Field Pea Research Articles

Delineating the role of plant stature towards heat stress tolerance in field pea (Pisum sativum L.)

Terminal heat stress severely affects field pea production in tropical climates. Identifying and characterizing marker-trait(s) remain vital for breeding heat-tolerant cultivars of field pea. Field pea genotypes are highly variable for plant stature; however, the significance of plant stature for yield stability under high-temperature conditions is not yet well understood. The study aimed to investigate the sensitivity and significance of plant stature toward yield sustainability of field pea under high-temperature environments. A panel of 150 diverse genotypes with variable plant statures [dwarf (<50 cm), semi-dwarf (50–80 cm), medium-tall (80–150 cm)] were grown under late sowing-induced high-temperature environments for two consecutive years (2017–2019). During the first year of the experiment, the late sown crops (15 and 30 days) were exposed to high-temperatures at flowering (+3.5 to +8.1 °C) and grain-filling (+3.3 to +6.1 °C) over timely sown crops. Likewise, elevated temperature during flowering (+3.7 to +5.2 °C) and grain filling (+5.4 to +9.9 °C) were recorded in late-sown environments (delayed by 27 and 54 days) in the next year. Medium-tall genotypes had longer grain-filling duration (7–10%), higher pod-bearing nodes (8–18%) and yield (22–55%), and lower yield losses (13–18%) over semi-dwarf and dwarf genotypes under high-temperature environments. Significant associations of plant height with yield, yield loss, and heat-susceptibility index in high-temperature environments suggested higher heat tolerance capacity of tall-type plants compared to dwarf and semi-dwarf types. GGEbiplot analysis revealed that the heat-tolerant genotypes were all medium tall-type (mean = 108 cm), while the heat-susceptible genotypes were mostly dwarf in stature. Hence, tall-type genotypes had better adaptability to high-temperature environments. Henceforth, the breeding approach for high-temperature tolerance in field pea may be designed by embracing tall-type backgrounds over dwarf plant to develop climate resilient cultivars.

Performance of diversified cropping sequences for productivity, profitability and land use efficiency under south-eastern Rajasthan, India

A field experiment was conducted during 4 consecutive years (2015–16 to 2018–19) at Agricultural Research Station, Ummedganj, Kota, Rajasthan to study the performance of diversified cropping sequences for productivity, profitability and land-use efficiency under south-eastern Rajasthan. The experiment comprised 10 cropping sequences in a randomized block design with 3 replications. Maximum soybean [Glycine max (L.) Merr.] equivalent yield (8,507 kg/ha), production efficiency (31.16 kg/ha/day) and relative production efficiency (79.85%) were obtained in fodder sorghum [Sorghum bicolor (L.) Moench]–bitter guard [Momordica charantia (L.)] (low tunnel) cropping sequence. The maximum land-use efficiency of (86.51%) was observed in direct-seeded rice [Oryza sativa (L.)] (short duration)-desi wheat (Triticum aestivum L.)–summer greengram [Vigna radiata (L.) R. Wilczek] cropping sequence followed by short duration soybean-Indian mustard [Brassica juncea (L.)]–cowpea [Vigna unguiculata (L.)] Walp.] (vegetable + fodder) (81.85%) and sweet corn [Zea mays (L.)]–field pea (Pisum sativum var. arvenses (L.) Poir.)–onion [Allium cepa (L.)] (transplanted) (81.03%) crop sequences. Maximum and significantly higher net returns (`163,240/ha) and relative economic efficiency (46.64%) were fetched in blackgram [Vigna mungo (L.) Hepper] (broad bed) + direct-seeded rice (furrow)–vegetable pea (broad bed) + coriander [Coriandrum sativum (L.)] (furrow)-spring greengram. The next best treatment was sweet corn–field pea–onion (transplanted), closely followed by quality protein maize (raised bed)–fennel [Foeniculum vulgare (L.)] (raised bed) to the tune of 39.23 and 36.69% over existing system, respectively. The maximum and significantly higher benefit: cost ratio (2.55) was fetched with quality protein maize (raised bed)–fennel (raised bed) cropping sequence, being at par with blackgram (broad bed) + direct-seeded rice (furrow)–vegetable pea (broad bed) + coriander (furrow)-spring greengram (2.52). Highest economic efficiency (`612/ha/day) was recorded in soybean (short duration) + red gram [Cajanus cajan (L.) Millsp.] (2:1 row)–oat [Avena sativa (L.)] for fodder–summer greengram cropping sequence, followed by blackgram (broad bed) + direct seeded rice (furrow)– vegetable pea (broad bed) + coriander (furrow)– spring greengram (`594/ha/day) and quality protein maize (raised bed)–fennel (raised bed) (`590/ha/day). Directseeded rice (long duration)–berseem [Trifolium alexandrinum (L.)] (fodder) crop sequence had the lowest soybean-equivalent yield (4,546 kg/ha), production efficiency (16.79 kg/ha/day), relative production efficiency (– 3.89%), economic efficiency (`348/ha/day) and relative economic efficiency (–15.43%). Thus, it can be concluded that blackgram (broad bed) + direct seeded rice (furrow)-vegetable pea (broad bed)-leafy coriander (furrow)-spring greengram was found more productive and remunerative cropping sequence followed by sweet corn–field pea-onion (transplanted) and quality protein maize (raised bed) –fennel (raised bed) as diversified cropping sequences for better productivity, profitability and land use efficiency compared to existing soybean-wheat cropping system under south-eastern Rajasthan, India.

Cover Crop Identity Differently Affects Biomass Productivity as well as Nitrogen and Phosphorus Uptake of Maize (Zea mays L.) in Relation to Soil Type

Cover crop integration in agriculture rotation is associated to multiple agronomic and environmental benefits. However, the effect of cover crop identity on the following cash crop productivity and nutrient uptake is still uncertain, particularly in relation to soil types. We set up an experiment to test the effects of four different cover crop species (Indian mustard, lupine, field pea, and oat) on maize above- and belowground biomass as well as on nitrogen and phosphorus nutrition after incorporation of the cover crop litter in two soil types (clay and sandy soil). We observed that aboveground and belowground biomass of maize was always higher in sandy than clay soil likely due to better soil physical properties. On general, in clay soil, the presence of a preceding cover crop promoted or did not modify the aboveground and the belowground maize productivity compared to bare soil. On the other hand, in sandy soil, the decomposing litter of non-leguminous cover crops decreased maize aboveground productivity whereas any preceding cover crop decreased maize root biomass. The burial of leguminous litter significantly increased the N uptake by maize in both soil types. For what concerns the phosphorus uptake by maize, it appears that due to high phosphorus soil availability, the selected cover crops did not play a major role in improving P uptake, with the only exception of field pea. Our data show that leguminous cover crops improved the N status of maize particularly under conditions of low N fertilization rates.

Energy and phosphorus utilization of pulses fed to broiler chickens

Energy and P utilization in faba beans and peas were evaluated in 3 broiler chicken experiments. In Exp. 1, 240 birds were allotted to 5 diets in a randomized complete block design with BW as a blocking factor on d 18 post hatching to determine the regression-derived energy utilization of faba beans (FB) and field peas (FP). In each of the respective Exp. 2 and 3, regression-derived P utilization in FB and FP were determined with 162 birds assigned to each of 3 diets in a randomized complete block design with BW as a blocking factor on d 19 post hatching. There were 8 replicate cages with 6 birds per cage in Exp. 1, and 6 replicate cages with 9 birds per cage in Exp. 2 and 3. The test ingredients were added to a corn-soybean meal-based diet at 15% or 30% in Exp. 1, whereas FB was included at 21%, 42%, or 63% and FP at 16%, 32%, or 48% in Exp. 2 and 3, respectively. In Exp. 1, the apparent ileal digestibility (AID) of gross energy (GE) and the ileal digestible energy (IDE) in the diets decreased linearly (P < 0.01). There was a quadratic response or a linear decrease (P < 0.05) with increasing concentrations of FB or FP, respectively, on the apparent total tract utilization (ATTU) of GE, metabolizable energy (ME), and nitrogen-corrected ME (MEn). The respective IDE, ME, and MEn determined were 2,541, 2,628, and 2,394 kcal/kg DM in FB and 2,254, 2,540, and 2,331 kcal/kg DM in FP. In Exp. 2 and 3, the ileal digestible and retainable P intake were linearly increased (P < 0.01). The estimated true ileal digestibility and true total tract utilization of P in FB were 66.5% and 66.7%, respectively. The respective corresponding values for FP were 73.4% and 73.8%. In conclusion, the information on utilization of energy and P in FB and FP provided could enhance proper diet formulation when using these ingredients.

First Report of Leaf Blight on Dumasia villosa Caused by Boeremia exigua in China.

Dumasia (Fabaceae, tribe Phaseoleae, subtribe Glycininae), a genus of trifoliate vines, is widely distributed in tropical and subtropical regions of Asia and Africa (Pan & Zhu 2010). In October 2021, lesions were observed on Dumasia villosa leaves on Longwen mountain of Guizhou Normal University, Guiyang City, Guizhou Province, China. The incidence of leaf blight on observed D. villosa leaves was 10%. All necrotic spots were close to insect-feeding sites. Necrotic spots were grey or black, and circular (2 to 10 mm in diameter) or irregular (2 to 20 mm long) in shape. Stems and pods showed no disease symptoms. Pathogen isolation was conducted following surface sterilization with ethanol. After growth for 5 days on potato dextrose agar in a moist climate chamber at 26°C under a 16 h/8 h light/dark cycle, colonies were 5.2 to 5.6 cm in diameter, olivaceous grey in colour, and sparse, white, aerial mycelia with irregular margins were evident. Conidia were hyaline, ellipsoidal to oblong, mostly 1-septate, and occasionally aseptate with dimensions ranging from 3.5 to 7.0 × 1.5 to 3.5 μm (n = 30). To confirm the species of the isolate, ribosomal DNA internal transcribed spacer (ITS) and β-tubulin (tub2) genes were amplified and sequenced using primers ITS1/ITS4 and Btub2Fd/Btub4Rd (White et al. 1990), respectively. The obtained 529 bp ITS sequence (GenBank accession no. OL872186) shares 99.61% identity with the sequences of Boeremia exigua (MF662797 and GU395499). The obtained 299 bp tub2 sequence (OM830712) shares 100% identity with the sequence of B. exigua (KR653201). Based on morphology and DNA sequence analysis, the isolate was identified as B. exigua. To fulfil Koch's postulates, healthy leaves of 8-week-old D. villosa plants (n = 6) were wounded with a sterilized hypodermic needle and inoculated with 2 μL of a conidial suspension (106 conidia/mL). Six plants were inoculated with 2 μL of sterile distilled water as controls. After 3 days in a moist climate chamber at 26°C under a 16 h/8 h light/dark cycle, dark spots were only present on conidia-inoculated leaves, while controls remained healthy. Boeremia exigua was reisolated from disease spots and confirmed using the same morphological and molecular methods described above. To our knowledge, this is the first report of leaf blight on D. villosa caused by B. exigua, although this fungus has been reported to infect leguminous plants, including field pea (Li et al. 2012), white clover (Wang et al. 2020), and soybean (Schaffrath et al. 2020). In China, B. exigua has also been reported to infect other plants, such as walnut (Cai et al. 2021; Wang et al. 2021) and Japanese ginseng (You et al. 2015). This identification suggests that D. villosa could be a potential reservoir for the pathogen affecting other leguminous crops that might be economically important.

Oat–Field Pea Intercropping for Sustainable Oat Production: Effect on Yield, Nutritive Value and Environmental Impact

The aim of the study is to evaluate the effect of Oat–field pea intercropping on the yield, nutritive value, and environmental impact of oat grown under a reduced level of nitrogen fertilisation. The trial was laid out in a randomized complete block design with the following treatments: oat-0 (oat (Avena sativa L., SRCP X 80 Ab 2291 variety) without N fertilization (urea)), oat-23 (oat fertilised with 23 kg N/ha), oat-46 (oat fertilised with 46 kg N/ha), O1P1 (oat intercropped with field pea (Pisum sativum L., local variety) a ratio of 1:1), O1P2 (oat intercropped with field pea a ratio of 1:2), and O2P1 (oat intercropped with field pea at a ratio of 2:1). All of the experimental plots received standard husbandry practices except for nitrogen fertilisation. Soil pH, organic matter, total nitrogen, available phosphorus, and organic carbon were determined before and after planting. The effect of nitrogen fertilization and intercropping of oat with field pea on carbon footprint, acidification footprint, eutrophication footprint, and human toxicity footprint was calculated for each plot. Oat-0 significantly reduced the total nitrogen content of the soil, while there was no significant effect of the other treatments. O2P1 significantly out-yielded all control groups; however, it was not significantly different from fertilisation treatments. Intercropping with field pea did not significantly increase the cost of production of dry matter, crude protein, or dry matter digestibility compared to control groups. Intercropping with field pea significantly reduced the carbon footprint, acidification, eutrophication, and human toxicity footprint compared to the control groups. Therefore, oat–field pea intercrops are recommended for the production of high-quality forage at low N input with reduced environmental impact.

Estimation of Heterosis and the Combining Ability Effect for Yield and Its Attributes in Field Pea (Pisum sativum L.) Using PCA and GGE Biplots

Field pea (Pisum sativum L.) is a highly nutritious winter-season pulse crop. It is used as food, feed, and fodder and offers nutritional security to low-income people in developing countries. Different graphical approaches like Principal Component Analysis (PCA) and Genotype + Genotype × Environment (GGE) biplots were used along with the conventional line × tester to identify efficient parents, combining ability effects and distinct heterotic groups in field pea (Pisum sativum L.). The study used a line tester design (9 × 3) for seed yield and its associated traits. In the conventional analysis, lines Aman and HFP 715 and the tester GP02/1108, as well as crosses HFP 715 × GP02/1108, Aman × GP02/1108, and Pant P-243 × HFP 1426 showed the best GCA (General Combining Ability) and SCA (Specific Combining Ability) effects, respectively, for seed yield and its attributes. The σ2SCA &gt; σ2GCA, and σ2D &gt; σ2A in almost all the traits indicated control of non-additive gene effects. High manifestations of heterobeltiosis for seed yield were evidenced by the superiority of 24 out of 27 crosses over the better parent. The highest significant heterobeltiosis was observed in the cross HFP 715 × GP02/1108, followed by IPF 14-16 × GP02/1108, IPF 14-16 × HFP 1426, DDR-23 × HFP 1426, DDR-23 × GP02/1108, and Aman × GP02/1108 for yield and its attributes. The biplot techniques were used to analyze data and compare their results with conventional line × tester analysis. Overall, graphical analysis results were very similar to those of traditional analysis. Consequently, it can surely be assumed that these methods could be helpful in presenting data from field pea breeding experiments carried out with line × tester design.

Infestation, distribution and diversity indices of bruchid species on edible stored pulses in India

The study aimed to understand the infestation, distribution and, diversity indices of bruchids infesting edible stored pulses in India. A total of 81 stored grain samples representing 14 crops were surveyed from 74 locations across 24 states. Five bruchid species were identified infesting samples, three of which were cosmopolitan Callosobruchus species. C. analis was distributed on 50% of the samples and locations, followed by C. maculatus and C. chinensis. Despite C. analis being present in the majority of samples, C. maculatus was the most abundant and dominant species. Six of the twenty-four states recorded all three Callosobruchus species, eight states recorded any two of the three, and the other ten states recorded any one of the three Callosobruchus species. C. analis and C. chinensis were abundant in four of the six regions, while C. chinensis in NE region. The overall species diversity index was 1.1, while Effective Number of species was 3. C. maculatus was the most abundant and dominant species in small-scale, whereas C. analis in large-scale, storage conditions. Small-scale storages recorded greater diversity and richness, whereas large-scale had greater evenness. Madhya Pradesh, Andhra Pradesh, and Uttar Pradesh states recorded greater diversity indices, whereas West Bengal and Tamil Nadu had lower indices. The maximum diversity indices were found in crops like chickpea (desi and Kabuli), and field pea. Small-scale storage conditions recorded higher infestation parameters than large-scale. Field pea, cowpea, chickpea, horse gram, and mungbean recorded higher infestations, while urdbean had the lowest. The order of grain infestation and damage for species was C. chinensis > C. analis > C. maculatus, whereas, it was the opposite for grain weight loss. The grain moisture and storage duration positively correlated with infestation and damage. This study provides vital information on prevailing species diversity and distribution of bruchids on edible stored pulses across the country.

Risk assessment for non‐crop hosts of pea enation mosaic virus and the aphid vector Acyrthosiphon pisum

Abstract Viral insect‐borne plant pathogens have devastating impacts in agroecosystems. Vector‐borne pathogens are often transmitted by generalist insects that move between non‐crop and crop hosts. Insect vectors can have wide diet breadths, but it is often unknown which hosts serve as pathogen reservoirs and which non‐crop host harbours the highest density of vectors. In the Pacific Northwest USA, the pea aphid (Acyrthosiphon pisum) is a key virus vector in pulse crops. Despite pea aphid having a large number of potential non‐crop plant hosts occuring in the region, no reservoir has yet been identified for the economically‐costly pathogen Pea Enation Mosaic Virus (PEMV). We addressed these issues by linking field surveys of an aphid vector and plant virus with statistical models to develop risk assessments for common non‐crop legumes; in 2018, we completed a 65‐site survey where aphids were surveyed in weedy legumes within and outside dry pea fields. We quantified the abundance of pea aphids on 17 hosts, and plant tissue was tested for PEMV. Relatively high densities of A. pisum were found in habitats dominated by hairy vetch (Vicia villosa), which was the only legume other than cultivated dry pea where PEMV was detected. Our results indicate that V. villosa is a key alternative host for PEMV, and that pest management practices in this region should consider the distribution and abundance of this weedy host in viral disease mitigation efforts for pulses.

Field Pea (Pisum sativum) Germplasm Screening for Seedling Ascochyta Blight Resistance and Genome-Wide Association Studies Reveal Loci Associated with Resistance to Peyronellaea pinodes and Ascochyta koolunga.

Ascochyta blight is a damaging disease that affects the stems, leaves, and pods of field pea (Pisum sativum) and impacts yield and grain quality. In Australia, field pea Ascochyta blight is primarily caused by the necrotrophic fungal species Peyronellaea pinodes and Ascochyta koolunga. In this study, we screened 1,276 Pisum spp. germplasm accessions in seedling disease assays with a mix of three isolates of P. pinodes and 641 accessions with three mixed isolates of A. koolunga (513 accessions were screened with both species). A selection of three P. sativum accessions with low disease scores for either pathogen, or in some cases both, were crossed with Australian field pea varieties PBA Gunyah and PBA Oura, and recombinant inbred line populations were made. Populations at the F3:4 and F4:5 generation were phenotyped for their disease response to P. pinodes and A. koolunga, and genotypes were determined using the diversity arrays technology genotyping method. Marker-trait associations were identified using a genome-wide association study approach. Trait-associated loci were mapped to the published P. sativum genome assembly, and candidate resistance gene analogues were identified in the corresponding genomic regions. One locus on chromosome 2 (LG1) was associated with resistance to P. pinodes, and the 8 Mb genomic region contains 156 genes, two of which are serine/threonine protein kinases, putatively contributing to the resistance trait. A second locus on chromosome 5 (LG3) was associated with resistance to A. koolunga, and the 35 Mb region contains 488 genes, of which five are potential candidate resistance genes, including protein kinases, a mitogen-activated protein kinase, and an ethylene-responsive protein kinase homolog.

Testa and hilum colour associations with seed traits of a Greek field pea landrace

AbstractPea landraces may hold genetic variation that can be exploitable in breeding/selecting new cultivars. In a small-seeded pea landrace, four phenotypes were distinguished according to testa (green, non-spotted and green, spotted) and hilum colour (white, black). The four phenotypes were tested for two growing seasons in the field for pod (seeds/pod) and seed traits (1000-seed weight, toughness, total phenols and tannins, testa colour, protein and carbon concentration, C/N ratio, bruchid infection). Significant differences were found for testa colour parameters, phenolic, tannin and carbon concentration and bruchid tolerance. The larger-seeded, spotted peas had darker testa and more phenols, while white-hilumed peas had lighter testa and more tannins. The spotted, black-hilumed phenotype, with the highest carbon concentration and C/N ratio was the most tolerant to bruchids. However, grouping the phenotypes, neither spotted nor black-hilumed ones showed to be more tolerant compared with their counterparts. Concluding, our results showed that phenotyping variation in seeds of a pea landrace revealed variation in seed traits, which could be exploitable. Since testa and hilum colour were associated with specific seed traits, they could, alone or in combination, be used as biomarkers of seed quality traits in pea. Testing of larger number of phenotypes is needed to solidify our findings.

Mapping of quantitative trait locus reveals PsXI gene encoding xylanase inhibitor as the candidate gene for bruchid (Callosobruchus spp.) resistance in pea (Pisum sativum L.).

Pea (Pisum sativum L.) is an important legume crop for both food and feed. Bruchids (Callosobruchus spp.) are destructive insect pests of pea in the field and during storage. In this study, we identified a major quantitative trait locus (QTL) controlling seed resistance to C. chinensis (L.) and C. maculatus (Fab.) in field pea using F2 populations derived from a cross between PWY19 (resistant) and PHM22 (susceptible). QTL analysis in the two F2 populations grown in different environments consistently identified a single major QTL, qPsBr2.1, controlling the resistance to both bruchid species. qPsBr2.1 was mapped onto linkage group 2 between DNA markers 18339 and PSSR202109 and explained 50.91% to 70.94% of the variation in resistance, depending on the environment and bruchid species. Fine mapping narrowed down qPsBr2.1 to a genomic region of 1.07 Mb on chromosome 2 (chr2LG1). Seven annotated genes were found in this region, including Psat2g026280 (designated as PsXI), which encodes a xylanase inhibitor and was considered as a candidate gene for bruchid resistance. PCR amplification and sequence analysis of PsXI suggested the presence of an insertion of unknown length in an intron of PWY19, which causes variation in the open reading frame (ORF) of PsXI. Moreover, the subcellular localization of PsXI differed between PWY19 and PHM22. These results together suggested that PsXI encoding xylanase inhibitor is responsible for the bruchid resistance of the field pea PWY19.

Ocena plonowania i zachwaszczenia mieszanek grochu siewnego z pszenżytem jarym uprawianych na zieloną masę w rolnictwie zrównoważonym

The paper presents the results of a 2016–2018 study to determine the effect of the share of components in the mixture and the harvest date on the weed infestation and yield of mixtures of field pea with spring triticale. Two factors were studied in the experiment: the proportion of components in the mixture: field pea – clean sowing 100%, spring triticale – clean sowing 100%, field pea 75% + spring triticale 25%, field pea 50% + spring triticale 50%, field pea 25% + spring triticale 75%; harvesting date: flowering stage of field pea (BBCH 65), flat green pod stage of field pea (BBCH 79). The results obtained allow us to conclude that the cultivation of pea in mixed sowings with spring triticale reduces the weed infestation in the canopy compared to pea grown in pure sowing. The highest fresh matter yield was obtained from the mixture of field pea and spring triticale with 50% share of both components, harvested at the stage of flat green pod of field pea.

Breeding indicators for high-yielding field pea under normal and heat stress environments

The warming Canadian summers have become a major abiotic stress to crops, including pea. In the past decade, attempts were made in the understanding of heat stress effect and genomic mapping for heat-responsive traits in field pea. In this study, a new recombinant inbred line population (PR-24) consisting of 39 lines was tested in 6 trials in the summers of 2020 (near normal weather conditions) and 2021 (hot/dry conditions). PR-24 was phenotyped for days to flowering (DTF), days to maturity, plant height, lodging, yield components, plot yield, and seed quality traits. Plant height could be an effective indicator for yield prediction, because its correlation with plot yield was significantly positive in all six trials despite varying degrees of heat and drought stress. Under normal summer weather conditions in 2020, relatively late maturity was correlated with greater seed yield; under heat/drought stress conditions in 2021, successful pod development on the main stem was important for final plot yield. Linkage mapping was used to dissect the genomic regions associated with the measured traits. Four QTLs were identified over multiple trials, one each for DTF (chromosome 7), reproductive node number (chromosome 5), pod number (chromosome 2), and seed protein concentration (chromosome 5). Furthermore, two indices, i.e., stress tolerance index and geometric mean yield, previously used in drought tolerance assessment were validated as useful criteria for heat tolerance assessment in this study.

Ovule abortion and seed set of field pea (Pisum sativum L.) grown under high temperature

In pea, high temperatures during reproductive development lead to severe yield loss. Although the ovule is the seed precursor, studies elucidating the effect of heat on this plant structure are scarce. We investigated the impact of heat in the field and growth chamber on ovules 4 days after the open flower (4DOF) stage. Objectives were to identify associations between ovaries and plant performance, and to evaluate seed set and ovule abortion of heat-treated plants for six cultivars from a diverse range of seed-to-ovule ratios. In the field, plants were seeded at early (control, [early seeded pea, ESP]) and late (stress plant [late seeded pea, LSP]) periods in the season. In growth chambers, plants were exposed to heat (35/18 °C) at early flowering for 4 days and then evaluated at maturity. Stressed plants (LSP) displayed twice as many aborted ovules than ESP during early embryo growth (pro-embryo to globular stage) in synchrony with reduced ovaries, ovules, and embryo sac size. Cultivars with reduced ovary size at 4DOF were related to a high number of reproductive nodes and pods in LSP ( r = −0.44 to −0.48). Similarly, under growth chamber conditions, heat caused seed reduction by increasing the abortion of immature ovules (early embryonic stages) at various reproductive nodes. Collectively, our results indicated that pea seed loss from heat in the field is largely due to early embryo abortion, a novel finding, rather than disruption of pre-fertilization events. Compensatory effects on plant performance infer plant resource adjustment. Our findings contribute to the assessment and selection of high-yielding pea cultivars for future warming seasons.

Influence of wheat based intercropping system by irrigation scheduling under limited water conditions

An experiment was conducted during three consecutive years of Rabi (2011-12 to 2013-14) at Agricultural Research Station-Ummedganj, Agriculture University, Kota (Rajasthan) on wheat based intercropping system. The experiment consisted of ten treatment combinations viz., two irrigation regimes (IW/CPE ratio 0.4 and 0.6) and five intercropping system (wheat + gram (6:4), wheat + mustard (6:4), wheat + fenugreek (6:4), wheat + field pea (6:4) and sole wheat) were under taken in split plot design with four replications.It is evident from pooled data the maximum wheat equivalent yield (53.68 q/ha) was observed with irrigation regime at IW/CPE ratio 0.6 over application of IW/CPE ratio 0.4 (45.04 q/ha). Among intercropping, wheat + gram (6:4) intercropping system gave significantly higher wheat equivalent yield (58.50 q/ha) overwheat + mustard (6:4)(50.91 q/ha), wheat + fenugreek (6:4)(46.28 q/ha) and wheat + field pea (6:4)(46.08 q/ha) intercropping system as well as sole wheat (45.04 q/ha), respectively. Significantly higher water use efficiency (23.49kg/ha-cm) was recorded under wheat + gram (6:4) intercropping system over wheat + mustard (6:4), wheat + fenugreek (6:4) and wheat + field pea (6:4) intercropping system as well as sole wheat.The maximum net return (Rs.55810/- ha-1) and B:C ratio (3.6) was observed with irrigation regime at IW/CPE ratio 0.6 as compared to IW/CPE ratio 0.4. Among intercropping, wheat + gram (6:4) intercropping system gave significantly higher net return (Rs.62426/- ha-1) and B:C ratio (4.0) over wheat + mustard (6:4), wheat + fenugreek (6:4) and wheat + field pea (6:4) intercropping system as well as sole wheat.

Cladosporium cladosporioides causes leaf blight on garden pea in Telangana, India.

Garden pea (Pisum sativum L.) is an important vegetable and pulse crop grown worldwide. Leaf blight symptoms with chlorotic lesions were observed on the pea genotypes, 2006-2008A and Arkel in field conditions at Asian Vegetable Research and Development Centre (AVRDC), Hyderabad (17°23' N; 78°29' E) and greenhouse conditions at University of Hyderabad, Hyderabad, India (17° 27' N; 78° 19' E) since 2010. The blight symptoms showed black lesions coated by a fine velvety layer of olive-grey conidia. The disease incidence on field and greenhouse pea plants ranged from 3-6%. The Cladosporium isolates, Gp01 and Gp02 were isolated from pea genotypes, Arkel and 2006-2008A in greenhouse and field conditions respectively. One fungus was predominantly isolated from infected leaf tissue plated onto potato dextrose agar (PDA), and it was identified as Cladosporium sp. based on colony morphology and conidial appearance. Single-spored cultures grown at 26±2 °C on PDA showed olive green mycelia on the obverse-side and dark green on reverse-side (Fig. 1 a,b). The conidia were limoniform with dimensions ranging from 5.91-7.33 x 3.19-4.58 µm (Table 1) and were produced on solitary conidiophores containing 1-2 septa, with no constriction whereas the aerial hyphae were septate and unbranched or rarely branched (Fig.1 c-d). To verify the pathogenicity of the fungus, detached leaf assay was carried on 30-day old Arkel leaves by point inoculation with 20 µL (106 spores/ml) spore suspension using a needle-less syringe to infiltrate the spores into the abaxial surface and the inoculated leaves were incubated at 26±2 °C for 3 days in petri plates containing moistened autoclaved absorbent cotton. Pea leaves inoculated with water served as controls. The experiment was repeated with a minimum of three times with five leaves per replication and three replications per experiment for each of the isolates. The appressorial germ tube formation was observed by scanning electron microscopy (SEM) at 12 hours post inoculation (hpi) (Fig.1 e-f). Thirty-day old pea plants were spray-inoculated with a spore suspension of 1-2 ml per plant with a concentration of 106 spores/ ml while the control plants were mock-inoculated (sprayed) with water. 5 plants per replicate per isolate with three replications per experiment and a minimum of three experiments were carried. The inoculated plants were covered with polythene zip-lock bags for two days post inoculation (dpi) and maintained in greenhouse at 26±2 °C with natural photoperiod of 14 hours. Wilting and necrosis symptoms accompanied by chlorotic lesions were observed on pea plants at 7 days post inoculation (dpi) (Fig. 2). Complying with Koch's postulates, the pathogen, which was re-isolated from the first appearance at 3 dpi from infected pea showed similar morphological characteristics as those used for inoculation. Sequencing analysis of the internal transcribed spacer (ITS) region using ITS1 and ITS4 primers (White et al. 1990), D1-D2 region sequencing (Kwiatkowski et al. 2012), Translation elongation factor 1-alpha (TEF) and Actin (ACT) gene sequencing (Nam et al. 2015) of Gp01 and Gp02 showed significant similarity with C. cladosporioides (Table S1). Further, concatenated phylogenetic trees constructed by maximum likelihood method using all the four (ITS, D1-D2, TEF and ACTIN) gene sequences of these isolates along with other reported Cladosporium species (Fig. S1a) and specific isolates of C. cladosporiodes which are reported as "sensu stricto" (Bensch et al. 2010) collected from different substrata (Fig. S1b) confirmed them as C. cladosporioides. Gp01 and Gp02 were also confirmed by Microbial Type Culture Collection (MTCC, India) as C. cladosporioides with Acc. No. MTCC 9994 and MTCC 9995. C. cladosporioides has been previously reported on Dalbergia sp. and Eucalyptus sp in India and on garden pea in other countries (Bensch et al. 2010). However, owing to the impact of this pathogen on growth and productivity of pea crop, further in-depth study needs to be carried. To our understanding this is the first report of Cladosporium cladosporioides infecting garden pea in India.

Morpho-Physiological and Biochemical Responses of Field Pea Genotypes under Terminal Heat Stress.

Field pea is one of the important short-duration cool season pulse crops which contributes significantly towards food and nutritional security. Two heat-susceptible (HS) and two heat-tolerant (HT) genotypes were selected from the previous study for further characterization. A significant variation was observed for morpho-physiological traits studied. Principal component analysis explained that first two principal components, i.e., PC1 and PC2 showed 76.5% of the total variance in optimal condition, whereas 91.2% of the total variance was covered by the first two PCs in heat stress environment. The seed yield per plant determined significant and positive association with superoxide dismutase and number of seeds per pod under optimal conditions, whereas under heat stress condition, it was positively associated with number of effective pods per plant, biological yield per plant, proline, pod length, number of seeds per pod, superoxide dismutase, and peroxidase. The significant reduction was noticed in the susceptible genotypes, whereas tolerant genotypes showed stable and non-significant reduction in chlorophyll content. Further, minimum cell damage and higher hydrogen peroxide production was noticed in the susceptible genotypes. In addition, the biochemical characterization of HS and HT genotypes revealed that the higher expression of peroxidase, superoxide dismutase, and catalase modulates the tolerant responses in HT genotypes. These genotypes were further used in developing heat-tolerant field pea genotypes.

Comparison of standardized ileal digestibility of amino acids in faba beans and field peas in broiler chickens and pigs.

An experiment, using the same set of five diets was conducted to determine and compare the standardized ileal digestibility (SID) of amino acids (AA) in faba beans and three cultivars of field peas in broiler chickens and pigs. Four test diets were prepared to contain faba beans, DS-Admiral field peas, Hampton field peas, or 4010 field peas as the sole source of nitrogen. A nitrogen-free diet (NFD), as the fifth diet, was prepared to estimate the basal endogenous losses of AA to determine the SID of AA in the test ingredients. A total of 416 male broiler chickens with an initial body weight (BW) of 951 ± 111 g were allotted to five diets in a randomized complete block design with BW as a blocking factor on day 21 posthatching. There were 8 replicate cages with 10 birds per cage for diets containing test ingredients and 12 birds per cage for NFD. All birds were allowed ad-libitum access to feed for 5 days. On day 26 posthatching, all birds were euthanized by CO2 asphyxiation and digesta contents were collected from the distal two-thirds of the ileum. Twenty barrows with an initial BW of 30.2 ± 1.58 kg, surgically fitted with T-cannulas in the distal ileum, were divided into four blocks according to BW and each block was assigned to a 5 × 2 incomplete Latin Square design that consisted of five dietary treatments and two experimental periods. For each experimental period, there was a 5-day adaptation period followed by a 2-day collection of ileal digesta samples. The data were analyzed as a 2 × 4 factorial treatment arrangement with the effect of species (i.e., broiler chickens and pigs) and test diets (i.e., four test ingredients). For broiler chickens, the SID of Lys in faba beans, DS-Admiral field peas, and Hampton field peas were above 90% but in 4010 field peas, it was 85.1%. The SID of Lys in faba beans, DS-Admiral field peas, and Hampton field peas for pigs was above 80% but was 78.9% in 4010 field peas. The respective SID of Met in faba beans, DS-Admiral field peas, Hampton field peas, and 4010 field peas were 84.1%, 87.3%, 89.8%, and 72.1% for broiler chickens, and 71.5%, 80.4%, 81.8%, and 68.1% for pigs. The SID of AA in 4010 field peas was the least (P < 0.05) for chickens, but in pigs, it was comparable with faba beans. In conclusion, the SID of AA in faba beans and field peas was greater in broiler chickens compared with pigs and there was a cultivar effect.

Replacing Summer Fallow With Field Pea in Western Nebraska

Replacing Summer Fallow With Field Pea in Western Nebraska