Effect of substrates on germination and seedling emergence of sunflower (Helianthus annuus L.) at the Yongka Western Highlands Research/Garden Park, Bamenda-Cameroon

A study was carried out at the Yongka Western Highlands Research Garden Park, Nkwen­Bamenda in Cameroon to evaluate the effect of substrates on the germination and seedling emergence of sunflower (Helianthus annuus L.). Seeds of African Giant variety were used with six substrate media (sawdust, sand, soil, sawdust­sand, sawdust­soil and sand­soil). The experiment was laid out in a Randomized Complete Block Design in three replications. Germinated seeds were counted daily for a 15 days period. To estimate seedling emergence from two Weeks After Sowing (WAS) up to four WAS, data on seedling height and number of leaves were recorded. The results showed that germination started 8 days after sowing for all substrates. Germination rate was significantly affected by the substrates but the rates were less than 80%. The highest germination rate was recorded on the soil substrate (75%) while the lowest rate (25%) was recorded on the sawdust substrate. Seedlings on the sawdust substrate were also less vigorous and had less leaves (12.67 cm height and 4.7 leaves) than those on other substrates at four WAS (50–63 cm and 12.6–15.3 leaves). Based on the results, it is recommendable to use the soil substrate to nurse African Giant seeds

Progress and bottlenecks in the early domestication of the perennial oilseed Silphium integrifolium, a sunflower substitute

Silflower (Silphium integrifolium Michx.) is in the early stages of domestication as a perennial version of oilseed sunflower, its close relative. Grain crops with deep perennial root systems will provide farmers with new alternatives for managing soil moisture and limiting or remediating soil erosion, fertilizer leaching, and loss of soil biota. Several cycles of selection for increased seed production potential following initial germplasm evaluation in 2002 have provided opportunities to document the botany and ecology of this relatively obscure species, to compare agronomic practices for improving its propagation and management, and to evaluate the differences between semi-domesticated and wild accessions that have accrued over this time through intentional and unintentional genetic processes. Key findings include: domestication has increased aboveground biomass at seedling and adult stages; seed yield has increased more, achieving modest improvement in harvest index. Harvest index decreases with nitrogen fertilization. Silflower acquires nitrogen and water from greater depth than typical crops. In agricultural silflower stands within its native range, we found that Puccinia silphii (rust) and Eucosma giganteana (moth) populations build up to unacceptable levels, but we also found genetic variation for traits contributing to resistance or tolerance. Breeding or management for reduced height and vegetative plasticity should be top priorities for future silflower research outside its native range.Fil: Vilela, Alejandra Elena. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: González Paleo, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Turner, Kathryn. The Land Institute; Estados UnidosFil: Peterson, Kelsey. The Land Institute; Estados UnidosFil: Ravetta, Damián Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Crews, Timothy E.. The Land Institute; Estados UnidosFil: Van Tassel, David. The Land Institute; Estados Unido

Hybrid sunflower seed yield, composition and deterioration after chemical desiccation

The impact of chemical desiccation on yield showed contrasting results depending on seed moisture content at the time of application. Its effects on seed deterioration are still unknown and could be modified by seed composition. Objectives were to evaluate the impact of chemical desiccation on: i) hybrid sunflower seed yield and composition at harvest time, ii) seed deterioration during long-term storage and iii) the relationship between seeds deterioration and oil or oleic acid content. Six hybrids including low, mid and high oleic were evaluated in three experiments. Two treatments were applied on female lines at 27-30% seed moisture: (i) spraying with Paraquat and (ii) detaching heads with a knife. Control remained in the field until 10% seed moisture. Seeds were stored during 19 months under room and cold chamber conditions. Yield, number of seeds and hybrid seed composition (thousand seed weight, kernel percentage, oil and acid oleic content) were determined. Seed deterioration during storage was analyzed by germination and vigour. Paraquat advanced harvest by 35-43 days, without affecting yield or seed composition. During storage the germination of Paraquat treatments remained above that of control, without differences between storage conditions, while vigour remained above control only in cold chamber, for low oleic hybrids. Associations between deterioration (germination and vigour) and oil or oleic acid content, were not significant. Desiccation with Paraquat allows advanced harvest without yield losses or modifications in seed composition. The deterioration of desiccated seeds was lower and independent from oil and oleic acid content.EEA Hilario AscasubiFil: Szemruch, C.L. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentina. Universidad de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación sobre Producción Agropecuaria, Ambiente y Salud; ArgentinaFil: Cantamutto, Miguel Angel. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; Argentina. Universidad de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación sobre Producción Agropecuaria, Ambiente y Salud; ArgentinaFil: García, F.A. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Aguirre, M. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Renteria, S.J. Advanta Semillas; ArgentinaFil: Rondanini, D.P. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Tecnológicas; Argentina. Universidad de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación sobre Producción Agropecuaria, Ambiente y Salud; Argentin

Effect of storage period and chemical treatment on sunflower seed germination

Hybrid sunflower seed, regularly protected with chemicals, is used for sowing in the second or the third year if not used in the first year after production. In that case, it is stored in warehouses, and the length of storage period may significantly affect the quality of seeds. An experiment was conducted in Laboratory for Seed Testing of Institute of Field and Vegetable Crops in Novi Sad, in order to examine the effect of storage period on germination of treated sunflower seeds of three commercial hybrids of the Novi Sad Institute. The seed was treated with fungicides - metalaxyl and fludioxonil, as well as with insecticides - thiamethoxam and imidacloprid, while untreated seeds served as control. The sowing was repeated throughout the year, at three-month intervals. The obtained results indicated that, on average, the hybrid Sremac had the highest (94.61%), and the hybrid Šumadinac the lowest seed germination (90.29%). After one year of storage, seed germination declined significantly. All three hybrids treated with fungicides and the control had a significantly higher germination than hybrids treated with insecticides. This regularity was not evident right after the treatment - it became noticeable during the storage

Energija klijanja kao parametar kvaliteta semena različitih genotipova suncokreta

Using the standard method, we studied the germination energy of seed of seven different sunflower genotypes (five hybrids and two cytoplasmically male sterile female lines) developed at the Institute of Field and Vegetable Crops in Novi Sad. The seed was treated with the fungicides benomil, metalaxyl and fludioxonil and the insecticides thiamethoxam and imidacloprid and kept for a year in a storage facility. Analysis of variance showed that there were highly significant differences among the genotypes, chemical treatments, and storage periods. Highly significant differences were also recorded for all the interactions among the factors studied. On average, the highest germination energy was found in the hybrid H2 (93.45%), whose values of this parameter were highly significantly higher than those of the rest of the genotypes, except for the hybrid H1. Also, each of the hybrids had highly significantly higher germination energy than either of the two lines, and the differences among the hybrids themselves were highly significant. Looking at the chemical treatments, the control had the highest germination energy by a highly significant margin (80.39%). The largest difference was observed in relation to the treatments with insecticides (5.48 and 9.56%). These treatments had highly significantly lower values of germination energy than those involving fungicides. Germination energy increased in the first nine months of storage, peaking at 81.29%. After that, there was a sharp drop to 68.94% after 12 months of storing. Differences among the different storage periods were all highly significant except for that between six and nine months of storage, which was not statistically significant.U radu je standardnom metodom ispitivana energija klijanja semena sedam različitih genotipova suncokreta, dve citoplazmatski muško sterilne forme linije majke i pet hibrida, stvorenih u Institutu za ratarstvo i povrtarstvo iz Novog Sada. Seme je tretirano fungicidima: benomil, metalaksil i fludioksonil, kao i insekticidima: tiametoksam i imidakloprid i čuvano godinu dana u skladištu. Analizom varijanse utvrđene su visoko značajne razlike između ispitivanih genotipova, hemijskih tretmana i dužina čuvanja. Ustanovljene su i visoko značajne razlike za sve interakcije ispitivanih faktora. U proseku, najveću energiju klijanja imao je hibrid H2 (93,45%), čija je vrednost bila je statistički visoko značajno veća nego kod ostalih genotipova, osim u odnosu na vrednost kod hibrida H1. Takođe, može se zaključiti da su svi hibridi imali visoko značajno veću energiju klijanja semena od linija kao i da su između ostalih ispitivanih hibrida razlike bile visoko značajne. Kod hemijskih tretmana energija klijanja u kontroli bila je visoko značajno najveća i iznosila je 80,39%. Najveća razlika bila je u odnosu na tretmane sa insekticidima (5,48% i 9,56%). Vrednost ispitivanog parametra kod ovih tretmana bila je i visoko značajno manja u odnosu na vrednosti dobijene kod tretmana sa fungicidima. Energija klijanja povećavala se sve do devetog meseca kada je i zabeležena najveća vrednost (81,29%), a zatim dolazi do naglog pada nakon dvanaest meseci čuvanja gde je zabeležena vrednost od 68,94%. Između svih ispitivanih varijanti su bile visoko značajne razlike, jedino razlika između šest i devet meseci čuvanja nije bila statistički značajna

Vigor of sunflower and soybean aging seed

Seed aging and deterioration affect seed vigor and viability. The characteristics of the chemical composition of oil crops seed are related to specific processes occurring in the seed during storage. This study was performed to examine the changes in seed vigor of different sunflower and soybean genotypes under controlled and conventional (uncontrolled) conditions of natural aging for six and twelve months. Obtained results show that the degree of seed damage and the ability of seed to resist the negative effects of aging were influenced by duration and type of storage, as well as seed characteristics of the tested genotypes. The most valuable vigor test for both sunflower and soybean was cold test

Pre-chill with gibberellic acid overcomes seed dormancy of Jerusalem artichoke

Jerusalem artichoke is a valuable source of inulin, a polysaccharide. Inulin is a sustainable source of dietary fiber that enhances the immune system in humans. Although Jerusalem artichoke can be propagated vegetatively, breeders use cross-fertilization to produce novel varieties and hybrids with higher inulin yields. Seed dormancy can hinder the breeding progress because dormancy reduces the number of generations a breeder can obtain in one year. Current methods for breaking seed dormancy are time-consuming, and usually involve removing or pin-pricking the seed coat of these very small seeds, or using several weeks of seed vernalization or several months of storage. Breeders thus require better methods that are less time-consuming and achieve higher germination percentages. Here we studied germination, dormant seed, dead seed and the seedling growth rate of different Jerusalem artichoke genotypes and seed lots after seeds were treated with different methods to break seed dormancy. We evaluated fresh and stored seed lots using the following treatments: seed samples were planted on top of media moistened with either potassium nitrate, gibberellic acid or distilled water as control. Two identical sets of samples were planted: one set was germinated in a chamber at alternate 15−25 °C for 28 days, while the second set was prechilled at 5 °C for 14 days, before moving the samples to the alternate 15−25 °C chamber for 14 days. Our findings reveal that the highest germination percentage up to 85.3% was obtained when applying pre-chill with gibberellic acid. This novel dormancy-breaking treatment was thus effective in promoting fresh seed germination

Beneficial microbes promote plant growth and induce systemic resistance in sunflower against downy mildew disease caused by Plasmopara halstedii

Seven plant growth promoting fungi (PGPF) native to the rhizosphere soil were screened for their potential to promote growth and to induce resistance in sunflower against Plasmopara halstedii, an incitant of sunflower downy mildew disease. Effect of seed priming with each of these seven PGPF isolates on seed quality parameters and resistance induction were studied under in vitro and green house conditions. Root colonization ability of these PGPF was also studied under green house conditions. The results showed that seed priming with conidial suspension of PGPF at 1 x 108 cfu ml-1 significantly increased seed germination and seedling vigor compared to non primed control. Plants raised with primed seeds demonstrated a significant reduction in downy mildew disease severity and provided a maximum of 61% protection under green house conditions when compared to the untreated control. The experimental results proved that the tested PGPF, promoted growth and induced systemic resistance (ISR) in sunflower plants against the downy mildew disease caused by P. halstedii, due to their growth promoting and biocontrol abilities. Present study has revealed the fact that there is a strong correlation between root colonization and resistance induction in PGPF treated plants