Sunflower Genotypes Research Articles

Genotype-by-environment interaction and yield stability of sunflower hybrids across production environments in South Africa

Genotype-by-environment interaction (GEI) is typical in multi-environment trials, which complicates the identification of superior genotypes, making selection and recommendation of new sunflower genotypes for different environments challenging and expensive. The objectives of this study were to investigate the GEI, identify the most discriminating and representative environments, and determine the performance and yield stability of 15 sunflower cultivars across diverse environments in South Africa. A randomised complete block design with three replicates was used. Seed yield data were subjected to combined analysis of variance, and a genotype main effects and genotype environment interaction (GGE) bi-plot method. The results showed that environment, genotype and genotype-by-environment interaction significantly affected seed yield. The environment effect was a predominant source of variation and accounted for 52.95% of the total sum of squares, whereas genotypic and GEI effects contributed 2.73% and 20.98%, respectively. The GGE bi-plot explained 60.67% of the total variation relative to genotype, GEI and showed that G9, G14, G12, G4 and G13 were high yielding, stable and might be considered as desirable genotypes. In terms of location, Senekal (E14) was identified to be the most discriminating and representative environment to evaluate sunflower genotypes.

Impacts of Meteorological Attributes on Agronomic Characteristics of Sunflower Cultivated in the Cerrado

The sunflower has adaptation for cultivation in Brazilian conditions and the main product is the oil extracted from the seeds. This study aimed to verify the impacts of meteorological attributes on agronomic characteristics of sunflower genotypes cultivated as a second crop, in Mato Grosso, Brazil. The experimental design was randomized complete block design (RCBD), cultivating the two sunflower genotypes, M734 and Hélio, in three years (2009, 2011, 2012) with four replications. The agronomic characteristics evaluated were: plant height, capitulum diameter, weight of a thousand achenes, yield of achenes, oil content and oil yield. Then, water deficit and the maximum crop yield are estimated for correlation analysis between meteorological attributes and agronomic characteristics. In both genotypes studied there was a very strong correlation between plant height with evapotranspiration (r=0.99*) and very strong negative correlation (r=-0.99*) with water deficit. For mass of a thousand achenes, there was a very strong negative correlation with the maximum (r=-0.98*) and minimum (r=-0.96*) temperatures, and with evapotranspiration (r=-0.98*) in the Helio 358. In addition, effect of the water deficit on the oil yield (r=-0.98*) was verified for the same genotype. Very strong negative correlation was found between maximum temperature and oil content (r=-0.96*) in genotype M734. In sunflower cultivation in Mato Grosso, Brazil, water deficit reduces plant height, capitulum diameter and oil yield. The oil content of the achenes reduces when the maximum temperature increases, during the cultivation. For those reasons, the use of sunflower genotypes with shorter cycles and the earlier sowing could benefit the crop developing, by suiting the management, to avoid unfavorable climatic conditions that can cause reduction in production parameters.

Sensitivity to hypoxia and microbial activity are instrumental in pericarp-imposed dormancy expression in sunflower (Helianthus annuus L.)

AbstractWe used two sunflower genotypes displaying pericarp-imposed dormancy at high incubation temperatures (i.e. 30°C) to investigate the role of the pericarp as a limitation to oxygen availability to the embryo (hypoxia), and its impact on embryo abscisic acid (ABA) content and sensitivity to ABA. Results showed that both genotypes displayed very different oxygen threshold values for inhibition of embryo germination when incubation was performed at 30°C. Expression of dormancy in one genotype was therefore related to exacerbated embryo sensitivity to hypoxia, whereas in the other genotype, the pericarp appeared to act as a more severe restraint to oxygen entry. Increased sensitivity to hypoxia was, in part, related to increased sensitivity to ABA, but not to alterations in ABA metabolism. The activity of pericarp-microbial communities (bacteria and fungi) at high temperatures was also assessed as a potential determinant of hypoxia to the embryo. Oxygen consumption in pericarps incubated at 30°C was attenuated with antibiotics, which concomitantly promoted achene germination. In agreement with the observed more severe oxygen deprivation to the embryo exerted by the pericarp, the bacterial load in the pericarp was significantly higher in the commercial hybrid than in the inbred line; however, the application of antibiotics strongly reduced the bacterial colony counts for each genotype. Different bacterial and fungal communities, assessed through their profiles of carbon-source utilization, were determined between genotypes and after treatment with antibiotics. This work highlights the relationship between enhancement of sensitivity to hypoxia with incubation temperature and seed dormancy expression, and suggests that microbial activity might be part of the mechanism through which hypoxia is imposed.

Genetic response of diverse sunflower genotypes in contrasting moisture regimes for various physiological and growth parameters at early developmental stage

Abstract Sunflower has great capacity for bridge the edible oil gap in Pakistan. It ranks second to soybean in worldwide vegetable oil production. A greenhouse experiment was performed in the research area of Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad. Eleven (11) advanced lines along with Hysun-37 (Check) were evaluated under complete randomized design (CRD) replicated thrice for two water regimes and three harvestings at early developmental stage. Different morphological and physiological plant traits were recorded to find out genetic analysis of water stress tolerance in sunflower. Results for analysis of variance exhibited significantly differences among all sunflower genotypes for all the traits. Genotypes performed different under contrasting water regimes. Genotypes like A-25, A-50 and A-57 performed best under both normal and water stress condition due to increased shoot length, deep rooting pattern, increased number of root branches and possessing enormousmass of fresh and dry shoot and root traits. Presence of these enviable plant traits make them superior among all genotypes in comparison with hybrid variety. Correlation analysis indicated strong genotypic and phenotypic correlation between shoot length and shoot dry weight. Traits that possessed significant positive phenotypic correlation with shoot length were dry root weight and fresh root weight. Stress tolerant genotypes viz. A-25, A-50 and A-57 could be recommended for utilization in future sunflower breeding program and can be grown under water stress conditions for high yield. Keywords: Correlation; Genetic variability; Seedling traits; Sunflower http://dx.doi.org/10.19045/bspab.2019.80024

Sunflower Resistance to Race G of Broomrape (Orobanche Cumana Wallr.) In the Russian Federation: the Development of the Lines and the Study of Inheritance

Abstract The objective of this work is the development of sunflower lines that are not affected by race G of broomrape, as well as the determination of genetic control of resistance. The testing of the resistance of VNIIMK’s collection accessions of a cultivated sunflower of various origins was carried out on an artificial background made from the seeds of race G of broomrape. 6 lines resistant to race G were developed by the method of inbreeding on the basis of the obtained unaffected forms. The genetic control of resistance of one of them was studied. The resistance was inherited monogeneuosly, with incomplete dominance. There was established the presence of a reciprocal effect and the dependence of the resistance characteristic on the genotype of a susceptible parent under crossbreeding with certain lines. The other 5 sunflower lines are in the process of a hybridological analysis in order to determine the genetic control of their resistance. The combination of different genes of resistance to the same race of broomrape in one sunflower genotype could contribute to the long-term resistance of the crop to the parasite. The results of the presented study are of high importance for breeders, since the gene that we studied provides a new source of resistance to race G, thereby ensuring the protection of sunflower from the spread of new Orobanche pathotypes.

Genome-Wide Association Mapping of Floral Traits in Cultivated Sunflower (Helianthus annuus).

Floral morphology and pigmentation are both charismatic and economically relevant traits associated with cultivated sunflower (Helianthus annuus L.). Recent work has linked floral morphology and pigmentation to pollinator efficiency and seed yield. Understanding the genetic architecture of such traits is essential for crop improvement, and gives insight into the role of genetic constraints in shaping floral diversity. A diversity panel of 288 sunflower genotypes was phenotyped for a variety of morphological, phenological, and color traits in both a greenhouse and a field setting. Association mapping was performed using 5788 SNP markers using a mixed linear model approach. Several dozen markers across 10 linkage groups were significantly associated with variation in morphological and color trait variation. Substantial trait plasticity was observed between greenhouse and field phenotyping, and associations differed between environments. Color traits mapped more strongly than morphology in both settings, with markers together explaining 16% of petal carotenoid content in the greenhouse, and 17% and 24% of variation in disc anthocyanin presence in the field and greenhouse, respectively. Morphological traits like disc size mapped more strongly in the field, with markers together explaining up to 19% of disc size variation. Loci identified here through association mapping within cultivated germplasm differ from those identified through biparental crosses between modern cultivated sunflower and either its wild progenitor or domesticated landraces. Several loci lie within genomic regions involved in domestication. Differences between phenotype expression under greenhouse and field conditions highlight the importance of plasticity in determining floral morphology and pigmentation.

Dynamics of Dry-Down in Seed, Head and Stalk from Sunflower Genotypes Sprayed with Chemical Desiccants After Physiological Maturity

Chemical desiccation can advance the sunflower harvest time. Paraquat has been extensively used, but other less risky chemicals, as Carfentrazone and Saflufenacil, can rise as an alternative. Moisture levels of seed, head and the upper portion of stalk are all relevant for mechanical harvesting, but dry-down dynamics of each tissue is unknown. The aim was to study the dry-down dynamics of seed, head and stalk in sunflower genotypes sprayed with Paraquat, Carfentrazone and Saflufenacil after physiological maturity. Seven experiments were carried out in the field in Argentina (from 29 to 39º S) during 2014/2015 and 2015/2016. The genotypes used included hybrids and female inbred lines of both oil and confectionery types. The dry-down of sunflower plant was accelerated by desiccants with Paraquat, reducing seed and stalk moisture to a greater extent. The head moisture remained very high (>80 and 70%) during several days after application, without differences among desiccants and control. Dynamics of seed, head, and stalk moisture was not associated to vapor pressure deficit or meteorological conditions after chemical application. Loss of green color of leaves was not a reliable indicator of seed dry-down dynamics. Seed germination was not affected by chemical desiccation on either oil-type or confectionery female plants. Under broad conditions of these experiments, the Paraquat was effective for seeds/grains and stalks drying in both sunflowers hybrids and inbred lines. The slowly drying of heads makes it necessary to continue investigating with new doses and combinations of desiccants to ensure an optimal harvest. Desiccants were safe for seed germination, which benefits their usefulness in the seed industry.

Developing a Selection Criterion Using Correlation and Path Coefficient Analysis in Sunflower (Helianthus AnnuusL.)

AbstractIn breeding programs, it is imperative to recognize the genetic variations and levels of association between traits that directly or indirectly affect the yield. Achene yield and related traits in forty-nine sunflower genotypes were studied for genetic variability, correlations and path coefficient analysis. The phenotypic coefficient of variation (PCV) were higher than the genotypic coefficient of variation (GCV) for the all the studied traits in sunflower. The most active association of achene yield was found with achene/head, 100-achene weight and plant height. However, oil contents had a negative association with achene filling percentage, 100-achene weight, number of leaves and stem diameter. The maximum direct influence on achene yield were exerted by head diameter followed by achene filling percentage, 100 achene weight, achene/head and number of leaves. In contrast, plant height, days to maturity and stem diameter had the negative direct impact on yield. The genetic correlations were higher than phenotypic correlations which suggest that environmental influences were very low. Our results showed that achene/head, 100 achene weight, plant height and head diameter are important plant traits which should be considered while planning any breeding program for higher achene yield in sunflower.

F-AFLP GENOME SCAN AMONG FOURTEEN GENOTYPES OF SUNFLOWER (Helianthus annuus L.)

Sunflower (Helianthus annuus L.) belongs to the family Asteraceae. The current study used the fluorescent amplified fragment length polymorphism (F-AFLP) technique for evaluating the genetic diversity among 14 sunflower genotypes including eight agronomical traits. Highly significant difference between genotypes was observed for all studied traits (p≤ 0.01). The results of correlation between the studied traits (p≤ 0.05) revealed that positive correlations were observed between most of the traits. Six F-AFLP combination were succeeded in the development of 178 molecular markers within a total of 1007 polymorphic bands, with 97.42% polymorphic percentage. Concerning the molecular markers associated traits, 73 were observed related to morphological and yield component traits. These results may facilitate the simultaneous selection of several economic traits and can thus improve the efficacy of selection based on F-AFLP in the sunflower breeding programs.

Comparative analysis of seed yield and biochemical attributes in different sunflower genotypes under different levels of irrigation and salinity

SUNFLOWER (Helianthus annus L.) is an important oilseed crop in so many countries which suffer from seed and oil yield reduction by limited water or soil salinity. Since some responses to water and salt stress are common, other responses may vary according to the genotype and/or stress level. The role of the genetic diversity on the responses of sunflower yield, oil quality and the fatty acid composition to the different levels of irrigation and soil salinity in two field experiments were investigated. Three registered parental lines; HA 429, HA 430 and HA 20 and two hybrids; H (A9xRF6) and H (A9xRF8), in addition to one cultivar; Sakha 53 were used in this study. The results showed significant effects of genotype, level of stress and their interactions on most of the examined characteristics. Water stress caused a major reduction of protein content and oil yield than salinity stress. Different genotypes with similar oil contents had different oil yields under stress treatments. The hybrids H (A9xRF6) and H (A9xRF8) showed less reduction in oil content by both irrigation and salinity treatments, compared to the other genotypes and this candidate them for cultivation in stressed regions. The results also showed that some fatty acids, particularly stearic acid and oleic acid, were dependent on the genotype and the stress level in both experiments.

Yield potential of different sunflower genetic classes: A multivariate approach

Breeding programs aim at obtaining superior genotypes. The multivariate analysis allows simultaneously assessing a large number of variables and interesting genotypes. The objective of the present study is to assess the yield potential of different sunflower genetic classes. A randomized block design, with four repetitions, and eight sunflower genotypes was used in the current experiment. Principal component analyses were performed for the variables plant height, lower stem diameter, upper stem diameter, chapter diameter, chapter weigh, achene weight and grouping. The method by UPGMA (Unweighted Pair Group Using an Arithmetic Average) was used to assess the oil content. The upper stem diameter, lower stem diameter and plant height variables showed high positive correlation, as well as chapter diameter, chapter weight and plant height. Variables lower stem diameter and achene weight were not correlated. Genotypes Olisun-3 and Aguará-4 showed potential for the selection of the chapter diameter, chapter weight and achene weight variables; the hybrids Charrua e Olisun-5 was adopted for upper stem diameter, plant height and lower stem diameter character selections. The open-cross varieties presented higher oil content percentage.

Effetcts of Different Sowing Dates on The Oil Quality of Some Sunflower (Helianthus annuus L.) Genotypes

Bu araştırma; Diyarbakır koşullarında farklı ekim zamanı uygulamasının Ayçiçeği çeşitlerinin kaliteözellikleri üzerine etkilerini incelemek amacıyla 2015 yılında yürütülmüştür. Araştırma bölünmüş parseller denemedesenine göre 3 tekerrürlü olarak kurulmuştur. Çalışmada 2 farklı ekim zamanı (erken ve geç ekim) ve 4 farklıayçiçeği çeşiti (Sanay MR, Sanbro, Sirena ve Tarsan 1018) kullanılmıştır. Araştırmada ayçiçeğinde doymuş vedoymamış yağ asitleri içerikleri incelenmiştir. Araştırma sonucunda; Ekim zamanı, çeşit ve ekim zamanı x çeşitinteraksiyonunun yağ oranı üzerine önemli bir etkisinin olmadığı, yağ asitleri kompozisyonu bakımından ekimzamanın, palmitik, palmitoleik, oleik, linoleik asit oranı üzerinde, çeşitler arasında ise oleik, linoleik ve oleik/linoleik yağ asitine oranı bakımından önemli farklılıklar olmuş ve ekim zamanı x çeşit interaksiyonunun, oleik,linoleik, palmitik, araşidik ve oleik/linoleik yağ asid oranı bakımından önemli bir etkisi bulunmuştur. Linoleik asitoranı bakımından en yüksek oran, geç ekim uygulaması Sanbro (% 62.12) ve Sirena (% 62.49) çeşitlerinde eldeedilirken, en yüksek oleik asit oranı erken ekim uygulaması Tarsan 1018 (% 35.79) çeşidinden elde edilmiştir.

Performance of Sunflower Genotypes in Non-Saline and Saline Soils of Southern Bangladesh

A research work was conducted with three sunflower genotypes to evaluate their performance in saline and non-saline soil after harvesting of T. Aman rice. The experiment was laid out in Randomized Complete Block Design (RCBD) with four replications. Three genotypes significantly influenced almost all the growth and yield parameters in both non-saline and saline field. Genotype Hysun-33 showed maximum germination percentage in non-saline soil but minimum in saline soil. Whereas, KUSL- 1 performed the best in saline soil but worst in non-saline condition. Hysun-33 produced maximum leaf at flowering in both conditions but minimum leaf by BARI Sunflower-2 in saline soil and by KU-SL-1 in non-saline soil. In both non-saline and saline soils, plant height at flowering, head diameter, total seed head-1 and filled seed head-1 were maximum for the genotype Hysun-33 and that of minimum for the genotype BARI Sunflower-2. Genotype KU-SL-1 showed maximum value for 1000- seed weight followed by Hysun-33 in both saline and non-saline soils. In case of seed yield head-1, Hysun-33 performed best in saline soils but worst in non-saline soil. In non-saline soil, KU-SL-1 produced maximum seed yield head-1. Biomass at harvest, head diameter and number of filled seed head-1 was well correlated with number of seed head and seed yield head-1. Thus genotype Hysun-33 may be considered as best for saline and KU-SL-1 for non-saline soil.
 Bangladesh Agron. J. 2018, 21(1): 1-7

Ayçiçeğinde Tuz Zararı Üzerine Bor Uygulamalarının Etkisinin Belirlenmesi

Tuzluluk, bitki yetiştiriciliğini kısıtlayan, dünyada ve Türkiye‘de özellikle kurak ve yarı kurak bölgelerde görülen, bitkisel verimi sınırlandıran ve geniş alanların tarım dışı kalmasına neden olan ciddi bir tarımsal problemdir. Dünyanın farklı bölgelerinde bitki yetiştiriciliğinde ortaya çıkan bor (B) noksanlığı ülkemizde de önemli bir beslenme problemidir. Son yıllarda yapılan çalışmalarda, B noksanlığı altında tuz stresinin yol açtığı zararın arttığı bildirilmiştir. Türkiye'nin en önemli yemeklik yağ bitkilerinden biri olan ayçiçeğinin B noksanlığına en duyarlı bitkilerden biri olduğu bilinmektedir. Bu çalışmada ayçiçeğinde tuz zararının etkisinin azaltılması üzerine B uygulamasının etkisinin belirlenmesi amacıyla su kültüründe tuzlu ve tuzsuz koşullarda artan oranlarda B uygulaması altında iki ayçiçeği genotipi denenmiştir. Denemede bitkilerin kök ve yeşil aksam kuru madde verimi, B konsantrasyonu ve K/Na ve Ca/Na oranları belirlenmiştir. Denemeden elde edilen sonuçlara göre, kontrol uygulamasına göre tuz ilavesinin yeşil aksam kuru madde verimini azalttığı, buna karşılık B uygulamalarının ise kontrol uygulamasına göre kuru madde verimini görülmüştür. Bitkinin tuz zararını gidermede B‘un belirgin bir rolünün olmadığı ve tuzlu koşullarda bitkinin B alım düzeyinin arttığı belirlenmiştir. Bu sonuçlara ilave olarak B noksanlığına ve tuz toksisitesine karşı dayanıklılıkta ayçiçeği genotipleri arasında farklılıkların olduğu gözlemlenmiştir.

Comparison of seed and seedling functional traits in native Helianthus species and the crop H.annuus (sunflower).

Seed functional traits of native Helianthus species contribute towards ecosystem services but limitations to their use in managed programmes exist. Many perennial Helianthus possess seed dormancy. The ability for germination to occur under different temperature and drought conditions, as well as the capacity of germinated seeds to convert into normal seedlings is rarely considered. Our aim was to identify and quantify these constraints through functional trait analyses. In five seed lots of native Helianthus (four perennial and one annual) and five genotypes of sunflower (H.annuus) for comparison, dormancy, thermal and hydro thresholds and times, morphology, mass, oil content and conversion into normal seedlings were quantified. The influence of the seed collection site environment on these traits was also explored. Seed dormancy of the perennial species was overcome by scarification followed by germination in 5mm GA3 . Thermal and hydro-time analyses revealed slower germination for the native seed lots (>1350°Ch) in comparison to the sunflower genotypes (<829.9°Ch). However, native seed lots had a higher capacity to convert into normal seedlings at high temperatures and low water potentials than sunflower genotypes. For the native seed lots, the average monthly temperature of the collection site was negatively correlated with thermal time. Variability in seed functional traits of native Helianthus and greater capacity for germinated seeds to convert into normal seedlings suggests they are better equipped to cope with high temperature and drought scenarios than sunflower. Effective dormancy alleviation is required to facilitate the use of native Helianthus species.

PHOTOSYNTHETIC PARAMETERS AS PHYSIOLOGICAL INDICATORS OF TOLERANCE TO CADMIUM STRESS IN SUNFLOWER GENOTYPES

ABSTRACT The objective of the present study was to evaluate the tolerance to cadmium (Cd) of sunflower genotypes grown in greenhouse conditions, and the effectiveness of using photosynthetic parameters as physiological indicators of this tolerance. Seeds of two sunflower genotypes previously identified as tolerant (H358) and Cd-sensitive (AG960) to Cd were used. The seeds were germinated in plastic cups containing plant substrate; after 9 days, the seedlings were transplanted to plastic basins containing a nutrient solution with 0 or 10 µM of Cd, where they remained for 16 days. Samples of the plants were harvested every 5 days. The experiment was carried out in a randomized complete design, using a 4×2×2 factorial arrangement (4 days of grown in a nutrient solution with Cd, 2 sunflower genotypes, and 2 Cd levels) with four replications. Cd stress decreased CO2 net assimilation, stomatal conductance, carboxylation efficiency, photosynthetic pigment contents, potential quantum yield (Fv/Fm), and effective quantum yield of plants of the two evaluated genotypes. The decrease in photosynthetic rates of these plants was caused by both stomatal and non-stomatal limitations. Plants of the AG960 genotype showed more pronounced deleterious effects due to Cd stress than those of the H358 genotype. Thus, CO2 net assimilation rate, stomatal conductance, and chloroplast pigment content are good physiological indicators of sunflower tolerance to Cd and can at least in part, explain the greater tolerance of the H358 genotype to Cd stress when compared to the AG960 genotype.

RESPONSE OF SOME SUNFLOWER GENOTYPES TO NITROGEN FERTILIZER LEVELS

Sunflower (Helianthus annuus, L.) is an important oil seed crop, which ranks a fourth next to groundnut, soybean and rapeseed which contributes as edible oils over the world. Due to the importance of this crop, this study was conducted to investigate the effect of three levels of nitrogen fertilizer (30, 45 and 60 kg fad.-1) and eight genotypes of sunflower i.e. two cultivars (Giza 102 and Sakha-53) as control and six genotypes (A-120, A-34, A-44, A-45, A-47 and A-48) under North Sinai conditions through two seasons of 2015 and 2016. In this study there were 24 treatments including three nitrogen fertilizer levels and eight sunflower genotypes. Results showed that increasing nitrogen levels increased yield and it′s components and protein content, while, oil content was decreased. The interaction between Giza 102 and nitrogen level 60 kg N fad.-1gave high value in each of 100-seed weight, head seed weight, oil yield, seed yield and protein yield in 2015 season, but, the interaction between the fertilizer level 60 kg N fad.-1 and genotype A-48 gave significant superiority in 100 seed weight, head seed weight, oil yield, seed yield and protein yield in the 2016 season, In conclusion, sowing A-48 genotype with 60 kg N fad-1 was the best treatment under North Sinai conditions.

Stability Analysis of Some Novel Cytoplasmic Male Sterile Sources of Sunflower and Their Hybrids

AbstractGenetic makeup along with environmental stimuli affect the expression of a trait in plants. Drought tolerance in addition to stability of characters over a wide range of environmental conditions is not well studied in sunflower. Therefore, here we have performed a stability analysis study of sunflower genotypes. The experimental material comprised of 19 lines of sunflower comprising 9 alloplasmic cms lines from different wild sources along with one common maintainer from petiolaris source, 4 cms lines and one maintainer from cultivated source (cytoplasm from H. petiolaris), 4 restorer lines and 60 F1 hybrids (developed in line x tester design). The experiment was conducted over two years i. e. spring season 2011 and spring season 2012 over the two environments one normal irrigated and another water stress environment at Punjab Agricultural University, Ludhiana, India. The data were recorded for different morphophysiology, yield and quality trais and analysis as per standard procedures. The genotype×environment interaction was further partitioned into linear and non-linear components according to Eberhart and Russel model. Eleven sunflower hybrids were found to be stable across the environments for seed yield. While, sufficient variability was also recorded for the oil content with the highest oil percentage in the cross combination ARG-2A×P100R (34.61). Overall, this study provides useful information regarding the stability of newly developed and cytoplasmically diverse sunflower hybrids under north Indian conditions.

Characterization for Drought Tolerance and Physiological Efficiency in Novel Cytoplasmic Male Sterile Sources of Sunflower (Helianthus annuus L.)

Sunflower is sensitive to drought, and furthermore, sunflower hybrids display limited cytoplasmic diversity. In addition, the wild cytoplasmic sources of sunflower are not well explored for their potential to introduce drought tolerance into newly developed hybrids. Therefore here, we carried out a Line × Tester-based genetic study using 19 sunflower genotypes representing, 13 cytoplasmic male sterile (CMS) lines from wild and conventional sources, 2 maintainer lines, and 4 restorer lines. The CMS and maintainer lines were crossed with restorer lines to develop sixty F1 hybrids. The parents and their hybrids were evaluated under two water regimes, normal irrigation and drought stress (i.e., withholding water). A total of twelve important plant descriptors were studied over a period of two years and the significant differences between parents and hybrids are reported here. More specifically, hybrid lines were higher in average values for all the descriptors. The contribution of female parent was more prominent in the expression of traits in hybrids as compared to male parents. The CMS sources varied significantly regarding seed yield per plant and other physiological traits. Proline content in the leaves of all the genotypes was three times higher in the water stress regime. Accession CMS-PKU-2A was identified as the best general combiner for leaf area and specific leaf weight., whereas CMS-234A was the best general combiner for biological yield and photosynthetic efficiency under both conditions. The cross combinations CMS-ARG-2A × RCR-8297, CMS-234A × P124R, and CMS-38A × P124R were found significant for biological yield, seed yield and oil content under both environments. Overall, this study provides useful information about the cytoplasmic effects on important sunflower traits and drought stress tolerance.

Silicon-mediated growth and yield improvement of sunflower (Helianthus annus L.) subjected to brackish water stress

Silicon is known to compensate crop yield losses under diverse biotic and abiotic stress conditions; however, reports about its protective role for plants exposed to brackish water stress are very limited. A pot culture experiment was conducted to assess the beneficial effect of silicon supplementation (0 and 100 mg/kg) in alleviating growth adversities of brackish water (saline, sodic, alkaline, and saline–sodic water) stress in two contrasting sunflower cultivars, SF-187 (salt tolerant), and Hysun-33 (salt sensitive) grown in greenhouse. Results demonstrated that hostile growth environments, mainly the combined stress of saline–sodic water, severely affected the physiological attributes, growth, yield, and yield contributing components in sunflower. However, the response to brackish water stress differed genotypically, with greater magnitude of damage to the Hysun-33 as compared to SF-187 genotype. It hampered plant growth due to membrane damage and reduced water uptake, but silicon supplementation minimized the negative effects of stress by limiting toxic Na+ ions uptake, improving membrane stability, and increasing relative water contents caused by higher silicon and K+ uptake that eventually led to improved biomass yield. The response was further evaluated at yield level and data regarding head diameter, achene yield, and 100 achene weight were taken. Results indicated that silicon supplementation to growth medium of saline and/or sodic water treated plants significantly enhanced the head diameter (22–30%), thus ultimately producing 15–25% higher achene yield, and weight of the biological harvest of both sunflower genotypes. Overall, the beneficial effect of silicon supplementation was more evident in Hysun-33 (salt sensitive) as compared to SF-187 (salt tolerant) genotype. Taken together, the results of this study suggest silicon fertilization as a potential strategy to increase crop productivity under brackish water stress; however, experimental trials at farmer field level should be conducted before setting any recommendations.