Dependence of Yields of Wheat Varieties on their Leaf Area Durations

Welbank, P. J.; French, Sue; Witts, K. J.

doi:10.1093/oxfordjournals.aob.a084075

Cited by 59 publications

(33 citation statements)

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“…In general, early flowering, relative to the environment, may be indicated as a means of gaining a maximum number of florets per unit of dry matter at flowering and a lengthened period of grain filling. And similarly the finding by WELBANK et al (1966) that leaf area duration (area of green leaf integrated with time) above the flag leaf node after anthesis is related to grain yield, suggests the desirability of strong persistence of the uppermost photosynthetic tissue. (May it be however that the persistence of these green surfaces is in part an effect rather than a cause of high yield?…”

Section: A Wheat Ideotypementioning

confidence: 70%

The breeding of crop ideotypes

1968

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Most plant breeding is based on "defect elimination" or "selection for yield". A valuable additional approach is available through the breeding of crop ideotypes, plants with model characteristics known to influence photosynthesis, growth and (in cereals) grain production. Some instances of the successful use of model characters of this kind are quoted.It is postulated that a successful crop ideotype will be a weak competitor, relative to its mass. Thus the like plants in the crop community will compete with each other to a minimum degree. This relationship of plant form to the exploitation of the enviroment may lead to two negative relationships among genotypes, namely : (a) Between the performance of cultivars at low density and at high density respectively, and (b) Between the competitive ability of cultivars against other genotypes on the one hand, and their capacity for yield in pure culture on the other.A crop ideotype will make a minimum demand on resources per unit of dry matter produced. Further, in cereals, each unit of dry matter will include such a number of florets as to ensure that the ear has sufficient capacity to accept all photosynthates either from its own green surfaces or from other parts of the plant. These criteria are to be satisfied especially at high fertility, and when the total pressure by the community on environmental resources is intensified by high density of population.A wheat ideotype is described. It has a short, strong stem; few, small, erect leaves; a large ear (this specifically means many florets per unit of dry matter of the tops); an erect ear; awns; and a single culm.The design of crop ideotypes is likely to involve concurrent modifications of the environment. The wheat ideotype here described will call for consideration of the density of planting, the fertilizer rate, the plant arrangement and weed control.Eventually most plant breeding may be based on ideotypes.

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Section: A Wheat Ideotypementioning

confidence: 70%

The breeding of crop ideotypes

1968

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“…This view would appear to be supported by numerous observations (Welbank, French, and Witts 1966;Bingham 1967;Lupton 1968;Simpson 1968) that the yield of grain is related to the area of photosynthetic tissues supplying carbohydrate to the grain, and the length of time during which these tissues are capable of fixing carbon dioxide. These findings imply that the production of sucrose by photosynthesis controls in turn the level of sucrose in the endosperm, and the rate of deposition of starch.…”

Section: Introductionmentioning

confidence: 86%

Relationship Between Levels of Soluble Carbohydrate and Starch Synthesis in Detached Ears of Wheat

Jenner¹

1970

Aust. Jnl. Of Bio. Sci.

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SummaryDetached ears of wheat were cultured on solutions of sugars. 'A highly significant correlation was observed between the concentration of sucrose in the endosperm and the rate of starch synthesis. Fluctuations in the level of sucrose in the endosperm were accomp!1nied by parallel changes in the rate of starch synthesis. It is suggested that the concentration of sucrose in the endosperm regulates the rate of starch synthesis.A linear relationship held over a wide range in concentration between the external level of sucrose and the amounts of sucrose in the floral organs and rachis. However, in the endosperm the relationship was curvilinear and the maximum level of sucrose recorded at high external concentrations was very much lower than the concentration in the rachis.These findings are discussed in relation to the regulation of starch synthesis in cereal grain.

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“…Among grain crops, the sourcesink relationships have been studied more extensively in wheat and barley (Tollenaar, 1977). Some authors have reported that grain yield was limited by the sink capacity (Bingham, 1967;Evans and Rawson, 1970); others have concluded that yield was limited by the source (Welbank et al, 1966;Simpson, 1968), whereas Fischer (1975) and Stoy (1976) (Yamaguchi, 1974;Goldsworthy and Coleogrove, 1974).…”

mentioning

confidence: 99%