WILD WHITE CLOVER SEED PRODUCTION. I. The effects of defoliation and fertilizer treatment on flowering and seed yields from ryegrass/white-clover swards

1963 ◽  
Vol 18 (2) ◽  
pp. 97-103 ◽  
Author(s):  
R. J. Haggar ◽  
W. Holmes ◽  
P. Innes
1980 ◽  
Vol 1 ◽  
pp. 64-67
Author(s):  
P.T.P. Clifford

White clover seed yields from crops derived from pure autumn broadcast sowings harvested in the first year after sowing were improved by increasing sowing rate from 3 to 6 kg/ha. On moisture-retentive soils or where irrigation was available, mid-November closings gave highest seed yields for crops derived from either spring undersowings of cereals or as ryegrass mixtures taken for ryegrass seed in the first year from sowing. Closing a month earlier gave similar yields if 30 cm rather than 15 cm row spacings were used. Harvest should be no later than one month from main flowering to reduce the numbers of seedheads lost. General management should aim to promote good primary stolon growth rates over the month prior to mid-December if high flowerhead densities are to be obtained. Therefore excessive grazing before closing and poor timing of herbicide spraying for grass control should be avoided. Keywords: Trifolium repens, seed production, plant density, closing date, pollination, seed harvesting, management.


1980 ◽  
Vol 1 ◽  
pp. 70-73
Author(s):  
J.K. Lay

Irrigation has removed much of the risk associated with white clover seed production in an area of poorly distributed annual rainfall of 530 mm. Machine-dressed seed yields range between 540 and 900 kg/ha. The importance of minimizing harvesting losses is emphasized. Key words: Trifolium repens, seed production, irrigation.


1986 ◽  
Vol 14 (1) ◽  
pp. 97-99 ◽  
Author(s):  
P. T. P. Clifford ◽  
S. D. White

Author(s):  
P.J. Gerard ◽  
T. Eden ◽  
W. Tozer

A small plot trial was undertaken in the Waikato to determine the potential impact of Sitona lepidus adults on white clover seed production. Five densities of adult weevil were caged on 1 m2 plots from the time of peak adult emergence in November 1998 until harvest in late January 1999. In the laboratory, weevil adults were found to severely damage clover inflorescences when no leaves were present. Although feeding damage on leaves was highly visible in the field plots, with over 80% of the leaflets damaged at the highest density of 600 adults/m2, weevil adults were found to have no effect on flowering or seed production.


Author(s):  
M.P. Rolston ◽  
R.J. Chynoweth ◽  
A.V. Stewart

Forage seed (brassica, grass and legume species) is the delivery vehicle for new plant genetics to the pastoral sector. Seed production technology associated with the release of the first bred pasture cultivars in the 1930s was largely based around horse-drawn reaper and binders and stationary threshing machines. The development of authenticity and quality controls also started in the 1930s with the NZ Seed Certification Scheme. Management inputs were minimal with closing and harvest dates being the major tools available. Over a 75 year period, seed yields have increased, with top growers now achieving seed yields that are three times greater than those reported 50 to 75 years ago. In the 1950s, harvest mechanisation developed rapidly and in the 1970s on-farm seed drying was developed. The availability of nitrogen (N) fertiliser was the first major input available for grass seed growers. The paper follows the science and changing recommendations on N rates and the eventual maximum limit achieved by additional N identified in trials in 2004. From the 1960s onwards, new herbicides have allowed for the control of a wider range of difficult to control weed species, especially the control of other grasses in ryegrass seed crops and broadleaved weeds in white clover. New generation fungicides, insecticides and plant growth regulators have provided improved management tools for increased seed yields. The paper concludes with changes in extension from Government driven (Department of Agriculture) to farmer funded R&D and extension by the Foundation for Arable Research. Keywords: ryegrass, white clover, brassica, seed production, history


1996 ◽  
Vol 6 ◽  
pp. 41-44
Author(s):  
R.G. Thomas

The causes of low seed set per floret in white clover (Trifolium repens L.) are reviewed. Three stages of flower head development are distinguished as important for a high level of seed set: a pre-fertilisation stage, a stage of anthesis leading to pollination, and a postfertilisation stage in which seed provisioning occurs. In sunny conditions the percentage seed set is limited at the pre-fertilisation stage by up to 20-30% ovule sterility. Relatively low light intensities during the postfertilisation stage can lead to abortion of a high proportion of fertilised ovules and developing seeds. Experimental results suggest that seed yields under optimal growing conditions can be limited solely by the level of pre-fertilisation ovule sterility and probably cannot be bettered, but further understanding of the seed-provisioning requirements for photosynthate could lead to improved management practices for seed production under conditions of lower light intensities. Keywords: abortion, light intensity, ovule, seed provisioning, sterility, white clover


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