Effects of seed size and seed weight on seedling establishment, vigour and tolerance of Argentine canola (Brassica napus) to flea beetles, Phyllotreta spp.

Abstract

. W. 2008. Effects of seed size and seed weight on seedling establishment, vigour and tolerance of Argentine canola (Brassica napus) to flea beetles, Phyllotreta spp. Can. J. Plant Sci. 88: 207Á217. 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: Chrysomelidae). 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 (1.4Á1.6, 1.6Á1.8, 1.8Á2.0 and 2.0Á2.2 mm diameter, respectively). Under controlled environmental conditions, leaf area, shoot weight and biomass of seedlings from large and very large seeds were 1.3Á2.0 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, 1.6Á2.0, 3.0Á3.5 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. . En milieu controˆle´, la superficie foliaire, le poids des pousses et la biomasse des plantules issues des grosses et tre`s grosses graines sont de 1,3 a`2,0 fois plus importants que ceux des plantules venant de petites semences. Au champ, sans application d'insecticide, les plantules issues des petites graines de chaque cultivar e´taient les plus abıˆme´es par l'altise, s'implantaient le plus difficilement et donnaient les pousses au poids, a`la biomasse et au rendement les plus faibles. Comparativement aux petites semences, les grosses graines ame´liorent l'e´tablissement des plantules, le poids des pousses, la biomasse et le rendement de 1,1, 1,6 a`2,0, 3,0 a`3,5 et 1,5 fois, respectivement. Les re´sultats indiquent que les plantules ne´es des grosses semences sont plus vigoureuses et tole`rent mieux les dommages des altises que celles issues de graines de petit ou de moyen calibre. La vigueur et la tole´rance des plantules sont attribuables a`une plus grande biomasse de la pousse au de´part et a`un taux de croissance plus rapide quand les altises causent le plus de dommages. Lorsque les dommages de´passent 50%, les grosses semences permettent l'e´tablissement du meilleur peuplement, la plus forte croissance des pousses et le rendement le plus e´leve´, peu importe le cultivar.

Insect invasions of agroecosystems in the western Canadian prairies: case histories, patterns, and implications for ecosystem function

“…A noteworthy recent development is the availability of wheat germplasm resistant to wheat midge, which promises to drastically reduce insecticide applications (Lamb et al 2002;Smith et al 2004). In the case of flea beetles, attempts to achieve host plant resistance and classical biological control have been unsuccessful, but several cultural practices have been developed that can be implemented in an integrated manner to substantially reduce insecticide use in some ecoregions (Dosdall et al 1999;Dosdall and Stevenson 2005;Elliott et al 2008). An early management success for controlling infestations of the wheat stem sawfly occurred in the 1940s with the development of solid-stemmed wheat (Platt and Farstad 1949), but additional complementary strategies including cultural and biological methods have since been developed that can be integrated with host plant resistance (Luginbill and McNeal 1958;Morrill et al 2001;Meers 2005;Weaver et al 2005).…”

Efecto del tiempo de almacenamiento sobre la calidad de semilla de canola

“…La variedad Monty mostró un peso más bajo en la semilla cosechada y almacenada desde 2007, pero con muy poca diferencia a la cosechada en 2012 (Cuadro 3). Las características del tamaño y peso de la semilla de canola son importantes, ya que lotes de semilla grande, en comparación con semilla mediana y chica de los mismos genotipos, mejoraron el establecimiento de plántulas, el peso de la parte área de la planta, la biomasa total y el rendimiento, así como la tolerancia a los escarabajos del género Phyllotreta (González, 1981;Elliott et al, 2008).…”

“…Resultados similares en cuanto al peso, rendimiento y componentes del híbrido Hyola 401 fueron reportados por Ortegón (2003); y Ortegón et al (2006) en un estudio de fechas de siembra con un grupo de variedades e híbridos en el Norte de Tamaulipas. Asimismo, el tamaño y peso de la semilla de canola fueron características importantes por Elliott et al (2008).…”

“…The Monty variety showed a lower weight in seeds harvested and stored since 2007, but with very little difference to that harvested in 2012 (Table 3). The characteristics of size and weight of canola seeds have been noted as important, as large seed lots, compared to medium and small seeds of the same genotypes, improved planting of seedlings, weight of the area part of the plant, total biomass and yield as well as tolerance to beetles of Phyllotreta genus (González, 1981;Elliott et al, 2008).…”

“…Similar results in weight, and even performance and components of the hybrid Hyola 401 were reported by Ortegón (2003); Ortegón et al (2006) in a study of dates of sowing conducted with a group of varieties and hybrids in the North of Tamaulipas. Also, the size and weight of canola seed were identified as important characteristics by Elliott et al (2008).…”