Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.)

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.

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.


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.


2001 ◽  
Vol 81 (1) ◽  
pp. 1-6 ◽  
Author(s):  
G. Chongo ◽  
P. B. E. McVetty

The physiological basis of seed yield in oilseed rape (Brassica napus L.) still remains unclear, and conclusions on the contribution of such traits to seed yield are difficult to make. Nine cultivars, classified into three yield groups (high, medium and low) based on significant differences in seed yield from previous trials, were tested over two locations and years. Leaf chlorophyll content, net photosynthetic rate per unit leaf area (PA), per unit leaf dry matter (PDM) and per unit leaf chlorophyll (PC), transpiration rate (TR) and water use efficiency (WUE) were investigated on fully expanded leaf numbers 4 (vegetative), 6 (early flowering) and 8 (early podding stage) on the main stem and related to seed yield, total dry matter (TDM) and harvest index (HI) of each yield group. Differences among yield groups for seed yield, TDM and HI were significant. Chlorophyll content was lowest on leaf 4, but increased with leaf age. Correlations between net photosynthetic rate and seed yield were not found. However, cultivars in the high yield group maximized their net photosynthetic rates (PA, PDM, and PC) on leaf 6 during early flowering at the time when TR was lowest and WUE at its highest. In the medium and low groups, photosynthetic rates were highest on leaf 4, but decreased to lowest values on leaf 8, together with the high yield group. In general, the results indicate that the largest contribution to net photosynthesis by oilseed rape leaves occurred during the vegetative and early flowering stages compared with the early pod-filling stage. Key words: Total dry matter, harvest index, photosynthesis, chlorophyll


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.


2021 ◽  
Vol 66 (1) ◽  
pp. 17-25
Author(s):  
Valiollah Rameeh ◽  
Maryam Niakan ◽  
Mohammad Mohammadi

The effects of four sulphur levels: S0, S1, S2 and S3, including 0, 12, 24 and 36 kg S ha-1, respectively, along with 115 kg N ha-1 were studied on yield-related traits of oilseed rape (Brassica napus L.). The significant variance of treatments was determined for plant height, yield component characters, seed yield and oil content. The sulphur application significantly increased most of the traits compared to the S0 level. The S3 (36 kg S ha-1) treatment led to the highest mean value of plant height (132 cm) which was classified with S2 (24 kg S ha-1) in the same statistical group. Sulphur had an increasing effect on pods per plant, and it ranged from 92 to 196 for S0 and S3 applications, respectively. S0 and S1 with 92 and 121 pods per plant were grouped in the same statistical group. In addition, S2, and S3 with 165 and 196 pods per plant showed no significant statistical difference. The sulphur application significantly increased seed yield compared to control (S0 level), and it ranged from 2744 to 3215 kg ha-1 in S0 and S3, respectively. The average oil contents of 45.69, 46.96, 47.46 and 49.53 % were detected for 0, 12, 24 and 36 kg S ha-1, respectively.


2012 ◽  
Vol 92 (1) ◽  
pp. 97-107
Author(s):  
Juliana J. Soroka ◽  
Larry F. Grenkow

Soroka, J. J. and L. F. Grenkow. 2012. When is fall feeding by flea beetles ( Phyllotreta spp., Coleoptera: Chrysomelidae) on canola ( Brassica napus L.) a problem? Can. J. Plant Sci. 92: 97–107. Two cultivars of Brassica napus canola were seeded in mid-May and early June in three field experiments in each of 3 yr near Saskatoon, Saskatchewan, to determine the effects of late-season flea beetle feeding on seed yields. In the first experiment, canola was sprayed with insecticide late in the summer to eliminate naturally-infesting flea beetles. In the second, 1×1×1.5 m screen cages were placed over early- and late-seeded canola at flowering and infested with flea beetles as canola matured. In the third investigation, sleeve cages were placed over individual plants and infested with 100 flea beetles. Flea beetles had no detrimental effects on early-seeded canola in any experiment, but did affect seed yields of late-seeded plots in some trials. Over two cultivars in 1 year, late-seeded plants in cube cages infested with about 350 flea beetles per plant when lower pods were turning from translucent to green in colour reduced yield by 241 kg ha−1 over control yields. Seed weights in these late-seeded plots were decreased from 2.68 g per 1000 seeds in uninfested cages to 2.44 g per 1000 seeds in infested cages. Populations of 100 flea beetles per plant in sleeve cages had no effect on harvest parameters in any seeding date or year.


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