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ABSTRACT: The claim that the 'classic' eight 'founder crop' package (einkorn wheat, emmer wheat, barley, lentil, pea, chickpea, bitter vetch, and flax) underlying the emergence of agriculture in the Near East is a relic of a larger number of domesticated species is addressed. The 'lost' crops concept relies on the idea that additional taxa were at certain points in time and in certain locations genuine crops, which were later abandoned. The issue is highly relevant to the debate concerning mono- versus polyphyletic domestication, because if there were numerous 'false starts' that were subsequently lost, this implies that plant domestication occurred over a protracted time period, and across a wide geographic range. Different criteria were used for declaring those taxa as 'lost' crops, including, but not limited to (i) identification in archaeobotanical assemblages of grains from species which are not known as crops at present; (ii) identification of such grains in what is interpreted to have been Neolithic storage facilities; and (iii) recent botanical observations on populations of crop wild relatives in disturbed habitats. The evidence for four presumed 'lost' crops (wild oat, rambling vetch, rye, and wild black lentil) and the broad bean is evaluated, and discussed in light of data on Croatian and Israeli wild pea, and Moroccan wild lentil in disturbed habitats. Based on present knowledge, the broad bean might emerge as a founder crop (without an identified wild progenitor). The same may hold true for rye, which was never lost since its adoption in the Pre-Pottery Neolithic B period in Anatolia. In the remaining three cases, there are alternative, more likely, explanations for the archaeological finds or the recent botanical observations rather than 'lost' domestication episodes.
Journal of Experimental Botany 03/2013; 64(4):815-22. · 5.36 Impact Factor
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ABSTRACT: The recent review by Fuller et al. (2012a) in this journal is part of a series of papers maintaining that plant domestication in the Near East was a slow process lasting circa 4000 years and occurring independently in different locations across the Fertile Crescent. Their protracted domestication scenario is based entirely on linear regression derived from the percentage of domesticated plant remains at specific archaeological sites and the age of these sites themselves. This paper discusses why estimates like haldanes and darwins cannot be applied to the seven founder crops in the Near East (einkorn and emmer wheat, barley, peas, chickpeas, lentils, and bitter vetch). All of these crops are self-fertilizing plants and for this reason they do not fulfil the requirements for performing calculations of this kind. In addition, the percentage of domesticates at any site may be the result of factors other than those that affect the selection for domesticates growing in the surrounding area. These factors are unlikely to have been similar across prehistoric sites of habitation, societies, and millennia. The conclusion here is that single crop analyses are necessary rather than general reviews drawing on regression analyses based on erroneous assumptions. The fact that all seven of these founder crops are self-fertilizers should be incorporated into a comprehensive domestication scenario for the Near East, as self-fertilization naturally isolates domesticates from their wild progenitors.
Journal of Experimental Botany 06/2012; 63(12):4333-41. · 5.36 Impact Factor
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ABSTRACT: Ascochyta blight, caused by Didymella rabiei, affects both domesticated chickpea and its congeneric wild relatives. The aim of this study was to compare the aggressiveness
of D. rabiei isolates from wild and domesticated Cicer spp. in Turkey and Israel on wild and domesticated hosts from both countries. A total of eight isolates of D. rabiei sampled from C. pinnatifidum, C. judaicum and C. arietinum in Turkey and Israel was tested on two domesticated chickpea cultivars and two wild Cicer accessions from Turkey and Israel. Using cross-inoculation experiments, we compared pathogen aggressiveness across the different
pathogen and host origin combinations. Two measures of aggressiveness were used, incubation period and relative area under
the disease progress curve. The eight tested isolates infected all of the host plants, but were more aggressive on their original
hosts with one exception; Turkish domesticated isolates were less aggressive on their domesticated host in comparison to the
aggressiveness of Israeli domesticated isolates on Turkish domesticated chickpea. C. judaicum plants were highly resistant against all of the isolates from different origins except for their own isolates. Regardless
of the country of origin, the wild isolates were highly aggressive on domesticated chickpea while the domesticated isolates
were less aggressive on the wild hosts compared with the wild isolates. These results suggest that the aggressiveness pattern
of D. rabiei on different hosts could have been shaped by adaptation to the distinct ecological niches of wild vs. domesticated chickpea.
KeywordsAscochyta blight–Disease severity–Host adaptation–Incubation period–Wild Cicer
European Journal of Plant Pathology 05/2012; 131(3):529-537. · 1.41 Impact Factor
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Genetic Resources and Crop Evolution 04/2012; 58(2):175-179. · 1.55 Impact Factor
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ABSTRACT: Here we argue that, based on evolutionary, ecological and agronomic considerations, climate change could not have been a suitable
background nor a probable cause of plant domestication in the Near East. This thesis is developed based on the year-to-year
yield dynamics in traditional rainfed grain farming in semi-arid environments, on the genetic basis that underlies temporal
yield dynamics in natural wild cereal populations as well as in traditional farming systems, and upon the recognition that
prior to elaborate high capacity and long-range trade networks, yield stability was more important than yield maximization.
We also briefly discuss the likely social and cultural responses to subtle and real climatic changes vs. responses to rapid
directional environmental trends. Taking into account the agronomic, ecological and genetic aspects discussed, it is suggested
that the Near Eastern founder crop assemblage was chosen to function within the normal east Mediterranean precipitation regime,
in which good rainy years create the ‘normal surplus’ that sustains farming communities during drought years, and the different
crop types provide the system with its compensating ability. A slow (but real) climatic change is unlikely to induce major
(revolutionary) cultural changes. Nor would a prominent environmental change provide the proper background for the origins
of agriculture because it would abolish the buffering capacity of the system. Therefore, farming cannot function as a sustainable
‘buffering mechanism’ to counterbalance climatic instability causing natural resource depletion.
Vegetation History and Archaeobotany 04/2012; 19(2):143-150. · 2.12 Impact Factor
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ABSTRACT: Wheat is undoubtedly one of the world's major food sources since the dawn of Near Eastern agriculture and up to the present day. Morphological, physiological, and genetic modifications involved in domestication and subsequent evolution under domestication were investigated in a tetraploid recombinant inbred line population, derived from a cross between durum wheat and its immediate progenitor wild emmer wheat. Experimental data were used to test previous assumptions regarding a protracted domestication process. The brittle rachis (Br) spike, thought to be a primary characteristic of domestication, was mapped to chromosome 2A as a single gene, suggesting, in light of previously reported Br loci (homoeologous group 3), a complex genetic model involved in spike brittleness. Twenty-seven quantitative trait loci (QTLs) conferring threshability and yield components (kernel size and number of kernels per spike) were mapped. The large number of QTLs detected in this and other studies suggests that following domestication, wheat evolutionary processes involved many genomic changes. The Br gene did not show either genetic (co-localization with QTLs) or phenotypic association with threshability or yield components, suggesting independence of the respective loci. It is argued here that changes in spike threshability and agronomic traits (e.g. yield and its components) are the outcome of plant evolution under domestication, rather than the result of a protracted domestication process. Revealing the genomic basis of wheat domestication and evolution under domestication, and clarifying their inter-relationships, will improve our understanding of wheat biology and contribute to further crop improvement.
Journal of Experimental Botany 07/2011; 62(14):5051-61. · 5.36 Impact Factor
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Xiaojun Zhang,
Chantel F Scheuring,
Meiping Zhang,
Jennifer J Dong,
Yang Zhang,
James J Huang,
Mi-Kyung Lee, Shahal Abbo,
Amir Sherman,
Dani Shtienberg,
Weidong Chen,
Fred Muehlbauer,
Hong-Bin Zhang
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ABSTRACT: Chickpea (Cicer arietinum L.) is the third most important pulse crop worldwide. Despite its importance, relatively little is known about its genome. The availability of a genome-wide physical map allows rapid fine mapping of QTL, development of high-density genome maps, and sequencing of the entire genome. However, no such a physical map has been developed in chickpea.
We present a genome-wide, BAC/BIBAC-based physical map of chickpea developed by fingerprint analysis. Four chickpea BAC and BIBAC libraries, two of which were constructed in this study, were used. A total of 67,584 clones were fingerprinted, and 64,211 (~11.7 x) of the fingerprints validated and used in the physical map assembly. The physical map consists of 1,945 BAC/BIBAC contigs, with each containing an average of 28.3 clones and having an average physical length of 559 kb. The contigs collectively span approximately 1,088 Mb. By using the physical map, we identified the BAC/BIBAC contigs containing or closely linked to QTL4.1 for resistance to Didymella rabiei (RDR) and QTL8 for days to first flower (DTF), thus further verifying the physical map and confirming its utility in fine mapping and cloning of QTL.
The physical map represents the first genome-wide, BAC/BIBAC-based physical map of chickpea. This map, along with other genomic resources previously developed in the species and the genome sequences of related species (soybean, Medicago and Lotus), will provide a foundation necessary for many areas of advanced genomics research in chickpea and other legume species. The inclusion of transformation-ready BIBACs in the map greatly facilitates its utility in functional analysis of the legume genomes.
BMC Genomics 01/2010; 11:501. · 4.07 Impact Factor
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Critical Reviews in Plant Sciences 01/2010; 29:317-328. · 4.66 Impact Factor
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ABSTRACT: For millennia, chickpea (Cicer arietinum) has been grown in the Levant sympatrically with wild Cicer species. Chickpea is traditionally spring-sown, while its wild relatives germinate in the autumn and develop in the winter. It has been hypothesized that the human-directed shift of domesticated chickpea to summer production was an attempt to escape the devastating Ascochyta disease caused by Didymella rabiei. We estimated genetic divergence between D. rabiei isolates sampled from wild Cicer judaicum and domesticated C. arietinum and the potential role of temperature adaptation in this divergence. Neutral genetic markers showed strong differentiation between pathogen samples from the two hosts. Isolates from domesticated chickpea demonstrated increased adaptation to higher temperatures when grown in vitro compared with isolates from the wild host. The distribution of temperature responses among progeny from crosses of isolates from C. judaicum with isolates from C. arietinum was continuous, suggesting polygenic control of this trait. In vivo inoculations of host plants indicated that pathogenic fitness of the native isolates was higher than that of their hybrid progeny. The results indicate that there is a potential for adaptation to higher temperatures; however, the chances for formation of hybrids which are capable of parasitizing both hosts over a broad temperature range are low. We hypothesize that this pathogenic fitness cost is due to breakdown of coadapted gene complexes controlling pathogenic fitness on each host and may be responsible for maintenance of genetic differentiation between the pathogen demes.
Applied and environmental microbiology 11/2009; 76(1):30-9. · 3.69 Impact Factor
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ABSTRACT: In this paper, we discuss, from both biological and cultural perspectives, the ancient human-plant liaison that gave rise to Near Eastern agriculture. We explain the biological aspects of Near Eastern plant domestication by a comparative analysis of legume vs. cereal crop evolution. This comparison is illustrated by the natural distribution, ecological affinity, physiology, population structure, floral biology, growth habit, plant stature, seed dispersal mode, and seed dormancy of both wild and domesticated plants of these crop groups. We discuss the differences between Near Eastern legumes and cereals with regard to each of the above aspects, and we highlight the relevance of these differences with regard to Neolithic decision-making, adoption for farming, and subsequent evolution under domestication. We reached the following conclusions: (1) Near Eastern legumes underwent different evolutionary trajectories under domestication as compared with their companion cereals, despite apparent similarities between selection under domestication of both crop groups. (2) Careful comparison of pea, lentil, and chickpea shows that each of the Near Eastern legume crops has a unique evolutionary history in its own right, and this also holds true for the cereal crops. (3) The evolutionary history of each of the Near Eastern crops, prior to as well as after domestication, is well-reflected in its adaptation profile in present-day cropping systems, which determines each crop's relative economic importance in different world regions (e.g., chickpea is a major pulse in the Indian subcontinent, and pea is a more important crop in temperate regions, while barley has the widest adaptation, extending from high-latitude temperate regions to semi-arid Mediterranean systems). (4) Ancient choice-making as reflected in the founder crops repertoire, involved nutritional considerations that may have outweighed grain yield per area and/or time unit criteria.
The Quarterly Review of Biology 04/2009; 84(1):29-50. · 7.73 Impact Factor
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ABSTRACT: Drought is the major factor limiting wheat productivity worldwide. The gene pool of wild emmer wheat, Triticum turgidum ssp. dicoccoides, harbours a rich allelic repertoire for morpho-physiological traits conferring drought resistance. The genetic and physiological bases of drought responses were studied here in a tetraploid wheat population of 152 recombinant inbreed lines (RILs), derived from a cross between durum wheat (cv. Langdon) and wild emmer (acc# G18-16), under contrasting water availabilities. Wide genetic variation was found among RILs for all studied traits. A total of 110 quantitative trait loci (QTLs) were mapped for 11 traits, with LOD score range of 3.0-35.4. Several QTLs showed environmental specificity, accounting for productivity and related traits under water-limited (20 QTLs) or well-watered conditions (15 QTLs), and in terms of drought susceptibility index (22 QTLs). Major genomic regions controlling productivity and related traits were identified on chromosomes 2B, 4A, 5A and 7B. QTLs for productivity were associated with QTLs for drought-adaptive traits, suggesting the involvement of several strategies in wheat adaptation to drought stress. Fifteen pairs of QTLs for the same trait were mapped to seemingly homoeologous positions, reflecting synteny between the A and B genomes. The identified QTLs may facilitate the use of wild alleles for improvement of drought resistance in elite wheat cultivars.
Plant Cell and Environment 03/2009; 32(7):758-79. · 5.22 Impact Factor
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ABSTRACT: Simple sequence repeat (SSR) markers have become a major tool in population genetic analyses. The anonymous genomic SSRs (gSSRs) have been recently supplemented with expressed sequence tag (EST) derived SSRs (eSSRs), which represent the transcribed regions of the genome. In the present study, we used 8 populations of wild emmer wheat (Triticum turgidum subsp. dicoccoides) to compare the usefulness of the two types of SSR markers in assessing allelic diversity and population structure. gSSRs revealed significantly higher diversity than eSSRs in terms of average number of alleles (14.92 vs. 7.4, respectively), polymorphic information content (0.87 vs. 0.68, respectively), and gene diversity (He; 0.55 vs. 0.38, respectively). Despite the overall differences in the level of diversity, Mantel tests for correlations between eSSR and gSSR pairwise genetic distances were found to be significant for each population as well as for all accessions jointly (RM=0.54, p=0.01). Various genetic structure analyses (AMOVA, PCoA, STRUCTURE, unrooted UPGMA tree) revealed a better capacity of eSSRs to distinguish between populations, while gSSRs showed a higher proportion of intrapopulation (among accessions) diversity. We conclude that eSSR and gSSR markers should be employed in conjunction to obtain a high inter- and intra-specific (or inter- and intra-varietal) distinctness.
Genome 04/2008; 51(3):187-95. · 1.65 Impact Factor
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ABSTRACT: The association between allelic diversity and ecogeographical variables was studied in natural populations of wild emmer wheat [Triticum turgidum ssp. dicoccoides (Körn.) Thell.], the tetraploid progenitor of cultivated wheat. Patterns of allelic diversity in 54 microsatellite loci were analyzed in a collection of 145 wild emmer wheat accessions representing 25 populations that were sampled across naturally occurring aridity gradient in Israel and surrounding regions. The obtained results revealed that 56% of the genetic variation resided among accessions within populations, while only 44% of the variation resided between populations. An unweighted pair-group method analysis (UPGMA) tree constructed based on the microsatellite allelic diversity divided the 25 populations into six major groups. Several groups were comprised of populations that were collected in ecologically similar but geographically remote habitats. Furthermore, genetic differentiation between populations was independent of the geographical distances. An interesting evolutionary phenomenon is highlighted by the unimodal relationship between allelic diversity and annual rainfall (r = 0.74, P < 0.0002), indicating higher allelic diversity in populations originated from habitats with intermediate environmental stress (i.e. rainfall 350-550 mm year(-1)). These results show for the first time that the 'intermediate-disturbance hypothesis', explaining biological diversity at the ecosystem level, also dominates the genetic diversity within a single species, the lowest hierarchical element of the biological diversity.
Plant Cell and Environment 02/2008; 31(1):39-49. · 5.22 Impact Factor
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ABSTRACT: Kislev et al. (Reports, 2 June 2006, p. 1372) described Neolithic parthenocarpic fig fruits and proposed that they derive from trees propagated only by cuttings and thus represent the first domesticated plant of the Neolithic Revolution. Because parthenocarpic fig trees naturally produce both seeded and seedless fruits and are capable of spontaneous reproduction, we argue that the finds do not necessarily indicate cultivation, nor horticulture predating grain crops.
Science 01/2007; 314(5806):1683; author reply 1683. · 31.20 Impact Factor
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ABSTRACT: Drought is the major constraint to chickpea (Cicer arietinum L.) productivity worldwide. Utilizing early-flowering genotypes and advancing sowing from spring to autumn have been suggested as strategies for drought avoidance. However, Ascochyta blight (causal agent: Didymella rabiei (Kov.) v. Arx.) is a major limitation for chickpea winter cultivation. Most efforts to introgress resistance to the pathogen into Kabuli germplasm resulted in relatively late flowering germplasm. With the aim to explore the feasibility of combining earliness and resistance, RILs derived from a cross between a Kabuli cultivar and a Desi accession were evaluated under field conditions and genotyped with SSR markers. Three quantitative trait loci (QTLs) with significant effects on resistance were identified: two linked loci located on LG4 in epistatic interaction and a third locus on LG8. Two QTLs were detected for time to flowering: one in LG1 and another on LG2. When resistance and time to flowering were analyzed together, the significance of the resistance estimates obtained for the LG8 locus increased and the locus effect on days to flowering, previously undetected, was significantly different from zero. The identification of a locus linked both to resistance and time to flowering may account for the correlation observed between these traits in this and other breeding attempts.
Theoretical and Applied Genetics 12/2006; 113(7):1357-69. · 3.30 Impact Factor
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ABSTRACT: Demographic expansion and (or) migrations leave their mark in the pattern of DNA polymorphisms of the respective populations. Likewise, the spread of cultural phenomena can be traced by dating archaeological finds and reconstructing their direction and pace. A similar course of events is likely to have taken place following the "Big Bang" of the agricultural spread in the Neolithic Near East from its core area in southeastern Turkey. Thus far, no attempts have been made to track the movement of the founder genetic stocks of the first crop plants from their core area based on the genetic structure of living plants. In this minireview, we re-interpret recent wheat DNA polymorphism data to detect the genetic ripples left by the early wave of advance of Neolithic wheat farming from its core area. This methodology may help to suggest a model charting the spread of the first farming phase prior to the emergence of truly domesticated wheat types (and other such crops), thereby increasing our resolution power in studying this revolutionary period of human cultural, demographic, and social evolution.
Genome 09/2006; 49(8):861-3. · 1.65 Impact Factor
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Science 08/2006; 313(5785):296; author reply 296-7. · 31.20 Impact Factor
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ABSTRACT: The transition from hunting gathering to a farming based economy – the Neolithic Revolution, was a crucial junction in the
human career, attracting the attention of many scholars: archaeologists, anthropologists, geographers, botanists, geneticists
and evolutionists among others. Our understanding of this major transformation is rather limited mainly due to the inability
to fully reconstruct the cultural, biological and environmental setup of the relevant period and organisms involved. Many
students of the subject of plant domestication have seriously entertained the hypothesis that man's first crop plants have
originated from weeds associated with the disturbed habitats surrounding pre-agricultural ancient human dwellings and or with
human refuse heaps – the so called ‘dump heap hypothesis’. In this paper we re-examine this hypothesis in light of the known
biology of the Near Eastern founder crops and the ecological preferences of their wild progenitors. Contrary to the ‘dump-heap
hypothesis’, we propose that Near Eastern farming originated as a result of a long term interaction between humans and plants
and was mainly driven by the nutritional features of the respective crops and cultural forces.
Genetic Resources and Crop Evolution 07/2005; 52(5):491-495. · 1.55 Impact Factor
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ABSTRACT: Chickpea (Cicer arietinum L.) is a major pulse crop in the Indian subcontinent and other world regions and is characterized by narrow adaptation relative to other cool season food legumes. Comparative ecophysiology employing closely related wild species is a powerful tool to broaden the understanding of the genetic and physiological basis of crop adaptation. However, meager data are available on the ecological preferences of annual wild Cicer species. Moreover, the geographic range, its size, shape, and boundaries as well as its in-ternal structure have never been studied for any of the wild Cicer taxa, thereby limiting our understanding of Cicer biology. Accordingly, this work focused on Israeli C. judaicum Boiss. a wild annual relative of chickpea. We defined the range of the species across the Mediterra-nean zone of Israel, characterized the ecogeographical profile of its habitats and studied two populated sites at the macro-and microsite levels in terms of plant density, frequency, and niche physical char-acteristics. Throughout the survey area the species is mostly confined to stony and rocky niches where competition with more aggressive annuals is small. This habitat preference dictates a patchy distribution pattern at all levels, from local niche to the region and beyond. C HICKPEA is a grain legume associated with the
Crop Science 01/2005; 46:1360-1370. · 1.64 Impact Factor
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ABSTRACT: The widely accepted models describing the emergence of domesticated grain crops from their wild type ancestors are mostly based upon selection (conscious or unconscious) of major features related either to seed dispersal (nonbrittle ear, indehiscent pod) or free germination (nondormant seeds, soft seed coat). Based on the breeding systems (self-pollination) and dominance relations between the allelomorphs of seed dispersal mode and seed dormancy, it was postulated that establishment of the domesticated forms and replacement of the wild ancestral populations occurred in the Near East within a relatively short time. Chickpea (Cicer arietinum L.), however, appears as an exception among all other "founder crops" of Old World agriculture because of its ancient conversion into a summer crop. The chickpea is also exceptional because its major domestication trait appears to be vernalization insensitivity rather than pod indehiscence or free germination. Moreover, the genetic basis of vernalization response in wild chickpea (Cicer reticulatum Ladiz.) is polygenic, suggesting that a long domestication process was imperative due to the elusive phenotype of vernalization nonresponsiveness. There is also a gap in chickpea remains in the archaeological record between the Late Prepottery Neolithic and the Early Bronze Age. Contrary to the common view that Levantine summer cropping was introduced relatively late (Early Bronze Age), we argue for an earlier (Neolithic) Levantine origin of summer cropping because chickpea, when grown as a common winter crop, was vulnerable to the devastating pathogen Didymella rabiei, the causal agent of Ascochyta blight. The ancient (Neolithic) conversion of chickpea into a summer crop required seasonal differentiation of agronomic operation from the early phases of the Neolithic revolution. This topic is difficult to deal with, as direct data on seasonality in prehistoric Old World field crop husbandry are practically nonexistent. Consequently, this issue was hardly dealt with in the literature. Information on the seasonality of ancient (Neolithic, Chalcolithic, and Early Bronze Age, calibrated 11,500 to 4,500 years before present) Near Eastern agriculture may improve our understanding of the proficiency of early farmers. This in turn may provide a better insight into Neolithic agrotechniques and scheduling. It is difficult to fully understand chickpea domestication without a Neolithic seasonal differentiation of agronomic practice because the rapid establishment of the successful Near Eastern crop package which included wheats, barley, pea, lentil, vetches, and flax, would have preempted the later domestication of this rare wild legume.
The Quarterly Review of Biology 01/2004; 78(4):435-48. · 7.73 Impact Factor
