POSSIBLE SOLUTIONS TO CONTAMINATION OF WHITE CLOVER SEED CROPS BY BURIED SEED

Buried hard seed from seed returned to the soil during harvesting and incorporated by cultivation, poses the greatest threat of contamination. When a different white clover (Trifolium repens L.) is sown, contamination will occur when hard seeds within the germinating zone soften and emerge. Harvest losses can return 40 to 210 kg/ha of hard seeds to the soil. Flowering management and efficient harvesting are necessary to minimise quantities of hard seed returned to the soil. For a buried seed load of 845/m* in the germinating zone of a cultivated seed bed at sowing in March, 8% of that seed load gave rise to establishing plants of which one-third (19/m') were surviving in mid-October. At closing the percentage crop contamination within the sown row was directly proportional to the within-row seeding rate of the sown cultivar. At wider-than-normal row spaces, (45 cm compared with 15 cm) either inter-row cultivation or spraying for removal of contaminants was necessary at closing to reduce contaminants to a density similar to that in 15 cm spacing treatments. Physical contamination of the harvested seedline, compared with levels present at closing, had doubled for normal, but trebled for wider-than-normal spacings. Lowest percentage physical contamination of a seedline gained was 13% for a 6 kg/ha seeding at 15 cm spacings. The results indicate that successful cultivar change on many areas will be difficult. A buried seed count is considered an essential guideline to aid choice of paddock. Future management systems now being developed, include the use of herbicides and direct drilling, and should help to minimise this problem. Keywords: White clover, Trifolium repens, seed production, contamination, cultivar change, harvest losses, hard seed, cultural practices.

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Contamination of white clover seed crops by buried seed

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1992.54.2033 ◽

1992 ◽

pp. 139-141

Author(s):

J.G.H. White ◽

G.R. Edwards ◽

K. Nicholson

Keyword(s):

White Clover ◽

Burial Depth ◽

Hard Seed ◽

Seed Loss ◽

Cultivation Practices ◽

Buried Seed ◽

Direct Drilling ◽

Clover Seed ◽

Seed Crops ◽

Practical Implications

The first study examined white clover seed loss in the offal trail of a header harvester. Seed counts in offal trails were 83 800/m* compared to intermediate areas at 22 500/m*. Consequent problems in sampling for buried seed are discussed. The second trial measured buried seed two years after a white clover seed crop. In the top 25 cm of soil 66 200 seeds/m* remained following conventional cultivation but only 26 000 occurred under direct drilling. With conventional cultivation 80% of seed was buried below 10 cm depth, but 63% of the buried seed was in the O-5 cm layer with direct drilling. In a third study the rate of hard seed breakdown was examined. Breakdown was rapid on the surface but after4 years 36% of seed survived at 10 cm depth and 65% at 20 cm buried. The practical implications on cultivation practices required to permit change of cultivars without contamination problems are discussed. Keywords Trijblium repens L., buried seed, offal trail, direct drill, conventional cultivation, burial depth

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Current issues of white clover (Trifolium repens L.) breeding, seed production and import substitution programs in Russia

Кормопроизводство ◽

10.25685/krm.2019.2019.49898 ◽

2019 ◽

Author(s):

В. Золотарев ◽

Н. Переправо

Keyword(s):

Seed Production ◽

White Clover ◽

Trifolium Repens ◽

Import Substitution ◽

Temperate Climate ◽

Biological Traits ◽

Forage Production ◽

State Register ◽

Trifolium Repens L ◽

Clover Seed

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.

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Trends in the global marketing of white clover cultivars

NZGA: Research and Practice Series ◽

10.33584/rps.6.1995.3374 ◽

1996 ◽

Vol 6 ◽

pp. 7-14

Author(s):

R.D.J. Mather ◽

D.T. Melhuish ◽

M. Herlihy

Keyword(s):

New Zealand ◽

South America ◽

White Clover ◽

Trifolium Repens ◽

Western Europe ◽

Leaf Size ◽

Global Market ◽

Production Region ◽

Trifolium Repens L ◽

Clover Seed

White clover (Trifolium repens L.) is the dominant legume of temperate pastures, having been improved by breeding since the 1930s. The 1994 OECD Register lists 93 cultivars, with a further 25-30 cultivars also known to commerce. Therefore, in excess of 100 cultivars are available to fulfil a world annual market of 8500-10,500 MT. Globally, New Zealand is the major white clover production region, providing 50- 55% of the seed. Other key production regions are Denmark, USA and South America. Consumption of white clover has been relatively static for some time, ranging from 8000-10,000 MT per annum. Between 55-60% of the seed is used in the northern hemisphere (approx. 40% by Western Europe - UK, France, Germany). USA, South America and New Zealand all consume similar tonnages annually (approx. 1000-2000 MT each) with smaller tonnages used in Australia. One cultivar, Grasslands Huia, has dominated the world white clover seed market for many years and it still remains the world's major cultivar by volume. However, in the last 10 years its position has come under increasing pressure from New Zealand and international proprietary cultivars. Eventually proprietary cultivars with improved agronomic performance will supersede the consumption of commodity/public white clovers in those countries where national listing is required to obtain release and recommended listing is need to ensure successful marketing. Despite this, Grasslands Huia will continue for many years to play a major role in supplying markets where national listing is not a prerequisite to release and price is a major factor in purchase decisions. Keywords: commodity cultivar, global market, Grasslands Huia, leaf size, market share, production trends, proprietary cultivar, seed industry, Trifolium repens L., white clover

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Relationship between Sitona lepidus larval numbers and white clover seed production

New Zealand Plant Protection ◽

10.30843/nzpp.2001.54.3755 ◽

2001 ◽

Vol 54 ◽

pp. 141-146

Author(s):

P.J. Gerard

Keyword(s):

Seed Production ◽

White Clover ◽

Trifolium Repens ◽

Negative Impact ◽

Early Flowering ◽

Sitona Lepidus ◽

Clover Root ◽

Second Year ◽

Clover Seed ◽

Seed Crops

Plots of two cultivars of white clover (Trifolium repens) Grasslands Prestige (smallleaved early flowering) and Grasslands Kopu (largeleaved later flowering) were established in coldframe beds Clover root weevil (Sitona lepidus) larval numbers were manipulated to obtain winter larval densities ranging from 0 to over 1000/m2 Increasing winter larval densities increased Prestige seed production (g/m2) when harvested on 28 December and 10 January and the trend was still evident on 24 January No such relationships were found in Kopu for the early and middle harvests but at the late harvest increasing winter larval densities had a negative impact on seed production The results indicate that the effect of clover root weevil larvae on second year clover seed crops may vary substantially between cultivars and may even be positive rather than negative

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STUDY AND ESTIMATION OF COLLECTION VARIETY-SAMPLES WHITE CLOVER

Adaptive Fodder Production ◽

10.33814/afp-2222-5366-2020-1-15-22 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 15-22

Author(s):

Alina Shmatkova

Keyword(s):

White Clover ◽

Trifolium Repens ◽

Seed Productivity ◽

Natural Conditions ◽

State Register ◽

Chemical Indicators ◽

Hard Seeds ◽

High Feed ◽

Trifolium Repens L ◽

Germinating Seeds

New collection varieties of creeping clover (Trifolium repens L.) from the VIR collection of the 1970s were studied. Samples were evaluated according to the main morphological and biological characteristics, seed productivity and chemical indicators. After 50 years of storage under natural conditions, the samples had up to 71% of germinating seeds (31% of germinated + 40% of hard seeds). As a result of the study of collection variety samples, valuable sources for selection were identified, which allowed the best genotypes to be included in hybridization for the construction of hybrids with high feed and seed productivity. It is noted that in the State register of selection achievements, varieties of clover creeping foreign breeding make up 67%.

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Genetic control of white clover seed yield potential

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.2004.66.2567 ◽

2004 ◽

pp. 111-117 ◽

Cited By ~ 3

Author(s):

D.R. Woodfield ◽

I.J. Baird ◽

P.T.P. Clifford

Keyword(s):

Genetic Control ◽

Seed Yield ◽

White Clover ◽

Trifolium Repens ◽

Yield Potential ◽

Commercial Viability ◽

Keywords Genetics ◽

Trifolium Repens L ◽

Selection For ◽

Clover Seed

Improving the seed yield potential of new white clover (Trifolium repens L.) cultivars is critical to their commercial viability and to overcoming the increasing pressures from land use change in Canterbury. The genetic control and response to selection was investigated for two seed yield characteristics, inflorescence density (no./m2) and seed yield per inflorescence (g/ inflorescence). Inflorescence density and seed yield per inflorescence were both responsive to selection and acted independent of one another to increase seed yield. Selection for high inflorescence density resulted in 34% higher seed yield than the low inflorescence density selection. This change in seed yield was associated with a 33% higher inflorescence density, while seed yield per inflorescence was unchanged. Similarly, selection for seed yield per inflorescence resulted in a 17% difference in seed yield between the high (HYI) and low (LYI) seed yield per inflorescence selections. This change in seed yield was associated with a 24% higher yield per inflorescence for the HYI selection, while inflorescence density remained unchanged. These results confirm that both mechanisms are under independent genetic control and can be utilized to increase seed yield of new white clover cultivars. Keywords: genetics, inflorescence density, seed production, Trifolium repens, white clover

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CONTAMINATION OF WHITE CLOVER SEED CROPS BY BURIED SEEDS

NZGA: Research and Practice Series ◽

10.33584/rps.2.1985.3303 ◽

1985 ◽

Vol 2 ◽

pp. 61-65

Author(s):

J. A. Lancashire ◽

M.P. Ralston ◽

D.J. Scott

Keyword(s):

New Zealand ◽

White Clover ◽

Picric Acid ◽

Morphological Characteristics ◽

Leaf Size ◽

Genetic Contamination ◽

Buried Seed ◽

Growth Scores ◽

Clover Seed ◽

Seed Crops

Thirty five certified seed lines of 'Grasslands Pitau' white clover produced under OECD rules showed marked variations in growth and morphological characteristics according to their region of origin. Of lines grown in Oamaru district, South Canterbury, 90% were significantly different from a Pitau breeders (pre-basic) line in winter growth scores, leaf size and picric acid scores. 90% of lines grown in Marlborough were similar to a Pitau breeders line. Buried white clover seed counts were 260/m' (2 kg/ha) in Marlborough and 1060/m (7.5 kg/ha) in Oamaru. Plants grown from buried seed collected in Canterbury generally had smaller leaves, less winter growth and lower picric acid scores than Pitau. The additional possibility that natural selection of genotypes occurred because some crops of Pitau have been grown under climates and/or managements to which it is not adapted, is also discussed. Preliminary studies of 43 commercial lines of 15 cultivars from 4 countries grown outside New Zealand indicated that 3540% showed significant differences in winter growth and leaf size between lines of the same cultivar. New Zealand grown commercial lines of Huia obtained overseas showed good uniformity. It appears that there is a world-wide problem of genetic contamination in white clover cultivars. High buried seed loads are a potential long term source of contamination which is being exaggerated by the increasing numbers of cultivars. New Zealand has already moved to implement tighter certification standards than those recommended by OECD. Keywords: Trifolium repens, 'Grasslands Pitau', buried seed, seed certification, OECD, genetic contamination.

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