A case of pleiotropy in sunflower was detected \ilhile studying the inheritance and inter-relations of genes governing anthocyanin pigmentation of the petiole, nidrib, leaf margin, leaf tiP, ray floret, and stigma in a cross between the inbred lines RM-l and lTp-1. Pigmentation was dominant in the F1 generation. Complementary gene action of 9 purple: Z green wâs observed for petiole, midrib, leaf margin, leaf tip, and ray floret colourations in the F2 generation. Colour of the stigma was found to be contrôled byiour pairs of factors which segregated into 207 coloured: 49 coulouress in the Fz. The gene symbols were designated for the above-mentioned characters. The genetic ratios obtaineà in thê Fz generation are verified with the data collected from the F: generation. The occurrence of pleiotropism in sunflowers is reported here for the first time.

Correlation studies revealed that seed yield per plant was highly and significantly associated with the number of seeds per head, head diameter, 100-seed weight, filled seed (%), plant height, and stem diameter. Path coefficient analysis indicated that the number of seeds per head, 100-seed weight, and head diameter were the most important traits of seed yield per plant.

Response to various degrees of self-fertilization (geitonogamy and autogamy) wàs compared in 6 lines with various levels of self-fertility and in their crosses. Incidence of lines with a high level of self-fertility at geitonogamy is considerable; self-fertile lines are rare at autogamy. Crosses of geitonogamic self-fertile plants display lower self-fertility at autogamy than their parents. The result of crossing is influenced, among other factors, by the specific combination ability of lines in this trait.

Phomopsis (Diaporthe) helianthi Munt -Cvet. et al., is an important phytopathogen that causes stem canker of sunflower. When grown in submerged culture,(cretes extracellular pectinase). Production of constitutive exo-pectinease by this fungus on glucose was established, while the endo-pectinase and peôtinesterase activities could be detected only in the presence of pectin in thè medium. TeÀperature optimum of endo- and eno-pectinases was obtained at 50 C. pH dependence of crude o

In this publication, we presented the latest results of a four-year research of the anamorph Phomopsis helianthi. In the past 4 years, we isolated about one hundred cultures from the pycnidia of the vegetative Helianthus annuw plants and debris. In the att pycnidia, both on diseased. sunflower plants in the field and those cultivated on substrates, no conidial type but p-conidia have been found. Nutritive factor did not influence the type of conidia formed.

This paper considers a hypothesis that Diaporthe (Phomopsis) spp. on herbaceous weed species were the initial inoculum, which, in the early 1980's triggeredihe epiphytotics of the sunflower disease caused by the fungus Diaporthe (Phomopsis) iitiortniquit. ldet. et al., in the Vojvodina Province. A ten-yeâr study on more than 5 herbaceous weed species, conducted in 40 locations, found 18 Diapontophylla and Phomapsis isolates. Correlation bêrween individual weed species populations and the frequency and intensity of occurrence of disease symptoms, ascomata, and conidiomata was low. A separate analysis studied the reaction of sunflowers to two of the three Phomopsis species isolated from Kanthium ita1cun Moretti. The conclusion that the extensive præencn oi Phomopsis helionthi on diseased sunflower plants in the Vojvodina Province is solely responsible for epiphytotic outbreaks of Phomopsis is still valid.

The objectives of this report were (a) to determine the amount of yield loss of 20 sunflower hybrid varieties in relation to their relative susceptibility to Verticillium wilt under field conditions, and (b) to associate this loss with the relative susceptibility of the s:tme genotypes evaluated by the hypodermic inoculation technique. Signifîcant differences among hybrids were detected for Verticillium wilt score (VWS) evaluated under field conditions, yield (kg/ha), and oil percent in two localities (Henderson and Ballenera). The WVS was negatively correlated with yield in both environments (r=4.68 and -0.44*) but not with oil percent. Depending on the environment evaluated, yield loss per point of the vws can range from 6.5% to 12.2% ilitis taken as percentages over the means of the trials. On the other hand, if it takes into account the extreme values of the VWS at each locality, yield loss for a given hybrid can range from 12 to ca. 50% at Henderson and from 0 to 20% at Ballenera, depending on the degree of susceptibility of the genotype considered. Verticillium wilt scores recorded under greenhouse conditions were positively correlated with the scores obtained under field conditions (r=0.56* and 0.45 for each locality) and negatively correlated with yield (r=0.56* and -0.55*). Both facts indicate that the hypodemic method permits to predict the degree of susceptibility (and its associated reduction in yield) of a given genotype when exposed to this disease under field conditions.

This research was conducted to determine the relationships among soil type, soil moisture, and various levels of seed vigor of sunflower (Helianthus annuus L.) and safflower (Carthamus tinctoious L.) pure live seed emergence (PlS). The experiment included three soil types were; silty clay (Vertic Haplaquols, fine montmorillonitic, frigid), which contains 11% sand,42% sand,47% clay; silt loam (fine silty, mixed Udic Haploborals), which contains 30% sand,45% silt, and 25% clay; maddock sandy loam (sandy, mixed Udorthentic Haploboroll), which contains 57% sand,30% silt, and 13% clay. Soil types were equilibrated to 15%, 30%, and 45% of the moisture holding capacity. Results indicated that soil type (silty clay, silt loam, and sandy loam) and soil moisture level (15, 30, and 45% water holding capacity) had a significant (P<0.01) effect on seedling emergence of both crops. Percent pure live seed emergence of low-vigor seed lots of both crops was significantly (P < 0.05) reduced to a greater degree than was high vigor seed lots at low soil moisture content, and silty clay soil type.

The performance of a sunflower (Helianthus annuus L.) hybrid at 3 row spacings (92,122 and 152 cm apart) was compared with intercropping with garden peas (Pisum uvense L) in 1990 and 1991: Sunflower fields were highest at the 92 cm spacing and, in most cases, did better when intercropped, particularly in 1990. The mean yield advantage with intercropping for the 2 years was 8%. Best Land Equivalent Ratio (1.40) was obtained with 92 cm spacing of sunflower intercropped with peas.

L'expérimentation porte sur 56 génotypes de tournâtel (Helianthus annuus) ensemis d'hiver (novembre) au Domaine Expérimental de l'Institut National de la Recherche Agronomique de Dâuyet, région du Sais-Fès, durant la campagne 1989-90. Le but de cet essai consiste à étudier les caractères morphologiques d'adaptation du tournesol aux sens précoces nommés les liens existants entre eux, en vue de dégager l'idéotype à prendre en compte dans une optique de sélection. Il ressort des résultats obtenus que le rendement en grains des génotypes en semis d'hiver dépend essentiellement de la durée semis-floraison (r=0,697** r) et ne peut guère être prédit ou expliqué par les caractères jeunes (nombre de feuilles, hauteur). ll semblg èependant qu" Ëur ieruttante finale en serait le principal indicateur. C-e qui a été démontré p"i lo *oèlutions très significatives energistrées entre le rendement et les pâramétres de tigu".r.; la hauteur (r:0,641t"t) et te diamètre du capitule (r:0,480*rt) mesurés à maturité physiologique, le d-iamètre de la tige au collet (r:0,619*rr) et le nombre de feuilles ir:O,sei';'; mesurés au stade floraison. L'ensemble de ces paramètres est aussi lié à la précocité, en outre la productivité des génotypes dépend très étroitement de la vigueur des jeunes plantules (r:0,422rtr) qui est très fortement liée à leur résistance au froid (r:0,849"r).

La caracterización del material genético de girasol según su reacción fenológica y fenométrica ante el ambiente puede poner en evidencia la variabilidad genética de los cultivares, permitir la elección de la fecha de siembra óptima, seleccionar los materiales regionalmente más adecuados, sortear las adversidades en los momentos biológicos críticos o ayudar a la sincronización de la fecha de floración de materiales que deban cruzarse. Se utilizó la técnica de fechas de siembra continuadas a campo para nueve cultivares de girasol (ARRAYAN F2, CONTIFLOR 8, DAKOTA 853, DAKOTA 854, FLORIDA 2000, G100, LI 75, M 731,SIGCO 490) durante 2 campafias agricolas. Se registraron las fenológicas según la escala de Schneiter y Miller (1981) desde VE hasta R9 y el número de hojas aparecidas hasta el estado Rl. Los girasoles ensayados se reunieron en clases de características similares: A) según la duración del subperíodo YE-RI (emergencia-estrella visible) medida en tiempo térmico y B) por la tasa de aparición de hoJas, mediante análisis de agrupamiento (clúster analisis). Según la característica A) se ubicaron en tres grupos: A') de escasa sensibilidad al foloperiodo (M 731), A") de media sensibilidad (CONTIFLOR 8, DAKOTA 853, DAKOTA 854, FLORIDA 2000, SIGCO 490 y ARRAYAN F2) y A ") de alta sensibilidad (G100 y LI75). Según la característica B) se clasificaron como de tasa alta (ARRAYAN F2, CON TIFLOR 8, G100, FLORIDA 2000, SIGCO 490, DAKOTA 853 y M 731), mediana (DAKoTA854) y baja (LI7s).

In situ hybridization on somatic metaphâse chromosome from sunflower root tips, by detection system of biotin-labeled DNA using streptavidin-alkaline phosphatase conjugate, was performed at INRA-Dijon, France. The metaphase chromosome slides were developed using 1.5 cm root tips of inbred lines CG-8034 and H-13L16, from ICCPT Fundulea, România. After nin sin" hybridization during 24 hours of incubation with biotin-labeled DNA (5 S ribosomal DNA of 330 bp), the microscopical view showed the signals at the end of the chromosomes, associated with satellites. Repetitive DNA sequences detected directly on somatic metaphase chromosomes are localized at the heterochromatic regions in the satellites.