Defoliation and its Effects on Pod and Seed Development in Oil Seed Rape (<i>Brassica napus</i>L.)

Pechan, P. A.; Morgan, D. G.

doi:10.1093/jxb/36.3.458

Cited by 52 publications

(34 citation statements)

References 6 publications

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“…Furthermore, in the absence of significant stand loss, the lack of substantial effect on kernel weight indicates that defoliation mostly reduced grain yield by reducing kernel number per unit area. Likewise, foliage loss during the flowering stage reduced the supply of assimilates to the developing pods resulting in reduced weight of pods and ultimately the yield (Freyman et al 1973;Pechan and Morgan 1984). Our results clearly demonstrate that defoliation in early stages of canola development leads to substantial yield losses.…”

Section: Effect Of Defoliation On Grain Yield Yield Components and Omentioning

confidence: 60%

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Response of canola to simulated diamondback moth (Lepidoptera: Plutellidae) defoliation at different growth stages

Ramachandran¹,

Buntin²,

All³

2000

Can. J. Plant Sci.

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In field trials conducted during 1995–1998, canola cultivar "Falcon" was subjected to different levels of simulated insect defoliation at four stages of crop growth. Plants were 0, 33, 67 and 100% defoliated at rosette and flowering stages during the 1995–1996 season as well as 2–4 leaf stage during the 1996–1997 and 1997–1998 seasons. Plants were 0, 50 and 100% defoliated at pod filling stage during all seasons. Over all seasons, defoliation did not consistently affect the number of plants per unit area, plant height, 1000 seed weight, and oil content of seeds for most of the defoliation treatments. However, defoliation at the 2–4 leaf and rosette stages made plants more susceptible to cold injury. Generally, canola could withstand a higher level of defoliation as crop development progressed. Maximum yield reductions occurred for defoliations at the 2–4 leaf stage followed by the rosette and flowering stages of the crop. No significant yield losses were recorded for defoliations at the pod filling stage. Results suggest that canola is most sensitive to defoliation in its early stages of growth. Greater amounts of defoliation can be tolerated as crop development progresses. The relationships between defoliation and yield loss were used to establish diamondback moth economic injury levels for canola at different crop growth stages. Key words: Canola, Brassica napus, oilseed rape, simulated defoliation, economic injury level

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Section: Effect Of Defoliation On Grain Yield Yield Components and Omentioning

confidence: 60%

“…Previous studies have applied a simulated defoliation technique to assess the relative importance of leaves during flowering and pod development in realizing final grain yield (Clarke 1978;Pechan and Morgan 1984). The importance of leaves to yield declines as the crop matures.…”

mentioning

confidence: 99%

Response of canola to simulated diamondback moth (Lepidoptera: Plutellidae) defoliation at different growth stages

Ramachandran¹,

Buntin²,

All³

2000

Can. J. Plant Sci.

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“…At the initiation of reproductive growth, there is a rapid increase in flowerbearing branches from the shoot apical meristem. The photosynthetic leaf area then quickly declines because of senescence (Pechan and Morgan, 1985), thereby removing one source of assimilate at a time when seeds have a great import demand. At this time, only the oldest seeds at the base of a plant would have begun storage product synthesis.…”

Section: Canberra Act 2601mentioning

confidence: 99%

Carbohydrate Content and Enzyme Metabolism in Developing Canola Siliques

1997

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Canberra, ACT 2601,Little biochemical information is available on carbohydrate metabolism in developing canola (Brassica napus L.) silique (pod) wall and seed tissues. This research examines the carbohydrate contents and sucrose (Suc) metabolic enzyme activities in different aged silique wall and seed tissues during oil filling. l h e silique wall partitioned photosynthate into Suc over starch and predominantly accumulated hexose. l h e silique wall hexose content and soluble acid invertase activity rapidly fel1 as embryos progressed from the early-to late-cotyledon developmental stages. A similar trend was not evident for alkaline invertase, Suc synthase (SuSy), and Suc-phosphate synthase. Silique wall SuSy activities were much higher than source leaves at all times and may serve to supply the substrate for secondary cell wall thickening. In young seeds starch was the predominant accumulated carbohydrate over the sampled developmental range. Seed hexose levels dropped as embryos developed from the early-to midcotyledon stage. Hexose and starch were localized to the testa or liquid endosperm, whereas Suc was evenly distributed among seed components. With the switch to oil accumulation, seed SuSy activity increased by 3.6-fold and soluble acid invertase activity decreased by 76%. These data provide valuable baseline knowledge for the genetic manipulation of canola seed carbon partitioning.The sources of assimilate for developing seeds of canola (Brassica napus L.; Brassica rapa L.) have not been clearly elucidated. During the life of a plant there is a clear sequence of developmental phases that proceed from leaf to stem to silique (pod) to seed (Mendham and Salisbury, 1995). Leaf photosynthesis provides assimilate for the growth of shoot and root meristems. At the initiation of reproductive growth, there is a rapid increase in flowerbearing branches from the shoot apical meristem. The photosynthetic leaf area then quickly declines because of senescence (Pechan and Morgan, 1985), thereby removing one source of assimilate at a time when seeds have a great import demand. At this time, only the oldest seeds at the base of a plant would have begun storage product synthesis. In the absence of leaves, silique wall photosynthesis is the main source of assimilates during this growth phase and may contribute up to 50 to 60% of final plant dry matter (Lewis and Thurling, 1994). Australia (S.P.K.)Like other dicotyledonous plants, canola produces seed storage products in the embryo (Murphy and Cummins, 1989). Early in development, the embryo is very small and the main seed constituents are the testa and liquid endosperm (Fowler and Downey, 1970). During these initial stages embryo cells are rapidly dividing. At the early-to midcotyledon stages (Pomeroy et al., 1991), embryo cells begin to rapidly expand, the resulting growth consumes the liquid endosperm, and the embryo fills the seed's interna1 space (Fowler and Downey, 1970). Coincident with rapid embryo growth, storage oil accumulates and peaks at maximum fresh weight (Ra...

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“…Na literatura, alguns trabalhos mostram que a prática de determinados tratos culturais podem otimizar ou mesmo direcionar o desenvolvimento de uma espécie. Pesquisas de campo mostram que a desfolha induz alterações fisiometabólicas profundas nas relações fonte-dreno, como por exemplo na síntese e distribuição de fotoassimilados (Hanson & West, 1982;Pandey, 1983;Wilkerson et al, 1984;Pechan & Morgan, 1985). A remoção das flores, observada em lentilha (Lens esculenta L.) três semanas após a antese, em ní-veis de 25 a 75% reduziu sensivelmente a produção de sementes, porém, essa redução não foi proporcional ao grau de remoção (Pandey, 1983).…”

Section: Introductionunclassified

Desenvolvimento de feijão-macuco em área de várzea

Melo¹,

Bueno²

2000

Hortic. Bras.

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Development of yam bean or "Feijão-Macuco" plant in a floodplain area.Pachyrrhizus tuberosus, popularly known as yam bean, ("feijão-macuco" or "jacatupé" in portuguese) is one of the tropical food plant species bearing edible tuberous roots. The purpose of this study was to evaluate the plant's growth, correlating the development of the plant parts in the vegetative, flowering, fruiting and tuberous root formation stages, as well as assessing the importance of staking the plants and pruning the inflorescence in the development of the plant and in the yield of tuberous roots. The study was carried out in a Rio Solimões' floodplain area from August 1993 to May 1994, with 1,925 mm of rainfall, 26 o C average temperature and 86.5% relative humidity. The behavior of three genotypes, identified as 1, 2 and 3, which were submitted to four kinds of plant management: with and without staking the plants and with and without pruning the inflorescences. The experimental design was completely randomized blocks in a factorial scheme of 3 x 2 x 2 (genotypes, staking, and inflorescences pruning, respectively) with three replications. Plots measuring 15.5 x 25.0 m were used. The staking treatment increased the plant and stems dry matter weight. Usually there was a steady increase of the above and below ground parts with staking. Growth rates were similar to all genotypes. Staked plants showed a tendency to higher relative growth. The pruning of the inflorescences promoted up to 4.6 fold increase in the tuberous roots weight. In addition to raising the leaves dry matter weight, inflorescence pruning also furthered an increase in the a, b and total chlorophyl grades 160 days after sowing. According to results obtained, it was concluded that staking plants associated with the pruning of the inflorescences improved the development of the "feijão-macuco".

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Defoliation and its Effects on Pod and Seed Development in Oil Seed Rape (Brassica napusL.)

Cited by 52 publications

References 6 publications

Response of canola to simulated diamondback moth (Lepidoptera: Plutellidae) defoliation at different growth stages

Response of canola to simulated diamondback moth (Lepidoptera: Plutellidae) defoliation at different growth stages

Carbohydrate Content and Enzyme Metabolism in Developing Canola Siliques

Desenvolvimento de feijão-macuco em área de várzea

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