scholarly journals Effect of Different Nitrogen Levels on Current Rate of Photosynthesis and Dry Matter Remobilization inTwo Cultivars of Rapeseed (Brassica napus L.)

2015 ◽  
Vol 5 (17) ◽  
pp. 97-109
Author(s):  
P. Tousi ◽  
A. Atabaki ◽  
A. R. Pirzad ◽  
◽  
◽  
...  
2014 ◽  
Vol 94 (8) ◽  
pp. 1461-1469 ◽  
Author(s):  
Yun Ren ◽  
Jianfang Zhu ◽  
Nazim Hussain ◽  
Shanlin Ma ◽  
Genru Ye ◽  
...  

Ren, Y., Zhu, J., Hussain, N., Ma, S., Ye, G., Zhang, D. and Hua, S. 2014. Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.). Can. J. Plant Sci. 94: 1461–1469. Seedling quality is an essential indicator for seed yield in canola, which is affected by many factors, including seedling age. Two field experiments were conducted to compare canola seedling quality and seed yield on 30-, 35-, 40-, 45-, 50-, 55-, and 60-d-old seedlings in 2011 and 2012. The relationship between seedling quality traits and seed yield of different seedling ages was also analyzed. Results revealed that the highest seed yield obtained from 40-d-old seedlings was attributed to more branches and siliques per plant. The negative effect of young seedlings (30-d-old) on seed yield was greater than that of old seedlings (60-d-old). The reduction rates in seed yield on the 30- and 60-d-old seedlings were 25.7 and 18.2%, respectively, compared with the 40-d-old seedlings. Increased root neck diameter, green leaf number, shoot, and root dry matter was the case on 40-d-old seedling transplanted plants compared with other ages. However, the increase was larger in the old seedlings than in the young seedlings. On average, the shoot and root dry weights of the 30-d-old seedlings were 1.9 and 1.7% of those in the 60-d-old seedlings. However, correlation analysis revealed that the seedlings with the highest shoot and root dry matter did not necessarily obtain the highest seed yield. Factor analysis suggested that the effects of root neck diameter and green leaf number on seed yield were more pronounced than those of shoot and root dry matter. Therefore, high seed yield in canola could be defined in terms of optimum green leaf numbers and branches per plant.


2008 ◽  
Vol 59 (6) ◽  
pp. 578 ◽  
Author(s):  
J. L. Jacobs ◽  
G. N. Ward ◽  
Gavin Kearney

In southern Australia, the majority of dry land dairy farms use a 2-pond system to treat and contain dairy effluent collected at the milking platform. This effluent contains a range of nutrients that have the potential to affect forage dry matter (DM) yields, nutritive characteristics, and mineral content of forages. The effect of applying second-pond dairy effluent to the summer-active forages chicory (Chichorium intybus L. cv. Grouse), Hunter (Brassica campestris L. × Brassica napus L.), Winfred (Brassica napus L.), and Sweet Jumbo (Sorghum bicolor (L.) Moench × Sorghum sudanese (Piper) Stapf.) over two summer periods was measured. Effluent was applied at rates of 0, 40, 80, and 100 mm with application split into two equal application times. The first occurred 6–10 weeks after sowing and the second immediately after the first grazing. Forages were assessed for DM yield, nutritive characteristics, and mineral content over the two growth periods in each year. Analysis of effluent showed that on average over the 2 years, the effluent contained 146, 34, 439, and 18 kg/ML of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S), respectively. Furthermore, the effluent also contained 161 kg/ML of calcium (Ca) and 222 kg/ML of magnesium (Mg). For the total growth period in Year 1, all crops showed a linear increase (P < 0.05) in DM yield to applied effluent, with response values varying for each crop. Responses were 49, 52, 29, and 51 kg DM/ha.mm applied effluent for chicory, Hunter, Sweet Jumbo, and Winfred, respectively. For Year 2, all crops also showed a linear increase (P < 0.05) in DM yield (15 kg DM/ha.mm applied effluent) with applied effluent. In Year 1, crude protein (CP) content of all crops increased (P < 0.05) in a linear manner at rates of 0.073 and 0.047% per mm applied effluent for growth periods 1 and 2. There were also linear responses (P < 0.05) in Year 2, with responses varying for each crop for each growth period. For chicory there was no effect of effluent application on CP content in either growth period, while other crops generally exhibited a linear increase with responses of up to 0.08% per mm applied effluent. The greatest changes in mineral content of herbage were those of K, Ca, and Mg. There was a linear increase (P < 0.05) in K content for all growth periods in Years 1 and 2. Magnesium content of chicory (periods 1 and 2) and Winfred (period 2) showed a linear decrease (P < 0.05) in response to effluent application in Year 1, whereas there was no effect in Year 2 for any crops. The results from this study highlight the potential of second-pond dairy effluent to increase DM yields of a range of summer-active forage crops. The data also suggest that while effluent can improve DM yields when soil moisture is limiting, when additional moisture as rainfall occurs, responses from effluent are even more pronounced. In addition, the CP content of forages can be improved when effluent is applied. The combination of increased DM yield with higher CP content provides greater flexibility in dairy cattle feeding options through the dry summer period.


2013 ◽  
Vol 64 (2) ◽  
pp. 115 ◽  
Author(s):  
A. N. Papantoniou ◽  
J. T. Tsialtas ◽  
D. K. Papakosta

For crops grown in Mediterranean environments, translocation of pre-anthesis assimilates to the fruit is of great importance, because hot and dry conditions during fruit ripening diminish net assimilation rate and nitrogen (N) uptake. This field study was conducted to assess the pattern of dry matter and N accumulation and the role of assimilate translocation in pod development of oilseed rape plants in a Mediterranean environment. Four cultivars of winter oilseed rape (Brassica napus L.), i.e. three hybrids (Royal, Exact, Excalibur) and an inbred line (Fortis), were grown for two growing seasons (2005–06 and 2006–07) in northern Greece. On average, 581, 1247, 1609, and 2749 growing degree-days (GDD) were required for six leaves, stem elongation, 50% anthesis in main stem, and physiological maturity in the first year, and 539, 1085, 1601, and 2728 GDD in the second year. The R2 of the modified Richards function indicated that aboveground biomass and N accumulation were described with high approximation efficacy. The across-cultivars genotype mean maximum predicted total aboveground dry matter and N content were 1368.8 and 21.4 g m–2 in 2006 and 1655.1 and 25.4 g m–2 in 2007. In 2007, dry matter and N translocation from vegetative tissues to pods were 464.4 and 21.0 g m–2, and significantly higher than the corresponding values recorded in 2006 (264.4 and 17.0 g m–2). These differences were due to greater amounts of dry matter and N accumulating at anthesis and the greater sink capacity of plants (pod number) in 2007. The fact that pod development occurred in a period when N accumulation by oilseed rape plants had stopped led to high values of contribution of pre-anthesis N accumulation to pod N content in both years (92.8% in 2006 and 96.6% in 2007). Results indicated that hot and dry weather post anthesis reduced dramatically the net assimilation rates; thus, translocation of pre-anthesis assimilates was crucial for pod development. The results demonstrate that variation in weather conditions between growing seasons is one of the main causes of seasonal variation in oilseed rape productivity under Mediterranean conditions.


Author(s):  
Necda Çankaya ◽  
Ulviye Kumova

This research was carried out in 2011 and 2012 in order to determine the flowering phenology, number of flowers, nectar and pollen potential in the Samsun province of the oilseed rape (Brassica napus L.), which is widely used in agriculture in our country. In the first year of the study (2011), it was determined that the rapeseed plant was in flower for 44 days, there were 2.694 flowers per plant, 1.89 kg/da nectar per day and 1330 kg/da pollen production. In the second year of the research (2012), it was revealed that the rapeseed plant was in flower for 39 days, there were 701 plants/flower in the plant, 0.38 kg/da nectar secreted daily and 331.57 kg/da pollen. According to the results of two years, the yield of rapeseed was found to be 41.5 days, the daily nectar production was 0.23 mg/flower/day, the nectar dry matter level was 20.25% and the pollen production was 0.48 mg/flower/day. In Samsun province, it was determined that rapeseed plants flowered before the flowering of many plants in the vicinity in the early spring, and provided honey bees, Apis mellifera L., and many other honey bees, nectar and pollen. It has been demonstrated that the cultivation of rapeseed is cultivated in the early spring, and it can be a convenient source of food for honey bees and other dusty insects.


1992 ◽  
Vol 43 (3) ◽  
pp. 623
Author(s):  
N Thurling ◽  
R Kaveeta

Agronomic characteristics of two groups of early flowering Brassica napus lines and their respective parents were compared at East Beverley in the Western Australian wheatbelt. These lines had been derived through two generations of backcrossing and subsequent selfing from crosses of the B. napus cultivar Wesbrook (recurrent parent) with an early flowering B. napus line RU2 and an even earlier flowering B. campestris population Chinoli C42. Lines selected for this experiment had flowered earliest in a previous controlled environment experiment. Only RU2 and one WesbrookxRU2 line (IB72) had significantly higher yields than Wesbrook (149% and 166% respectively), and one Wesbrookxchinoli C42 line was the only line to have a significantly lower yield than Wesbrook. None of the lines had significantly higher yields than their respective non-recurrent parents. Although RU2 and IB72 flowered much earlier than Wesbrook, there was no significant relationship between flowering time and seed yield over all lines. Lines which were the earliest to commence stem elongation tended to have higher seed yields. However, of all the growth and development characters measured, the biological yield and the dry weight increment between commencement of flowering and maturity were most closely related to seed yield. RU2 and IB72 accumulated far more dry matter over the post-anthesis period than Wesbrook and all other lines except another WesbrookxRU2 line. The superior post-anthesis growth of RU2 and IB72 may simply be a manifestation of the longer period available for growth under more favourable environmental conditions or deeper roots extracting more water from a greater depth. However, since there was no relationship between flowering time and the post-anthesis dry matter increment, it seems more likely that IB72 has received genes for superior post-anthesis growth as well as those determining early flowering from RU2. Given the rapid decline in soil moisture availability during post-anthesis development in this environment, these genes may affect post-anthesis growth through determining a greater capacity for drought avoidance. The implications of these results are discussed with particular reference to the breeding of higher yielding B. napus cultivars for lower rainfall environments.


1979 ◽  
Vol 59 (3) ◽  
pp. 819-830 ◽  
Author(s):  
W. DIEPENBROCK ◽  
G. GEISLER

Plants of rape (Brassica napus L. ’Erglu’) were grown under controlled greenhouse conditions. The growth and composition of pods (hulls) and seeds was followed from the day when flowering took place to maturity. Pod development could be divided into three stages. In the first stage hull growth was more rapid than seed growth. Nitrogen accumulation in hulls occurred at a maximum and seeds were characterized by a high protein content but a low oil content and a fatty acid composition similar to that of photosynthetic tissue. During the second phase dry matter of hulls began to decrease, nitrogen was exported and the rates of seed dry matter accumulation grew to a maximum. At the same time the protein content of seeds declined while oil content increased rapidly. The fatty acid composition had reached the final condition. In the third stage hulls continued to lose dry matter and the rates of seed dry matter accumulation decreased dramatically. Pod growth was affected by the location of the pod on the plant. The individual seed weight and the fatty acid compvsition at 16 days after flowering indicated an accelerated development of seeds from axillary branches. Pods from the main branch generally produced the largest amount of seed dry matter. From these results the ideal high-yielding rape plant was characterized.


Sign in / Sign up

Export Citation Format

Share Document