A systematic fan design was adopted to study the performance of sunflower and groundnut at 26 density variables in sole and intercrop systems with two planting patterns at the Andhra Pradesh Agricultural University during summer 1983 and 1984 and kharif 1983. The yield densiry relationships were best fitted to the exponential model Y=abx for either component. The two-row groundnut intercrop planting pattern to share 67% virtlual area in sunflower densities of 35,467 to 162,134 plants/ha enhanced the total oilseed production over sole sunflower in the summer seasons. In kharif intercrop, yield total sxceded the sole crop feld either or sunflower of groundnut. The three row groundnut intercrop planting pattern to share75% virtual area in sunflower densities of 23,616 to 107,959 plants/ha produced more yield than either components in sole crop during the summer seasons as well as kharif. The most productive density of sunflower ranged from about 75,000 to 100,000 plants/ha for intercropping groundnut in a pattern to share 75% virtual area in summer or kharif.

The age of achenes at harvest of Heilanthus annuus and H. petiolaris had a significant influence on germination. A majority of germination took place by 21 days. Achene dormancy does not appear to be overcome by using a combination of storage temperatures or times. Helianthus argophyllus had the highest overall germination of 84%, followed by H. debilis ssp. silvestris with 16%, H. petiolaris with 51%, and H. annuus wirh 44%. Despite the large differences in germination percentage, the coefficient of velocity was similar for all species.

The rate of CO2 assimilation photosynthetic efficiency and assimilate accumulation were measured in 15 field-grown NS sunflower (Helianthus annuus L.) lines and hybrids. Transpiration and water use efficiency were also measured in sunflower leaves in order to evaluated the behavior of the examined genotypes under water stress. Photosynthetic efficiency, determined at saturating CO2 and at low light intensity, was high in sunflower leaves. At a high light intensity and ambient C02, however, the rate of carbon assimilation was 1/3 of the potential rate of photosynthesis at saturating COz. The tested sunflower genotypes differed in the efficiency of water use and transpiration at a high light intensity and ambient CO2. Our results on water use efficiency and/or transpiration efficiency can be used as indicators of hybrid sunflower adaptability to arid conditions.

A set of diallel crosses which included six inbred lines from a gene pool of the Institute of Field and Vegetable Crops in Novi Sad was analyzed for components of genetic variability (D, H1, H2, F, h²) of leaf length andwidth. The dominant component (H1) was highlysignificant for both traits, the additive one (D) was not. The dominant and recessive genes that controlled the two trâits were not uniformly distributed in the parent lines. Superdominance was registered for both traits. Leaf width was controlled by at least four genes, leaf length by at least three. High values of thewide-sense heritability (h²b) and low values of the natrow-sense heritability (h²n) were found for borh traits.

This research was carried in order to determine theyield components of four sunflower hybrids (Helianthus annuus L.) which differed in plant height. The hybrids were grown in three variants of plant population. The research lasted for two years, 1991 and 1992, and it was conducted at the Thrace Agricultural Research Institute in Edirne, Turkey. Experiments were established in a split- plot arrangement in RCBD, in four replicates. The hybrids used in the experiments were two semidwarf hybrids, Sunbred- 265 and DO- 855, a standard height hybrid Trakya- 259 and a tall hybrid Tordillo. The three plants populations were a high population (71430 plants/ha; 70 x 20 cm), a standard population (47620 plants/ha; 70x 30 cm), and a low population (35710 plants/ha; 70 x 40 cm). Both plant height, and population were found to have a significant (P<0.05) effect on seed yield components. According to the two-year results, the semidwarf hybrids had 8.4 and 18.8% higher seed yields in the high population than in the standard and the low population, respectively. For the standard and the tall hybrid, however, the standard plant population of 47620 plants/ha (70 x 30 cm) was determined as most suitable for high seed yield and oil yield per hectare.

Sixty-hree Helianthus tuberosus L. populations collected in Montenegro were analyzed for thirty-one morphological characteristics. The data obtained were grouped in two clusters, in accordance with their morphological characteristics which indicated obvious differences in origin. One of the clusters was further subdivided into groups which gathered populations collected in a close geographic proximity. It was concluded that the Jerusalem artichoke populations collected in Montenegro displayed a high interspecific variability which makes them valuable for breeding programs.

Polymorphism of the major storage protein of sunflower seed, 11S globulin (helianthinin), was studed using the method of one-dimensional sodium dodecylsutphate polyacrilamide gel electrophoresis. The examined materials included seventeen accessions of annual and perennial Helianthus species, one accession of Tithonia sp. and six simple and complex interspecific hybrids. The helianthinin polypeptide compositiori differed considerably among the species of the genus. The annual and perennial species were most different. A numberof polypeptides were stable within the genus, the othèr ones were characterized by high variability. In the crosses of genetically close species, the polypeptide composition was inherited as a Mendelian character..However, by hybridization of distant species having non-homologous genomes (e.c., H. rigidus x H. annuus), poor polypeptide composition of hybrid protein was obtained. In hybrid seeds, only those polypeptides were expressed which were presents in both parents. This probably explains the seed non-viability in interspecific crosses of the genus Helianthus L.

Two non-allelic unlinked genes designated tph-1 and tph-2, controlling tocopherol composition in sunflower seeds, were identified for the first time. Recessive alleles of the genes were found by wide-scale screening and selfing as spontaneous mutations on the base of "half-seed technique". Inbred lines with modified tocopherol composition have been developed. The tph-1 gene controls the ratio of alfa- and beta-tocopherols whereas tph-2 gene controls that of alfa- and gamma-tocopherols.

Protein content in seed and amino acid composition of proteins were studied in 30 genotypes of 16 Helianthus species. The results indicate that some entries of wild Helianthus can be used as a source of genes for improving the protein nutrient value in modern cultivars and hybrids.The entriesl H. hirsutus- M007, H.rigidus-M002 and M 028, H.mollis-M033,and H. eggerttii-M 001 were distinguished for a much higher protein content as compared with cv. Peredovik. Compared with the standard the entries H. annuus-E 004, H.petiolaris-E 021 and E 037, H. praecox-E 027, H. laevigatus-M 016, H. egertti- M 001, and H. rigidus-M 002 had increased contents of some amino acids. These entries are maintained at the Dobroudia IWS and can be used for wide hybridization of sunflower.

Effect of sodium chloride on callus development in hypocotyl explants and seed germnation in two c.v. Morden and EC 68415 of sunflower was studied. Better callus development and germination were noticed in the former. Pattern of changes in water relations and accumulation of reducing sugars, soluble amino acids and proline were also studied in germinated seeds and calli. These studies indicated that turgor can not be related to salt tolerance. Proline accumulation seems more due to the effect of salinity. In the light of inconsistencies noticed in water relations and solute contents wiih respect to germination and seedling vigour, role of any one of these in greater salt tolerance of c.v. EC 68415 is not beyond doubt. Since better callus dwelopment and seed germination and vigour are associated, the former could be a more reliable index of salt tolerance in the two cultivars.

Fiften sunflower genotypes wer studied for ion accumulation in leaves. A high degree of genetic variability was found among sunflower genotypes for accumulation of ions. Chloride ions accumulation increased at moderate and high salinity. Sodium ions accumulation decreased at moderate salinity but increased at higher level of salinity while potassium ions accumulation first increased at moderate.salinity then decreased at higher salinity level. A similar behaviourwas observed for K+/Na+ ratio in young leaves at moderate and high salinity levels. Sunflower genotypes showed tolerance to salinity by maintaining Na+ at lower and K+/Na+ ratio at higher level in young growing leaves and it was found to be a good criterion of salt tolerance in sunflower.

A root rot disease of wild sunflower species (Helianthus tuberosus L) was observed during May, 1992 at National Agricultural Research Centre (NARC), Islamabad. Infected roots showed light brown discoloration, covered with white, fan shaped mycelium with small, round, tan to brown coloured sclerotia of mustard seed size (0.5-2 mm) on the roots and in adjacent soil. Disease incidence ranging from 30-40 % was recorded. On the basis of disease symptoms and cultural characteristics, the causal agent was identified as Sclerotium rolfsii Sacc. Thus, Helianthus tuberosus appears as a new host of this pathogen in Pakistan.