Nectar quality in open-pollinated, <i>pol</i> CMS hybrid, and dominant SI hybrid oilseed summer rape

Pernal, Stephen F.; Currie, R. William

doi:10.4141/p97-071

Cited by 18 publications

(12 citation statements)

References 27 publications

(40 reference statements)

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“…Nectar was then allowed to accumulate in these flowers for 24 h, prior to being sampled to measure 24-h secretion rate. To control for potential diel patterns of nectar production within flowers (Pernal & Currie, 1998), all plants that were flowering within a block were sampled during a defined, 1-h period (Table S1). As plants started flowering on different days, nectar samples were collected over multiple days (Table S2).…”

Section: Nectar Collection and Analysismentioning

confidence: 99%

“…Oilseed rape breeding programmes have conserved the function of nectar production in varieties (Pernal & Currie, 1998;Pierre et al, 1999), but little is known about the production of nectar in the three breeding systems. There is limited evidence that Ogura cytoplasm used in CMS hybrids may result in less developed nectaries with associated lowered nectar production (Pelletier et al, 1987;Mesquida et al, 1991), but Pierre et al (1999) found no differences between the nectar volumes and sugar concentrations between three Ogura CMS hybrids and three OP varieties.…”

Section: Introductionmentioning

confidence: 99%

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Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems

et al. 2017

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Oilseed rape (OSR; Brassica napus L.) is a major crop in temperate regions and provides an important source of nutrition to many of the yield‐enhancing insect flower visitors that consume floral nectar. The manipulation of mechanisms that control various crop plant traits for the benefit of pollinators has been suggested in the bid to increase food security, but little is known about inherent floral trait expression in contemporary OSR varieties or the breeding systems used in OSR breeding programmes. We studied a range of floral traits in glasshouse‐grown, certified conventional varieties of winter OSR to test for variation among and within breeding systems. We measured 24‐h nectar secretion rate, amount, concentration and ratio of nectar sugars per flower, and sizes and number of flowers produced per plant from 24 varieties of OSR representing open‐pollinated (OP), genic male sterility (GMS) hybrid and cytoplasmic male sterility (CMS) hybrid breeding systems. Sugar concentration was consistent among and within the breeding systems; however, GMS hybrids produced more nectar and more sugar per flower than CMS hybrid or OP varieties. With the exception of ratio of fructose/glucose in OP varieties, we found that nectar traits were consistent within all the breeding systems. When scaled, GMS hybrids produced 1.73 times more nectar resource per plant than OP varieties. Nectar production and amount of nectar sugar in OSR plants were independent of number and size of flowers. Our data show that floral traits of glasshouse‐grown OSR differed among breeding systems, suggesting that manipulation and enhancement of nectar rewards for insect flower visitors, including pollinators, could be included in future OSR breeding programmes.

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Section: Nectar Collection and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems

et al. 2017

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“…In our study of annual caraway (var. There is indirect evidence from indeterminate-flowering, non-apiaceaen species (Andrejeff, 1932;Fahn, 1949;Pernal and Currie, 1998) to support the hypothesis that nectar sugar yields in later flowers are reduced by sparser resources. Under these conditions, seed set in this self-compatible species was low (Ͻ10%), in accordance with a previous study (0-12%;Németh, Bernáth, and Petheô, 1999), and it would be interesting to determine whether or not maternal resources are adequate (Stephenson, 1981) to allow higher umbel orders to produce as much nectar when lower orders had previously been pollinated and commenced seed filling.…”

Section: Floral Nectar Yields Among Umbel Orders and Individual Plants-mentioning

confidence: 99%

“…Under these conditions, seed set in this self-compatible species was low (Ͻ10%), in accordance with a previous study (0-12%;Németh, Bernáth, and Petheô, 1999), and it would be interesting to determine whether or not maternal resources are adequate (Stephenson, 1981) to allow higher umbel orders to produce as much nectar when lower orders had previously been pollinated and commenced seed filling. There is indirect evidence from indeterminate-flowering, non-apiaceaen species (Andrejeff, 1932;Fahn, 1949;Pernal and Currie, 1998) to support the hypothesis that nectar sugar yields in later flowers are reduced by sparser resources. Similarly, a relationship between low seed set and surplus of photosynthate in nectar had been postulated for Daucus carota (Erickson, Peterson, and Werner, 1979).…”

Section: Floral Nectar Yields Among Umbel Orders and Individual Plants-mentioning

confidence: 99%

Temporal changes in floral nectar production, reabsorption, and composition associated with dichogamy in annual caraway (Carum carvi; Apiaceae)

Langenberger

Davis

2002

American J of Botany

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The dynamics of nectar production were studied in perfect florets of two varieties (Karzo, Moran) of annual caraway (Carum carvi L., Apiaceae). Florets were protandrous and strongly dichogamous, lasting 7-15 d but producing nectar from the stylopodia for 4-12 d, in an interrupted fashion. Nectar secretion began during a floret's phase of stamen elongation and anther dehiscence. After reabsorption of uncollected nectar, at which point nectary surfaces were completely dry, the two styles elongated and a second bout of secretion commenced during the female phase, up to 5 d later, when a floret became receptive to pollination. During the male and female phases, respectively, 0.392 ± 0.064 μL and 1.083 ± 0.261 μL of nectar of similar solute concentration (844 mg/mL) was produced per ten florets. On a daily basis, florets yielded 1.5-fold more nectar in the female than during the male phase. First-time nectar removal throughout the female phase did not match the sum of nectar quantities from male and female phases combined, suggesting that under natural conditions, any uncollected male-phase nectar, once reabsorbed, is not made available to visitors of the same florets when in the female phase. Nectar-sugar composition differed between bouts of secretion; it was hexose-rich (59.6% fructose, 26.9% glucose, 13.6% sucrose) initially, but hexose-dominant (70.2, 26.8, 3.1) during the female phase. A 5.7-fold difference in mean nectar production per floret occurred among plants.

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“…Bumble bees may not be ideal pollinators for hybrid oilseed rape production because they often restrict their foraging to the collection of nectar only (Pyke 1982 and references therein). Although Oguru male-sterile hybrid oilseed rape flowers may have greatly decreased levels of nectar compared with pollen parent flowers (Mesquida and Renard 1979a,b;Pierre et al 1999), recent research found the production and quality of nectar sugar in Polima oilseed rape hybrids to be similar to those of open-pollinated varieties (Pernal and Currie 1997). Our yield data from 1994 (Table 6) and the fact that the bumble bee colonies increased over the summer indicate that R-lines were well visited by bumble bees.…”

Section: Discussionmentioning

confidence: 99%

Alfalfa leafcutting bee (Hymenoptera: Megachilidae) pollination of oilseed rape (Brassica napus L.) under isolation tents for hybrid seed production

Soroka¹,

Goerzen²,

Falk³

et al. 2001

Can. J. Plant Sci.

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. 2001. Alfalfa leafcutting bee (Hymenoptera: Megachilidae) pollination of oilseed rape (Brassica napus L.) under isolation tents for hybrid seed production. Can. J. Plant. . In this 3-yr field study, the activities of alfalfa leafcutting bees (Megachile rotundata Fabricius) (LCB) at varying stocking levels were monitored in shade cloth isolation tents containing male-sterile and male-fertile rows of oilseed rape Brassica napus L. to determine optimum conditions for hybrid seed production. Bumble bees, Bombus impatiens Cresson, were similarly tested in 1 yr; their pollination activities were minimal, and weight of seed produced on female lines in tents containing bumble bees was similar to that in tents without pollinators. Leafcutting bee activity, as measured by the number of female bees at the entrance to tunnels in the hive, at first increased, then decreased with increasing stocking rate. Duration of time spent visiting flowers did not vary with stocking rate, but was longer on male-fertile than on male-sterile flowers. Production of hybrid seed within tents varied with leafcutting bee stocking rate, with the highest seed yield achieved at stocking rates equivalent to three charges at weekly intervals of 400 000 leafcutting bees per hectare. At optimum LCB stocking rates, the method described provided sufficient seed quantity for small-plot multi-location field evaluation of oilseed rape hybrids. L'objet des travaux était d'établir les conditions optimales pour la production de semences hybrides. Les bourdons (Bombus impatiens Cresson) étaient essayés dans une année suivant la même technique. L'activité pollinisatrice des ces derniers était néglige-able, de sorte que le poids de graines produites sur les lignées femelles dans les tentes contenant cette espèce d'insecte était semblable à celui obtenu dans les tentes sans pollinisateurs. Mesurée par le nombre d'abeilles femelles vues à la sortie des galeries de la ruche, l'activité des mégachiles commençait par augmenter puis diminuait à mesure que les populations étaient plus denses. La densité n'avait pas d'effet sur le temps passé à butiner, lequel, par ailleurs était plus long sur les fleurs fertiles que sur les fleurs androstériles. La production de graines hybrides dans les tentes variait selon la densité de colonisation des mégachiles, le rendement le plus élevé étant réalisé à des densités équivalant à 3 lâchérs à intervalle d'une semaine de 400 000 mégachiles par hectare. Aux densités optimales, la méthode permettait de recueillir assez de graines pour l'évaluation des hybrides de colza en essais multilocaux en petites parcelles.

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Nectar quality in open-pollinated, pol CMS hybrid, and dominant SI hybrid oilseed summer rape

Cited by 18 publications

References 27 publications

Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems

Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems

Temporal changes in floral nectar production, reabsorption, and composition associated with dichogamy in annual caraway (Carum carvi; Apiaceae)

Alfalfa leafcutting bee (Hymenoptera: Megachilidae) pollination of oilseed rape (Brassica napus L.) under isolation tents for hybrid seed production

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