Some effects of leaf posture on the yield and water economy of winter wheat

Abstract

Selections for erect-(E) and lax-leaf (L) posture in winter wheat were made from a cross between parents which contrasted in the character. By the F b generation there were consistent, heritable differences between E and L lines. The lines were evaluated in three field experiments and a glasshouse experiment.In an experiment in which plots were automatically sheltered from rain and in which there were three irrigation treatments, there was no treatment-posture interaction, and over all treatments E lines outyielded L lines by 0-26 t/ha. When fully irrigated the water use of both E and L lines between 1 May and maturity was approximately 280 mm. Withholding water caused a reduction in water use and a corresponding reduction in grain yield for both E and L lines.When the four most erect-and the four most lax-leaved lines were considered over all three field experiments, E lines maintained a slight, though not significant, grain yield advantage of 0-17 t/ha over L lines. However, the E lines produced significantly more biomass, averaging 0-7 t/ha more than L lines, and this extra biomass was not produced at the expense of additional water requirement. However, results from the glasshouse experiment suggested that the E lines may be more susceptible to a substantial pre-anthesis drought.It is concluded that varieties of winter wheat with the erect-leaf habit may provide an opportunity of increasing biomass production. In an environment in which a preanthesis drought is unlikely to occur, such varieties may give the highest yields. However, on light soils prone to early drought or at sites which would not permit the maximum expression of leaf area index at anthesis, varieties with a lax-leaf posture may give greater yield. Tanner et al. 1966;Hadfield, 1968;Pendleton et al. i g 6 8 j A n g u S ) J o n e g & W i l s o n ( 197 2) also found The photosynthesis of crops is affected by the that leaf posture was a factor contributing to the distribution of radiation over the leaves in the higher photosynthetic rate of an erect-leaved canopy, and leaf posture is a factor affecting the compared with a lax-leaved cultivar, although the interception of incident radiation and the yield of the lax-leaved cultivar was higher, uniformity with which it is distributed within the probably because of the low values of LAI achieved canopy. The models of Monteith (1965) and de Wit by both canopies and also the inherently higher (1965) predict that crops with erect leaves will yielding potential of the lax-leaved cultivar. have higher photosynthetic rates than those withIn winter wheat (Triticum aestivum L.), LAI lax leaves when leaf area index (LAI) is greater reaches a maximum about 2 weeks before anthesis than 3-4, while at lower LAI the situation will be and then declines to zero during the following reversed. Thus the conditions required for the 8-10 weeks (Watson, Thome & French, 1963), with expression of the advantage of erect leaves may the maximum LAI attained in the United Kingdom occur for only short periods in the life of the ...

Changes in physiological attributes of the dry matter economy of bread wheat (Triticum aestivum) through genetic improvement of grain yield potential at different regions of the world

“…This would be associated with different patterns of radiation distribution within the canopy (Rasmusson, 1987;Aikman, 1989;Green, 1989). Innes & Blackwell (1983) found that wheat crops with erect upper leaves produced a greater grain yield, and similar results have been reported regarding other cereals, e.g. barley (Angus et al, 1972) and rice (Chang & Tagumpay, 1970).…”

Effects of Reduction in Plant Height Induced by Chlormequat on Radiation Interception and Radiation-Use Efficiency in Wheat in Southwest Japan

“…5). In spite of the Si in chlormequat was not significantly different from that of the control, a higher MTA in chlormequat should provide effective distribution of radiation within the canopy, which should increase a photosynthetic performance (Angus et al, 1972;Innes and Blackwell, 1983;Green et al, 1985). Even if that was the case, however, the effect of higher MTA in chlormequat on photosynthetic performance should be restricted to the duration from about the heading time to the premature ripening stage (Fig.…”

Genetics Options for Improving the Productivity of Wheat in Water‐Limited and Temperature‐Stressed Environments

“…Leaf glaucousness (Richards et al 1986), rolling (Ayeneh et al 2002), pubescence, and erect habit (Innes and Blackwell 1983) can reduce radiation load on the leaf surface, thus reducing transpiration. These traits show a largely facultative response to drought and therefore would not be associated with reduced radiation-use efficiency under favorable conditions (Reynolds et al 2007b).…”