future challenges. A review of the tools that are used for exploring the genetic and genome changes associated with sunflower domestication is given in the paper, along with a discussion of their possible implications on classical sunflower breeding techniques and goals

Genetic and Genomic Tools in Sunflower Breeding for Broomrape Resistance

Broomrape is a root parasitic plant causing yield losses in sunflower production. Since sunflower is an important oil crop, the development of broomrape-resistant hybrids is the prime breeding objective. Using conventional plant breeding methods, breeders have identified resistant genes and developed a number of hybrids resistant to broomrape, adapted to different growing regions worldwide. However, the spread of broomrape into new countries and the development of new and more virulent races have been noted intensively. Recent advances in sunflower genomics provide additional tools for plant breeders to improve resistance and find durable solutions for broomrape spread and virulence. This review describes the structure and distribution of new, virulent physiological broomrape races, sources of resistance for introduction into susceptible cultivated sunflower, qualitative and quantitative resistance genes along with gene pyramiding and marker assisted selection (MAS) strategies applied in the process of increasing sunflower resistance. In addition, it presents an overview of underutilized biotechnological tools, such as phenotyping, -omics, and genome editing techniques, which need to be introduced in the study of sunflower resistance to broomrape in order to achieve durable resistance

Genetic advance and regression analysis in sunflower

The knowledge about the magnitude and nature of variability that is present in a breeding population is an important prerequisite for designing efficient breeding programme in order to improve the yield potential of genotypes. The objective of this research was to evaluate heritability and genetic advance of important quantitative traits in new crosses of sunflower as well as to evaluate ratio of dominant and recessive genes in parental genotypes. The plant material selected for this research consisted of 6 sunflower genotypes, which according to literary data possess important characteristics for the production of sunflower. According to presented results there is significant variability of evaluated quantitative traits. Phenotypic variance was higher than genotypic demonstrating strong environment effect in expression of traits. The broad sense heritability was found very high for plant height (83.25%), high for 1000 seed weight (69.33%), moderate for seed yield/plant (46.53%) and head diameter (56.89%), while low for oil content (29.35%). Genetic advance expressed as a percentage of the mean ranged between 2.23% and 19.96%. Placement of array points displayed that the highest frequency of dominant genes for seed yield/plant, 1000 seed weight and head diameter was found in parental genotype Rodnik. Position of expected line of regression pointed over dominance in inheritance for seed yield/plant, oil content and head diameter, while for 1000 seed weight and plant height additive gene action played role in inheritance suggesting that selection in early generations for these traits will be effective. By testing the coefficients of regression interallelic interaction was not determined

Epigenetics: possible applications in climate-smart crop breeding

To better adapt transiently or lastingly to stimuli from the surrounding environment, the chromatin states in plant cells vary to allow the cells to fine-tune their transcriptional profiles. Modifications of chromatin states involve a wide range of post-transcriptional histone modifications, histone variants, DNA methylation, and activity of non-coding RNAs, which can epigenetically determine specific transcriptional outputs. Recent advances in the area of '-omics' of major crops have facilitated identification of epigenetic marks and their effect on plant response to environmental stresses. As most epigenetic mechanisms are known from studies in model plants, we summarize in this review recent epigenetic studies that may be important for improvement of crop adaptation and resilience to environmental changes, ultimately leading to the generation of stable climate-smart crops. This has paved the way for exploitation of epigenetic variation in crop breeding

Rapeseed breeding for multiple uses assisted by biotechnological tools at Novi Sad

Rapeseed is not only one of the most important edible oil source, but also raw material for industry and feed. Furthermore, it has proven to be very efficient in remediation of heavy metal polluted soils. Institute of Field and Vegetable Crops (IFVCNS) has more than 20 year long tradition of rapeseed breeding during which more than 30 spring type varieties and lines, as well as more than a 1000 winter type varieties and lines have been developed. Proper examination and exploitation of such collection requires use of a multidisciplinary approach. By use of in vitro tests, we have analyzed tolerance of chosen rapeseed genotypes to heavy metals such as lead and cadmium. The most tolerant genotypes from NS gene pool, which have proven to have stable and high oil yield and composition in different field experiments, were included in NS rapeseed hybrid breeding program and have been used as components for rapeseed hybrid production

Genetic control of broomrape in sunflower

Broomrape (Orobanche cumana Wallr.) is a major biotic constraint in sunflower (Helianthus annuus L.) production in Europe and Asia. It produces a large number of small seeds that are easily disseminated, leading to the build-up of O. cumana populations, and the constant appearance of new, and more virulent races. Current racial situation of broomrape in the main infested areas is unclear, since there is a lack of information on whether races under the same name reported in different countries are the same or differ in terms of virulence. Among the several control options proposed, genetic control of broomrape has been found to be most effective and environmental friendly way. Since O. cumana resistance is broken frequently, multiple sources of resistance are needed to control the emerging races. Some resistance sources have been found to be controlled by major genes, some have recessive inheritance, but some showed QTL resistance

Genetic improvement in sunflower breeding—integrated omics approach

Foresight in climate change and the challenges ahead requires a systematic approach to sunflower breeding that will encompass all available technologies. There is a great scarcity of desirable genetic variation, which is in fact undiscovered because it has not been sufficiently researched as detection and designing favorable genetic variation largely depends on thorough genome sequencing through broad and deep resequencing. Basic exploration of genomes is insufficient to find insight about important physiological and molecular mechanisms unique to crops. That is why integrating information from genomics, epigenomics, transcriptomics, proteomics, metabolomics and phenomics enables a comprehensive understanding of the molecular mechanisms in the background of architecture of many important quantitative traits. Omics technologies offer novel possibilities for deciphering the complex pathways and molecular profiling through the level of systems biology and can provide important answers that can be utilized for more efficient breeding of sunflower. In this review, we present omics profiling approaches in order to address their possibilities and usefulness as a potential breeding tools in sunflower genetic improvement

Genomics-assisted speed breeding for crop improvement: present and future

Global agricultural productivity and food security are threatened by climate change, the growing world population, and the difficulties posed by the pandemic era. To overcome these challenges and meet food requirements, breeders have applied and implemented different advanced techniques that accelerate plant development and increase crop selection effectiveness. However, only two or three generations could be advanced annually using these approaches. Speed breeding (SB) is an innovative and promising technology to develop new varieties in a shorter time, utilizing the manipulation of controlled environmental conditions. This strategy can reduce the generation length from 2.5 to 5 times compared to traditional methods and accelerate generation advancement and crop improvement, accommodating multiple generations of crops per year. Beside long breeding cycles, SB can address other challenges related to traditional breeding, such as response to environmental conditions, disease and pest management, genetic uniformity, and improving resource efficiency. Combining genomic approaches such as marker-assisted selection, genomic selection, and genome editing with SB offers the capacity to further enhance breeding efficiency by reducing breeding cycle time, enabling early phenotypic assessment, efficient resource utilization, and increasing selection accuracy and genetic gain per year. Genomics-assisted SB holds the potential to revolutionize plant breeding by significantly accelerating the identification and selection of desirable genetic traits, expediting the development of improved crop varieties crucial for addressing global agricultural challenges

New approaches in phenotype prediction – machine learning techniques

Use of multivariate modelling in order to improve prediction accuracy has been widely applied in plant breeding programs. In these models phenotype prediction is based on large number of independent variables which is at the same time strength and weakness. Lately, intensive research in order to improve prediction accuracy resulted in extensive use of different machine learning techniques. The aim of this study is to present new approaches in phenotype prediction based on complex relationships between genotypes and phenotypes. Widely used, one of the main tools in machine learning is artificial neural network (ANN). Although it has a long history, this powerful class of algorithms has been recently used as a state-of-the-art solution for non-linear relationship between the genotype and the trait of interest. Another important advance, capable of identifying extremely complex patterns of prediction and classification of information is called deep learning (DL). Main difference between DL and ANN is in the numbers of layers of neurons. Being based on how humans learn and process information, machine learning is powerful tool for processing complex data in order to make accurate predictions

Sunflower broomrape – update on virulence in Serbia

Broomrape Orobanche cumana, widespread achlorophyllous plant parasite, is considered as major constraint in sunflower production. Presently, research of parasite virulence indicating new and continuously changing patterns in most areas of its distribution. This is commonly noticed as occurrence of isolated parts of field with parasite presence. In sunflower production regions in Serbia race E dominates although race F was reported. The aim of this research was to further improve knowledge of O. cumana virulence in Serbia. Sunflower broomrape for this research was sampled on six locations for virulence determination. Universally susceptible inbred line, four inbred lines with resistance to race E and a line resistant to race F were used. Results of interaction were obtained after growing sunflower in pots with broomrape seed for seven weeks. Broomrape from each sample was successful in attaching to roots of line AD66 and line LC-1003. Inbred line P96 was completely resistant to all broomrape populations