An analysis of leaf growth in sugar beet.

Abstract

SUMMARY The increase of leaf area index (L) was examined in a series of sugar‐beet crops grown on different sites (Broom's Barn, Suffolk and Trefloyne, Dyfed) or with different husbandry treatments (sowing dates and nitrogen rates) between 1978 and 1982. The development of L could be described as a function of thermal time using three parameters; DE, which was essentially an estimate of the thermal time required for crop establishment, and rHL and DL, the thermal rate and duration, respectively, of the increase of L. Variations in DE between seasons and with sowing date were small, but significant; they were attributed to factors affecting the condition of the seedbed. There were much larger variations in rHL, especially between seasons, sites and crops given different rates of nitrogen fertiliser, and there was a strong negative relationship between rHL and DL. Much of the variation in rHL was associated with differences in the concentrations of nitrogen in the lamina dry matter. Faster rates for rHL at Trefloyne than at Broom's Barn, and in the crop grown in 1982 as compared with other years, were also partly attributable to particularly warm conditions during the early development of some of the larger, faster‐growing leaves within the canopy. The wider application of the relationships established from these experiments was tested with data from a series of crops grown on other sites between 1960 and 1962. The relationships held particularly well for beet grown on soils with high water‐holding capacity but not for those on soils of low water‐holding capacity.

Carbohydrate remobilization from storage root to leaves after a stress release in sugar beet (Beta vulgaris L.): experimental and modelling approaches

“…In the field trials, leaf regrowth was observed after drought stress was relieved. This ability of sugar beet has already been described by Owen & Watson (1956) and Milford et al (1985). The primary explanation is of a botanical nature: the sugar beet crop is cultivated during its vegetative phase only, i.e.…”

“…no ontogenic signal prevents leaves from growing during this period (Perata et al 2004). Milford et al (1985) showed, on a series of distinct sugar-beet crops grown during five consecutive seasons, that a linear relationship could be fitted between leaf number and thermal time until 2000°C after sowing, with no plateau, suggesting that it could increase at the same rate for longer. This result was confirmed in the present work by the last measurements made in December in the Avignon trial, illustrating sugar beet's ability to produce new leaves throughout its life.…”

“…Owen & Watson (1956) reported that small amounts of rainfall after prolonged drought caused rapid leaf growth in sugar beet and that these plants temporarily grew faster than irrigated ones that had never been submitted to severe water stress. Milford et al (1985) showed that rainfall was able to slow leaf senescence of rainfed sugar beet crops, unlike irrigated crops. Perata et al (2004) demonstrated by means of a field experiment coupled with a molecular probe that young sugar beet leaves behaved like sink tissues, whereas the root system acted as a source organ.…”

Effect of Sugar Beet Genotype, Planting and Harvesting Dates and Their Interaction on Sugar Yield

“…The number of days (DNo) was calculated from planting to harvest date. Thermal time (growing degree-days, GDD) was calculated by summing the daily values of mean temperatures minus the threshold value of 3°C (Milford et al, 1985), from the planting to the harvest date. Weather conditions in the years 2016 and 2017 differed especially in the precipitation, average temperatures and insolation (Table 4, Supplementary Table 1).…”

Impact of Climatic Variables on Carbon Content in Sugar Beet Root

“…Previous works by Milford et al [51] suggested that ca. 750 • C·d is necessary for beet to form a closed canopy, while Malnou, Jaggard and Sparkes [42] reported that 900 • C·d and 100 kg N·ha −1 were required for the crop to reach 85% canopy.…”