Management of defoliation in Trifolium vesiculosum S. for the production of seeds

ABSTRACT The present study aims to determine the appropriate defoliation management for the production of seeds and forage in arrowleaf clover via trail analysis. The results obtained demonstrated that defoliation practices have a great influence on the composition of seed yield and germination power. In addition, when the goal is the maximum balance between dry matter production and seed yield, this can be achieved in up to two defoliation practices. These results are confirmed by analyzing the positive association between the weight of a thousand seeds and the seed yield. When the third defoliation practice is performed, it negatively correlates with the weight of a thousand seeds, suggesting that, with the increase in defoliation frequency, there is a lower weight of a thousand seeds, and, therefore, lower seed yield. Therefore, management planning in Trifolium vesiculosum Savi that aims at natural reseeding, maximum yield and seed germination must prioritize one to two defoliation practices, aiming to promote favorable conditions for the perennialization of the species. In this context, the trail analysis proved to be a useful tool as a criterion for obtaining the ideal management aiming at the production of seeds and forage in vesicular clover.

Trifolium vesiculosum (Fabaceae) in Ukraine: a new find and historical overview

Trifolium vesiculosum is listed in the current floristic inventories as a species native to Ukraine. In order to clarify the native versus alien status of this taxon, we studied historical and recent literature and herbarium data.We also report here our new record of the species. We found T. vesiculosum in 2020 in Mykolayiv Region (Mykolayiv District, Andriivka village, on the alluvial terrace of the Southern Bug River valley), in a disturbed habitat with predominantly synanthropic and alien species. Previous finds of T. vesiculosum in Ukraine were reported mainly in publications of the 19th century and were based on a few herbarium specimens from the present-day territory of Odesa Region. Due to characteristics of these records, dates and localities of the finds of T. vesiculosum in Ukraine, we have traced its probable introductions during the 19th century in the port of Odesa, on the sand deposits of the Danube River, in the German settlements, and therefore we can confirm the conclusion of Paczoski (1921) who assumed the alien status of the species in Ukraine. Thus, T. vesiculosum is classified as a kenophyte (introduced before 1808). Taking into account the current climatic changes in Ukraine, we emphasize the need for further monitoring of the species, changes in its dispersal strategy, and for registration of its introduction and dispersal pathways.

Isotermas de adsorção de umidade e cinética de secagem de sementes de trevo persa (Trifolium resupinatum L.) e trevo vesiculoso (Trifolium vesiculosum) ¬¬¬¬

The aim of this work was to obtain adsorption isotherms and to study the drying kinetics of persian clover (Trifolium resupinatum L.) and arrowleaf clover (Trifolium vesiculosum) seeds, in addition, fitting the experimental data by the predicted models of the literature. The equilibrium moisture content and the moisture adsorption behavior were found by isotherms curves at 40, 45 and 50 ºC, and the Peleg model was the most suitable. The drying kinetics was determined by thin layer assays in an air parallel flow dryer at all three temperatures. In addition, it was demonstrated the predominance of the falling drying rate period for the two species of seeds, and the critical moisture content values were approximately of 0.20 and 0.25 gwater gdry matter-1 for persian clover and arrowleaf clover seeds, respectively. The effective diffusivity values were estimated in ranges of values of 3.61×10-11 – 6.81×10-11 m² s-1 for persian clover and 6.76×10-11 – 1.15×10-10 m²s-1 for arrowleaf clover seeds and the temperature effect was expressed by an Arrhenius relation. Thus, drying kinetics confirmed the greater difficulty in moisture removal from the arrowleaf clover seeds, compared to the persian clover seeds drying, in agreement with the results obtained through adsorption isotherms.

Primera cita de Trifolium vesiculosum Savi (Fabaceae) en la provincia de Sevilla (Andalucía, España)

Se cita por primera vez la leguminosa Trifolium vesiculosum Savi para la provincia de Sevilla.

Primera cita de Trifolium vesiculosum Savi (Fabaceae) en la provincia de Sevilla (Andalucía, España)

Se cita por primera vez la leguminosa Trifolium vesiculosum Savi para la provincia de Sevilla.

Seed development of arrowleaf, balansa, gland and Persian clover

The development process from floral bud formation to seed maturity of four top flowering annual clovers was quantified from a field experiment across 10 sowing dates at Lincoln University, Canterbury, New Zealand. For each species, a numeric reproductive scale was created as a field guide to document morphological changes as the bud progresses through reproductive development. The duration from bud visible to open flower was 341 °C days for 'Cefalu' arrowleaf, 215 °C days for 'Bolta' balansa, 196 °C days for 'Prima' gland and 186 °C days for 'Mihi' Persian clover. The inflorescence then required a further 274-689 °C days, 185 °C days , 256 °C days and 425 °C days for each respective species to reach physiological maturity. This was indicated when 50% of seeds had turned red/brown for 'Cefalu' arrowleaf, 100% pods turned yellow for 'Bolta' balansa, 100% of seeds were yellow and hard for 'Prima' gland, and pods turned brown with the first sign of colour change in seeds for 'Mihi' Persian clover. These results can be used to facilitate on farm decision making in relation to grazing management or seed set for subsequent regeneration. Keywords: floral development chart, harvest maturity, peak flowering, pollination, seed filling, thermal time, Trifolium vesiculosum, T. michelianum, T. glanduliferum, T. resupinatum

Dry matter yield and radiation use efficiency of four autumn sown top flowering annual clovers

Monocultures of arrowleaf (Trifolium vesiculosum), balansa (T. michelianum), gland (T. glanduliferum) and Persian (T. resupinatum) clovers were sown on four dates in autumn and winter 2010. Dry matter (DM) accumulation was dependent on the duration of crop growth which was influenced by the time of sowing. Autumn sown crops which flowered latest had a longer duration of vegetative growth and consequently produced the highest dry matter yields. In the establishment year, autumn sown crops produced up to 17.5 t DM/ha for balansa, 12.5 t DM/ha for Persian, 11.0 t DM/ha for gland and 9.4 t DM/ha for arrowleaf at physiological maturity (P