Lentil Lines Research Articles

Field screening in Australia of lentil germplasm for resistance to botrytis grey mould

Lentil is a relatively new crop in Australia, having undergone a rapid expansion in planting area since new cultivars were released in 1994. However, botrytis grey mould, caused by the pathogens Botrytis cinerea and B. fabae, is a serious threat to lentil production and has caused extensive crop losses in susceptible commercial lentil crops grown throughout Victoria and South Australia. At present, most commercial cultivars of lentil grown in Australia have limited resistance to botrytis grey mould. In naturally infected disease screening trials at Horsham, Victoria, in 1999 and 2000, 36 lentil lines were evaluated for their resistance to botrytis grey mould under field conditions. Large differences in resistance to botrytis grey mould were found between genotypes. The most resistant cultivars evaluated were the Canadian lines Indianhead and Matador. Indianhead had significantly higher levels of resistance to botrytis grey mould than the current susceptible Australian cultivars Aldinga, Cobber and Northfield but was not significantly better than the Australian cultivars Digger and Nugget. Results of these trials suggest that it will be possible to develop new lentil cultivars that are both resistant to botrytis grey mould and are adapted to Australian growing conditions.

Dış Kaynaklı Mercimek Hatlarının Tarımsal ve Morfolojik Özellikler için Yerel Çeşitlerle Karşılaştırılması

This research was conducted at University of Dicle, Faculty of Agriculture experimental areas during 2004/2005 and 2005/2006 growing seasons. Sixty-three lines assured from ICARDA in 2003/2004 were evaluated according to plant stand, and 22 lentil lines were selected, and these were experiment material. Standard cultivars, Kislik Kirmizi 51 and Yerli Kirmizi, and lines were evaluated over two years. Experiment design was set up Randomized Complete Block design (RCBD) with three replications. According to the results, differences among cultivars/lines were significant for days to flowering and days to maturity, plant height, first pod height, number of pods and seeds per plant, 1000 seed weight, seed yield per plant and grain yield were selected for evaluating in further experiments.

Genetic Variation in Root Traits and Nutrient Acquisition of Lentil Genotypes

ABSTRACT Lentil (Lens culinaris L.), a pulse crop, is grown in nutrient-poor soils in many developing countries, often with little or no fertilization. Knowledge on root traits of lentil and the assessment of their role in nutrient capture would help to sustain its production in these nutrient-poor soils. Root traits (root length, root hairs, root-induced acidification, and phosphatase enzymes) of 10 lentil genotypes (Barimasur-3, Barimasur-4, PLX-79542, GP-8407-5, GP-8403, BLX-79542, L-5 × 8704(2), L-107 × 87012, L-5 × 87272 and 8406-122) were investigated and then related to the plant uptake of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulphur (S), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), and cobalt (Co) in laboratory and pot experiments. There were significant (p < 0.05) differences in root length (RL) and root-hair density (number mm−1 root) among the genotypes. The genotypes did not differ to induce rhizosphere acidification and acid phosphatase activity (aptase). Uptake of most nutrients differed significantly (p < 0.05) among the genotypes, but root length (RL) was, in general, weakly correlated to the uptake of the most nutrients in the shoot dry matter (DM). The genotypes with prolific root-hair formation (Barimasur-4 and Barimasur-3) were particularly superior in uptake of those nutrients (K, P, Fe, Mn, Cu, Zn, Mo) whose availability in soils is usually low and whose transport to the roots is diffusion limited. The results of this investigation, though based on a small sample of lentil accessions/cultivars, suggest that genetic variation in lentil root traits and nutrient uptake can be pronounced. Screening of a large number of local and exotic cultivars or lines of lentil should be conducted by including more root traits (N2 fixation, organic acids, mycorrhizae) to find nutrient-efficient germplasm to promote lentil production.

Screening techniques and sources of resistance to abiotic stresses in cool-season food legumes

The adaptability and productivity of cool-season food legumes (chickpea, faba bean, lentil, pea) are limited by major abiotic stresses including drought, heat, frost, chilling, waterlogging, salinity and mineral toxicities. The severity of these stresses is unpredictable in field experiments, so field trials are increasingly supplemented with controlled-environment testing and physiological screening. For drought testing, irrigation is used in dry fields and rain-out shelters in damp ones. Carbon isotope discrimination (Δ13C) is a well-established screen for drought tolerance in C3 cereal crops which is now being validated for use in grain legumes, but it is relatively expensive per sample and more economical methods include stomatal conductance and canopy temperature. Chickpea lines ICC4958 and FLIP87-59C and faba bean line ILB938 have demonstrated good drought tolerance parameters in different experiments. For frost tolerance, an efficient controlled-environment procedure involves exposing hardened pot-grown plants to sub-zero temperatures. Faba beans Cote d’Or and BPL4628 as well as lentil ILL5865 have demonstrated good freezing tolerance in such tests. Chilling-tolerance tests are more commonly conducted in the field and lentil line ILL1878 as well as derivatives of interspecific crosses between chickpea and its wild relatives have repeatedly shown good results. The timing of chilling is particularly important as temperatures which are not lethal to the plant can greatly disrupt fertilization of flowers. Salinity response can be determined using hydroponic methods with a sand or gravel substrate and rapid, efficient scoring is based on leaf symptoms. Many lines of chickpea, faba bean and lentil have shown good salinity tolerance in a single article but none has become a benchmark. Waterlogging tolerance can be evaluated using paired hydroponic systems, one oxygenated and the other de-oxygenated. The development of lysigenous cavities or aerenchyma in roots, common in warm-season legumes, is reported in pea and lentil but is not well established in chickpea or faba bean. Many stresses are associated with oxidative damage leading to changes in chlorophyll fluorescence, membrane stability and peroxidase levels. An additional factor relevant to the legumes is the response of the symbiotic nitrogen-fixing bacteria to the stress.

Diversity of boron-toxicity tolerance in lentil growth and yield

Boron (B) toxicity is increasingly being recognized as a problem in arid areas of West Asia, where lentil is widely grown. This study investigated whether or not: (1) phenotypic variation of B-toxicity tolerance exists at the seedling stage in lentil, (2) such variation persists to affect adult performance, and (3) there is geographical diversity in seedling tolerance. Four experiments were conducted in a greenhouse. Boric acid was added and mixed uniformly into the soil-mix to prepare high-B soil. Experiment I screened 77 lentil lines randomly selected from ICARDA's international nurseries. Visual growth scores and foliar B-toxicity symptom scores were taken 4–5 weeks after sowing, and used as an indicator for B-toxicity tolerance. In Experiments II and III, four selected lines were studied beyond the seedling stage. In Experiment IV, 231 lentil accessions from seven different countries/regions of the world were screened. There were highly significant differences between the 77 lines in B-toxicity tolerance at the seedling stage as indicated by their degree of B-toxicity symptom, and plant growth. The two tolerant and two sensitive selections from Experiment I showed diverse performance up to maturity as reflected by their differences in leaflet loss, dry mass reduction, and seed yield when grown in high-B soil. There were significant differences in B-toxicity tolerance between the 231 accessions. On average, accessions from Afghanistan were the most tolerant, followed by those from India, Iraq, Syria, Europe, Ethiopia, and Nepal.

Genetic analysis of the raffinose oligosaccharide pathway in lentil seeds

Two lentil (Lens culinaris) cultivars, Syrian Local Large (SLL) and PANT-L-406 (PL), have been used to study the genetics of the raffinose family of oligosaccharides (RFO) and a related compound, ciceritol, which is a galactosyl cyclitol. The RFO and ciceritol are the major soluble α-galactosides in lentil seeds. Crosses were made between the two lentil lines and the patterns of inheritance for the total α-galactoside content and for individual RFO compounds (raffinose, stachyose, verbascose) and ciceritol were determined in the embryos and seed coats from single seeds of the reciprocal F1s, the F2s and ten F3 families. The inheritance patterns for each of the α-galactosides were complex and much of this complexity was attributed to an interaction between the embryo and its surrounding testa. A clear-cut segregation pattern was observed for verbascose. This was the result of PL embryos having very low, or no, verbascose. The F2 embryos had a segregation ratio of 3 high to 1 low level for this compound, suggesting that within this cross a low verbascose content was determined by a single recessive gene. There was good evidence from the F2 and F3 generations of a negative correlation between low levels of verbascose and high levels of ciceritol, which suggests a metabolic link between the RFO pathway and the pathway leading to ciceritol. The data are discussed in terms of defining strategies for genetically manipulating thea-galactoside composition in lentil seeds, such that their negative effects on nutrition may be overcome without reducing significantly their positive role in abiotic stress resistance.

Genetic analysis of the raffinose oligosaccharide pathway in lentil seeds

Two lentil (Lens culinaris) cultivars, Syrian Local Large (SLL) and PANT-L-406 (PL), have been used to study the genetics of the raffinose family of oligosaccharides (RFO) and a related compound, ciceritol, which is a galactosyl cyclitol. The RFO and ciceritol are the major soluble alpha-galactosides in lentil seeds. Crosses were made between the two lentil lines and the patterns of inheritance for the total alpha-galactoside content and for individual RFO compounds (raffinose, stachyose, verbascose) and ciceritol were determined in the embryos and seed coats from single seeds of the reciprocal F(1)s, the F(2)s and ten F(3) families. The inheritance patterns for each of the alpha-galactosides were complex and much of this complexity was attributed to an interaction between the embryo and its surrounding testa. A clear-cut segregation pattern was observed for verbascose. This was the result of PL embryos having very low, or no, verbascose. The F(2) embryos had a segregation ratio of 3 high to 1 low level for this compound, suggesting that within this cross a low verbascose content was determined by a single recessive gene. There was good evidence from the F(2) and F(3) generations of a negative correlation between low levels of verbascose and high levels of ciceritol, which suggests a metabolic link between the RFO pathway and the pathway leading to ciceritol. The data are discussed in terms of defining strategies for genetically manipulating the alpha-galactoside composition in lentil seeds, such that their negative effects on nutrition may be overcome without reducing significantly their positive role in abiotic stress resistance.

Pattern of accumulation of some major and trace elements in salt‐tolerant and salt‐sensitive lines of lentil under nitrogen deficiency

The response of two lines of lentil (Lens culinaris), ILL 6796 (salt‐tolerant) and ILL 6778 (salt‐sensitive), to nitrogen (N) deficiency was examined under glasshouse conditions. Plants of the two lines were subjected to 56(control), 28, 14, and 7mgN L‐1 in Rorison's nutrient solution. The ILL 6796 had significantly greater dry matters of shoots and roots, and seed yield than ILL 6778 at varying external N levels of the growth medium. Concentrations of N and P in different plant parts of the two lines generally decreased with decrease in N levels of the rooting medium. By contrast, an increase in leaf calcium (Ca2+) concentrations in both lines was observed with decreasing external N levels, although root Ca2+ concentrations decreased considerably and those of seed remained unaffected. An antagonistic effect between N and Ca2+ was observed in the leaves of both lines. Magnesium (Mg2+) in the leaves and roots of both lines generally decreased, whereas those of seed remained unaffected under N deficient regimes. Comparison of lines showed that ILL 6796 had greater N in the leaves and roots, and potassium (K+) in the roots than those of ILL 6778. By contrast, ILL 6778 accumulated significantly greater Mg2+ and zinc (Zn2+) in leaves and manganese (Mn2+) in seed than ILL 6796 at the lower N levels. Of the different trace elements analyzed only iron (Fe2+), Mn2+ and Zn2+ in seed of both lines slightly increased with decrease in N level of the growth medium. The concentrations of trace elements in different plant parts of both lines did not bear any relationship with the uptake of major nutrients under N deficient regimes. It is concluded that in lentil uptake of maj or nutrients such as N, P, K, Ca, and Mg was perturbed due to N deficiency, but in contrast, the uptake of trace elements Fe, Mn, Zn, and copper (Cu) in the leaves and roots remained unaffected except the leaf Zn2+ in ILL 6778.

Effect of potassium deficiency on growth and some biochemical characteristics in two lines of lentil (Lens culinaris Medic.)

The effect of low potassium regimes on two lines, ILL 6796 (salt-tolcrant) and ILL 6439 (salt-sensitive), of lentil (Lens culinaris) was studied in a pot experiment under glasshouse conditions. Plants of the two lines were treated with 78, 39, 19.5, and 9.75 mg K·L−1 in Rorison’s nutrient solution. ILL 6796 excelled ILL 6439 in biomass production under varying K regimes. Of the various organic solutes measured in the present study only total soluble sugars proved to be helpful in discriminating the lines, i.e., total sugars increased consistently in ILL 6796 with a decrease in K level of the growth medium, whereas in ILL 6439 they decreased significantly with a decrease in K levels. ILL 6796 showing high efficiency for K utilisation (high shoot growth) could be of great economic value in terms of its use in soils deficient in K.

Pathogenic variability in Australian isolates of Ascochyta lentis

Variation for virulence was examined amongst 39 isolates of Ascochyta lentis from Australia. The reactions of 22 lentil (Lens culinaris L.) lines showed considerable differences between isolates in their pathogenicity. The isolates of A. lends could be divided into six distinct pathotypes with different virulence patterns on the lentil lines ILL 358, ILL 7537, ILL 7515, ILL 5588, ILL 5244 and Eston. Pathotype six was most virulent, causing disease on all differentials, while pathotype one was avirulent on all differentials. There were also differences between isolates in their aggressiveness.

Field reactions of lentil lines and cultivars to isolates ofAscochyta fabaef. sp.lentis

Field reactions of lentil lines and cultivars to isolates of<i>Ascochyta fabae</i>f. sp.<i>lentis</i>

Effect of nitrogen deficiency on growth and some biochemical characteristics in salt‐tolerant and salt‐sensitive lines of Lentil (lens cul1narismedic.)

The response of a salt‐tolerant line ILL 6793 and a salt‐sensitive line ILL 6439 of lentil (Lens culinaris) to N deficiency was studied in a pot experiment under glasshouse conditions. Plants of the two lines were treated with 56, 28, 14 and 7 mg N L−1 in Rorison's nutrient solution. The salt‐tolerant line excelled the salt‐sensitive line in relative biomass production (per cent of control basis) under varying N regimes. Of the various physiological/biochemical variables measured in the present study only chlorophyll b and total soluble sugars proved to be helpful in discriminating the lines. Chlorophyll b was significantly greater in ILL 6793 as compared with ILL 6439 at the two lower N levels. Total soluble sugars increased consistently in both lines with decrease in N level of the growth medium and the salt‐tolerant line ILL 6793 had significantly greater soluble sugars than the salt‐sensitive ILL 6439 at 28 and 14 mg N L−1. Chlorophyll a and free amino acids were uniformly reduced in both lines with d...

Carbon Isotope Discrimination and Indirect Selection for Seed Yield in Lentil

Carbon isotope discrimination (CID) has been proposed as a secondary trait to indirectly select for improved seed yield and water‐use efficiency. To determine the effectiveness of CID to indirectly select for seed yield, 10 diverse lentil (Lens culinaris Medikus) genotypes were grown at four locations in Saskatchewan in 1992 and 1993. Samples were collected for CID determination from leaves at flowering (CIDLF), leaves at maturity (CIDML) and seed at maturity (CIDMS). Variability for CID was present, but no crossover G × E interactions were observed. A significant crossover genotype by sampling date interaction for CID resulted from a change in ranking of genotypes for CIDLF and CIDML. Seed yield was positively correlated with CIDLF and CIDML. The phenotypic correlation between seed yield and CIDLF was 0.82** (dr = 8). However, this highly significant relationship was an artifact resulting from the fact that samples for CIDLF were collected for all genotypes on the same day, although PI 244026, an early maturing genotype, flowered about 15 d earlier than the other lentil lines. When PI 244026 was removed from the analysis, variability in CID was greatly reduced and the correlation between CIDLF and seed yield approached zero (r = 0.22, df = 7). The correlation between seed yield and CIDML remained positive and significant, but was inconsistent across locations and years. The broad sense heritability for CIDML (0.73 ± 0.16) was lower than the broad sense heritability for seed yield (0.98 ± 0.029). These results suggest that under the conditions tested CID should not be used to indirectly select for seed yield in lentil.

An Assessment of Variation for Nutritional and Non‐nutritional Carbohydrates in Lentil Seeds (Lens culinaris)

AbstractThe levels of the raffinose family of α‐galactosides (raffinose, stachyose, verbascose and ciceritol) and of the nutritional carbohydrates (fructose, sucrose and starch) were determined in the seed of a range of lentil lines from germplasm collections and commercial Spanish cultivars. Significant levels of variation were found for all the measured characters, and particularly for the α‐galactosides. The greatest variation was found in verbascose content, which ranged from about 1 % of the seed dry weight to undetectable amounts. The relationship between these chemical components and morphological seed characteristics was assessed. The only significant relationship between the different groups of characteristics was a positive correlation between the level of verbascose and the average seed weight for each genotype.

Association of isozyme markers with quantitative trait loci in random single seed descent derived lines of lentil (Lens culinaris Medik.)

Polymorphism at isozyme loci was used to locate factors responsible for variation in quantitative traits of lentil. Eight sets of random single seed descent (RSSD) derived lines were developed by advancing individual F3 plants of interspecific (L. culinaris Medik. × L. orientalis Boiss.) hybrids to the F6. The RSSD lines in each of the eight sets differed for alleles at 2–8 isozyme loci. In each set, association of isozyme loci with variation in seven quantitative traits (days to flower, days to mature, plant height, biomass, seed yield, harvest index, seed weight) was determined for each pairwise combination of a quantitative trait with a marker locus. Loci affecting variation in all seven quantitative traits were detected by their association with 14 isozyme markers (Aat-c, Aat-m, Aat-p, Adh-1, Fk, Gal-1, Gal-2, Lap-1, Lap-2, Pgd-p, Pgi, Pgm-c, Pgm-p, Skdh). The known position of 10 the 14 isozyme loci on the lentil genetic map was used to mark the genomic regions for possible location of associated quantitative trait loci (QTL). Detected QTL were found to be located in six of the seven linkage groups on lentil genetic map. Regions of the genome represented by linkage groups, 1, 5 and 7 appeared to affect a greater number of traits than other genomic regions represented by linkage groups 2, 3 and 4. Results indicated that the mean expression of quantitative traits at segregating marker locus classes can be used to locate the genetic factors in lentil which influence the behavior of economically important traits.

Adaptation of Lentil to the Mediterranean Environment. II. Response to Moisture Supply

SummaryLentil is generally grown as a rainfed crop in areas of West Asia and North Africa where rainfall is highly variable. This study aimed to measure genetic responses to variation in moisture supply in the yield of seed and straw, evapotranspiration and water use efficiency, to guide the lentil breeding programme. The response of 25 diverse lentil lines to a soil water gradient was studied in 1987/88 and 1988/89 at Breda, northern Syria, using a line-source sprinkler system. The coefficient of determination between rainfed and irrigated seed yield in the dry 1988/89 season was r2 = 0.26, and the genotypes that were well adapted to dry conditions were different from those well adapted to wet conditions. However, there were also widely adapted genotypes that yielded well under both wet and dry conditions. The selection of such genotypes might be appropriate for the region receiving 300–400 mm annual rainfall, in contrast with the approach to selection suggested for drier areas (less than 300 mm annual rainfall) in a companion article. Soil moisture extraction from the time of maximum profile recharge to maturity in 1987/88 and cumulative crop evapotranspiration in the 1987/88 rainfed crop did not differ among lentil lines. In the irrigated treatment, however, evapotranspiration in the medium to late maturing lines exceeded that in the early maturing lines towards maturity.

Adaptation of Lentil to the Mediterranean Environment. I. Factors Affecting Yield Under Drought Conditions

SummaryLentil frequently suffers from drought stress towards the end of the growing season in rainfed Mediterranean farming systems. This study aimed to quantify the contribution of yield potential under irrigated conditions and of drought escape to the adaptation of lentils to drought, and to identify traits of value in selection for adaptation to a rain-fed Mediterranean environment. Twenty-five diverse lentil lines were sown under both irrigated and rainfed conditions in the 1987/88 and 1988/89 seasons in northern Syria. In 1987/88 the total seasonal rainfall was 403 mm and average rainfed biomass and seed yields were 5.0 and 1.8 t ha-l, respectively. In contrast, in 1988/89 the total season rainfall was 180 mm and average biomass and seed yields were only 0.67 and 0.12 t ha-1, respectively. Early vigour (estimated as a visual score) and percentage ground cover were strongly associated with final biomass, and were of value in predicting economic yield (seed + straw). Early maturity was correlated with seed yield. In the dry season 1988/89, 49% of the variation in seed yield among lines was accounted for by variation in flowering time. Drought escape was clearly the key response to drought. For severely drought-prone areas, selection for early flowering is therefore required. Variation in flowering time and seed yield under irrigated conditions accounted for 62% of seed yield variation under drought stress.

A comparison of seed yields of winter grain legumes in Western Australia

Field trials were conducted in 2 seasons at 13 sites on neutral to alkaline soils in Western Australia, to compare the growth and seed yield of 6 winter grain legume species: field pea (Pisum sativum L.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), lentil (Lens culinaris Medik), narrow leaf lupin (Lupinus angustifolius L.), albus lupin (L. albus). In a dry year (1991), overall site mean seed yield was highest for field pea (1.35 t/ha), then faba bean (1.22 t/ha) and narrow leaf lupin (0.85 t/ha). Chickpea, lentil line ILL5728, and albus lupin produced an average seed yield of 0.64 t/ha. Rainfall in 1992 was above average and seed yields of all species except field pea were higher than in 1991. Heavy rainfall in winter and spring caused transient waterlogging at several sites, affecting growth and seed yield of most species. Faba bean responded positively to the increase in rainfall and produced exceptional seed yields of &gt;4 t/ha at 3 sites. Mean seed yield was highest for faba bean, at 2.87 t/ha, then narrow leaf lupin (1.19 t/ha), chickpea (1.1 t/ha), and field pea (1.0 t/ha). Field pea performed poorly at several sites due to its susceptibility to transient waterlogging and black spot disease (caused by Mycosphaerella pinoides). Albus lupin and lentil line ILL5728 produced similar seed yields (0.78 t/ha). Lentil cvv. Laird (1991) and Kye (1992) had low seed yields due to poor adaptation. Seed yield differences between species at various locations were not simply related to any soil chemical parameters or to depth to clay. On a calcareous soil of pH(CaC12) 8 at Dongara, the growth of narrow leaf lupin was severely affected and the crop failed. Days to flowering varied between species; faba bean was earliest to flower (76 days), then field pea. Faba bean and field pea (particularly in 1991) generally produced the most dry matter, both early and at final harvest. The relationship between seed yield and rainfall was complicated by transient waterlogging and fungal disease (e.g. black spot in field pea) at many sites. Seed yield was significantly positively related to final dry matter production but not to harvest index.

Germplasm evaluation of dual-season lentil (Lens culinaris) lines for the arid highlands of west Asia

SUMMARYExperiments to evaluate the suitability of lentil lines using an innovative dual-season approach for improved and reliable production under the harsh environmental conditions of the highlands of west Asia were conducted in Balochistan for 3 years (1986/87, 1987/88 and 1988/89) by the Arid Zone Research Institute. Two ICARDA-bred lines, ILL5865 and ILL5677, when assessed using a wide range of seeding times, appeared to be sufficiently flexible and well adapted to the conditions of extreme cold and aridity to be able to replace the ultra small-seeded local landrace. These ICARDA lines have seed sizes approximately double those of the local landrace and results of consumer acceptability studies suggest that the lines will have desirable marketing qualities. These two lines were selected for further larger-scale agronomy trials at multiple sites in Balochistan in subsequent seasons. Other lines, ILL5690, ILL1939 and ILL5730, have also shown potential, but only at certain seeding times and, as such, will be retained for further assessment in ongoing germplasm evaluation trials.Initial findings indicate that there are now good prospects for identifying dual-season lentil lines suitable for introduction into highland farming systems. However, further research will be required before new lentil lines will be an attainable reality for a large proportion of the dryland farming community of west Asia.

Effect of Sowing Date on the Growth and Yield of Lentil in a Rainfed Mediterranean Environment

SummaryThe effect of advancing the sowing date from early February to November on the growth and seed and straw yields of three large seeded and three small seeded lines of lentil (Lens culinaris) was studied under rainfed conditions in northern Syria between 1982 and 1985. The average seed and straw yields from early winter sowing were 838 and 2476 kg ha−1 compared with 679 and 1470 kg ha−1, respectively, from a late sown crop. There were seasonal differences in the advantage in seed yield from early sowing, largely because infestation by Orbanche species limited the use of early sowing. There were no overall differences between the growth and yields of large and small seeded lines, but genetic variation within groups was apparent for all characters. A high rate of dry matter accumulation, manifested as early vigour, was always related to a high final economic biomass.