It is usually thought that adequate winter chill is required for the full flowering of many tempe... more It is usually thought that adequate winter chill is required for the full flowering of many temperate woody species. This paper investigates the sensitivity of blackcurrant bud burst and flowering to natural weather fluctuations in a temperate maritime climate, and compares a range of chill models that have been proposed for assessing the accumulation of winter chill. Bud break for four contrasting cultivars are compared in an exceptionally cold and in a mild winter in Eastern Scotland. The results confirm the importance of chilling at temperatures lower than 0 • C and demonstrate that no single chilling function applies equally to all blackcurrant cultivars. There is a pressing need for further model development to take into account the relationship between chilling temperatures and warming temperatures occurring both during and after the chill accumulation period.
Page 1. 8 Mechanical Harvesting of Berry Crops Adam Dale Horticultural Research Institute of Onta... more Page 1. 8 Mechanical Harvesting of Berry Crops Adam Dale Horticultural Research Institute of Ontario Box 587, Simcoe, ON, N3Y 4N5 Canada Eric J. Hanson Department of Horticulture, Michigan State University East Lansing ...
Gall mite (Cecidophyopsis ribis) is the most serious pest of blackcurrant (Ribes nigrum L.), caus... more Gall mite (Cecidophyopsis ribis) is the most serious pest of blackcurrant (Ribes nigrum L.), causing the damaging condition known as 'big bud' and also transmitting blackcurrant reversion virus (BRV) within and between plantations. The identiWcation of resistant germplasm is at present a time-consuming and expensive process, dependent on Weld infestation plots. Resistance based on gene Ce introgressed from gooseberry has been used in UK breeding programmes for blackcurrant. Using a bulked segregant analysis, 90 AFLP primer combinations were screened and a linkage map constructed around the resistance locus controlled by Ce. Sixteen of the primer combinations produced a fragment in the resistant bulked progeny and the gall mite-resistant parent, but not in the susceptible bulked progeny and parent; subsequent testing on individual progeny identiWed an AFLP fragment closely linked to gall mite resistance. This fragment, designated E41M88-280, was converted to a PCR-based marker based on sequence-speciWc primers, amplifying only in resistant individuals. Validation of this marker across a range of susceptible and resistant blackcurrant germplasm with diVerent genetic backgrounds conWrmed its reliability in the identiWcation of mite-resistant germplasm containing gene Ce. The conversion of an AFLP fragment to a sequencebased PCR marker simpliWes its application and therefore increases its utility for selection of mite-resistant germplasm in high-throughput breeding programmes for blackcurrant.
The drought stress tolerance of two blackcurrant cultivars (Ribes nigrum L., 'Narve Viking' and '... more The drought stress tolerance of two blackcurrant cultivars (Ribes nigrum L., 'Narve Viking' and 'Ben Gairn') during the flowering period and their ability to recover following drought stress were studied by examining the effects of drought stress on growth and various physiological traits. The experiment was conducted under greenhouse conditions, and plants were either fully irrigated (FI), with a volume of water replacing the previous day's evapotranspiration, or non-irrigated (NI) for 12 days. Hereafter irrigation was continued (FI) or resumed (NI) to allow for 17 days of recovery.
The tolerance to water deficit and ability to recover was studied during flower initiation in two... more The tolerance to water deficit and ability to recover was studied during flower initiation in two blackcurrant cultivars (Ribes nigrum L., 'Titania' and 'Ben Hope'). The experiment was conducted under greenhouse conditions, and plants were either fully irrigated (FI), with a volume of water replacing the previous day's evapotranspiration, or deficit irrigated (DI) for 3, 4, 5, 7 or 10 days. Deficit-irrigated plants received a volume of nutrient solution corresponding to 50% of the volume supplied to FI plants. Here after full irrigation was continued (FI) or resumed (DI) to allow for 2 and 10 days of recovery for stomatal conductance and leaf area increment, and 7 and 14 days of recovery for root intensity. Full irrigation was continued until the spring when the numbers of strigs and flowers per node were recorded.
The fatty acid compositions of seeds from 29 black currant genotypes were determined using a rapi... more The fatty acid compositions of seeds from 29 black currant genotypes were determined using a rapid small-scale procedure. There was interest in alpha-linolenic, stearidonic, and, especially, gamma-linolenic acid (GLA) contents, and most samples showed values between 11.1 and 18.7%, between 2.5 and 4.5%, and between 11.6 and 17.4%, respectively. However, six genotypes exhibited gamma-linolenic contents >18%, and values >20% were recorded in four of these genotypes. The fatty acid contents of the six genotypes were also analyzed by using a conventional procedure, and only slight differences in fatty acid composition were found between the two methods. Although GLA content was not strongly correlated with juice parameters, some genotypes had both high GLA contents and desirable juice characteristics. The results obtained provide evidence that it is possible to select for GLA contents without negatively affecting juice quality, and both aspects can be combined in a single cultivar, thereby increasing the added value of the whole fruit.
Putative flavanol-anthocyanin condensation products were detected in a polyphenol-rich concentrat... more Putative flavanol-anthocyanin condensation products were detected in a polyphenol-rich concentrate from black currant (Ribes nigrum L.). These compounds had UV-vis spectra similar to those of delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside, but eluted before all previously described anthocyanins on reversed phase HPLC. Mass spectrometric data indicated that they were rutinoside derivatives of novel aglycons 304 amu greater than delphinidin and cyanidin, respectively. The compounds were partly purified by semipreparative HPLC and gave MS and MS2 spectra consistent with anthocyanin rutinosides covalently linked to epigallocatechin or gallocatechin. These compounds are similar in structure to compounds thought to influence color and quality in red wines and strawberry juice products. There was also evidence for the presence of a range of other flavanol-anthocyanin condensation products. The compounds were present at differing levels in juices of 10 black currant varieties, which were roughly correlated to the content of the parent anthocyanins. The flavanol-anthocyanin products were present in polyphenol-enriched concentrates obtained by solid phase extraction, in commercially produced concentrates, and in fresh extracts of black currants. This suggests that the compounds were not artifacts formed during concentration or purification. However, differences in their comparative contents may be related to the lability of the parent anthocyanins during processing. Although present at low levels, the flavanol-anthocyanin products may influence color or quality parameters of black currant juices, and they may confer enhanced stability to the biological activities reported for their anthocyanin parents.
Background: The detrimental effects of mild winter temperatures on the consistency of cropping of... more Background: The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L.) in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak.
It is usually thought that adequate winter chill is required for the full flowering of many tempe... more It is usually thought that adequate winter chill is required for the full flowering of many temperate woody species. This paper investigates the sensitivity of blackcurrant bud burst and flowering to natural weather fluctuations in a temperate maritime climate, and compares a range of chill models that have been proposed for assessing the accumulation of winter chill. Bud break for four contrasting cultivars are compared in an exceptionally cold and in a mild winter in Eastern Scotland. The results confirm the importance of chilling at temperatures lower than 0 • C and demonstrate that no single chilling function applies equally to all blackcurrant cultivars. There is a pressing need for further model development to take into account the relationship between chilling temperatures and warming temperatures occurring both during and after the chill accumulation period.
Page 1. 8 Mechanical Harvesting of Berry Crops Adam Dale Horticultural Research Institute of Onta... more Page 1. 8 Mechanical Harvesting of Berry Crops Adam Dale Horticultural Research Institute of Ontario Box 587, Simcoe, ON, N3Y 4N5 Canada Eric J. Hanson Department of Horticulture, Michigan State University East Lansing ...
Gall mite (Cecidophyopsis ribis) is the most serious pest of blackcurrant (Ribes nigrum L.), caus... more Gall mite (Cecidophyopsis ribis) is the most serious pest of blackcurrant (Ribes nigrum L.), causing the damaging condition known as 'big bud' and also transmitting blackcurrant reversion virus (BRV) within and between plantations. The identiWcation of resistant germplasm is at present a time-consuming and expensive process, dependent on Weld infestation plots. Resistance based on gene Ce introgressed from gooseberry has been used in UK breeding programmes for blackcurrant. Using a bulked segregant analysis, 90 AFLP primer combinations were screened and a linkage map constructed around the resistance locus controlled by Ce. Sixteen of the primer combinations produced a fragment in the resistant bulked progeny and the gall mite-resistant parent, but not in the susceptible bulked progeny and parent; subsequent testing on individual progeny identiWed an AFLP fragment closely linked to gall mite resistance. This fragment, designated E41M88-280, was converted to a PCR-based marker based on sequence-speciWc primers, amplifying only in resistant individuals. Validation of this marker across a range of susceptible and resistant blackcurrant germplasm with diVerent genetic backgrounds conWrmed its reliability in the identiWcation of mite-resistant germplasm containing gene Ce. The conversion of an AFLP fragment to a sequencebased PCR marker simpliWes its application and therefore increases its utility for selection of mite-resistant germplasm in high-throughput breeding programmes for blackcurrant.
The drought stress tolerance of two blackcurrant cultivars (Ribes nigrum L., 'Narve Viking' and '... more The drought stress tolerance of two blackcurrant cultivars (Ribes nigrum L., 'Narve Viking' and 'Ben Gairn') during the flowering period and their ability to recover following drought stress were studied by examining the effects of drought stress on growth and various physiological traits. The experiment was conducted under greenhouse conditions, and plants were either fully irrigated (FI), with a volume of water replacing the previous day's evapotranspiration, or non-irrigated (NI) for 12 days. Hereafter irrigation was continued (FI) or resumed (NI) to allow for 17 days of recovery.
The tolerance to water deficit and ability to recover was studied during flower initiation in two... more The tolerance to water deficit and ability to recover was studied during flower initiation in two blackcurrant cultivars (Ribes nigrum L., 'Titania' and 'Ben Hope'). The experiment was conducted under greenhouse conditions, and plants were either fully irrigated (FI), with a volume of water replacing the previous day's evapotranspiration, or deficit irrigated (DI) for 3, 4, 5, 7 or 10 days. Deficit-irrigated plants received a volume of nutrient solution corresponding to 50% of the volume supplied to FI plants. Here after full irrigation was continued (FI) or resumed (DI) to allow for 2 and 10 days of recovery for stomatal conductance and leaf area increment, and 7 and 14 days of recovery for root intensity. Full irrigation was continued until the spring when the numbers of strigs and flowers per node were recorded.
The fatty acid compositions of seeds from 29 black currant genotypes were determined using a rapi... more The fatty acid compositions of seeds from 29 black currant genotypes were determined using a rapid small-scale procedure. There was interest in alpha-linolenic, stearidonic, and, especially, gamma-linolenic acid (GLA) contents, and most samples showed values between 11.1 and 18.7%, between 2.5 and 4.5%, and between 11.6 and 17.4%, respectively. However, six genotypes exhibited gamma-linolenic contents >18%, and values >20% were recorded in four of these genotypes. The fatty acid contents of the six genotypes were also analyzed by using a conventional procedure, and only slight differences in fatty acid composition were found between the two methods. Although GLA content was not strongly correlated with juice parameters, some genotypes had both high GLA contents and desirable juice characteristics. The results obtained provide evidence that it is possible to select for GLA contents without negatively affecting juice quality, and both aspects can be combined in a single cultivar, thereby increasing the added value of the whole fruit.
Putative flavanol-anthocyanin condensation products were detected in a polyphenol-rich concentrat... more Putative flavanol-anthocyanin condensation products were detected in a polyphenol-rich concentrate from black currant (Ribes nigrum L.). These compounds had UV-vis spectra similar to those of delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside, but eluted before all previously described anthocyanins on reversed phase HPLC. Mass spectrometric data indicated that they were rutinoside derivatives of novel aglycons 304 amu greater than delphinidin and cyanidin, respectively. The compounds were partly purified by semipreparative HPLC and gave MS and MS2 spectra consistent with anthocyanin rutinosides covalently linked to epigallocatechin or gallocatechin. These compounds are similar in structure to compounds thought to influence color and quality in red wines and strawberry juice products. There was also evidence for the presence of a range of other flavanol-anthocyanin condensation products. The compounds were present at differing levels in juices of 10 black currant varieties, which were roughly correlated to the content of the parent anthocyanins. The flavanol-anthocyanin products were present in polyphenol-enriched concentrates obtained by solid phase extraction, in commercially produced concentrates, and in fresh extracts of black currants. This suggests that the compounds were not artifacts formed during concentration or purification. However, differences in their comparative contents may be related to the lability of the parent anthocyanins during processing. Although present at low levels, the flavanol-anthocyanin products may influence color or quality parameters of black currant juices, and they may confer enhanced stability to the biological activities reported for their anthocyanin parents.
Background: The detrimental effects of mild winter temperatures on the consistency of cropping of... more Background: The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L.) in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak.
Uploads
Papers by Rex Brennan