Two experiments carried out in 1968 and 1969 are described which examined, through growth and yield analysis, the effect of nitrogen on the growth of oilseed rape. The results of the second experiment, when 0, 105-5 and 211-0 kg N/ha were compared, are presented and discussed. The application of nitrogen increased the yields of seed and oil, principally through increased production of seeds by a larger number of pods. However, the application of nitrogen had little effect on average pod weight or average seed weight. Crop growth rates were increased by the application of nitrogen and reached their highest levels during the period of pod development when the leaf areas had declined to very low levels. The order of effects of nitrogen (N 2 > Nl > NO) was similar for LAI, number of pods per plant and number of seeds per pod and it is likely that the effect of nitrogen was achieved indirectly through an increase in the supply of assimilates to the flowers and young pods. This suggests that the maintenance of a large and photosynthetically efficient leaf area during the period of flowering is necessary for high yields in this crop.The results also suggest that once pods are macroscopic they produce much of the assimilates needed for their own growth.The implications of these findings with regard to both practice and further research are discussed.There is renewed interest in the oilseed rape affected by the treatments and to assess the relative crop in Great Britain resulting from its use as a importance of any effects on the yield of the econo-'break' crop in intensive cereal systems. Bunting mic product. (1969) has reviewed the published information on As pointed out in the preliminary report of this oilseed rape but much of it is derived from surveys, work (Allen, Morgan & Ridgman, 1971), there have old experiments or experiments carried out in been very few intensive field studies of the effect of Scandinavia and Canada, where the crop is grown genotype and agronomic treatment on the growth extensively under climatic conditions different from and yield of seed crops, other than cereals, those in Great Britain. Thus, there is very limited Information from this type of analysis is of imexperimental evidence on the performance of the portance to the agronomist in manipulating crop in this country. In view of this dearth of in-the crop's environment to best advantage and formation a series of experiments was begun in to the plant breeder in providing physiological Cambridge in 1968 to examine the effect of nitrogen, selection criteria, variety and row width on the growth and development of the crop. The preliminary experiment in 1968 and a more detailed study in 1969 are consi-T H E EXPERIMENTS dered here. The experimental approach followedThe experiments were carried out in 1968 and was both analytical and physiological, so that in 1969 on soils of the Milton series derived from old addition to studying effects on the ultimate yield r i v e r gravel and well supplied with phosphate and of oil, an attempt was made to...
The growth and development of single plants of oil seed rape, variety Zollerngold, are described quantitatively and particular attention paid to the sequence and pattern of flower and pod production on the different inflorescences. The period of flower opening over the whole plant spanned an average of 26 days and more than 75 % of the pods which were retained to maturity were formed from flowers which opened within 14 days of anthesis. Most of these flowers were found on the terminal raceme and on the basal and middle regions of the axillary inflorescences arising from the uppermost three nodes.
Experiments were carried out on oil-seed rape, variety Zollerngold, to determine the effects on flower and pod development when (1) the supply of carbon assimilates was reduced by shading or leaf removal at different stages of development or (2) the supply of assimilates to the more apically positioned flowers or pods on the terminal raceme was increased by removing 15 of the most basal flowers or pods.A decrease in the production of carbon assimilates led to fewer flowers and pods developing to maturity and when the stress continued over most of the period of pod development the pods were smaller and had fewer seeds which were also lighter in weight.Removal of the 15 basal flowers or pods led to more of the apically positioned flowers developing into mature pods and the other pods becoming heavier with bigger husks, heavier seeds and sometimes a greater number of seeds.The results of a shading experiment in a controlled environment cabinet suggest that stresses in the supply of carbon assimilates around the time of anthesis are particularly harmful since in addition to reducing the number of pods which develop they appear to restrict the capacity for compensatory growth in the pods that remain when the supply returns to normal.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.