Showing papers on "Lathyrus published in 2003"

Adaptation and potential contribution of temperate perennial legumes to the southern Australian wheatbelt: a review

Abstract: Deep-rooted perennial pasture plants can play an important role in solving the environmental problems of rising watertables, dryland salinity and soil acidification in the wheatbelt of southern Australia. These problems are attributed to the extensive clearing of perennial native vegetation and its replacement with shallow-rooted winter-growing annual crops and pastures. Deep-rooted, herbaceous perennial legumes, particularly lucerne (Medicago sativa L.), are seen as making an increasing contribution in the cropping zones where high rates of symbiotic nitrogen fixation and increased water use are high priorities. This paper reviews the current use and the potential of a range of temperate perennial legumes for the wheatbelt of southern Australia. The genera examined include Medicago, Hedysarum, Trifolium, Onobrychis, Lotus, Galega, Astragalus, Lathyrus, Anthyllis, Psoralea, Dorycnium, Lespedeza and Securigera. There is considerable scope to expand the use of lucerne; however, there is also a need for alternative perennial species to increase biodiversity and to fill niches where lucerne is less suited. Based on current knowledge, the species with the most promise to complement lucerne include sainfoin (Onobrychis viciifolia Scop.) and sulla (Hedysarum coronarium L.) on alkaline soils, strawberry clover (Trifolium fragiferum L.) in wet or mildly saline niches and Lotus and Dorycnium spp. on waterlogged and/or acid soils.

Karyotype analysis and chromosome evolution in South American species of Lathyrus (Leguminosae).

Abstract: The karyotypes of 10 species and one variety of South American Lathyrus were determined and compared with those obtained of five entities from the Northern Hemisphere. Although all the species have a chromosome number of 2n = 14, they could be differentiated by their karyotype formula and quantitative parameters of the karyotypes. Phenetic distance and principal component analysis showed that in spite of the differences observed among entities, they can be grouped in clusters that coincide with the taxonomic sections established by F. K. Kupicha and with the life cycle of the species. South American species form a homogeneous group and can be distinguished by the presence of a subtelocentric pair, which has a macrosatellite in the long arm, and the lack of a short metacentric pair characteristic of most species of the Northern Hemisphere. From an evolutionary point of view, variation in total chromosome length without major changes in the karyotype formula suggests that changes in the amounts of genomic DNA are proportional to the relative length of each chromosome arm and that species of Notolathyrus evolved in a concerted fashion. Variation in genome size, however, is congruent with morphological variation of some reproductive organs as well as with the life cycle and minimum generation time, as predicted by the nucleotype hypothesis.

Characterization of Italian and exotic Lathyrus germplasm for quality traits

Abstract: The aim of the following work is to characterize quality traits (protein, ashes, 100 seed weight and ODAP content) of 117 accessions of Lathyrus, from either Italian or foreign countries. Significant differences among entries were estimated for all traits and accessions were classified into similar genetic groups. Principal component and hierarchical cluster analyses produced five different groups. In particular, the absence of a strong association among the investigated traits and their dominant independent roles in each separate principal component allows the achievement of a useful recombinant in breeding work. An interpretation of each cluster, based on the data obtained from the accessions, provides practical information to establish a subset of grass pea collection for further activities.

Rumen degradability of some feed legume seeds

Abstract: The aim of this work was to determine the effective degradability (ED) of CP for differ- ent feed legume seeds and the possible relationship with their physical and chemical characteristics. The ED was measured using nylon bags and rumen outflow rate techniques on three rumen cannulated wethers fed at 40 g DM·kg -0.75 , with a 2:1 (on DM basis) hay to concentrate diet. Nine seed samples of the following legume species were tested: lupin (Lupinus albus L., cultivar multolupa), dwarf chickling (Lathyrus cicera L.) ,c ommon chickling (Lathyrus sativus L.), common vetch (Vicia sativa L.) hairy vetch (Vicia villosa Roth.), bitter vetch (Vicia ervilia L.), monantha vetch (Vicia monantha Desf.) and field bean (Vicia faba L., variety minor Beck). Two different cultivars of this last species were studied: P69 (sample 1) and Jasper (sample 2). Estimates of ED of dry matter (DM) and crude protein (CP) were obtained for rumen outflow rates of 5.04 ± 0.31%·h -1 , determined for the diet concentrate. The variation of the ED of DM was moderate (from 58.8 to 69.2%) and correlated with the proportion of nitrogen linked to the acid detergent fibre (r = -0.847). Values of ED of CP of these seeds (in the above indicated order) were 79.4, 71.3, 80.7, 75.3, 75.4, 69.3, 76.6, 77.0, and 73.8%. Significant correlations between the ED of CP and the chemical composition or CP buffer solubility were not found. legume seeds / rumen degradability / protein

A rooting procedure for lentil ( Lens culinaris Medik.) and other hypogeous legumes (pea, chickpea and Lathyrus ) based on explant polarity

Abstract: The present study assessed the rooting response of lentil nodal segments in relation to explant polarity, hormone, salt and carbohydrate concentrations of the medium. Nodal segments of lentil with an axillary bud cultured in an inverted orientation (apical end in medium) showed higher rooting frequencies than explants cultured in a normal orientation (basal end in medium). The highest rooting percentage (95.35%) and average number of shoots regenerated per explant (2.4) were obtained from explants placed in an inverted orientation on Murashige and Skoog (MS) medium salts with 3% sucrose, supplemented with 5 μM indole acetic acid (IAA) and 1 μM kinetin (KN). Reducing or increasing phytohormone concentration did not alter significantly root regeneration of inverted explants. Sucrose at 3% allowed higher root regeneration frequencies compared to 1.5% sucrose. MS full concentration permitted regeneration of longer shoots with more nodes per regenerated shoot, compared to MS half-strength, which regenerated more shoots of shorter length and with less nodes. Inverted nodal segments of other hypogeous legumes (pea, chickpea and Lathyrus) also exhibited higher rooting frequencies than explants cultured in a normal orientation on MS medium with 3% sucrose and supplemented with 5 μM IAA and 1 μM KN. The most novel application of this study is the culture of nodal segments of hypogeous legumes in an inverted orientation. This procedure is a considerable improvement over other published procedures concerning in vitro rooting of lentil, pea, chickpea and Lathyrus.

Variation and association of morphological and biochemical characters in grass pea (Lathyrus sativus L.)

Abstract: Fifty grass pea land race populations of Ethiopia that were selected based on administrative regions and different altitude classes were used in this study to determine variability in morphological characters, Oxalyl Diamino Propanoic acid(ODAP) – a causative agent of lathyrism, and protein contents and their associations. Highly significant differences were observed among the populations for most of the morphological characters. Populations collected from Gondar region and the higher altitude group (>2550 m) showed the highest mean and coefficient of variation indicating the presence of high genetic diversity in this region and altitude group. ODAP analysis from single plants showed significant variation both within a population and between populations. Four individual plants with low ODAP contents ranging from 0.149% to 0.182% (range within safe level) were identified in populations collected from different regions, indicating the diversity and variation of this trait with in one population and between regions. These low ODAP lines are considered important for further breeding. The association of ODAP with grain yield, biomass, plant height and seed size was negative, suggesting that the selection of tall and late maturing varieties with large seed size and high grain yield potential will enable the development of varieties with low ODAP content.

Review: A brief history of grasspea and its use in crop improvement

Abstract: Introduction Grasspea (Lathyrus sativus L.) is an annual pulse crop belonging to the family Fabaceae (4) and the tribe Vicieae. Grasspea is known by a wide range of common names, include chickling vetch, Indian vetch (UK and USA), khesari or Batura (India) and dhal . Along with Pisum, Lens and Vicia, this genus may be a source of new and useful genetic traits for closely related genera for future plant breeding work improving commercially valuable species.

The significance of a facultative bacterium to natural populations of the pea aphid Acyrthosiphon pisum

Abstract: . 1. Laboratory studies have implicated various accessory bacteria of aphids as important determinants of aphid performance, especially on certain plant species and under certain thermal regimes. One of these accessory bacteria is PABS (also known as T-type), which is distributed widely but is not universal in natural populations of the pea aphid Acyrthosiphon pisum in the U.K. 2. To explore the impact of PABS on the performance of A. pisum , the nymphal development time and fecundity of aphids collected directly from natural populations and caged on the host plant Vicia faba in the field were quantified. Over 4 consecutive months June–September 1999, the performance of PABS-positive and PABS-negative aphids did not differ significantly. 3. Deterministic modelling of the performance data showed that the variation in simulated population increase of PABS-positive and PABS-negative aphids would overlap substantially. 4. Analysis of aphids colonising five host plants ( Lathyrus odoratus , Medicago sativa , Pisum sativum , Trifolium pratense , Vicia faba ) between April and September 2000 and 2001, identified no robust differences between the distribution of PABS-positive and PABS-negative aphids on different plants and with season or temperature. 5. It is concluded that PABS is not an important factor shaping the performance or plant range of A. pisum under the field conditions tested. Reasons for the discrepancies between this study and laboratory-based studies are considered.

The significance of a facultative bacterium to natural populations of the pea aphid Acyrthosiphon pisum

Abstract: Laboratory studies have implicated various accessory bacteria of aphids as important determinants of aphid performance, especially on certain plant species and under certain thermal regimes. One of these accessory bacteria is PABS (also known as T-type), which is distributed widely but is not universal in natural populations of the pea aphid Acyrthosiphon pisum in the U.K. 2. To explore the impact of PABS on the performance of A. pisum, the nymphal development time and fecundity of aphids collected directly from natural popula- tions and caged on the host plant Vicia faba in the field were quantified. Over 4 consecutive months June-September 1999, the performance of PABS-positive and PABS-negative aphids did not differ significantly. 3. Deterministic modelling of the performance data showed that the variation in simulated population increase of PABS-positive and PABS-negative aphids would overlap substantially. 4. Analysis of aphids colonising five host plants (Lathyrus odoratus, Medicago sativa, Pisum sativum, Trifolium pratense, Vicia faba) between April and September 2000 and 2001, identified noro bust differences between the distributio n o f

Phenotypic diversity of Ethiopian grass pea (Lathyrus sativus L.) in relation to geographical regions and altitudinal range

Abstract: Fifty grass pea (Lathyrus sativus L.) populations collected from different administrative regions and altitude classes in Ethiopia, were evaluated for variations of five morphological traits. Shannon-Weaver diversity index was calculated for traits, populations and altitude classes. Monomorphism was recorded in flower color (blue) for most of the populations. Olive seed colour was dominantly distributed in all regions with mean frequency of 50% while black seed colour is rare with mean frequency of 4% in Ethiopia. Much variability was observed within populations. High diversity values for pattern of testa colour and leaflet size were recorded in populations of highland origin (>2550 m.a.s.l.). Shannon's diversity index is highest in Gondar (H′ = 0.65) followed by Tigray region (H′ = 0.64) even though there was no significant variation in H′ values between regions. These regions with high diversity are recommended for immediate in situ and ex situ conservation.

Content of amino acids in fresh and preserved physiologically immature grass pea (Lathyrus sativus L.) seeds

Abstract: The aim of the work was to determine the level of amino acids in fresh and preserved physiologically immature grass pea seeds. Seeds of the grass pea cv. Krab at five stages of maturity, corresponding to dry matter content from 26 to 50%, were evaluated. The estimation was conducted at the stages of the raw material, the frozen product after 6 months storage cooked to consumption consistency, and the canned product within 6 months of production. In the later stages of seed maturity the content of total amino acids and of total non-essential, essential, and sulphuric amino acids computed per 100 g fresh matter increased. The computation per 16 g N showed increasing amounts of sulphuric amino acids and variation depending on the degree of maturity in the content of the remaining amino acids. Cystine with methionine were amino acids limiting the biological value of the first order, irrespective of the degree of maturity, leucine playing the same role with regard to the second order. For these amino acids the index of the limiting amino acid was 64–82 and 83–95 for the raw material, 72–77 and 91–99 for frozen seeds after cooking, and 70–75 and 86–99 for canned seeds. The integrated index of essential amino acids, depending on the degree of maturity, for the raw material was 120–126, for frozen seeds cooked 123–126, and for canned seeds 120–123.

Qualitative resistance to powdery mildew in hybrid sweet peas

Abstract: Lathyrus odoratus L. × Lathyrus belinensis L. hybrids were produced using L. belinensis as the pollen parent, with fertile seed produced by the L. odoratus parent. The F1 hybrid plants were completely self-sterile, but produced viable seeds when backcrossed to L. odoratus. The plants produced by backcrossing resembled L. odoratus, the flower colour being purple/magenta, and were self-fertile. Both hybrid plants and those produced by back crossing to L. odoratus were resistant to Erysiphe pisi DC that causes powdery mildew in sweet peas. Continued backcrossing resulted in hybrid plants, that closely resembled the L. odoratus parent, but segregated for complete resistance/susceptibility to E. pisi,with a ratio of 2.46:1 resistant to sensitive plants. This suggests the presence of a single dominant gene that confers resistance. When resistant and sensitive plants were inoculated with E. pisi and their leaf surfaces examined,using a Scanning Electron Microscope, it was found that although spores germinated on the leaves of both resistant and sensitive plants, spores present on resistant plants collapsed shortly after germination. Possible reasons for this are discussed.

Effect of 1-octylcyclopropene and 1-methylcyclopropene on vase life of sweet pea (Lathyrus odoratus L.) flowers

Abstract: SummarySweet pea (Lathyrus odoratus L.) flowers have a very short postharvest life and are sensitive to exogenous ethylene. Exposure to 1 μl l–1 ethylene enhanced flower senescence and reduced the display life of flowers to less than 3 d. Flowers pre-treated with 200 nl l–1 1-octylcyclopropene (1-OCP) or 200 nl l–1 1-methylcyclopropene (1-MCP) for 6 h at 20°C were protected against ethylene and the display life was prolonged up to almost 7 d. 1-OCP (200 nl l–1) was applied for different exposure times of 0.5, 1, 2, 4, 6, 12 h and at temperatures of 0, 5, 10, 15, 20°C. The optimum conditions for protection against ethylene were ≥4 h exposure and temperature 20°C. No significant differences in display life were observed between 1-OCP and 1-MCP at their optimum treatment concentrations, but both compounds were excellent blockers of ethylene responses in sweet pea flowers.

Large changes in the structure of the major histone H1 subtype result in small effects on quantitative traits in legumes.

Abstract: Electrophoretic analysis of the most abundant subtype of histone H1 (H1-1) of 301 accessions of grasspea (Lathyrus sativus) and 575 accessions of lentil (Lens culinaris) revealed allelic variants which most probably arose due to recent mutations In each species, a single heterozygote for a mutation was taken for construction of isogenic lines carrying different H1-1 variants Sequencing of alleles encoding H1-1 in lentil, grasspea, pea and Lathyrus aphaca showed the presence of an extended region in C-terminal tail which we termed ‘regular zone’ (RZ) It consists of 14 6-amino-acid units of which 12 (pea and Lathyrus species) or 13 (lentil) are represented by an AKPAAK sequence The structure of the hypervariable unit 8 is species-specific At the DNA level most AKPAAK units differ in the third codon positions, implying the action of natural selection preserving the RZ organization In lentil, the fast variant lost two units (including unit 8), while one AKPAAK repeat of the slow variant is transformed into an anomalous SMPAAK The mutant variant of the grasspea H1-1 differs from the standard one by duplication of an 11-amino-acid segment in N-terminal tail The isogenic lines of lentil and grasspea were compared for a number of quantitative traits, some of them showing small (1–8%) significant differences

The pattern of seed development and maturation in beach pea (Lathyrus maritimus)

Abstract: The developmental patterns of seed, seed coat, and hardseededness were studied in naturally growing crop plants of beach pea (Lathyrus maritimus (L.) Bigel.) at six reproductive growth stages (S1–S...

Changes in chemical composition during development of grass pea (Lathyrus sativus L.) seeds.

Abstract: The level of chemical components was determined in seeds of grass pea (Lathyrus sativus L.), cv. Krab, harvested at a dry matter content between 25.9 and 49.6 g/100 g of the raw material, and divided into five degrees of maturity. The results presented suggest that, in general, with an increasing maturity of seeds, the level of the following components increased if related to fresh matter: starch, dietary fibre, acids, total and protein nitrogen, total amino acids and sulphur amino acids, ash and its alkalinity, magnesium, calcium, total phosphorus and phytic phosphorus, and thiamine. The following components were reduced: vitamin C, riboflavin, carotenoids, beta-carotene, and chlorophylls. No such regularity could be found with respect to the accumulation of sugars, essential amino acids, and iron. By expressing the results in dry matter, increases were noted in starch, protein nitrogen, and thiamine. The content of sugars, total nitrogen, total amino acids, essential and sulphur amino acids, ash and its alkalinity, magnesium, phosphorus, vitamin C, riboflavin, carotenoids, beta-carotene, and chlorophylls were reduced while that of dietary fibre, iron, calcium, and phytic phosphorus varied.

Productivity of grasspea (Lathyrus sativus L.) under different levels of phosphorus and foliar spray of molybdenum

Abstract: Introduction Grasspea (Lathyrus sativus L.) is one of the important food legumes in many countries of Southern Europe, North Africa and Asia Minor . It is grown in dry and warm regions due to its potential among grain legumes to tolerate dry and unfavourable conditions . Being drought and flood tolerant, with a high seed protein content and suitability for soil amelioration, grasspea accounts for about 5% of total area in India under pulses and 4% of production. It is a significant crop of the Indo-Gangetic plains grown mainly on residual moisture as a crop succeeding another crop. Adoption of promising varieties and suitable crop management practices are important factors for exploring yield potential of grasspea. Phosphorus is the most essential nutrient for increasing pulse productivity . Molybdenum is important in the nutrition of legumes as it is essential for the activity of the enzyme nitrogenase . Hence an experiment was undertaken to study the response of grasspea varieties to phosphorus and molybdenum in a rainfed alluvial soil (entisol).

Effect of chickling vetch (Lathyrus sativus L.) or alfalfa (Medicago sativa) hay in gestating ewe diets

Abstract: Lathyrus sativus (grasspea or chickling vetch, guaya in Ethiopia, khesari in India; IPBO, 2003) is a common food legume widely grown and eaten throughout many parts of the world (Jaby El-Haramein et al., 1998; Small, 1999; IPBO, 2003). The nutritional composition of L. Sativus and L. cicera (two closely related species) is similar to that of other feed grain legumes (e.g. field pea [Pisum sativum], faba bean [Vicia faba], lupine [Lupinus angustifolius]; Hanbury et al., 2000; White et al., 2001). However, Lathyrus spp. can contain a large number of antinutritional substances that can reduce their potential as a raw, unprocessed feedstuffs (Foster et al. 1996; Grela et al., 2001). Most notable is a neurotoxin, 3-N-oxalyl-L-2,3-diaminopropionic acid (acronymns: β-oxalyl-diaminopropionic acid or ODAP and β-oxalyl-amino-alanine or BOAA), which can cause a paralysis of the lower limbs known as Alathyrism@ (Hanbury et. al., 2000; Grela et al., 2001).

Distribution of the Lathyrus L. 1753 (Fabales, Fabaceae) species in the Vojvodina Province

Abstract: Most of the Lathyrus species of the Vojvodina Province arc cultivated for fodder. They are protein-containing herbs which easily recover after grazing. Some perennial species survive in grassland communities for ten years or more. Certain species are important melliferous plants. In the Vojvodina Province, they inhabit different habitats like forests and grasslands, dry and wet sites, thus showing a wide distribution range. Besides their floristic and vegetation aspects, their role as green and dry fodder crops should be emphasized.

Heritability of seed weight in an inbred population of large-seeded Lathyrus sativus

Abstract: Introduction The grass pea (Lathyrus sativus L.) cultivated in Chile has a large, mostly clear white, grain. It is valued by European communities as the basis for the preparation of traditional dishes. Small Chilean farmers are exporting grass pea to these markets, which pay higher prices for larger seed. However, the size of the grain currently being produced is quite heterogeneous, and the export grain is produced after severe sorting of the harvested grain. A short-term project is underway , which aims to improve crop management and grain quality, particularly seed diameter. This preliminary work provides an estimate on how much of the observed variation for seed weight in a local grass pea population has a genetic basis. Seed mass appears to be a reasonably good estimator of seed diameter .

Patterns of variation in Lathyrus sativus and some related species

Abstract: The main objective of the present work is to broaden our knowledge on grass pea germplasm. 280 entries mainly represented by L. sativus, L. cicera, L. ochrus have been included in this study. Eighteen quantitative and qualitative descriptors were observed. Quantitative data together with qualitative information were subject to multivariate statistical procedures. The analysis of the principal components on quantitative traits was carried out to study the total variation of the entries under test. To summarise between-species variation and to get information in accordance with the classification of each entry, a canonical discriminant analysis was applied. Descriptive statistics for 8 quantitative traits relative to the investigated species are reported. Frequency distributions for 8 qualitative traits have also been considered. The species L. ochrus showed earliness, tallest plants, smallest seeds, lowest 100-seed weight and more secds/pod; late flowering, late maturity, shortest plants and intermediate values for the other traits were observed for L. cicera. Biggest seeds and highest 100-seed weight have characterised the L. sativus entries. The presence of high diversity within the L. sativus (primary gene pool) and L. cicera (secondary gene pool) confirms the use of both species as a valuable source of genetic material for grass pea improvement.

Luanco-INIA, a large-seeded cultivar of Lathyrus sativus released in Chile

Abstract: A new large-seeded cultivar, named Luanco-INIA, was obtained through pure line selection from accession LS-0027, from the Chilean grass pea germplasm collection . After preliminary evaluation, it was included in yield trials over three years at five central-south and south locations. Seed yield is not superior to the prevalent grass pea landraces, but seed size is larger. Mean seed weight is usually around 300 mg seed though it can reach 350 mg in a favourable environment. Generally, mean seed weight of LuancoINIA is about 50 mg over the prevalent local landrace. A mean seed weight of 300 mg seed matches with a seed calibre (longest seed diameter) of between 9 and 10 mm.

Performance of Rhizobium strains isolated from Lathyrus sativus plants growing in southern Chile

Abstract: Introduction Grass pea (Lathyrus sativus L.) is grown in southern Chile by small farmers , in poorly managed soils characterised by a high level of erosion and low fertility . As with any other legume, the symbiotic nitrogen fixation is a process that must be improved. Grain legume crops are rarely inoculated in Chile and empirical evidence suggests that ineffective Rhizobium strains may be a significant proportion of the nodulating bacteria. This may be particularly relevant in the case of grass pea, where areas not previously cultivated with this legume are being utilised. Being a low-cost, environmentally friendly, simple technology, the use of inoculants should be promoted. However, there is a lack of an inoculant specific for grass pea in Chile. Consequently, we have undertaken the task of developing a quality inoculant for grass pea, starting with the evaluation of Rhizobium strains isolated from well-nodulated grass pea plants sampled in three locations of the La Araucania region of Chile.

Seasonal changes in abscisic acid concentration of perennial root nodules of beach pea (Lathyrus maritimus (L.) Bigel.)

Abstract: Introduction Beach pea (Lathyrus maritimus [L.] Bigel.), a potential cold-climate circumpolar legume crop, naturally grows along the shorelines of Newfoundland, Canada. It is perennial and persistent for many years, and is resistant to drought and frost. It forms large continuous stands by rhizomes and has prolific seed production. Sometimes, the vegetative parts of beach pea are used as fodder for cattle (1) and seeds have been used for food or feed purposes during scarcity of other foods by stranded sailors . Vigorous plant growth has occurred in both greenhouse and field trials . The added advantage of the nutritional value of the seeds and other plant parts (5) suggests that beach pea may be a good candidate as a cold-climate crop for food, feed or forage. Having a symbiotic association with the nitrogen-fixing soil bacterium, Rhizobium, makes it even more attractive as a crop, which allows beach pea to grow well in nutrient-poor areas that can be inhospitable to other plants .

Plant defense multigene families: I. Divergence of Fusarium solani-induced expression in Pisum and Lathyrus

Abstract: The defense response in plants challenged with pathogens is characterized by the activation of a diverse set of genes. Many of the same genes are induced in the defense responses of a wide range of plant species. How plant defense gene families evolve may therefore provide an important clue to our understanding of how disease resistance evolves. Because studies usually focus on a single host species, little data are available regarding changes in defense gene expression patterns as species diverge. The expression of defense-induced genes PR10, chitinase and chalcone synthase was assayed in four pea species (Pisum sativum, P. humile, P. elatius and P. fulvum) and two Lathyrus species (L. sativus and L. tingitanus) which exhibited a range of infection phenotypes with Fusarium solani . In P. sativum, resistance was accompanied by a strong induction of defense genes at 8 hr. post-inoculation. Weaker induction was seen in susceptible interactions in wild species. Divergence in the timing of PR10 expression was most striking between P. sativum and its closest realtive, P. humile. Two members of this multigene family, designated PR10.1 and PR10.2, are strongly-expressed in response to Fusarium, while the PR10.3 gene is more weakly expressed, among Pisum species. The rapidity with which PR10 expression evolves raises the question, is divergence of defense gene expression a part of the phenotypic diversity underlying plant/pathogen coevolution?