White Clover Seed Production: III. Cultivar Differences under Contrasting Management Practices

Crop Science ◽  
2000 ◽  
Vol 40 (5) ◽  
pp. 1317-1324 ◽  
Author(s):  
R. B. Medeiros ◽  
J. J. Steiner
1985 ◽  
Vol 2 ◽  
pp. 25-31
Author(s):  
P.T.P. Clifford

Leaf size is a major determinant of white clover seed yield. A three-fold increase in leaf size halves seed yield. From a survey of commercial crops, an optimum leaf size concept was used to explain the reduction in yield potential for extremes in leaf size. Overgrazing gave small leaves and lowered seed yields. Closing too early gave large leaves and lowered yields. With good management, optimum leaf size was the smallest size possible, consistent with ensuring an adequate bulk for efficient harvesting. A healthy highly-reproductive stolen population has to be developed before closing. Secondly, moisture regulation over the crop season, preventing excess watering to minimise plant exploitation of surplus fertility, reduces the potential for large leaves to develop. Mid-November closing coupled with maintaining soil moisture at about 25% plant available, over flowering, are sound management practices. Amongst cultivars, differences in seed yield potential may also be related to leaf size. In general the larger the mean cultivar leaf size the lower the seed yield. Keywords: Trifolium repens, white clover, seed production, leaf size, soil fertiity, moisture, management options.


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.


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


Author(s):  
В. Золотарев ◽  
Н. Переправо

Среди многолетних трав клевер ползучий (Trifolium repens L.) является одним из лучших бобовых компонентов для создания культурных луговых и пастбищных агрофитоценозов в районах с умеренным климатом. На основе биологических особенностей клевера ползучего показана эффективность использования этой культуры для лугопастбищного кормопроизводства страны. Дан краткий анализ опыта возделывания клевера ползучего за рубежом. Показано значение хозяйственно полезных признаков сортов на эффективность их использования в травосмесях. Приведён материал по ботанической классификации разновидностей клевера ползучего и особенностям хозяйственного использования сортов разных морфотипов. Показана различная эффективность импортных и отечественных сортов клевера при их возделывании в почвенно-климатических условиях России. В настоящее время в Государственном реестре селекционных достижений, допущенных к использованию на территории РФ, зарегистрировано 27 сортов клевера ползучего, из них девять (33) отечественной селекции. Актуализирована необходимость усиления селекционной работы по выведению новых сортов, адаптированных к разнообразным почвенно-климатическим условиям и определённым режимам пастьбы. На основании этого обозначены направления селекции. Высокий рыночный спрос вызывает необходимость организации товарного семеноводства клевера ползучего сортов отечественной селекции. Установлено, что основной объём семян завозится из-за рубежа. Однако сорта зарубежной селекции мало приспособлены для произрастания в континентальном климате России. В статье в ретроспективе показано состояние и перспективы семеноводства клевера ползучего в России, включая систему воспроизводства его семян. Представлена научно обоснованная потребность в необходимых объёмах производства посевного материала на разных этапах репродуцирования для обеспечения лугопастбищного кормопроизводства. Для существенного увеличения сборов семян клевера ползучего предложено широко внедрять в производство сортовые посевы при оптимальных технологиях их выращивания, что позволит раскрыть потенциальные возможности каждого сорта в конкретных почвенно-климатических условиях и повысить урожайность семян в 23 раза. White clover (Trifolium repens L.) is one of the best perennial legume components for grassland and pasture ecosystems in regions with temperate climate. This report describes the effectiveness of this crop in forage production basing on its biological traits. It presents the experiment on clover cultivation abroad. The influence of economically important traits is shown on clover performance in grass mixtures. The article includes white clover botanical classification and cultivation methods of different morphotypes. Performances of foreign and domestic varieties were tested under Russian environment. Currently State Register for varieties accepted for cultivation in Russia lists 27 white clover varieties, and nine of them (33) are domestic. It is important to work further on breeding of new clover varieties adapted to various conditions. There is a high demand for white clover seeds of domestic origin. The main part of white clover comes from abroad. However, such varieties poorly grow under Russian climate. This paper shows the state and perspectives of white clover seed production in Russia. When producing grassland forage efficient seed production of this crop is of great importance. Introduction of white clover varieties to particular regions is a way to stimulate its seed production using optimal cultivation techniques.


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.


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