Green Field Pea Research Articles

Cover Image, Volume 17, Issue 2

Journal of Plant RegistrationsVolume 17, Issue 2 COVER IMAGEFree Access Cover Image, Volume 17, Issue 2 First published: 10 May 2023 https://doi.org/10.1002/plr2.20244AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract On the cover: ND Victory' green field pea at the flowering stage. See N. Bandillo et al., “Registration of ‘ND Victory’ green field pea,” https://doi.org/10.1002/plr2.20266. Photo by Hannah Worral. Volume17, Issue2May 2023 RelatedInformation

Registration of ‘ND Victory’ green field pea

Abstract‘ND Victory’ (Reg. no. CV‐31, PI 701908) is the first semi‐leafless, green cotyledon field pea cultivar (Pisum sativum L.) developed by the North Dakota State University Pulse Crops Breeding Program and approved for release by the North Dakota Agricultural Experiment Station. It has white flowers, opaque seed coat, and smooth, round seed. It is semi‐dwarf, with lodging score of 3.3/9 and canopy height of 57 cm. Based on 30 environments (location‐year) of replicated yield trials in North Dakota, seed yield of ND Victory (2847 kg ha−1) was similar to commercial cultivar ‘CDC Striker’ (2819 kg ha−1) but significantly greater than ‘Cruiser’ (2653 kg ha−1) and ‘Aragorn’ (2639 kg ha−1) by 7.3 and 7.9%, respectively. ND Victory was also tested across 14 environments in Montana, where it had an average seed yield of 3264 kg ha−1, which was similar to ‘Hampton’ (3355 kg ha−1) but significantly greater than Aragorn (3110 kg ha−1) by 4.9%. ND Victory matures in approximately 90 days. ND Victory is a high protein cultivar, with protein content of 25.2%, exceeding the premium protein threshold of 24%. ND Victory (20%) is resistant to powdery mildew and performed similarly with resistant check ‘Spider’ (15%) and had significantly lower disease severity than ‘Salamanca’ (97%, susceptible check) and CDC Striker (82%). In irrigated field trials conducted under high Ascochyta blight pressure, ND Victory (5%) had lower disease severity than ‘AC Agassiz’ (10%) and CDC Striker (14%). ND Victory and CDC Striker exhibited similar response but significantly lower severity than AC Agassiz to Fusarium root rot inoculated with multiple Fusarium species pathogenic to pea.

Hindgut fermentation of starch is greater for pulse grains than cereal grains in growing pigs.

The nutritive value of starch, the major source of dietary energy in pigs, varies depending on its susceptibility for digestion. The botanical origin of starch determines starch structure, and therefore, digestibility. To compare digestibility of starch, fiber, gross energy (GE), crude protein, and amino acid (AA), and to characterize undigested starch of grains in growing pigs, seven ileal-cannulated barrows (initial body weight, 30 kg) were fed six diets containing 96% of one of six test ingredients (three pulse grains: zero-tannin faba bean, green field pea, or mixed-cultivar chickpea; three cereal grains: hulled barley, hard red spring wheat, or hybrid yellow, dent corn), or a N-free diet in a 7 × 7 Latin square at 2.8 × maintenance digestible energy. Grain samples were ground with a hammer mill through a 2.78-mm screen. Amylose content ranged from 29% to 34% for pulse grains and from 22% to 25% for cereal grains. The apparent ileal digestibility (AID) of starch was greater (P < 0.05) in cereal (94% to 97%) than pulse grains (85% to 90%) and was lowest (P < 0.05) in faba bean (85.3%) followed by field pea (87.2%) and chickpea (90.1%). However, apparent total tract digestibility (ATTD) of starch of all tested grains was close to 100%. Apparent hindgut fermentability (AHF, as ATTD - AID) of starch was greater (P < 0.05) in pulse grains (9.9% to 15%) than cereal grains (3.3% to 4.8%). The AHF of total dietary fiber tended to be the greatest (P < 0.10) for corn (43.5%) and lowest for wheat (25.3%). The AHF of GE was greater (P < 0.05) in pulse grains (17% to 20%) than in cereal grains (9% to 11%) and resulted in greater (P < 0.05) digestible energy (DE) contribution from hindgut fermentation for pulse grains than cereal grains (0.9 vs. 0.5 Mcal/kg). Wheat had the greatest standardized ileal digestibility of total AA (90.2%; P < 0.05). Confocal laser scanning microscopy images revealed that 20% to 30% of starch granules of pulse grains were entrapped in protein matrixes. In scanning electron microscopy images, starch granules were larger in faba bean and field pea than cereal grains. Digesta samples revealed pin holes and surface cracks in starch granules of corn and wheat, respectively. In conclusion, hindgut fermentation of starch and fiber was greater in pulse grains than cereal grains resulting in a greater DE value despite lower ileal DE for pulse grain than cereal grains. Defining the digestible and fermentable fractions of starch may enhance the accuracy of equations to predict the net energy value of these feedstuffs.

Effect of Different Pulse and Oilseed based Cropping Systems on Yield and Nutrient Budgeting under Rainfed Conditions of Jammu

Background: Maize-wheat is the predominant cropping system of dryland ecology of Jammu region, but due to their comparatively higher input requirements especially of nutrients and water under the fragile ecology of these dry lands an untenable threat has been posed to their factor productivities. Therefore, all cropping sequences that suit and sustain better on the natural resources of the dryland ecosystems for a longer period of time needs to be explored.Methods: The treatments consisted of two oilseeds i.e. mustard) and gobhi sarson and two pulse crops i.e. chickpea and field pea taken during rabi were followed by two oilseed i.e. soybean and sesame and two pulse crops i.e. green gram and black gram grown during kharif. The experiment was laid out in randomized block design with four replications.Result: Significantly higher chickpea equivalent yield of green gram was observed with field pea- green gram sequence (10.26 q/ha) which was at par with the chickpea – green gram and field pea - black gram system. The available nitrogen status was significantly influenced and recorded highest (166.82kg/ha) under field pea- green gram system. Further overall nutrient mining by this system was quite low as compared to other systems.

Bleaching color‐loss of green field pea: An investigation on inference of genotypic‐resistance based on chlorophyll and phenolic acid content

AbstractColor‐loss of green field pea, commonly referred to as bleaching, can occur prior to harvest once the grain has ripened or during grain storage and is thought to be the result of chlorophyll depletion in the cotyledon. However, the mechanisms of bleaching‐resistance, exhibited within some genotypes, are not well understood. The antioxidant activity of phenolic compounds can inhibit chlorophyll degradation, and therefore, the presence of phenolic compounds may improve bleaching‐resistance. In this study, five green pea genotypes, differing in resistance to bleaching, were assessed for grain‐color as well as content of chlorophyll and major phenolic acids, in both the hull and cotyledon. For each genotype, resistance to bleaching was inferred by the range of color scores observed. Chlorophyll and phenolic acid contents both decreased overall as the whole‐grain color became lighter (bleached); however, there was no direct relation found between these compounds and the known resistance of each genotype. Chlorophyll content in the cotyledon was correlated (r = −0.735, p &lt; 0.001) with cotyledon color but not with whole‐grain color (r = −0.212, p = 0.01). Furthermore, the ratio of cotyledon chlorophyll A/B and the ratio of phenolic acid content (hulls) to total chlorophyll content (cotyledon) were not directly correlated with resistance. Although the total chlorophyll and phenolic acid contents were both depleted as the extent of bleaching increased, neither could fully explain differences in bleaching‐resistance between genotypes. Furthermore, the green color and color‐loss of whole‐grain samples could not be fully attributed to chlorophyll pigments. Therefore, it is likely that other phenolic compounds contribute to both the grain color and the resistance to bleaching.

PSIII-38 Pepsin-pancreatin protein digestibility of various protein sources intended for pet food

Abstract Pet food companies need quality protein ingredients to offer new and different options for pet owners. Evaluating these proteins with animal feeding trials are time consuming and expensive. An in vitro (benchtop) method could provide detailed information about protein quality for novel ingredients. Therefore, the objective of this experiment was to develop a pepsin-pancreatin digestibility assay and determine the appropriate incubation time for enzyme hydrolysis to approximate results from animal studies. Ingredients evaluated were faba beans, navy beans, spray-dried granulated egg, chick pea, pea protein concentrate (72% CP and 50% CP), green field peas, and sunflower meal. One gram of test ingredient was mixed with an HCl-pepsin solution and then incubated for 3 or 6 hours at 37°C before NaOH was added, stopping the pepsin reaction. Phosphate buffer with pancreatin was then added and the tubes were incubated for an additional 18 hours. Samples were then centrifuged, washed, filtered, and dried at 105°C overnight. Residual protein was determined with a modified Kjeldahl assay and was used to calculate protein digestibility. Data were analyzed using the GLIMMIX procedure for mixed models (SAS v 9.4, SAS Institute Inc, Cary, NC). There was no interaction between test ingredient and time (P = 0.63). Incubation time did not influence protein digestibility (P = 0.69). Test ingredient did impact protein digestibility. Spray-dried granulated egg, faba bean, green field pea, and pea protein concentrate (50% CP) did not differ with digestibilities above 97% (P &amp;lt; 0.0001). Navy bean had a digestibility of 93%. The lowest digestibilities were sunflower meal and pea protein concentrate (72% CP). Overall, the crude protein digestibility was higher than expected. This data would suggest other factors, such as the amount and activity of the enzyme used, should be altered to obtain digestibility values that are consistent with reported values from animal studies.

Quantifying the colour loss of green field pea (Pisum sativum L.) due to bleaching.

Post-harvest change in the colour of green field pea (Pisum sativum L.) is undesirable as this impacts the visual quality and market value of the seed. To date, there is no standard, objective method to determine bleaching. Therefore, the aim of this study was to develop an objective method for scoring bleaching based on colour reflectance spectra, measured both by spectrophotometer and multispectral Image Analysis (IA). Green field pea seeds were sorted into samples of uniform colour and these were used to train the model. Spectra calculated from multispectral images (with colour bands at 405,470,530,590,660 and 850nm) were matched to the spectrophotometer output through multiple linear regression. All spectra were transformed to emphasize the wavelength regions most impacted during bleaching, following which two critical reflectance values were scaled to a single bleaching score. The bleaching assessment method was tested in a time-course experiment comprising seeds from five green-pea genotypes stored for six months. Each sample was divided into two so that half of the seeds were stored in the dark and the remainder were exposed to controlled light to exaggerate bleaching. Throughout this period, the samples were imaged at six-weekly intervals. Assessment of bleaching by the IA method agreed well with spectrophotometer measurements, achieving a Lin’s concordance statistic of 0.99 and 0.96 for the calibration and time-course samples respectively. The IA method proved more versatile because assessments could be made on individual seeds enabling the computation of bleaching uniformity within each sample. This method captured differences between genotypes in the extent, rate and uniformity of bleaching. All genotypes exhibited susceptibility to bleaching when stored under the controlled light conditions. Excell was observed to be the most susceptible genotype with the greatest bleaching-rate and OZB1308 displayed the most colour-stability.

CDC Greenwater green field pea

Warkentin, T. D., Vandenberg, A., Tar’an, B., Banniza, S., Arganosa, G., Barlow, B., Ife, S., Horner, J., de Silva, D., Thompson, M., Parada, M., Wagenhoffer, S. and Prado, T. 2014. CDC Greenwater green field pea. Can. J. Plant Sci. 94: 1551–1553. CDC Greenwater, a green cotyledon field pea (Pisum sativum L.) cultivar, was released in 2014 by the Crop Development Centre, University of Saskatchewan, for distribution to Select seed growers in Saskatchewan and Alberta through the Variety Release Committee of the Saskatchewan Pulse Growers. CDC Greenwater has good lodging resistance, powdery mildew resistance, medium-sized seeds with round shape, good cotyledon bleaching resistance, and good yielding ability. CDC Greenwater is adapted to the field-pea- growing regions of western Canada.

CDC Raezer green field pea

Warkentin, T. D., Vandenberg, A., Tar'an, B., Banniza, S., Arganosa, G., Barlow, B., Ife, S., Horner, J., de Silva, D., Thompson, M., Parada, M., Wagenhoffer, S. and Prado, T. 2014. CDC Raezer green field pea. Can. J. Plant Sci. 94: 1535–1537. CDC Raezer, a green cotyledon field pea (Pisum sativum L.) cultivar, was released in 2011 by the Crop Development Centre, University of Saskatchewan, for distribution to Select seed growers in Saskatchewan and Alberta through the Variety Release Committee of the Saskatchewan Pulse Growers. CDC Raezer has good lodging resistance, powdery mildew resistance, medium-sized seeds with round shape, good cotyledon bleaching resistance and good yielding ability. CDC Raezer is adapted to the field-pea-growing regions of western Canada.

CDC Limerick green field pea

Warkentin, T. D., Vandenberg, A., Tar’an, B., Banniza, S., Arganosa, G., Barlow, B., Ife, S., Horner, J., de Silva, D., Thompson, M., Parada, M., Wagenhoffer, S. and Prado, T. 2014. CDC Limerick green field pea. Can. J. Plant Sci. 94: 1547–1549. CDC Limerick, a green cotyledon field pea (Pisum sativum L.) cultivar, was released in 2012 by the Crop Development Centre, University of Saskatchewan, for distribution to Select seed growers in Saskatchewan and Alberta through the Variety Release Committee of the Saskatchewan Pulse Growers. CDC Limerick has good lodging resistance, powdery mildew resistance, medium-sized seeds with round shape, good cotyledon bleaching resistance, high protein concentration, and good yielding ability. CDC Limerick is adapted to the field-pea-growing regions of western Canada.

Reduced tillage in temperate organic farming: Effects on soil nutrients, nutrient content and yield of barley, rye and associated weeds

AbstractIn temperate regions, reduced tillage is still not broadly accepted in organic farming although the guidelines often recommend the reduction of tillage intensity. During the years 5–7 of a long-term experiment, we studied the effects of the three tillage systems moldboard plowing (MP, soil inversion to 30 cm depth), two-layer plowing (TP, inversion to 15 cm, loosening to 30 cm) and layer cultivation (LC, loosening to 30 cm) on soil nutrients, nutrient content of barley, rye and associated weeds, and yield on a clay loam soil. Crops were cultivated within a five-course crop rotation consisting of green fallow, winter wheat, field peas, winter rye and spring barley; no additional fertilizers were applied. Tillage affected only soil nitrate under barley, which decreased with decreasing tillage intensity. Soil humus, phosphorus (P) and potassium (K) were unaffected by tillage under both crops. Barley shoot nitrogen content was significantly influenced by tillage, with, across years, 38 and 83% higher values under MP than under TP or LC, respectively. Weeds in barley had a higher P and K content at LC than at MP or TP. This resulted, across years, in 73% higher barley yields in MP than in LC. The TP showed a 29% higher barley yield than the LC. Tillage methods had no effect on rye nutrient contents, rye yields or on weeds associated with rye. The significant interaction between tillage and year for rye yield suggests that weather conditions in a given year (e.g., amount of rainfall) can considerably alter the effect of reduced tillage.

Lentils (Lens culinaris L.), a Rich Source of Folates

The potential for genetic biofortification of U.S.-grown lentils ( Lens culinaris L.) with bioavailable folate has not been widely studied. The objectives of this study were (1) to determine the folate concentration of 10 commercial lentil cultivars grown in Minot and McLean counties, North Dakota, USA, in 2010 and 2011, (2) to determine the genotype (G) × environmental (E) interactions for folate concentration in lentil cultivars, and (3) to compare the folate concentration of other pulses [field peas ( Pisum sativum L.) and chickpea ( Cicer arietinum L.)] grown in the United States. Folate concentration in lentil cultivars ranged from 216 to 290 μg/100 g with a mean of 255 μg/100 g. In addition, lentil showed higher folate concentration compared to chickpea (42-125 μg/100 g), yellow field pea (41-55 μg/100 g), and green field pea (50-202 μg/100 g). A 100 g serving of lentils could provide a significant amount of the recommended daily allowance of dietary folates (54-73%) for adults. A significant year × location interaction on lentil folate concentration was observed; this indicates that possible location sourcing may be required for future lentil folate research.

HARDNESS PHENOMENON IN BEACH PEA (Lethyrus maritimus L.)

Beach pea is mostly grown on seashores and it contains higher amount of protein than other legumes. However, the pea has several undesirable attributes, such as long cooking time and hard to germinate (imbibitions) that limited its use as food. The present investigation aimed to study the physico-chemical properties, cooking characteristics and hull crude fibre structure of beach pea as compare to other similar legumes. Standard methods of processing pulses were used for present study. Beach pea seeds contained very low grain weight, density, hydration capacity, hydration index, swelling capacity and swelling index than the green pea and field pea. Beach pea had higher amount of crude protein, ash, crude fibre and polyphenols, but lower in starch content than the green pea and field pea. Without any treatment to beach pea seeds the water uptake capacity was very low. Mechanical treatment to beach pea seeds increased&lt;br /&gt;the water uptake percentage. The recovery of hull was 3 to 6 times higher in beach pea than that of green pea and field pea. The crude protein content in beach pea hull was 2-5% higher than others. The beach pea hull, dhal and whole seeds were good source of macro- and micro- minerals than that of the other two peas. The electron microscopic structure of beach pea hull crude fibre showed a very close and compact structure than green pea and field pea hull crude fibre structure. Lowering the hardness of beach pea seeds with mechanical or chemical treatments will give more scope for their utilization in the human nutrition.

HARDNESS PHENOMENON IN BEACH PEA (Lethyrus maritimus L.)

Beach pea is mostly grown on seashores and it contains higher amount of protein than other legumes. However, the pea has several undesirable attributes, such as long cooking time and hard to germinate (imbibitions) that limited its use as food. The present investigation aimed to study the physico-chemical properties, cooking characteristics and hull crude fibre structure of beach pea as compare to other similar legumes. Standard methods of processing pulses were used for present study. Beach pea seeds contained very low grain weight, density, hydration capacity, hydration index, swelling capacity and swelling index than the green pea and field pea. Beach pea had higher amount of crude protein, ash, crude fibre and polyphenols, but lower in starch content than the green pea and field pea. Without any treatment to beach pea seeds the water uptake capacity was very low. Mechanical treatment to beach pea seeds increased&lt;br /&gt;the water uptake percentage. The recovery of hull was 3 to 6 times higher in beach pea than that of green pea and field pea. The crude protein content in beach pea hull was 2-5% higher than others. The beach pea hull, dhal and whole seeds were good source of macro- and micro- minerals than that of the other two peas. The electron microscopic structure of beach pea hull crude fibre showed a very close and compact structure than green pea and field pea hull crude fibre structure. Lowering the hardness of beach pea seeds with mechanical or chemical treatments will give more scope for their utilization in the human nutrition.

CDC Tetris green field pea

Warkentin, T. D., Vandenberg, A., Tar'an, B., Banniza, S., Bett, K. E., Barlow, B., Ife, S., Horner, J., de Silva, D., Thompson, M., Parada, M., Wagenhoffer, S. and Prado, T. 2012. CDC Tetris green field pea. Can. J. Plant Sci. 92: 217–219. CDC Tetris, a green cotyledon field pea (Pisum sativum L.) cultivar, was released in 2010 by the Crop Development Centre, University of Saskatchewan for distribution to Select seed growers in Saskatchewan and Alberta through the Variety Release Committee of the Saskatchewan Pulse Growers. CDC Tetris has good lodging resistance, powdery mildew resistance, medium-sized seeds with blocky shape, good cotyledon bleaching resistance and good yielding ability. CDC Tetris is adapted to the field pea growing regions of western Canada.

CDC Pluto small green field pea

Warkentin, T. D., Vandenberg, A., Tar'an, B., Banniza, S., Bett, K. E., Barlow, B., Ife, S., Horner, J., de Silva, D., Thompson, M., Parada, M., Wagenhoffer, S. and Prado, T. 2012. CDC Pluto small green field pea. Can. J. Plant Sci. 92: 215–216. CDC Pluto, a green cotyledon field pea (Pisum sativum L.) cultivar, was released in 2010 by the Crop Development Centre, University of Saskatchewan, for distribution to Select seed growers in Saskatchewan and Alberta through the Variety Release Committee of the Saskatchewan Pulse Growers. CDC Pluto has a semileafless leaf type, fair lodging resistance, powdery mildew resistance, small seeds with round shape, good cotyledon bleaching resistance and good yielding ability. CDC Pluto is adapted to the field pea growing regions of western Canada.

Enzyme pretreatment of fibrous ingredients for carnivorous fish: Effects on nutrient utilisation and technical feed quality in rainbow trout ( Oncurhynchus mykiss)

Carnivorous fish have limited ability to utilise fibrous structures as a source of energy. Treatment with exogenous enzymes targeted at degradation of non starch polysaccharides (NSP) could help to improve the nutritive value of these components. Two experiments were conducted. In the first in vitro experiment, three defatted oilseeds; soybean meal (SBM), rapeseed meal (RSM) and sunflower cake (SFC) as well as green field peas were incubated individually at semi-moist conditions (45% water, 45 min, 45 °C) with or without NSP degrading enzymes (RONOZYME® VP). The amount of total NSP was significantly (P < 0.05) reduced after enzyme treatment of SBM and SFC, but no effect was seen for RSM or field peas. A prolonged wet incubation (85% water, 180 min) with SBM and RSM at three different temperatures (30, 45, 60 °C) was also conducted with RONOZYME® VP. An overall significant (P < 0.05) effect on degradation of total NSP was seen for SBM at wet conditions, but there was no significant difference between the three temperatures, and increased incubation time or moisture level did not improve the degree of degradation any more than the semi-moist treatments. In the following fish experiment three diets were made with combinations of SBM, RSM and SFC: Diet A (SBM + RSM), diet B (SBM + SFC) and diet C (RSM + SFC). In addition to a conventional feed production, the plant ingredients in the three diets were pretreated (45 min, 45% moisture, 45 °C) in the presence of RONOZYME® VP, and mixed with the remaining dry ingredients prior to conditioning and extrusion. Diet A was also pretreated without enzyme as a sham treatment. The temperature in the extruder barrel decreased in the feeds that had been pretreated, but there was no negative effect on the pellet durability index (PDI) or water stability index (WSI). Each of the seven dietary treatments was fed to triplicate groups of rainbow trout raised in seawater tanks (average initial weight, 205 g). The fish body weight was more than doubled during the experimental period. The enzyme pretreatment did not improve the nutrient digestibilities, and the overall feed conversion ratio (FCR) increased significantly (P < 0.05) from 1.04 to 1.10. We conclude that treatment with NSP degrading enzymes has significant effects on reductions in total NSP in vitro, but the released substrates did not contribute to an improvement in fish performance under the current experimental conditions.

Genetic control and identification of QTLs associated with visual quality traits of field pea (Pisum sativum L.).

Visual quality of field pea (Pisum sativum L.) is one of the most important determinants of the market value of the harvested crop. Seed coat color, seed shape, and seed dimpling are the major components of visual seed quality of field pea and are considered as important breeding objectives. The objectives of this research were to study the genetics and to identify quantitative trait loci (QTLs) associated with seed coat color, seed shape, and seed dimpling of green and yellow field peas. Two recombinant inbred line populations (RILs) consisting of 120 and 90 lines of F(5)-derived F(7) (F(5:7)) yellow pea (P. sativum 'Alfetta' × P. sativum 'CDC Bronco') and green pea (P. sativum 'Orb' × P. sativum 'CDC Striker'), respectively, were evaluated over two years at two locations in Saskatchewan, Canada. Quantitative inheritance with polygenic control and transgressive segregation were observed for all visual quality traits studied. All 90 RILs of the green pea population and 92 selected RILs from the yellow pea population were screened using AFLP and SSR markers and two linkage maps were developed. Nine QTLs controlling yellow seed lightness, 3 for yellow seed greenness, 15 for seed shape, and 9 for seed dimpling were detected. Among them, five QTLs located on LG II, LG IV, and LG VII were consistent in at least two environments. The QTLs and their associated markers will be useful tools to assist pea breeding programs attempting to pyramid positive alleles for the traits.

First Report of Ascochyta Blight of Field Pea Caused by Ascochyta pisi in South Dakota

Tan lesions approximately 1.7 × 0.8 cm with distinct dark brown margins and small pycnidia were observed on leaves of field peas (Pisum sativum L. 'Agassiz') growing in Campbell County, South Dakota (45°45.62'N, 100°9.13'W) in July 2008. Small pieces of symptomatic leaves were surface sterilized (10% NaOCl for 1 min, 70% EtOH for 1 min, and sterile distilled H2O for 2 min) and placed on potato dextrose agar (PDA) for 7 days under fluorescent lights with a 12-h photoperiod to induce sporulation. A pure culture was established by streaking a conidial suspension on PDA and isolating a single germinated spore 3 days later. The culture was grown on clarified V8 media for 10 days. Conidia were 10 to 16 × 3 to 4.5 μm and uniseptate with a slightly constricted septum, similar to those of Ascochyta pisi Lib. The exuding spore mass from pycnidia growing on the medium was carrot red. No chlamydospores or pseudothecia were observed (1,2). To confirm the identity of A. pisi, DNA was extracted from the lyophilized mycelium of the 10-day-old culture with the DNeasy Plant Mini Kit (Qiagen, Valencia, CA). Internal transcribed spacer (ITS) regions I and II were amplified with PCR primers ITS 5 and ITS 4 (3). PCR amplicons were cleaned and directly sequenced in both directions using the primers. A BLASTN search against the NCBI nonredundant nucleotide database was performed using the consensus sequence generated by alignment of the forward and reverse sequences for this region. The consensus sequence (GenBank Accession No. GU722316) most closely matched A. pisi var. pisi strain (GenBank Accession No. EU167557). These observations confirm the identity of the fungus as A. pisi. A suspension of 1 × 106 conidia/ml of the isolate was spray inoculated to runoff on 10 replicate plants of 2-week-old, susceptible green field pea 'Sterling'. Plants were incubated in a dew chamber for 48 h at 18°C and moved to the greenhouse bench where they were maintained at 20 to 25°C with a 12-h photoperiod for 1 week. Tan lesions with dark margins appeared 7 days after inoculation and disease was assessed after 10 days (4). No symptoms were observed on water-treated control plants. A. pisi was reisolated from lesions and confirmed by DNA sequencing of the ITS region, fulfilling Koch's postulates. Currently, states bordering South Dakota (North Dakota and Montana) lead the United States in field pea production. Although acreage is limited in South Dakota, the identification of A. pisi in this region is serious. The disease is yield limiting and foliar fungicides are used for disease management (1). To our knowledge, this is the first report of Ascochyta blight on P. sativum caused by A. pisi occurring in South Dakota and the MonDak production region (the Dakotas and Montana).

Genetic control and QTL analysis of cotyledon bleaching resistance in green field pea (Pisum sativum L.).

Resistance to bleaching is an important factor for quality grading of Canadian green field pea and an important selection criterion in green pea improvement. This research was conducted to determine the genetic control of bleaching resistance in green peas using 90 recombinant inbred lines (RILs) derived from a cross between cultivars Orb and CDC Striker. These lines were evaluated under field conditions for two years in two locations in Saskatchewan, Canada. Harvested whole seeds and cotyledons were evaluated for greenness using the Hunter Lab colorimeter before and after exposure to a high light intensity accelerated bleaching treatment. The RILs were genotyped using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) molecular markers. Heritability estimates for whole seed and cotyledon greenness were moderate (0.72 and 0.69, respectively) and increased when assessed after exposing whole seeds and cotyledons to accelerated bleaching conditions (0.83 and 0.82, respectively). The genetic linkage map constructed based on a total of 224 AFLP and SSR markers spanned over 890 cM of the pea genome. Multiple QTL mapping detected major QTLs on LG IV and LG V as well as location- and year-specific QTLs on LG II and LG III associated with green cotyledon bleaching resistance in field pea. The results demonstrated the importance of the seed coat in protecting the cotyledons from bleaching.