scholarly journals Studies on Matter Production of Rape Plant (Brassica napus L.) : I. Changes with growth in rates of photosynthesis and respiration of rape plant population

1974 ◽  
Vol 43 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Shinobu INANAGA ◽  
Atsuhiko KUMURA
2012 ◽  
Vol 63 (1) ◽  
pp. 17 ◽  
Author(s):  
Penny Riffkin ◽  
Trent Potter ◽  
Gavin Kearney

Area and production of canola (Brassica napus L.) in the High Rainfall Zone (HRZ) of southern Australia has increased significantly over the past decade. Varieties available to growers have not been bred specifically for the HRZ and are generally adapted to the drier regions of the cropping belt. Field experiments were conducted at Hamilton in south-west Victoria in 2005, 2006 and 2008 to identify canola traits and management suited to the HRZ of southern Australia. Nine varieties with different reported maturities (winter and spring types) were sown at either two times of sowing and/or under different nitrogen (N) fertiliser regimes. Dates of key phenological development were recorded, dry matter was determined at bud, flowering and maturity and grain yield and yield components were determined at harvest. Plant traits and climate data were assessed in relation to grain yield. Yields of the winter types were either significantly (P < 0.05) greater or not significantly less than the spring types in all 3 years and similar to those reported under experimental conditions in Europe. This was despite the winter types flowering up to 35 days later than the spring types and spring rainfall being approximately half that of the long-term average. In general, the winter types had greater early vigour, greater dry matter production at the bud, flowering and maturity stages and were taller than the spring types. Regression analysis showed positive relationships between grain yield and pod density and plant size (dry matter and plant height). Plant size was influenced by variety, time of sowing and N fertiliser application rates. Crops in the HRZ were able to sustain more seeds per pod at larger canopy sizes and pod densities than those achieved in the northern hemisphere. Despite the number of pods per g of dry matter at flowering being nearly double that reported in the UK, there was little apparent reduction in the number of seeds per pod. It is possible that higher solar radiation and warmer minimum temperatures in the HRZ of Australia provide conditions more favourable for growth before, and during grainfill. This indicates that different dry matter production and yield component targets may be appropriate for canola in this environment especially in more typical seasons. It is likely that growers will need to sow new, later maturing varieties earlier and with higher rates of N fertiliser than is current practice in Australia. This study indicates that winter types may have the potential to provide improvements to the yield of canola in the HRZ either through the direct importation of varieties from overseas or through the identification and incorporation of desired traits into existing material. It is recommended that a wider range of germplasm be assessed over a greater geographical area to identify traits and management practices to optimise phenology and canopy structure. This information can be used to help inform breeders on crop improvement priorities as well providing tailored management practices to maximise grain yields for this environment.


1978 ◽  
Vol 58 (3) ◽  
pp. 587-595 ◽  
Author(s):  
J. M. CLARKE ◽  
G. M. SIMPSON

Growth analysis of field-grown rape (Brassica napus L.) was carried out during 1975 and 1976 at Saskatoon. Plant morphology was altered by the use of four planting densities under three water regimes. High seeding rates and non-irrigated conditions caused a greater proportion of dry matter production to occur before flowering than after flowering, while the reverse occurred at low seeding rates and under irrigated conditions. Leaf area index reached a maximum near the start of flowering, and then declined rapidly. Pod surface area was increased by irrigation and was higher at the high seeding rates than at the low seeding rates. Maximum leaf area index was correlated with seed yield. Correlations between pod area and seed yield were poor, particularly in 1976. The growth functions mean net assimilation rate [Formula: see text] and mean crop growth rate [Formula: see text] were influenced by both seeding rates and irrigation. There was an increase in [Formula: see text] during the ripening phase, suggesting increased photosynthetic efficiency. No evidence of a distinct optimum leaf area index was found.


1987 ◽  
Vol 67 (1) ◽  
pp. 43-51 ◽  
Author(s):  
D. I. McGREGOR

The ability of rapeseed crops (Brassica campestris L. ’Torch’ and B. napus L. ’Tower’) to recover from, and compensate for, loss of plants at the early vegetative stage of development was investigated by hand thinning plant populations established at commercial seeding rates with commercial seeding equipment. Plant density was reduced from 100-200 plants m−2 to 40 plants m−2 with less than a 20% loss in seed yield. Seeds per pod and seed weight in some instances increased with reduced plant density. However, compensation was attributed predominantly to an increased number of pods on the remaining plants, which increased from 20-90 to as many as 600. Branching increased from as few as 3 to, in some instances, almost 40. With reduced plant population there was a tendency for increased and prolonged accumulation of dry matter by the plants following flowering.Key words: Brassica campestris L., Brassica napus L., rapeseed, development, seed yield, hail.


2019 ◽  
Vol 51 (6) ◽  
Author(s):  
Samrin Gul ◽  
Razi Uddin ◽  
Naqib Ullah Khan ◽  
Shahid Ullah Khan ◽  
Sardar Ali ◽  
...  

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