The effect of osmotic and water stresses on various morphological traits was studied in eight experimental varieties of sunflower bred for Moroccan conditions or issued from interspecific hybridization with H.argophyllus or H.debilis. Seed yield of the same genotypes was also evaluated under rainfed and irrigated field conditions. Shoot and root growth were significantly reduced by osmotic stress (-0.6 and -1.0 MPa) induced with polyethylene glycol (PEG 6000). Considerable genotype variation was expressed for all traits. Significant genotype by stress interaction was observed for root dry weight and volume as well as seed yield. The morphological traits were not related to seed yield in the correlation and principal component analyses. Four genotypes issued from introgression with H.argophyllus were grouped and distinct from other genotypes according to hierarchical ascending classification. One genotype issued from introgression with H.debilis and three non-introgressed sunflower varieties were found to be very distinct from each other and from those introgressed with H.argophyllus.

Sunflower seeds have more than 90% of the total tocopherols in the form of alpha-tocopherol, which exerts a weak antioxidant protection of the extracted oil. A partial substitution of alpha-tocopherol by another tocopherol deriva tive with greater antioxidant action would improve the oxidative stability of sunflower oil. The objective of the present research was to identify sources of modified tocopherol profile in sunflower germplasm. A total of 952 germplasm accessions were evaluated by analyzing the tocopherol profile of 12 half-seeds per accession by HPLC. The screening resulted in the identification of a source of increased beta-tocopherol content and a source of increased gamma-toco pherol content. In both cases the accessions corresponded to old populations of Peredovick. The line T589 presented a beta-tocopherol content from 30.4 to 48.5% of the total tocopherols, whereas the line T2100 had a gamma-tocopherol content from 87.9 to 93.9%. Genetic studies revealed that both traits were partially recessive in crosses with material with standard tocopherol profile. In both lines, the altered trait was determined by alleles at a single locus. Com parative studies with previously developed sunflower lines with similar levels of beta- and gamma-tocopherol will elucidate whether the new lines have the same or different genetic modifications within the tocopherol biosynthetic pathway.

Present investigation aims at determining the developmental stage at which the male sterile anthers of DSF-15 Helianthus petiolaris Nutt. deviate from their isogenic fertile counterparts and the underlying histochemical factors responsible for that deviation. The flower buds of fertile and male sterile H.petiolaris were fixed in the Carnoy’s fluid, dehydrated in ethyl alcohol series, embedded in paraffin and microtomed. The sections were stained for the localization of insoluble polysaccharides, RNA and total proteins using periodic acid Schiff’s toluidine blue and mercuric bromophenol blue reagents, respectively. The results of the present investigation reveal that, during premeiotic stages, anthers of fertile and sterile lines are indistinguishable except in the occurrence of starch storage in the sterile anthers during the onset of meiosis. In the sterile anthers, precocious degeneration of callose, failure of microscope wall information, persistent abnormal tapetum (hypertrophied or premature plasmodial formation), failure of formation of endothecial thickenings accompany the abortion process of microspores. The malfunctioning of the tapetum seems to be responsible for male sterility in DSF-15 H.petiolaris.

Production of microspore-derived embryos from cultured anthers is now a well-established technique for the isolation of homozygous lines in sunflower. Experiment was conducted to optimize the culture composition for wild Helianthus and inerspecific hybrids. Anthers of uninucleate microspores were cultured in basal MS media with different hormonal combinations. The induction of callus was quick and proliferation high with the presence of 2,4-D, low cytokinin and auxin contents. Excess cytokinin and auxin had no significance in callus induction. Regeneration potential increased with the increased/optimum amount of casein hydrolysate and benzyl amino purine. Kinetin had no specific influence of regeneration frequency of callus. Genotype had a significant effect on the capacity of callus induction and plantlet formation. H.annuus × H.tuberosus responded well and produced plantlets in optimum culture medium. Androgenesis of interspecific hybrid H.annuus × H.tuberosus formed plantlets that surpassed the embryoid stage.

An alteration in the cytoplasm reaction was provoked during the transfer of sunflower line M-C-5 into the cytoplasmic male sterility ARG-3. The new source of CMS was different from CMS ARG-3. The differences were proved by investigating the fertility restoration in hybrid plants produced with the participation of line M-C-5A in CMS ARG-3 as well as the restorer lines for CMS PET-1 and CMS ARG-3 - lines 147R, 7015R, 7042R and 7045R. Combinations M-C-5A in CMS ARG-3 and lines 7015R and 7045R gave 100% sterile hybrid plants, while combinations M-C-5A in CMS ARG-3 and lines147R and 7042R gave 60.3% and 23.8% sterile plants, respectively. As a result of the combinations between other nine lines in CMS ARG-3 and these four R lines, only fertile hybrid plants were produced. The hybrid plants obtained from combinations between line M-C-5A in CMS DEB-1 and CMS ANN-16 with line 7015R were also fertile. These facts led us to conclude that the mutation has been provoked in the process of transfer of line M-C-5A into CMS ARG-3. Thus a new different CMS source has arisen out of an existing CMS source and it was named CMS ARG-3-M-1. The newly obtained CMS source seems to be a separate type. The way of origination of CMS ARG-3-M-1 was entirely different from the already existing methods for obtaining CMS in sunflower.

Restoration behavior of 20 CMS sources in combination with 11 restorer lines has been studied. Genetic mechanism of fertility restoration was determined for all investigated CMS sources. Three groups of CMS sources were distinguished in dependence of the exhibited differences in restoration response from CMS-Rf PET1 system. The group of alternative CMS sources that exhibited regular restoration effect in crosses with different fertility restorers but completely failed to restore fertility in crosses with PET1 restorer lines rep resents material of practical value. When discovered, these new CMS sources will permit to use new CMS-Rf systems in sunflower breeding.

In order to study the influence of different alloplasmic male sterile lines on quantitative characters, three alloplasmic male sterile lines of the inbred line 852 were developed. The three different CMS sources used are CMS 852A (H.petiolaris), FMS 852A (H.petiolaris ssp. petiolaris) and IMS 852A (H.annuus ssp. lenticularis). These three lines were crossed to three restorers Acc. Nos. 1229, 232 and TUB 365 producing 9 hybrids (3 hybrids in three dif ferent sources). Similarly inbred line IB24A in two backgrounds FMS IB24A and IMS IB24A were crossed to four restorer lines 1229, 232, Tub 365 and 346 producing another set of 8 hybrids. These 17 hybrids along with their parents were evaluated during rainy season in the field by following randomized complete block design with three replications. Observations were recorded on seven quantitative characters. The different CMS sources did not significantly influence the traits such as plant height, days to maturity, head diameter, percent seed set, test weight and seed yield per plant. Thus alloplasmic hybrids were uniform suggesting that the new CMS sources can be commercially exploited like classical source with out any negative effect. However, in case of seed oil content the CMS source from lenticularis showed superiority over the classical cytoplasm by producing hybrids with significantly higher oil content. Therefore, these new male sterility sources can replace the classical source with added advantage.

An investigation was taken up at the Directorate of Oilseeds Research, Hyderabad, India, to determine the extent of genetic divergence with respect to eleven characters in 85 sunflower genotypes consisting of 80 inbreds and five check cultivars. Univariate and multivariate analysis of variance revealed the presence of significant differences among the genotypes. Mahalanobis’ D2 statistic indicated the presence of substantial genetic diversity. The genotypes were grouped into fifteen clusters. Based on the intercluster distance and cluster mean for various characters, potential lines were identified from clusters III, IV, VI, VIII, XI, XII and XIV for crossing program. Among the investigated characteristics, the number of filled seeds per head, test weight, kernel to hull ratio and seed yield per plant exhibited high contribution towards genetic divergence. The present study indicates that the inclusion of GP-347, GP-1341, 300-B, ARM-244, ARM-248, HAR-5, 853-B, GP-913, GP-507 and GP-831 in future breeding programs could result in the development of superior sunflower cultivars.

Factors associated with variation in harvest index and approaches to improve harvest index (HI) and productivity in sunflower are discussed in this article. In recent years, higher productivity in sunflower has been achieved mainly through increased crop growth rates. Besides, an improvement in harvest index also has contributed for improved productivity to a certain extent. In our study we observed that medium duration types (100 to 110 days) had high HI compared with early or long-duration varieties and we also attempted to understand the ways and means to improve HI in sunflower types with varied duration. Genotypes which had low partitioning of dry matter to stem plus thalamus had high HI. Genotypes which accumulated high biomass during post flowering stages of development also showed high HI and seed yield. In a few genotypes remobilization of photosynthates from vegetative plant parts to the seed resulted in high HI and seed yield. Among the sink characters, the number of seed per head, test weight and seed density (weight/volume) also contributed to achieving high HI values. Identification and selection of genotypes based on these criteria will increase the production further. Since large amount of biomass is still locked up in the vegetative plant parts, any practice to manipulate the mobilization of photosynthates from vegetative parts to head also improves HI and thus seed yield. In our experiment, we observed that foliar application of boron nutrient and application of growth regulators to the head improved the translocation of photosynthates to the head and thus increased the HI and seed yield.

Immature zygotic embryos from the Spanish self-pollinated sunflower line Z-8-A (Helianthus annus L.) were used as donor material to induce direct organogenesis. A portion of the isolated immature embryos were treated with gamma radiation (137Cs) at a dose of 5 Gy before plating. The range of the spontaneously induced somaclonal variation among the obtained regenerants was investigated and compared with that of the variants induced through irra diation. The genetic changes occurring during the regeneration procedure included sixteen morphological and biochemical characters. The most significant changes were observed for the following characters: plant height, number of leaves, stem diameter, head diameter, length of branches, oil content in seed (%) and 1000-seed weight. The study showed that the somaclonal- (R9) and the radiation-induced (M9R9) variants revealed similar spectra of morphological and biochemical changes, thought with different frequency.

As a result of hybridization between the Bulgarian fertility restorer line R 2574 and mixed pollen from a polycross population of known genetic composition, and treatment of immature embryos with gamma radiation or ultrasound, a large number of new fertility restorer lines were developed. Lines R 114, R 115, and R 116, subjected to investigation in this study, are characterized with significant changes concerning most of the studied characters. The increased number of seeds per head in lines R 115 and R 116, the increased 1000 seed weight in line R 114, the 100% resistance to the parasite Orobanche in lines R 114 and R 116, and the very good combining ability in hybridization are the desired combination in the breeding program of sunflower. The hybrids Rada and 80, developed with the participation of lines R 114 and R 116, considerably exceeded the mean standard (the Bulgarian commercial hybrids Albena and Super Start) in seed and oil yields, simultaneously possessing high resistance to the Orobanche population of races distributed in Bulgaria. In 2002, the hybrid Rada was registered for testing by State Variety Testing Commission and it exceeded the mean standard of the country. The combined use of inter linear hybridization with physical mutagenesis or ultrasound and the embryo culture method leads to increased genetic variability in sunflower and to a considerable shortening of the breeding process, producing 5 generations within a single year.

Five genotypes showing differential field reactions to Alternaria leaf and stem blight were tested for their reaction to pathogen culture filtrate under in vitro conditions. The pathogen culture filtrate reduced in vitro germination, root and shoot growth and reduction was not uniform in all the genotypes. There was significant negative association between in vitro root growth and field disease score of genotypes suggesting the reliability of this trial for in vitro evaluation. The germination and shoot length in vitro did not show any definite trend to be reliable. Similarly, the detached leaf evaluation under in vitro did not show definite trend of association with field disease score. It is suggested to test a large number of genotypes with varying degree of resistance/susceptibility to confirm the results.

Alternaria leaf and stem blight is a potential destructive foliar disease of sunflower in India and elsewhere causing significant yield losses during rainy season. Thirty-two interspecific lines derived from 11 Helianthus species were evaluated under natural epiphytotic conditions. Highly susceptible line L-101 was planted all along the borders and in between as an infector and spreader of the disease. The disease severity was assessed by taking 0-9 numerical rating system at three stages. The results indicated none of the wild derivatives showed resistant reaction. All the lines were highly susceptible to Alternaria leaf and stem blight.

A mono- and bifactorial dispersional analysis has been applied to determine the rate of influence of different factors on variability in the contents of auxins (AIA) and gibberellins (GA3) in sunflower leaves and inflorescences. It was found that environmental conditions influenced very little the contents of the studied phytohormones, the greatest influence being manifested in line MB 514 which was treated with gibberellins. Diverse affinity of organs to GA3 was established in this line, as well as different functional roles of auxins and gibberellins, correlated with spatial isolation mechanisms. The ontogenetic phase had an important role in the variability of auxin content in leaves. The genotypes´ rate is mainly significant in the gibberellins contents` variability on the inflorescence level.

First sunflower varieties sown in Argentina had been brought by immigrants from Russia. This germplasm was the base for both official and private nurseries to create new varieties adapted to the country by selection. In the 1960’s, many varieties were obtained from intercrosses with wild species in official nurseries. These new varieties had the characteristic of resistance to the diseases present in the crop at that time. In the 1970’s, in both official and private nurseries, re-selections on Russian varieties with black achenes were done and also, even if on a small scale, several varieties were registered. In the 1980’s the activity of official nurseries was predominant. Varieties were registered which originated from very extensive crosses, and they at are still used for the development of important lines due to their differential reaction to diseases.

Forty-seven specimens from the world germplasm collection of VIR were crossed as male with a high oleic line HA89A OL as female. The mean of 10 seed samples of F1 was 83% oleic acid content. High oleic trait was mainly dominant. Two crosses showed intermediate inheritance with the means of 62% and 68%. The range of single-seed variability of these two crosses was from 53% to 89% oleic acid. The genotypes showing abnormal segregation in F1 have been selected to develop a set of normal lines with a suppressor for Ol mutation. The inheritance of mid- (increased) oleic content (about 62%) was studied in the F1, F2 and BC generations of the inbred line LG27 crossed with the high oleic line HA89 OL. Mid-oleic acid content was shown to be controlled by a recessive allele of ol gene, designated ol1. An inbred line with 92% oleic content was obtained to investigate a super high oleic genotype. Another high oleic line was selected for low stearic content, about 1%. High palmitic (about 24%) line is being developed. High-oleic mutation is quite detectable both in immature and germinated seeds. Mutations for tocopherol composition, tph1 and tph2, have a high level of expressivity in different parts of the plant. It was shown for tph2 mutation that its heterozygotes could be clearly identified by the analysis of pollen from a single head. The open pollinated variety Favorite was developed in VNIIMK in 1993. It was shown that seed oil of the variety had about three times higher hydrolytic stability estimated as the lower level of free fatty acid value of crude oil.

The influence of imposed pollination methods viz., clothbag, cloth + assisted pollination, clothbag + bulk pollen pollination and open pollination was assessed for seed yield, 100-seed weight and oil content in 22 sunflower genotypes over two seasons. In general, the genotypes, in general, recorded higher seed yield, test weight and oil content in summer as compared with rainy season. In both seasons, seed yield was highest under open pollination and lowest under cloth bag. Seed yield was significantly improved under cloth bag with assisted pollination and cloth bag with bulk pollen pollination and cloth bag with bulk pollen pollination compared with seed yield under cloth bag. Increased test weight under cloth bag was related to low seed yield. Decreased oil content of genotypes in cloth bag treatment was ascribed to increased husk content as a consequence of low seed yield.

This study was carried out to determine yield response factors (ky), under the conditions where 0%, 25%, 50%, 75% and 100% of the water requirement was supplied over the groving season. Relative water requirements were also supplied during the individual growth periods; namely, early vegetative, late vegetative, total vegetative, flowering and yield formation periods of sunflower (Helianthus annuus L.) under Tekirdag conditions. In the experiment, total of 554 and 560 mm irigation water were applied and 799 and 762 mm seasonal evapotranspiration were measured in T1 treatment in which adequate irrigation water was applied during irrigated growing season in the year 1998 and 1999, respectively. The yield response factor (ky) was obtained as 0.85 for total growing season and 0.67, 0.43, 0.40, 0.28 and 0.20 for flowering, total vegetative, yield formation, late vegetative and early vegetative period, respectively. Flowering period was more sensitive to water deficit than the other periods.

To investigate seasonal variation effects on oil contents and fatty acid pro file of some commonly grown sunflower hybrids, field experiments were conducted at the University of Arid Agriculture, Rawalpindi, Pakistan, during spring and autumn 2000. Five sunflower hybrids were sown in a randomized complete block design replicated thrice. Spring crop was planted in February and harvested in June, while autumn crop was planted in August and harvested in November. Results showed reduction of oil contents and oleic acid in autumn crop as compared with those of spring crop. However, palmatic and linoleic acid percentages increased more in autumn than in spring crop. It is concluded from this study that spring crop accumulated higher oil contents than of autumn crop with higher percentage of oleic acid. However, autumn crop produced seeds having higher percentage of linoleic acid.