Effects of seed size and seed weight on seedling establishment, seedling vigour and tolerance of summer turnip rape (Brassica rapa) to flea beetles, Phyllotreta spp.

2007 ◽  
Vol 87 (2) ◽  
pp. 385-393 ◽  
Author(s):  
R. H. Elliott ◽  
L. W. Mann ◽  
O. O. Olfert

A 3-yr study was conducted on three synthetic Brassica rapa L. cultivars to determine the effects of seed size and seed weight on seedling establishment, seedling growth and susceptibility to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysomelidae). Seed lots of AC Boreal, Fairview and Hysyn 110 were sieved to obtain small, medium and large seeds (1.4–1.6, 1.6–1.8 and 1.8–2.0 mm, respectively). In the laboratory, seedlings grown from large seeds had the largest cotyledons, highest shoot dry weight and highest biomass. Shoot weights increased as seed size increased. Sized seeds of the three cultivars were grown in the field without insecticides in 1998–2000. Seedlings of small seeds had the highest flea beetle damage and poorest seedling establishment. Shoot dry weight and biomass 14–35 d after planting increased as seed size and seed weight increased. Compared with small seeds, large seeds improved shoot dry weight, biomass and seed yield by 13–43, 25–57 and 12%, respectively. Results indicated that seedlings of medium and large seeds are more vigorous and tolerant to flea beetle damage than seedlings of small seeds. Tolerance was due to a higher initial seedling weight rather than higher relative growth rate. Shoot dry weights, biomass and yield of the three cultivars were more strongly correlated with 1000-seed weight than with seed diameter. Key words: Canola, flea beetles, seed size, seedling vigour, tolerance, seed weight

2008 ◽  
Vol 88 (1) ◽  
pp. 207-217 ◽  
Author(s):  
R. H. Elliott ◽  
C. Franke ◽  
G. F. W. Rakow

A 3-yr study was conducted on four Brassica napus L. cultivars to determine the effects of seed size and seed weight on the performance and tolerance of canola seedlings to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysom elidae). Seed lots of a doubled haploid cultivar Cyclone, hybrid cultivar AC H102 and two open-pollinated cultivars Profit and AC Elect were sieved to obtain small, medium, large and very large seeds (1.4–1.6, 1.6–1.8, 1.8–2.0 and 2.0–2.2 mm diameter, respectively). Under controlled environmental conditions, leaf area, shoot weight and biomass of seedlings from large and very large seeds were 1.3–2.0 times greater than those of seedlings from small seeds. Under field conditions without insecticides, seedlings from small seeds of each cultivar had the highest flea beetle damage, poorest establishment, and lowest shoot weight, biomass and yield. Compared with small seeds, large seeds improved seedling establishment, shoot weight, biomass and yield by 1.1, 1.6–2.0, 3.0–3.5 and 1.5 times, respectively. Results indicated that seedlings from large seeds are more vigorous and tolerant to flea beetle damage than seedlings from medium or small seeds. Seedling vigour and tolerance was due to a higher initial shoot biomass and higher growth rate when flea beetle damage was severe. When damage exceeded 50%, large heavy seeds had the best stand establishment, best shoot growth and highest yield in each cultivar. Key words: Canola, flea beetles, seed size, seed weight, seedling vigour, tolerance


1993 ◽  
Vol 125 (4) ◽  
pp. 703-713 ◽  
Author(s):  
R.J. Lamb ◽  
P. Palaniswamy ◽  
K.A. Pivnick ◽  
M.A.H. Smith

AbstractFive cycles of single-plant and progeny-row selection in lines derived from Brassica rapa L. "Tobin" were used to identify plants with incomplete resistance to flea beetles, Phyllotreta cruciferae (Goeze). This line, called C8711, had higher survival, grew larger, and yielded more seed than Tobin when the two lines were compared in field plots at Glenlea, Manitoba, unprotected by insecticide. C8711 without insecticide yielded more seed than Tobin treated with a lindane seed dressing, but less than Tobin treated with carbofuran granules. With carbofuran, which prevents most flea beetle damage, the yield of C8711 was 35% higher than for Tobin. At Saskatoon, Saskatchewan, the differences between C8711 and Tobin were not statistically significant, although the trends were similar to those at Glenlea. C8711 was late maturing, produced small seed, and was not of canola quality. The resistance in C8711 is attributed to a low level of antixenosis, rapid growth at the cotyledon stage, and tolerance to damage during the first 3–4 weeks of growth.


2004 ◽  
Vol 44 (1) ◽  
pp. 57 ◽  
Author(s):  
L. J. Latham ◽  
R. A. C. Jones ◽  
B. A. Coutts

Field experiments provided quantitative information on the yield losses caused by virus infection within 4 different combinations of non-persistently aphid-transmitted virus and cool-season crop legume: Alfalfa mosaic virus (AMV) in chickpea, faba bean and lentil, and Cucumber mosaic virus (CMV) in lentil. Virus infection foci were introduced into plots and naturally occurring aphids spread infection from these to the other plants. Plants were tagged individually when typical virus symptoms first appeared during the growing period. Paired plant comparisons between symptomatic and asymptomatic plants were made to measure different yield loss parameters. Late infection with AMV in faba bean cv. Fiord diminished shoot dry weight by 41% and seed yield by 45%, but plants infected earlier recovered sufficiently from their initial shock reaction not to produce significant yield losses. In plants of lentil cv. Matilda first showing symptoms at different times, infection with AMV decreased shoot dry weight by 74–76%, seed yield by 81–87% and individual seed weight by 10–21%, while CMV diminished shoot dry weight by 72–81%, seed yield by 80–90% and individual seed yield by 17–25%. Early infection with AMV killed plants of chickpea cv. Tyson while later infection decreased shoot dry weight by 50%, seed yield by 98% and individual seed weight by 90%. The first tentative evidence for seed transmission of AMV in faba bean is reported with a transmission rate of 0.04%.


Author(s):  
Ogbuehi HC ◽  
Ibe PK

A pot experiment was conducted under rainfed condition to study the effect of water hyacinth compost on the morpho-physiological parameters of soybean (Glycine max L.) at the Teaching and Research Farm of Faculty of Agriculture and Veterinary Medicine, Imo State University, Owerri. The treatments were control (T1) 100g (T2), 150g (T3) and 200g (T4) of water hyacinth compost and replicated four times. The treatments were arranged in Complete Randomized Design (CRD). The parameters measured were plant height, number of leaves, leaf area (cm2), leaf area index, relative growth rate (RGR), Net assimilation rate (NAR), shoot dry weight(g), yield and yield components (Number of pods, pods weight, 100 seed weight). The results obtained indicated that T3 significantly produced highest plant height (57.6cm) compare to control. While it was observed that T4 (200g) significantly produced the highest number of leaves (233.25), leaf area (631.80cm2), shoot dry weight (15.445g), number of pods (129.75), pod weights (25.38g) seed weight (7.23g) and yield (0.72kg/ha) relative to control and other treatment levels. Root parameters were also significantly improved by the rates of water hyacinth application compared to control. It will be worthy to note that there was no nodulation perhaps that was why the yield was poor. The results showed that soybean growth can effectively be improved with incorporation of water hyacinth into soil.


1996 ◽  
Vol 23 (2) ◽  
pp. 129-133
Author(s):  
P. E. Igbokwe ◽  
N. V. K. Nkongolo

Abstract This study was conducted on a Memphis silt loam at Alcorn State University in 1992 and 1993 and investigated row-intercropping as a low-input alternative to the conventional cropping system for peanut (Arachis hypogaea L.) production in southwestern Mississippi. Extractable P and exchangeable cations were significantly (P ≤ 0.05) higher for vetiver-peanut row-intercropping in 1992. Extractable S and P were significantly (P ≤ 0.05) higher for vetiver-peanut row-intercropping and conventional peanut monocropping, respectively, in 1993. Plant height, shoot dry weight, the number of yellow nutsedge (Cyperus esculentus L.) per row, insect lesions per leaflet, and rodent diggings per row were significantly (P ≤ 0.05) higher for conventional peanut monocropping than when peanut was intercropped with vetiver grass [Vetiveria zizanioides (L.) Nash]. Peanut pod number, pod weight, seed number, and seed weight also were higher for conventional peanut monocropping. The seed mineral composition generally was not affected by cropping system and plant spacing. Peanut yield was higher for 15.2 cm within-row plant spacing compared to 10.2- and 20.3-cm spacings investigated in this study. Interaction between cropping system and plant spacing was significant for pod number, pod weight, seed number, seed weight, and seed Ca and Fe compositions in 1992, but only significant for seed number, seed weight, and seed Fe and Zn compositions in 1993.


1993 ◽  
Vol 125 (5) ◽  
pp. 903-912 ◽  
Author(s):  
P. Palaniswamy ◽  
R.J. Lamb

AbstractLaboratory experiments were conducted to determine the effect of wounding the cotyledons of Sinapis alba L. cv. Ochre, Brassica napus L. cv. Westar, B. rapa L. cv. Tobin, and C8711, a selection from Tobin, on subsequent feeding damage by the flea beetle, Phyllotreta cruciferae (Goeze). Cotyledons of 7-day-old seedlings were wounded either by puncturing them with needles (mechanical wounding) or by exposing them to flea beetles. One, 2, or 9 days following wounding, the wounded and unwounded seedlings were exposed to flea beetles and the feeding damage was estimated as a measure of antixenosis. Mechanical wounding of one of the cotyledons with 96 needle punctures induced a significant reduction in the damage of the unwounded cotyledons of S. alba, 1 or 2 days following wounding. True leaves of the wounded seedlings also showed consistently less damage than unwounded controls, 9 days following wounding. In S. alba, all three levels of mechanical wounding (i.e. 6, 24, or 96 punctures per cotyledon) reduced subsequent flea beetle damage to a similar extent. Wrapping a cotyledon of S. alba with a plastic film produced an effect similar to wounding it with needles. As with mechanical wounding, flea beetle wounding also reduced subsequent flea beetle damage in S. alba. Other plant species (B. napus and B. rapa) tested showed no measurable induced effects on subsequent feeding damage.


1991 ◽  
Vol 71 (2) ◽  
pp. 397-404 ◽  
Author(s):  
R. P. Bodnaryk ◽  
R. J. Lamb

Seedlings of Brassica napus L. 'Westar' or Sinapis alba L. 'Ochre' grown from seeds of various size were offered to flea beetles, Phyllotreta cruciferae (Goeze) in feeding tests for damage assessment. The proportion of cotyledon area damaged in both species was highest for seedlings grown from small seeds in choice and no-choice feeding tests. The proportion of seedlings killed by flea beetle feeding was also highest in seedlings from small seeds, an effect that was especially pronounced at high beetle densities (10/seedling) where 100% of seedlings from small seeds of B. napus were killed compared to 28.3% of seedlings from big seeds. For S. alba, at 20 beetles/seedling, 45.4% of seedlings from small seeds were killed compared to only 9.1% of seedlings from big seeds. Seedlings grown from big seeds of S. alba tolerated low levels of damage caused by flea beetle feeding or by scissors. No evidence for tolerance was obtained for seedlings from small seeds of S. alba or for seedlings from big or small seeds of B. napus. "Big seeds" appears to be a desirable trait that enhances crucifer seedling resistance to flea beetle attack and results in increased seedling survival. Key words: Brassica napus 'Westar', Sinapis alba 'Ochre', Phyllotreta cruciferae, flea beetle, seed size, resistance


2003 ◽  
Vol 83 (1) ◽  
pp. 69-70 ◽  
Author(s):  
A. Mellish and B. Coulman

This study compared the seed weight, and seedling emergence vigor of four tetraploid crested wheatgrass populations. S9240H, a population selected for seed size, had larger seeds than the cultivars Kirk and CD-II. Heavy seeds had greater emergence and heavier seedlings than light seeds, but there were no differences in these characters among the four populations. Key words: Crested wheatgrass, seed size, seedling vigour


1980 ◽  
Vol 60 (4) ◽  
pp. 1439-1440 ◽  
Author(s):  
R. J. LAMB

Pods of the mustard Brassica hirta ’Gisilba’, which have stiff hairs, showed no significant flea beetle damage, while adjacent rapeseed plots showed heavy pod damage. Removal of hairs from mustard pods caused an increase in feeding damage by the flea beetles. Breeding for pod hairiness in rapeseed may reduce pod damage caused by this pest to an insignificant level.


1988 ◽  
Vol 68 (1) ◽  
pp. 85-93 ◽  
Author(s):  
R. J. LAMB

A 5-yr field study to develop a method for assessing the susceptibility of crucifer seedlings to damage by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) is described. The recommended method consisted of five replicate 5-m rows per cultivar in a randomized complete-block design. Each test was sown three times at weekly intervals, to assure that at least one test received an appropriate level of flea beetle damage. Each test was assessed 4–5 wk after seeding by counting the number of surviving seedlings in each row and by weighing the dried aboveground portion of 10 randomly selected seedlings, although the latter discriminated fewer lines. The damage caused by flea beetles varied spatially, but this source of variation was minor and did not compromise the tests. This method proved adequate for discriminating among crucifer species and agronomically similar cultivars, some of which showed consistent, significant differences in their responses to flea beettle damage.Key words: Crucifer, rapeseed, flea beetle, pest resistance


Sign in / Sign up

Export Citation Format

Share Document