YIELD STRUCTURE OF DOUBLE LOW WINTER OILSEED RAPE (BRASSICA NAPUS L.) VARIETIES IN DIFFERENT ENVIRONMENTAL CONDITIONS
Marek Wójtowicz, Franciszek Wielebski, Jan Krzymański
Plant Breeding & Acclimatization Institute, (IHAR) Strzeszyńska 36,
60-479 Poznań, Poland, E-mail: fwiel @ nico.ihar.poznan.pl
KEYWORD: yield, yield components, nitrogen fertilization, moisture conditions, cultivar
Yield of oilseed rape is dependent on cultivar yield potential, climatic conditions, kind of soil and agronomical practices. Genetic, habitat and agronomical factors influence plant growth and development and also morphological character of plants what results in adequate yield level. One of the best yield-forming factors is nitrogen fertilization. Efficiency of a nitrogen dose depends on moisture conditions in period from March to July. Cultivar differentiation in reaction to nitrogen fertilization and moisture conditions makes that factor also very important.
The experiment was designed to examine the influence of spring nitrogen fertilization, various soil moisture and some cultivars of winter oilseed rape on variability of yield and yield components and their effectiveness on the yield. Effectiveness of yield components was a subject of study of many papers (Schrimpf 1954, Stolle 1954, Olsson 1960, Allen and Morgan 1972, Thurling 1974, Muśnicki 1974, 1979, Clark and Simpson 1978 Bechyne 1983, Kandil 1983, Muśnicki and Muśnicka 1986, Mcpherson et al 1987, Vasak et al 1988, Horodyski 1990, Kuchtowa et al 1996). The results induced us to start the experimental work on that subject.
MATERIAL AND METODS
Two experiments were carried out in a glasshouse in pots on loamy soil in six replication. In two experiments nitrogen fertilization was applied in two doses: 0,8 and 2,4 g N per pot. The dose of 2,4 g N per pot was divided in two and applied as follows: half of the dose at the beginning of vegetation in spring and half of the dose at the fullness of budding. The whole dose of 0,8 g N per pot was applied at the beginning of vegetation. In the first experiment eight cultivars of winter oilseed rape (Bolko, Mar, Samourai, Panter, Tapidor, Liporta, Diadem, PN 2000/90) were compared. In the second experiment apart from nitrogen fertilization moisture conditions were taken into consideration. Five water deficiency treatments were applied as follows:
S1 - from the outset of vegetation to the fullness of budding,
S2 - from the fullness of budding to the flowering start,
S3 - from the start to the end of flowering,
S4 - from the end of flowering to maturity,
K - control (plants watered regularly throughout)
As water deficiency the level of 30% of full water capacity of soil was adopted, as compared to the level of 70% of full water capacity of soil in the control treatment.
After harvest the yield of seed per pot was estimated. Number of plants per pot and number of pods per main and lateral branches were measured. Pods were removed to determine the number of seeds per pod and 1000 seed weight. Based on these components, number of pods per area unit and weight of seeds per pod were calculated.
RESULTS
Variability
Yield of seeds was changed the most under the influence of nitrogen fertilization, less under the influence of water deficiency and the least under the influence of cultivar (table 1). In the same degree these factors changed numbers of pods per plant and area unit. Number of seeds per pod were changed the most under the influence of genetic factor, greatly under the influence of water deficiency and little under the influence of nitrogen fertilization. Water deficiency also changed the most weight of 1000 seeds. Weight of seeds per area unit was changed under the influence of genetic factor and water deficiency on the same level and little under the influence of nitrogen fertilization.
Table 1
Variance coefficient of yield and yield components under the influence of experimental factor
|
Experimental factor |
Yield (g/pot) |
Number of pods per area unit |
Weight of seeds per pod (mg) |
Number of pods per plant |
Number of seeds per pod |
Weight of 1000 seeds (g) |
|
Nitrogen fertilization |
32,0 |
33,9 |
4,9 |
33,9 |
0,9 |
4,3 |
|
Water deficiency |
21,4 |
15,6 |
12,0 |
15,6 |
7,3 |
14,6 |
|
Cultivar |
10,3 |
12,0 |
12,3 |
12,0 |
10,9 |
3,6 |
Increase of nitrogen dose from 0,8 to 2,4 g per pot had significant effect on yield and yield components except number of seeds per pod (table 2). The feature most modifiable by nitrogen fertilization was number of pods per plant.
Table 2
|
Dose of nitrogen fertilizer |
Yield (g/pot) |
Number of pods per area unit |
Weight of seeds per pod (mg) |
Number of pods per plant |
Number of seeds per pod |
Weight of 1000 seeds (g) |
|
0,8 |
23,4 |
347 |
74,4 |
69 |
16,0 |
4,65 |
|
2,4 |
37,1 |
566 |
79,7 |
113 |
16,2 |
4,94 |
|
LSD0,05 |
1,26 |
12,1 |
4,34 |
2,4 |
ni |
0,09 |
Also water deficiency did not have significant influence on number of seeds per pod (table 3). The most unfavourable conditions for high yield appeared when water deficiency occurred from the end of flowering to maturity (variant S4). Small number of pods per plant were not compensated by increase of weight of 1000 seeds, unlike when water deficiency occurred on flowering. When water stress reduced number of pods per plant weight of 1000 seeds had decisive effect on yield level.
Table 3
|
Water deficiency treatments |
Yield (g/pot) |
Number of pods per area unit |
Weight of seeds per pod (mg) |
Number of pods per plant |
Number of seeds per pod |
Weight of 1000 seeds (g) |
K |
24,4 |
580 |
71,2 |
116 |
19,8 |
3,58 |
S1 |
23,3 |
580 |
62,0 |
116 |
17,3 |
3,63 |
S2 |
19,7 |
485 |
64,8 |
97 |
17,4 |
3,79 |
S3 |
21,4 |
410 |
75,5 |
82 |
16,3 |
4,63 |
S4 |
13,3 |
444 |
55,3 |
89 |
17,7 |
3,13 |
LSD0,05 |
1,97 |
86,5 |
10,6 |
17,3 |
ni |
0,18 |
On main branch there was 38% and on lateral branches 62% of all pods (table 4). Number of seeds per pod and weight of 1000 seeds were higher in pods from main branch what results in higher weight of seeds in pod also from main branch. Pod position on a plant varied the number of seeds per pod (table 5). The most seeds were in central part of main branch and bottom plant of lateral branches.
Table 4
|
Feature |
Main branch |
Lateral branches |
|
Number of pods per plant |
38,5 |
62,9 |
|
Number of seeds per pod |
17,7 |
15,9 |
|
Weight of 1000 seeds (g) |
5,21 |
4,53 |
|
Weight of seeds per pod (mg) |
92,2 |
72,0 |
Table 5
Effect of pod position on a plant on number of seeds per pod
|
Zone of fructification main branch |
Zone of fructification lateral branches |
|||
|
top |
central |
bottom |
top |
bottom |
|
14,2 |
20,7 |
15,3 |
11,3 |
24,4 |
|
LSD0,05 2,91 |
3,90 |
|||
Table 6
Effect of number of pods per area unit and weight of seeds per pod on yield
dependent on experimental factor
|
Experimental |
n |
Number of pods per area unit |
Weight of seeds per pod (mg) |
||
|
factor |
|
t-value |
R2 |
t-value |
R2 |
|
Nitrogen fertilization |
16 |
14,0 |
70,0 |
7,8 |
14,9 |
|
Water deficiency |
15 |
3,1 |
13,1 |
2,6 |
6,0 |
|
Nitrogen fertilization and water deficiency |
30 |
7,9 |
57,5 |
4,6 |
21,3 |
Table 7a
Effect of yield components on yield dependent on experimental factor
|
Experimental |
|
T-value for |
||
|
factor |
n |
Number of pods per plant |
Number of seeds per pod |
Weight of 1000 seeds (g) |
|
Nitrogen fertilization |
16 |
11,4 |
6,2 |
2,3 |
|
Water deficiency |
15 |
3,9 |
2,3 |
3,7 |
|
Nitrogen fertilization and water deficiency |
30 |
8,6 |
3,8 |
5,7 |
Table 7b
Effect of yield components on yield dependent on experimental factor
|
Experimental |
|
R2change (%) |
||
|
factor |
|
Variable entered into an equation |
||
|
|
n |
Number of pods per plant |
Number of seeds per pod |
Weight of 1000 seeds (g) |
|
Nitrogen fertilization |
16 |
54,8 |
16,0 |
2,3 |
|
Water deficiency |
15 |
48,3 |
16,5 |
44,4 |
|
Nitrogen fertilization and water deficiency |
30 |
46,6 |
9,0 |
20,5 |
1. Yield and number of pods were the most variable under changes of nitrogen fertilization, less under the influence of water deficiency in soil and the least under a cultivar. Water deficiency had almost the some effect on number of pods and weight of 1000 seeds.
2. Number of seeds per pod and weight of 1000 seeds were varied by pod position in fructification. Pods from main branch had more seeds than pods from lateral branches. The most seeds were in central part of main branch and bottom part of lateral branches.
3. Experiment proved the most significant effect of number of pods per plant and number of pods per area unit on yield.
Allen E.J., Morgan D.J. (1972): A quantitative analysis of the effects of nitrogen on the growth, development and yield of oilseed rape. J. agric. Sci., Camb. 78, s. 315-324.
Bechyne M. (1983): Untraditional methods of yield increases in winter and summer rape. Proc. of the 6 th Intern. Rapeseed Congress, Paris, nr 1, s. 801-807.
Clarke J. M., Simpson G. M. (1978): Intra-plant variation in number of seeds per pod and seed weight in Brassica napus cv. Tower. Can. J. Plant. Sci. 58, s. 731-737.
Horodyski A. (1990): Double low oilseed rape. PWRiL Poznań.
Kandil A.A. (1983): Effect of seeding date on yield, yield components and some agronomic characters of oil seed rape (Brassica napus L.). Proc. of the 6 th Intern. Rapeseed Congress, Paris, nr 3, s. 779-784.
Kuchtova P., Baranyk P., Vasak J., Fabry A. (1996): Yield forming factors of oilseed rape. Rośliny Oleiste, t. 17 z. 1, s. 223-234.
McPherson H., Scarth R., Rimmer S.R., McVetty P.B.E. (1987): The Effect of Drought Stress on Yield Determination in Oilseed Rape. Proc. of the 7 th Intern. Rapeseed Congress, Poznań, nr 3, s. 822-827.
Muśnicki Cz. (1974): Investigation on native and foreign winter rape varieties in Poland. Proc. of the 4 th Intern. Rapeseed Congress, Giessen, s. 201-215.
Muśnicki Cz. (1979): Variability and interdependence of some oilseed rape features and their influence on yield. Zesz. Probl. Post. Nauk roln., z. 229, s. 22-25.
Muśnicki Cz., Muśnicka B. (1986): Yield structure of different quality types of winter oilseed rape. Zesz. probl. IHAR “ Rzepak ozimy”, s. 107-122.
Olsson G. (1960): Some relationships between number of seeds per pod, seed size, oil content and the effects of selection for these characters in brassica and sinapis. Hereditas 46, s. 29-70.
Schrimpf D. (1954): Untersuchungen über den Blüten - und Schotenansatz bei Raps, Rübsen und Senf. Zschr. Acker. u, Pfl. bau 97, s.305-336.
Stolle G. (1954): Ein Beitrag zur Ertragszüchtung beim Winterraps. Züchter 24, s. 202-215.
Thurling N. (1974): Morphophysiological Determinates of Yield in Rapeseed (Brassica campestris and Brassica napus). II Yield Components. Aust. J. Agric. Res. 25, s. 711-721.
Vasak J. i in. (1988): System vyroby repky. Vystavnictvi C. Budejovice, MZVz CSR.