Seed development of arrowleaf, balansa, gland and Persian clover

Abstract

<jats:p>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</jats:p>

Availability of seed for hill country adapted forage legumes

“…The value proposition for balansa clover requires further investigation of hardseededness and the ability to successfully integrate it into a wider range of hill country farm systems by modifying the resident vegetation. It is less likely to become a major component of hill country pastures in areas where summer and autumn rainfall promote grass competition when it is regenerating from seed (Nori et al 2015b).…”

“…It produces excellent end of its growth season. It has an extremely hard seed coat and requires hot, dry summers to ensure seed coat cracks so it can regenerate (Nori et al 2015b). It is small seeded and requires close contact to soil surface at time of sowing, and can to be sensitive to competition from existing vegetation, requiring Group C rhizobia (Nangul et al 2013;Nori et al 2014).…”

“…Hardseeded cultivars such as 'Lightening' may have similar issues as arrowleaf clover for use on farm but the soft seeded 'Mihi' has been reported to germinate while still in the calyx (Nori et al 2015b) which means it may be lost due to a false strike (MacFarlane et al 2015). Again it is most likely to be serviced by a regionallybased seed company supplying a niche market.…”

Phenological development of subterranean clover cultivars under contrasting environments

“…The phenophases of important legumes such as soybean ( Glycine max L.) (Fehr, Caviness, Burmood, & Pennington, 1971; Rowntree et al, 2014) and lucerne ( Medicago sativa L.) (Enriquez‐Hidalgo, Trinidad, Teixeira, & Steinfort, 2020; Freer & Jones, 1984; Teixeira, Brown, Meenken, & Moot, 2011) have been well documented and quantified. Similarly, the vegetative stages (germination, emergence, leaf appearance and stem elongation) have been quantified for a few annual clovers (Nori, Monks, & Moot, 2015) and subterranean clover cultivars (Enriquez‐Hidalgo et al, 2020; Lonati, Moot, Aceto, Cavallero, & Lucas, 2009; Moot, Black, Scott, & Richardon, 2003). Flower appearance was the most commonly reported phenological event (Aitken, 1955; Nichols et al, 2013; Smetham, Jack, & Hammond, 1994).…”

“…Therefore, the main objectives of this study were to create a practical phenological scale for different subterranean cultivars (from the three subspecies) and to quantify key vegetative and reproductive development phases for cultivars previously classified as mid and late flowering using the phenological scale (Nichols et al, 2013; Teixeira, Hampton, & Moot, 2020) with emphasis on relevant phenophases from a pastoral management perspective (Ates, Lucas, & Edwards, 2013). To do this, six cultivars were sown on eight dates over 12 months to create a range of abiotic conditions (Hay & Kirby, 1991; Nori et al, 2015). We tested the null hypothesis that phenology and plant life cycle of the six cultivars would be constant (degree days, °Cd) and not be affected by the contrast environments (sowing period).…”