This report presents the current knowledge of Orobanche resistance in sunflower from the breeder’s standpoint and from the biochemists’ standpoint. The parasitic relations in Helianthus annuus / Orobanche cumana asso ciations differ in many respect from relations of other Orobanche spp. and their hosts. A major difficulty for the breeder is the fast development of new patho types of Orobanche cumana, which overcome the resistance of newly devel oped sunflower lines. The basis of increasing aggressiveness of Orobanche cumana pathotypes is discussed. Nevertheless, there is still large potential for resistance breeding in the genus Helianthus, since very different resistance fac tors are already known or shall be elucidated. A survey is presented of known resistance factors, such as low stimu lants, mechanical barriers and how they develop, phytoalexins, Orobanche seed germination inhibitors, inhibition of exoenzymes of the Orobanche radicles, in particular of polygalacturonase, which enables the penetration of Orobanche tissue into the host root along the middle lamellae. In this context an interesting new approach may be found in the polygalacturonase-inhibiting proteins occurring in cell walls, which inhibit the invasion of pathogenic fungi. The need for molecular biological studies will be stressed. Interdiscipli nary collaboration of breeders with biochemists and molecular biologists may lead to more advanced breeding strategies.

Seven species of Glomus (Glomus mosseae, G. fasciculatum, G. scintillans, G. versiforme, G. geosporum, G. macrocarpum and G. diaphanum) from sunflower rhizosphere are described and illustrated. A key to species of the genus Glomus is also prepared based on morphological characters. Spores of these species were identified on the basis of their morphological characters such as hyphal attachment, spore ornamentation, wall layers and spore color and size.

Amongst the diseases on the cultivated sunflower (Helianthus annuus L.) in India, the downy mildew disease caused by the fungus Plasmopara halstedii (Farl.) Berl. & De Toni is counted as important one. The disease is quite destructive as it is seed-borne and there are large chances for its fast spread to other sunflower growing localities. Use of resistant hybrids/varieties appears to be the only way to combat the disease. During the kharif season of 2005-2006, 21 newly developed hybrids and 10 varieties were included in Initial Hybrid Trial (IHT), Advanced Hybrid Trial (AHT) and Initial/Advanced Variety Trial (I/AVT) within the framework of All India Coordinated Program and were screened for downy mildew disease reac tion. The hybrids/varieties were tested under high disease pressure in downy mildew infected plots at Oilseeds Research Station, Latur (M.S.), India. The data revealed that almost all newly developed varieties were susceptible to the disease. However, five hybrids, NSH-23, Sunbred-2077, NSSH-303, K-678 and MLSFH-93, were totally free from downy mildew incidence. Such hybrids can be exploited for commercial use.

Sunflower necrosis disease (SND) is a new threat for sunflower cultiva tion in India. The disease was observed during 1997 in Karnataka, a major sunflower growing state of India. Later, its occurrence was reported from almost all sunflower growing states of India, posing threat to sunflower cultiva tion. Presently no reliable resistant sources are available. The disease being viral in nature is very much difficult to combat by single approach. At Oilseeds Research Station, Latur (M.S.), India, three-year (2002-2004) field experiments revealed that if the sunflower crop is bordered with sorghum, and sunflower seeds treated with imidacloprid (Gaucho 70 W.S., 5 g/kg) along with sunflower spraying with imidacloprid (Confidor 200 S.L., 0.05 percent, three sprays at 15, 30 and 45 days after sowing), the incidence of sunflower necrosis disease can be minimized.

A several-year study of distribution, phytocoenological differentiation, flo ristic composition and structure of ruderal flora and vegetation and relevant anthropogenic influence was conducted at Pančevački Rit in Serbia. Ten clearly distinctive ruderal communities were identified in the study, including the newly formed community Matricario-Helianthetum annuae. This community is a unique combination of transitional ruderal and agrestal vegetation developing spontaneously in close vicinity of intensively cultivated agricultural fields, in which sunflower (Helianthus annuus L.), an annual crop, appears and persists subspontaneously and often massively, rendering a physiognomical character to ruderal habitats in which ephemeral ruderal weed veg etation often develops, consisting predominantly of annual plants of Sisymbrion officinalis R.Tx., Lohm. et Prsg.1950.

A novel variant devoid of rayflorets was identified in the interspecific derivatives of the cross between cultivated sunflower and H. divaricatus. The outermost whorl of the capitulum was comprised of modified disc florets which had longer petals than the regular disc florets and were hermaphrodite unlike the ray florets which are unisexual with non-functional stigmas. Inherit ance studies indicated that the apetalous trait is under monogenic recessive gene control. Utility of the trait in physiological and breeding studies is under investigation.

A three-year experiment (2005, 2006, 2007) including three sunflower hybrids and eight sowing dates was carried out in order to study the impact of hybrid × sowing date interaction on oil yield of sunflower hybrids. With an aim of attaching biological significance to the interaction interpretation, informa tion on four climatic factors (minimum, maximum and mean temperature and precipitation) were used. Significant differences were found between hybrids, sowing dates and years regarding their impact on oil yield. The results of 3-way ANOVA showed that all sources of variation were highly significant (main effects and interaction effects). This indicated variations among sunflower hybrids for oil yield and variations in sowing date and hybrid × sowing date effects. The multiplicative interaction between H × R was further separated in two bilinear terms (PC1 and PC2), and both were highly significant. The SREG2 biplot indicated that the hybrid Miro was the best performer at 11 planting dates. During the three-year experiment, Pobednik produced highest oil yields at 10 planting dates and Rimi only at 3. Sowing dates R1-6, R2-6 and R3-6 were best for oil yield, because they had highest PC1 values and near-zero PC2 values were (SREG2). On the basis of percentages in the first significant dimension, three variables (pr3, mx3, mn3) higher than 50% and with high positive values of loading were extracted. The PLS regression tri-plot shows that all variables were distributed in 4 groups with similar (or different) effects on the total interaction. Minimum temperature (mn4) at physiological maturity had the smallest contribution to the H × R interaction for oil yield. Sowing dates R4-5 and R5-5 also had smallest contributions to the H × R interaction, because they were located near zero point (0.0) and because their oil yields were smaller than the average. The results for sunflower oil yield indicated that the relative performance of the hybrids and sowing dates was strongly under the influence of their differ ent reactions to precipitation, maximum and minimum temperatures at the flowering stage.

Twelve cytoplasmic male sterile lines belonging to four cytoplasmic male sterility (cms) sources were crossed with twelve inbreds to identify fertility restorer lines for each cms source. For the same source differing in line, the inbred behaved as either maintainer/restorer. Out of the twelve new inbred lines tested, fertility was restored in 9 inbreds for DRSF-114A (PEF), DRSF 132A (PET-2) and DRSF-105A (PET-1), 11 inbreds for DRSF-116A (PEF) and DRSF-127A (CMSI), 4 inbreds for DRSF-115A (PEF), 5 inbreds for DRSF 125A (CMSI) and DRSF-107A (PET-1), 6 inbreds for DRSF-124A (CMSI), DRSF-131A (PET-2) and 10 inbreds for DRSF-109A (PET-1). However, DRSF 117A (PEF) was not restored by any of the inbreds tested. The study identified several effective restorers for newly developed cms sources for the first time in India, which can be exploited in developing highly heterotic hybrids possessing alternate cytoplasms.

The experiment was carried out to induce variability in the sunflower varieties Morden and CO 4 (TNAUSUF 7) by a physical mutagen, i.e., gamma rays. The LD50 value was fixed at 15 kR for both varieties based on germina tion percentage. Progressive decreases in germination and survival with increase in gamma ray dose were recorded in the M1 generation. Stimulatory and inhibitory effects were noticed in quantitative characters with lower and higher doses, respectively. The mean expression and variability in quantitative characters increased considerably in the M2 generation. The different muta genic treatments showed an inconsistent relationship with respect to mutagen mean and variability. However, considerable increase in variance was observed in traits such as plant height, seed yield per plant and oil content. Regarding seed yield per plant, heritability and genetic advance were maximum at 20 kR and 5 kR in the genotypes Morden and CO 4, respectively.

A dwarf mutant has been derived from M2 gamma irradiated Morden population of sunflower (Helianthus annuus L.). The dwarf mutant has the height of 35 cm and the earliness of 65 days. This mutant has been selfed and forwarded to the M3 and M4 generations and it did not deviate significantly from the expected segregation ratio since it has the recessive monogenic char acter. Althogh the earliness and height showed a drastic reduction, the seed yield and oil content were on par with the parent Morden.

Three varieties, CO 4, Morden and TNHSF 239 (a pre-release culture) and two hybrids, TCSH 1 and KBSH 44, were selected for this study. Simple correlation coefficients were estimated among characters for individual varie ties and hybrids. Two traits, seed yield and 100-seed weight, are important selection indices for oil yield improvement in both varieties and hybrids. Head weight can be considered as a selection index for improvement of seed and oil yield in hybrids only. Likewise, oil content is an important selection index for oil yield improvement in varieties. It can also be inferred that the results obtained from the association analysis of pooled data for varieties and hybrids will give ambiguous results and have a negative impact on the yield improve ment program. Thus it is desirable to compute separate association analyses for each variety and hybrid to identify effective selection indices for the improvement of sunflower.