Effect of plant density on stolon growth and development of contrasting white clover (<i>Trifolium repens</i>) varieties and its influence on the components of seed yield

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An experiment is described in which the effects of different spring managements on the potential seed yield and seed yield components of three white clover cultivars of contrasting leaf types were assessed. Cv. S184, the small-leaved variety, produced more but smaller inflorescences than CVS Olwen, a large-leaved variety, or Menna, a medium-leaved variety. However, cv. Olwen, produced inflorescences with more florets, seeds per inflorescence and a higher seed yield per ten inflorescences than the other cultivars. Both potential seed yield and the individual yield components were influenced by management. Cv. Olwen produced more inflorescences and a higher potential seed yield under a cutting system than under grazing systems, which reduced the number and size of the inflorescences. Cvs S184 and Menna were less influenced by management system and performed similarly under cutting and grazing. The highly significant relationship between the number of ripe inflorescences and potential seed yield showed clearly that high seed yields are only achieved if the crop is harvested when the number of ripe inflorescences is at a maximum. The relatively short duration of the period of maximum ripre inflorescences emphasized the importance of determining the correct harvesting date, although weather conditions Correspondence to: Dr P. A. Hollinglon, Institute for Grassland and Anima! Production, Welsh Plant Breeding Station, Aberyslwyth, Dyfed. SY23 3EB, U.K. also play an important part in deciding when to harvest. Florets per inflorescence, seed set and 1000 seed weight remained relatively constant over the harvest period, and were not influenced by harvest date. The results are discussed in relation to the management of white clover seed crops and the importance of climatic conditions during seed production.

Section: Discussioosupporting

confidence: 92%

Effect of seed crop management on potential seed yield of contrasting white clover varieties

Hollington

Marshall

Hides

1989

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“…The previous pajjer identified the optimal harvest date as late August in both 1987and 1988(Marshall et ai, 1993. This was when numbers of ripe inflorescences were highest, numbers of lost inflorescences were increasing, and when numbers of brown inflorescences were declining and therefore unlikely to contribute further to yield.…”

Section: Introductionmentioning

confidence: 99%

Spring defoliation of white clover seed crops. 2. Potential harvestable seed yield and seed yield components of contrasting white clover cultivars

Marshall

Hollington

Hides

1993

Self Cite

The effects of difTerent spring defoliation managements on potential harvestable seed yield and seed yield components of three contrasting white clover cultivars were assessed. The smallleaved cv. SI 84 produced more but smaller inflorescences than the large-leaved cv. Olwen and Menna, a medium-leaved cultivar. Cultivar Olwen, however, produced more ripe and brown (nearly ripe) inflorescences with more florets, seeds per floret and a higher seed yield per ten inflorescences than the other cultivars. Potential harvestable seed yield and individual seed yield components were only influenced by defoliation after bud emergence, as defoliation before bud emergence had no effect on seed yield components. Defoliation after bud emergence had a similar effect on all cuitivars: the number of ripe inflorescences was unaffected by defoliation but the number of brown and therefore harvestable (ripe + brown) inflorescences was highest following defoliation three weeks after bud emergence. Florets per inflorescence, seed per floret, 1000 seed weight, seed yield per ten inflorescences and potential harvestable seed yield were not influenced by defoliation after bud emergence. Season had a signiflcant efTect on seed yield components and influenced the effect of defoliation treatCorrespondence: A. H. Marshall, AFRC Insijtule of Grassland and Environmenlal Research, Welsh Plant Breeding Station, Plas Gogerddan, Aberystwyth, Dyfed, Sy23 3EB, UK. t Present address: Cenire for Arid Zone Studies, University College of North Wales. Bangor, Gwynedd, UK. 310ments, emphasizing the importance of climate in white clover seed production. The results are discussed in relation to the spring defoliation of white clover seed crops, harvesting techniques and the provision of guidelines for optimizing seed yield.

“…This coincided with an exhaustion of soii available water to a depth of 40cm in 1989 and 70cm in 1990, implying that this clover suppression might be due to drought stress. During spring and early summer, prior to the onset of drought stress, growing point populations and stolon dry weights at the restored site increased in a manner described by others (Brock et al, 1988;Mamott, 1988;Marshall and James, 1988). The reduction in clover DM accumulation in the middle of the second silage crop, followed by a subsequent reduction in stolon growth at the restored site, follows the response by white clover to drought stress described by Turner (1990).…”

Section: Performance Ofthe Clover Component In the Mixturementioning

confidence: 50%

The influence of soil factors on the growth of a grass/clover sward on a restored opencast site in Northumberland, UK

Chapman

Younger

Davies

1994

The growth of grass and clover components in mixed swards on a site restored after opencast coal mining and an undisturbed control site were compared. Soil nitrogen supply was reduced at the restored site. This inhibited grass growth but was beneficial for the clover component.Growth at the restored site was also inhibited by a compacted subsoil, which reduced available soil water content and impeded access to available soil water. This inhibited crop production from the middle ofthe second silage crop onwards. In 1989 this was associated with the soil at the restored site reaching permanent wilting point at 40cm. In 1990 this effect was associated with the restored site soil reaching permanent wilting point at 70cm. These drought effects reduced clover growing point population and stolon mass. Grass tiller populations were unaffected.