Background Transition to flowering at the right time is critical for local adaptation and to maximize grain yield in crops. Canola is an important oilseed crop with extensive variation in flowering time among varieties. However, our understanding of underlying genes and their role in canola productivity is limited. Results We report our analyses of a diverse GWAS panel (300–368 accessions) of canola and identify SNPs that are significantly associated with variation in flowering time and response to photoperiod across multiple locations. We show that several of these associations map in the vicinity of FLOWERING LOCUS T ( FT ) paralogs and its known transcriptional regulators. Complementary QTL and eQTL mapping studies, conducted in an Australian doubled haploid population, also detected consistent genomic regions close to the FT paralogs associated with flowering time and yield-related traits. FT sequences vary between accessions. Expression levels of FT in plants grown in field (or under controlled environment cabinets) correlated with flowering time. We show that markers linked to the FT paralogs display association with variation in multiple traits including flowering time, plant emergence, shoot biomass and grain yield. Conclusions Our findings suggest that FT paralogs not only control flowering time but also modulate yield-related productivity traits in canola. Electronic supplementary material The online version of this article (10.1186/s12864-019-5964-y) contains supplementary material, which is available to authorized users.

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Twenty-two samples of raw hoof and horn materials have been examined in the laborator> with particular reference to their nitrogenous constituents. The samples, which included hoof, horn and mixtures of these two materials, were milled in the laboratory before testing. The nitrogen content of the samples and their ' availability ' in the soil, as shown by incubation for 10 weeks, indicate that hoof and horn materials constitute a reasonably homogeneous class of nitrogenous fertilizer. Considerable differences were, however, found in the initial rates of mineralization of nitrogen from the samples.Highly significant correlations were found between the initial rates of mineralization of nitrogen and the bulk densities and ease of hydrolysis of the samples. Hoof was at first more rapidly decomposed in the soil than horn, though after incubation for 10 weeks there was little difference between the two. Soil tests made with different sieved fractions of hoof and horn showed that the nitrogen of the finest particles was most rapidly mineralized at first, but the coarsest samples ultimately showed the highest ' availability '.Among the properties desirable in a given type of fertilizer reproducibility of effect must be accounted of considerable practical importance. Recommendations for the specific use of one fertilizer in preference to another for a given purpose depend on this quality of reproducibility. The composition of inorganic fertilizers can in general readily be found by chemical analysis, and apart from gross differences in particle size, deterioration in storage or unwise combinations in mixing, there is little reason for variation from sample to sample. With organic fertilizers, however, the possibility of variation in composition is considerably greater, the materials being obtained from varying sources throughout the world and processed in different ways. Organic fertilizers are, in addition, prone to biological decomposition in storage. Very marked differences have already been shown in the nitrogenous constituents of a group of bone materials;' these cannot, however, be regarded as a major source of nitrogen, and further experiments were therefore made with other organic nitrogenous fertilizers. For this purpose 41 commercial samples of hoof and horn were obtained from widely different sources. Originally it had been intended to group these samples under the three headings of hoof, horn, and mixed hoof and horn. Preliminary examination of the materials soon showed, however, that heat treatment by the manufacturers greatly affected the physical properties of the products, variations due to this cause being in many ways more marked than the differences found between hoof as compared with horn. The samples were accordingly separated into two groups, only those samples which had not been subjected to heat treatment during processing being included in the present paper. These raw materials included 7 samples of hoof, 5 samples of horn and 10 of mixed hoof and horn. For the purpose of statistical correlation ...

Ammonia production and subsequent nitrate formation have been followed in several types of glasshouse soils after partial sterilization by steam. If soil is steamed in situ and left undisturbed ammonia production continues for a considerable time and nitrate formation is negligible, despite the fact that the soil is open to any aerial and other fortuitous infections. If the same soil is incubated in bulk after steaming and disturbed periodically by sampling, ammonia concentration falls comparatively quickly and nitrification proceeds rapidly. This method of sampling apparently stimulates nitrification and has the same effect as deliberate contamination of the steamed soil by unsteamed soil. Results are adduced to show that a second or subsequent steaming is not so effective as the first one in stimulating ammonia production. There is some evidence that increase in ammonia production is accompanied by a reduction in the nitrate concentration at the same time.

Where soil in a glasshouse border was left undisturbed after steam‐sterilization, high ammonia concentrations were maintained for a much longer period than where the soil was dug at regular intervals. Depth sampling of undisturbed soil in the house revealed high concentrations of nitrate (and other water‐soluble salts) in the top half‐inch, with decreasing concentrations at increasing depths, and ammonia was uniformly distributed. This nitrate accumulation is largely due apparently to an upward moisture movement concentrating soluble salts near the surface, and is not to be attributed to renewed nitrification in the surface soil as a consequence of aerial contamination by nitrifying organisms. Evidence is presented which suggests that contamination of undisturbed soil in the glasshouse by nitrifying organisms arises mainly from the subsoil and to a lesser extent from chance surface‐infections.

Samples of urea‐formaldehyde materials, prepared by various methods, have been tested in the laboratory with reference to their possible use as nitrogenous fertilizers. In particular the rate and extent of mineralization of the nitrogen of urea‐formaldehyde products in soil has been investigated in relation to the ratio of urea to formaldehyde initially present in the reaction mixture. The product from equal molar quantities of urea and formaldehyde is almost insoluble and inert in the soil, but the proportion of soluble and available nitrogenous constituents in these substances increases markedly with the urea/formaldehyde ratio of the reactants. Soil tests show that urea‐formaldehyde samples can be prepared which closely resemble natural products such as hoof and horn in their rate of decomposition in the soil. The high degree of availability of the nitrogen of these materials expected in view of their low carbon/nitrogen ratios has not, however, been observed in the present work, unless the water‐soluble nitrogen in the products was high. The form of the curves for mineralization of nitrogen in the soil is discussed in relation to the contents of free urea and water‐soluble nitrogenous constituents, and to the conditions of preparation of the samples.

Nineteen samples of ' calcined ' hoof and horn materials have been examined in the laboratory with particular reference to their nitrogenous constituents. All the samples, which included hoof, horn and mixtures of the two materials, were milled in the laboratory before testing.Considerable differences were found in the initial rates of mineralization of the nitrogen of the samples in soil. Highly significant correlations were found between the initial rates .of mineralization of nitrogen and the contents both of water-soluble nitrogen and of ammonia as determined by distillation with magnesia.A rapid test, in which aqueous extracts of the hoof and horn samples were titrated with a standard solution of sodium hydroxide in the presence of formaldehyde, was found to give results approximating to the ammonia values as determined by distillation and highly correlated with the soil-incubation tests. A positive correlation was also found between the initial rates of mineralization of nitrogen and the bulk density of the samples. After incubation for 10 weeks in the soil the percentage mineralization of nitrogen in the samples ranged from 62 to 767; ; no correlation could be found between these values and the other properties of the samples tested.It is concluded that calcined hoof and horn materials constitute a reasonably homogeneous class of nitrogenous fertilizer, except where the preliminary heat treatment was insufficient to destroy the fibrous nature of the horn samples.The nitrogen content of the samples ranged from 12.98 to 15.10%.In Part I the results of laboratory tests made on raw hoof and horn were reported. Such materials are somewhat difficult to grind into forms suitable for use as fertilizers, and require heavy milling equipment for this purpose. Much of the hoof and horn sold for horticultural purposes does, however, receive some form of heat treatment which renders it easier to crush. The actual conditions of this preliminary treatment differ considerably from one manufacturer to another, and little information is available concerning the temperatures and periods of heating of the samples used in the present work. The terms used to describe this preliminary treatment are also diverse. Thus samples 35, 36 and 37 were described as being ' dried ' at 300° F before milling, sample 33 is of ' steamed ' horn and other samples are referred to as ' calcined '. For convenience in the present work the term ' calcined ' will be used to denote all samples that have been subjected to any form of heat treatment during processing. Such materials are almost invariably characterized by their colour, ranging from pale-straw to darkbrown in contrast to the paler colours, frequently grey or white, of the original materials. This visual effect of calcining is accompanied by marked changes in the physical and chemical properties of the materials, as will be seen by comparison of the results here reported with those already given for ' raw ' samples in Part I of the present investigation. All samples were ground before testi...