Crop genetic diversity

Thirty (30) accessions of okra (Abelmoschus spp. (L.) Moench) germplasm were collected from four major production regions in Ghana and were evaluated under field conditions at the Department of Horticulture, Kwame Nkrumah University of Science and Technology, KNUST, during the minor and major seasons of 2008 and 2009. The International Plant Genetic Resources Institute (IPGRI) descriptor list for okra was used as a guide for data collection. Variations were observed among the different accessions based on their vegetative traits, inflorescence, fruit and seed characteristics. There was a wide variation in plant height among the accessions; flowering and fruiting periods varied considerably among all accessions based on the output of the Principal Components, Correlation and Cluster analyses. There was a strong positive correlation between total fruit production and first fruit producing node (r = 0.76); first fruit producing node and first flowering node (r = 0.79); and number of fruits per plant and stem diameter at base (r = 0.88). The observed variabilities in the traits studied strongly indicate the possibility of selecting plants with suitable morphology when considering integration into any improvement programme towards preservation and conservation of okra diversity in Ghana. The distant relatedness among the various accessions could also be considered and incorporated into hybridisation programme in breeding for different consumer preferences and market demands.

Leclerc, C., Labeyrie, V., Coppens d’Eeckenbrugge, G. 2017. Diversité des plantes cultivées, sociétés et territoires. In: Caron, P., Valette, E., Wassenaar, T., Coppens d'Eeckenbrugge, G., Papazian, V. (eds.): Des territoires vivants pour transformer le monde. Editions Quae (Agricultures et défis du monde), Versailles, 147-150.

Background : The main goal of the work was to analyse intraspecific variation in Elettaria cardamomum Maton (cardamom) using genome size, cytological studies and molecular marker data. Nuclear DNA content and molecular marker details furnish data on genome size and genetic diversity respectively among the studied accessions and both complement each other for evolutionary and taxonomic studies.
Results: The relative 2C genome size and total number of base pairs of cardamom was determined through flow cytometric analysis using propidium iodide staining. The nuclear DNA content was estimated in various sections of the species representing individuals from wild and cultivar genotypes following Zea mays L. CE-777 (2C = 5.43 pg) as internal reference standard. Chromosome number from growing root tip was examined following standard protocols. Twenty-six ISSR primers that generated polymorphic bands were used for genetic diversity analysis of the thirty accessions of cardamom. Estimated nuclear 2C DNA content ranged from 2.57 to 3.22 pg demonstrating 1.25-fold variation. The mean amount of 2C nuclear DNA of the cardamom was calculated as 2.87 pg which is equivalent of 2806 Mbp as the diploid genome size. The chromosome number was found to be 2n = 48. Among the thirty accessions of carda-mom studied using ISSR markers, C53 (feral from Bonacaud) showed a very prominent level of genetic diversity and was lowest for C96 (Avinash-I, a released variety from Indian Institute of Spices Research, Kozhikode).
Conclusion: These analyses revealed the existence of genetic variability within the studied cardamom accessions. The plant specimens also differed significantly in their genome size. However, the genetic variability parameters did not show any correlation with genome size.

A huge part of Pakistani economy  is spent on importing edible oil every  year to meet
its own requirements. The need is to enhance and improve the production of the local
cultivars and for that purpose the genetic diversity of the local cultivars must be fully
explored.  The  present  study  was  carried  out  to  estimate  genetic  diversity  and
associations  among  studied  genotypes  of  Brassica  napus  L.  through  agro-
morphological  traits  and  SDS-PAGE  of  total  seed  proteins.  To  estimate  the  genetic
diversity  through  agro-morphological  traits,  data  was  recorded  on  12  qualitative  and
21 quantitative traits among 211 genotypes. The recorded data were analyzed through
two  complementary  methods,  i.e.,  cluster  analysis  and  principal  component  analysis.
Among  the  genotypes  studied  valuable  variability  was  observed  for  different
agronomic and morphological parameters. Among the traits, the shattering percentage
was found to have leading variations followed by plant height, days to 50% flowering
and  days  to  100%  flowering.  Medium  levels  of  variances  were  observed  among  the
genotypes  for  the  traits  of  siliquae  on  main  raceme  followed  by  silique  length  and
days  to  100%  maturity.  Among  the  studied  traits  the  greatest  and  highly  significant
correlation  (0.95**)  was  observed  between  days  to  100%  maturity  and  days  to  50%
flowering  among  the  genotypes  followed  by  correlation  (0.83**)  between  silique
length  and  silique  length/width  ratio  and  0.79**  between  main  raceme  length  and
siliquae  main  raceme-1. Through  cluster  analysis  all  the  genotypes  were  divided  into
five  main  groups.  It  was  found  that  7  out  of  21  principal  components  with  an
eigenvalue of ≥ 1.0 accounted for 69.99% of the overall differences found among 211
genotypes of Brassica napus L. studied during the present study. The contribution of
first three PCs in overall PCs was 26.96%, 10.00% and 8.9%, respectively. Among all
studied genotypes three accessions 1697, 26068 and 24854 showed great potential for
seeds  per  silique,  seed  yield  per  plant  and  1000-seed  weight,  respectively.  So  these
accessions  are  recommended  for  use  in  future  breeding  programs  for  getting
promising results.
          In  the  second  part  of  the  present  study  the  genetic  diversity  among  136
genotypes  of  Brassica  napus L.  was  characterized  through  biochemical  technique  of
SDS-PAGE.  The  germplasm  used  in  the  study  consisted  of  135  accessions  and  one
check cultivar obtained from Gene bank of Plant Genetic Resources Institute (PGRI),
NARC, Islamabad, Pakistan. During this study 12.25% polyacrylamide gels were used
following method designed by Laemmli (1970) and total of 21 protein sub-units were
observed among the genotypes. Out of these 21 bands, 16 (76.19%) were polymorphic
and the rest of 5 (23.81%) were monomorphic. These 21 protein sub-units were found
within  the  range  of  molecular  weights  from  ~6  to  ~180  kDa.  The  similarity
coefficients  among  these  genotypes  were  found  from  0.83  to  0.98.  The  genotypes
studied were divided into five major clusters through constructing the dendrogram on
the basis of dissimilarity matrix using  UPGMA (unweighted pair  group method with
arithmetic  averages).  Overall  low  levels  of  genetic  differences  were  found  in  these
studied genotypes of Brassica napus L. So, it is suggested that to find out high level of
genetic  diversity  among  these  genotypes,  2-D  gel  electrophoresis  along  with  other
modern techniques should be practiced in future because SDS-PAGE technique alone
is insufficient to fully explore the genetic diversity present in these genotypes.

One of the major issues facing humankind is global food security. A changing climate, coupled with a heightened consumer awareness of how food is produced and legislative changes governing the usage of agrichemicals for improving plant health and yield, means that alternative, more integrated and sustainable approaches are needed for crop management practices. To this end, there is increasing recognition of the value of the role of microbial inoculants in agriculture. The focus of this review is to understand how plant-growth-promoting bacteria and arbuscular mycorrhizal fungi can play a part in improving crop yield by promoting the health status of the plant through the sequestration of various nutrients and in the control of plant diseases.

Genetic diversity study in crop species is an effective tool for agrobiodiversity exploitation. The world has far too long been over-dependent on a paltry number of homogeneous varieties of a few major crops (e.g. maize, rice, wheat and potato), with their related potential vulnerabilities to biotic and abiotic stresses (pest, disease, and global climate change) particularly in parts of Asia and Africa. Sustainable conservation and utilisation of Neglected and Underutilised species (NUS) in Africa and elsewhere around the world is gaining prominence in recent times. Crop species need to be diversified and adapted to specific environments for maximum returns with resilience under variable agro-ecological climates. The teeming global population can only live and survive when there is commensurate food supply. Vegetables are major staples for most populace the world over. Okra (Abelmoschus spp L.) is an invaluable species in Agrarian economies of most countries in Asia, Africa and the Americas. The genetic worth, bioactive constituents and biochemical potential in Okra were studied and well documented for both domestic and industrial utilisation.

El género Chenopodium está integrado por numerosas especies y subespecies y por tipos cultivados y silvestres. Entre las especies cultivadas se encuentra la quinua (Chenopodium quinoa Willd.), la cañahua (Ch. pallidicaule Aellen) y los cultivares Kelite y Chía (Ch. nuttalliae Safford). De estas tres especies cultivadas, la quinua es el cultivo de mayor importancia (Bonifacio 2001). La quinua es una planta alotetraploide (2n=4x=36), muestra una herencia disómica para la mayoría de los caracteres cualitativos (Simmonds 1971, Risi y Galwey 1984, Ward 2000) y es esencialmente autógama.

La quinua fue domesticada en Bolivia, en inmediaciones del lago Titicaca (Gandarillas, 1986) hace mas o menos 6000 años atrás. Desde este centro de domesticación, su cultivo se ha extendido por toda la cordillera de los Andes. Actualmente la quinua se cultiva en Argentina, Chile, Bolivia, Perú, Ecuador y Colombia, siendo Bolivia el principal país productor. Se la cultiva desde el nivel del mar hasta los 4,000 m. Su período de crecimiento varía entre 90 y 220 días, dependiendo de las variedades. Produce aproximadamente entre 1 y 5 t/ha de semillas.

En Bolivia la quinua se produce principalmente en el altiplano y de forma marginal en los valles interandinos. Desde el punto de vista agro-ecológico, el altiplano boliviano puede ser dividido en tres regiones: Altiplano Norte, Centro, y Sur. En el Altiplano Norte, el sistema productivo esta basado en el cultivo de papa, quinua, cebada y avena. La producción de papa y quinua está destinada principalmente al consumo familiar. El principal factor limitante para la producción de quinua en esta región es la enfermedad del mildeu (Peronosproa farinosa) que puede reducir los rendimientos hasta en un 99% (Danielsen et al., 2000). Otro factor que desalienta la producción de quinua en esta zona es la baja calidad del grano de las variedades nativas (tamaño pequeño del grano que no es apreciado en el mercado de exportación).

En el Altiplano Central el sistema de producción está basado en la rotación de cultivos de papa, quinua y forrajeras. Las variedades de quinua cultivadas en esta zona son de ciclo semi-tardío y tardío, de grano pequeño a mediano. La quinua representa el 30% del ingreso anual del agricultor. Los principales factores limitantes de la producción de quinua en esta región son las enfermedades fungosas (mildiú) y las plagas. Entre las plagas se tienen a los gusanos cortadores o “ticonas” (Feltia spp., Agrotis spp. y Spodoptera spp.), y “kona-konas” que son larvas de la polilla de la quinua (Eurysacca quinoae).

En el Altiplano Sur las condiciones climáticas son extremas, la región es muy árida (precipitación anual promedio de 200 mm), con alto riesgo de heladas. Los suelos son generalmente arenosos, de baja fertilidad y afectados por la salinidad. En algunos casos, un período prolongado de sequía puede ocasionar la pérdida total del cultivo. La quinua es el único cultivo capaz de tolerar satisfactoriamente estas condiciones climáticas. Aparte de su importancia en la dieta diaria de la población del Altiplano Sur, la quinua es una fuente importante de ingresos para los pobladores, representando cerca de la mitad de su ingreso anual. Actualmente existen numerosas empresas y organización de productores que se dedican al beneficiado y comercialización de la quinua. El 60% de la producción de quinua de esta región es destinada a mercados domésticos y de exportación.

La colección Boliviana de quinua cuenta en la actualidad con más 3000 accesiones, siendo la más grande del mundo, la misma que se conserva en la estación experimental de Quipa-Quipani (La Paz). Las accesiones provienen del Altiplano Sur, Centro y Norte, de los valles interandinos. Adicionalmente se cuenta con accesiones del Norte Peruano, de Argentina y Chile, y una colección internacional. Esta colección ha sido caracterizada morfológicamente y evaluada para numerosos caracteres de interés agronómico y económico.

Si bien existe la creencia generalizada de que en los bancos de germoplasma se encuentran genes útiles para mejorar los cultivos, la realidad muestra que los científicos no han tenido mucho éxito en identificar e incorporar esos genes a cultivos comerciales (Tanksley y McCouch, 1997). La mayoría de las accesiones de los bancos de germoplasma no han contribuido, en la medida que se espera, a las variedades modernas, particularmente en lo que respecta a los caracteres complejos, como son el rendimiento, la calidad, etc. Esto se debe en gran parte a que la caracterización y utilización del germoplasma ha estado exclusivamente basado en la búsqueda del fenotipo apropiado. Sin embargo, existen evidencias que demuestran que la diversidad genética almacenada en los bancos de germoplasma puede ser aprovechada con una eficiencia nunca antes imaginada, si no se toma en cuenta a priori el fenotipo apropiado como criterio de elección. Así por ejemplo, se ha comprobado, mediante técnicas moleculares, que en arroces de bajo rendimiento existen genes para aumentar el rendimiento (Xiao et al. 1996).

En consecuencia, es importante complementar las caracterizaciones y evaluaciones fenotípicas con estudios similares a nivel molecular, para un mejor aprovechamiento del germoplasma conservado. En esta perspectiva, mediante esta actividad, se ha caracterizado molecularmente más de 2500 accesiones de quinua.

Jamun has higher nutraceutical properties and has been proved as a upcoming fruit crop in the country. To harness the genetic variability in the existing seedling population being a cross pollinated fruit crop, the survey of seedlings growing as wind break at Government Garden, Attari, were evaluated for various physico-chemicals attributes. Significant variation was observed in the tree characters i.e., trunk girth, tree height, canopy volume in different genotypes. The highest tree height was measured in Selection-III and minimum in Selection-II. Maximum fruit weight (11.0 g) was registered in Selection-I and minimum in Desi seedlings. Wide variability for fruit length (1.83 to 3.53 cm), fruit breadth (1.75 to 2.53 cm), pulp stone ratio (2.41 in Desi seedlings) to maximum (3.18) in Selection-II was observed. Maximum TSS/acid ratio, total sugar and reducing sugar to the tune of 50.8 was recorded in Selection I and minimum (26.2) in Selection III. Selection I and 'Desi' had high. Though the fruits of 'Desi' were smaller as compared to fruits of Selection I, II and III but had good eating quality because of high in TSS content.Titratable acidity was found to be at the highest level of 0.80% in 'Desi' ,while it was found lowest (0.32 per cent) in Selection-I. Selection-I registered the highest TSS/acid ratio to the level of 50.82 followed by Selection-II having TSS/acid ratio of 44.93. Selection-III recorded the lowest TSS/acid ratio 26.18 and the highest total sugars content (21.08 per cent) was in 'Desi' among all the selections. The lowest total sugar content (11.06 per cent) was found in Selection-III. 'Desi' recorded the highest reducing sugars content of 14.48 per cent while Selection-III recorded the lowest reducing sugar content i.e., 7.61 per cent.

Forage and grazing (FG) systems can store a substantial amount of soil organic carbon (SOC) under appropriate land use management and reduce atmospheric CO2 concentrations. Increasing SOC levels along with many interlinked ecosystem services are essential for increased productivity and sustainability of FG lands (FGLs). Although adoption of improved management practices (MPs) that support SOC sequestration (SOCq) is necessary, clear understandings of challenges and opportunities which are sometimes unique to individual FGLs, are also important for implementation of MPs. The objective of this forum paper is to explore the latest scientific knowledge on opportunities to address major challenges for increasing SOCq in FGLs. In intensively managed FGLs where the goal is often to maximize yields, lands are heavily fertilized and thus, usually drive towards SOC loss. Diversifications of both forage and grazing species along with strategic grazing plans have been proven as effective MPs for increasing SOCq. However, challenge of maintaining productivity levels still remains. Implementing improved grazing for nutrient cycling and integrating forage diversification for increased biodiversity are found to improve soil health attributes, which are critical for SOCq. However, to achieve this, we also need to consider site- and soil- specific factors. Extreme climatic events which often lead to decline in soil fertility status, SOCq and overall productivity of FGL systems. To address these challenges, uses of models to simulate the FGL systems and have definite choices of suitable MPs are helpful. However, we must be able to have access of wide range of datasets to develop system-level adaption-strategies which are effective to mitigate these adverse effects. Ultimately, participatory researches with novel views and improved perceptions based on the value of SOCq and long-term benefits of implementation of best MPs, developing education and outreach materials to enrich the producers’ knowledge gaps are helpful for climate resilient FGL systems.

Genetic diversity among 35 rice accessions, which included 19 landraces, 9 cultivars and 7 wild relatives, was investigated by using microsatellite (SSR) markers distributed across the rice genome. The mean number of alleles per locus was 4.86, showing 95.2% polymorphism and an average polymorphism information content of 0.707. Cluster analysis based on microsatellite allelic diversity clearly demarcated the landraces, cultivars and wild relatives into different groups. The allelic richness computed for the clusters indicated that genetic diversity was the highest among wild relatives (0.436), followed by landraces (0.356), and the lowest for cultivars. Allelic variability among the SSR markers was high enough to categorize cultivars, landraces and wild relatives of the rice germplasm, and to catalogue the genetic variability observed for future use. The results also suggested the necessity to introgress genes from landraces and wild relatives into cultivars, for cultivar improvement.

Combining ability for grain yield and its contributing characters was carried out in maize through line × tester analysis of 60 hybrids developed by crossing 15 females and four testers along with parents and checks. The 60 hybrids along with 19 parents and three standard checks were grown in Randomized Completely Block Design with two replications and were evaluated for grain yield and its 12 contributing characters. The experiments were conducted at Zonal Agricultural Research Station, V.C. Farm, Mandya, University of Agricultural Sciences, Bangalore, Karnataka state during rabi 2010.The analysis of variance indicated the presence of significant variability among the genotypes for almost all the quantitative traits studied. Combing ability analysis showed the predominant role of non-additive gene action for inheritance of all the characters studied. The lines MAI31, MAI28, and MAI35 were best general combiners exhibiting high gca effects in a desirable direction for three traits each. The tester CM500 was identified as a best combiner for grain yield per plot and some other traits studied. The hybrids MAI45×CM202, MAI33×CM202 and MAI43×CM500 were promising with respect to sca effects for grain yield as they showed high sca for that trait. These best crosses involved high × low and low × low performing parental combinations. Further, the promising single cross hybrids having a parental combination of high × high, high × low gca effects could be used for the improvement of parental lines for desired characters by selecting in advanced generations. Get more articles at: http://www.innspub.net/volume-7-number-1-july-2015-ijaar/

The  present  study  was  conducted  to  characterize  the  indigenous  rice
germplasm  on  the  basis  of  morphological  characteristics  at  Khyber
Pakhtunkhwa Agricultural University Peshawar. The germplasm consisted
of  30  rice  accessions  were  planted  in  randomized  complete  block  design
(RCBD). The data were recorded on 32 different agro-morphological traits
(15  qualitative  and  17  quantitative).  The  rice  germplasm  exhibited
sufficient  genetic  variation  for  most  of  the  qualitative  and  quantitative
traits.  Variation  was  observed  for  all  the  qualitative  traits  except  anther
color  and  ligule  shape.  Highly  significant  differences  (p<0.01)  were
observed  for  the  traits  of  flag  leaf  length,  flag  leaf  breadth,  culm  length,
days to 50% flowering, panicle length, length of primary branches panicle-
1, secondary branches panicle-1, grain length, grain width, awn length and
percent  leaf  lession  while  significant  differences  (p<0.05)  were  observed
for  peduncle length and  primary branches  panicle-1. Rice accession 6531
took  minimum  days  (95)  in  reaching  to  50%  flowering  while  accession
6512 displayed maximum panicle length (35.37 cm). Rice accession 6508
showed  the  highest  values  for  flag  leaf  length  (59.95  cm),  primary
branches  panicle-1  (13),  secondary  branches  panicle-1  (51),  spikelets
panicle-1  (240),  and  grain  width  (3.06  mm).  The  genetic  potential  of
accessions  6508,  6547,  6512  and  6531  on  account  of    excellent
performance  for  various  traits  can  be  used  in  future  rice  breeding
programs.

Quinoa (Chenopodium quinoa Willd.) is an important seed crop due to the beneficial nutritional traits. In Peru, there are 8 genebanks conserving 6302 quinoa accessions. The study of the genetic diversity of quinoa allows to know its potential to adapt to the adverse conditions of the environment besides helping to identify varieties with optimal agronomic traits. The objective of this thesis was to characterize to a molecular level 129 quinoa accessions from Puno. Genetic diversity and population structure were evaluated using 15 microsatellite markers through multiplex PCR and capillary electrophoresis. A total of 179 alleles were detected among the quinoa accessions, ranging from 7 to 19 alleles per locus with an average of 11.93, whereas the total expected heterozygosity was 0.77. Three genetic groups were detected (K1, K2, K3) whose genetic differentiation levels between groups were very low (FST = 0.028 – 0.046), so there were not discrete groups according to the PCoA and DAPC analysis. No duplicated accession was found within the 129 accessions. Bioinformatic analysis suggested polysomic inheritance in quinoa therefore it was treated as an autopolyploid organism. The results showed that the 129 accessions presented a high genetic diversity without any population structure. This work is one of the first steps for the applications of methods oriented to the good genebank management or plant breeding.

The introduction of hybrid varieties cocoa has led to the progressive disappearance of the complex agroforestry systems in Côte d’Ivoire. However in forests-savannah transition area, these systems seem to persist in despite the high frequency of bushfires, low rainfalls and the change of cocoa trees varieties. To understand the farming practices in that zone, data were collected in 68 cocoa farms located in three major cocoa producing in the sub-prefecture of Kokumbo. We used 105 plots of 0.0625 ha (25 m X 25 m) to characterize the botanical composition, structure, biophysical variation and management practices. In the 6.56 ha cocoa farm surveyed 2,149 stems belonging to 86 species and 36 families were encountered. The average species richness varied from 4 species to 6.4 per 625 m2 plot. The global density of associated plants was 227.3 trees/ha for a basal area of 24.1 m2 / ha. Results also showed significant differences in farmers’ practices which enabled us to distinguish three main cocoa agroforestry Systems (AFS): Simple AFS with open canopy and high density of plantain trees, characterized by the hybrid varieties; young complex AFS with high species diversity and opened canopy; and complex AFS with dense and closed canopy characterized Amelonado variety. These results highlight the strategy adopted by the farmers in the management of cocoa plantations in the zone of transition forest-savannah. Additional analyses must be done to assess their yield and the biomass.

Contents
1 Introduction 7
2 Taxonomy, nomenclature and geographical distribution 8
2.1 Taxonomy 8
2.2 Botanical and vernacular names 10
2.3 Geographical distribution 10
3 Description of the cultivated species 12
3.1 Morphological description 12
3.2 Ecology 14
3.3 Development of the stem and inflorescence 16
3.4 Reproductive biology 17
4 Uses and properties 20
4.1 Traditional food products 20
4.2 Current food products and their properties 20
4.3 Minor products 24
5 Origin and domestication 26
6 Genetic resources 28
6.1 Diversity among and within landraces 28
6.2 Existing germplasm banks 30
6.3 Useful and unusual phenotypes 32
6.4 Genetic erosion 33
6.5 Germplasm collecting and conservation 33
7 Genetic improvement strategies 36
8 Propagation 39
8.1 Pollen collecting, handling and controlled pollination 39
8.2 Seed 40
8.3 Asexual propagation 42
9 Agronomy of fruit and heart-of-palm production 44
9.1 Fruit: planting density and pruning 44
9.2 Fruit: mineral nutrition 44
9.3 Fruit: harvest and post-harvest handling 45
9.4 Heart-of-palm: planting density and pruning 46
9.5 Heart-of-palm: mineral nutrition 49
9.6 Heart-of-palm: harvest and post-harvest handling 52
9.7 Pests and pathogens 54
10 Production areas and commercial potential 58
10.1 Fruit 58
10.2 Heart-of-palm 59
11 Limitations and prospects of the crops 61
12 Future research needs 63
References 66

A study was conducted to determine the genotype by environment interaction (GEI) effects on yield and its components in sesame grown at three different locations across the Awash valleys in Ethiopia using AMMI and Joint Regression models. Ten released sesame varieties were evaluated in a randomized complete block design with 3 replications for two different seasons (2010/11 & 2011/12). Both models revealed that the mean squares for genotypes, environments and GEI were significant for the characters viz., seed yield, harvest index and number of capsules, indicating the presence of sufficient genetic variation among varieties and possible selection of stable entries. However, the variances due to GEI (linear) for number of capsules was not significant with rather high environmental variances, showing that the variability due to environments was higher than that due to genotypes for this particular trait. Moreover, the squared deviation from regression (S 2 di) was not significant for all characters indicating that the nonlinear sensitivity in the expressions of these traits was not important. Ranking of genotypes based on the different stability indices discriminated genotypes (Adi and Srk) for seed yield and number of capsules; (M-80, Srk and Tat) for harvest index showed high mean yield and low interaction effect which can be considered as stable varieties across environments. Whereas, genotypes (Abs and Tat) for both seed yield and number of capsules; (Adi, Arg and Klf) for harvest index, exhibited high interaction effect and are suitable for specific environments. Overall ranking revealed that genotype Srk is identified as the best variety across all environments and traits; hence it is recommended for diverse environmental conditions of the Awash valleys to exploit its yield potential. Assaita season-II and Werer season-I were the best environments where the highest mean of all traits recorded. Therefore, these environments can be ideal for increased sesame production along the Afar Rift valley of Ethiopia.

In 2005, the newly established Global Crop Diversity Trust initiated a consultation process leading to the development of over 30 global crop and regional strategies for the ex situ conservation and utilisation of crop diversity. These strategies represent a major undertaking the field of plant genetic resources, mobilizing experts to collaboratively plan for the more efficient and effective conservation and use of crop diversity. The strategies are reviewed for eight themes: regeneration, crop wild relatives, collecting, crop descriptors, information systems, user priorities, new technologies and research, and challenges to building a strategy for rational conservation. The themes shed light upon the status, constraints, and promising directions regarding ex situ conservation and utilization of plant genetic resources globally, and provide insight into the current challenges to planning for an efficient and effective global system. The primary constraints affecting conservation, use, and planning are the quality and availability of accession-level information, and availability of resources for regeneration, collecting, and research. A series of connected organizations working at the global level are addressing some of the major constraints in regeneration, collecting, information systems, descriptors, user involvement, and new technology development, although certain crops and regions will need additional support beyond the activities currently funded, particularly in collecting and in the development of specific conservation technologies. Achieving an efficient and effective global system will depend on active support by stakeholders, and will be aided by continuing to develop the strategies and by supporting the strategies’ recommendations for efficient and effective practices in plant genetic resources.

La Fundación Hondureña de Investigación Agrícola (FHIA) cada año reseña sus actividades como son los de mejoramiento de banano y plátanos, ensayos en cacao y agroforestería, hortalizas y la diversificación de cultivos. Esta síntesis le permite conocer de forma somera importantes avances de investigación y transferencia de tecnología en apoyo al desarrollo económico sustentable del país, la región y el trópico mesoamerican.

Caesalpinia bonduc L. is an important medicinal plant threatened by overexploitation. In the present study, the impact of climate on seed morphology, germination capacity, seedling, and plant growth of C. bonduc were evaluated. A total of 2000 seeds were collected in Sudanian and Guinean climate zones of Africa and their length, width, thickness, weight and color were recorded. A hierarchical classification and canonical discriminant analysis were applied to the above traits of seeds from the different climatic zones. An analysis of variance with repeated measures was applied to seeds morphotypes identified by the hierarchical classification to test for the effect of these morphotypes on seed germination, seedling and plant growth. Hierarchical classification helped to identify four seed morphotypes. Canonical discriminant analysis performed on these morphotypes revealed highly significant differences. Morphotypes 1 and 3 comprised green seeds mainly from the Sudanian zone while morphotypes 2 and 4 gathered grey seeds mainly from Guinean zone. Morphotype 3 had the longest seeds while the shortest seeds were from morphotype 1. The heaviest seeds were found in morphotype 4 whereas the lightest ones were from morphotype 1. Seeds of morphotype 4 were the thickest and widest, while the slimmest and most narrow ones were grouped in morphotype 1. Morphotype 3, consisting of large green seeds mainly from Sudanian zone, was superior in terms of seedling and plant growth among all morphotypes and should be the best choice for planting purposes of the species.

Ollitrault, P., Bruyère, S., Ocampo, J.A., de Lapeyre, J.L., Gallard, A., Argoud,  L., Duval, M-F., Coppens d'Eeckenbrugge, G., F. Le Bellec. 2007. Papaya breeding for tolerance to bacterial decline (Erwinia sp.) in the Caribbean region. Acta Horticulturae, 740: 79-91.

This paper investigates a situation of coexistence of landraces and modern crop varieties for market-oriented production in the Yunnan rice fields in China. Through a fieldwork survey of an experiment by the government with the introduction of modern varieties in traditional villages, the paper shows that landraces and modern crop varieties can co-exist. The analysis shows that the major features that play a role in the choices made by the individual farmers between modern crop varieties and landraces are not the agronomic conditions, although they certainly play a role, but economic and social drivers. The results of the analysis allows a better under- standing of the distinct socio-economic drivers and impacts of each of the production systems. The latter can provide insights for policy strategies aimed at promoting agrobiodiversity rich landscapes in situations of co- existence of heterogeneous socio-technical production systems.

This essay takes as its central explanandum the survival of an unusual personal seed collection within a larger government institution, ultimately asking why individu- als and institutions save seeds. To answer this question, it considers the cultures of seed collecting and preservation among amateurs, enthusiasts, and others without professional status in botanical or agricultural research and, simultaneously, among profes- sional breeders, geneticists, and seed scientists. The essay also reviews the roles played in saving seeds by institutional policies, technical procedures, and biological realities. Returning to the particular collection in question, the author suggests that its survival is not surprising but, instead, overdetermined given the many circumstances that drive the preservation of seeds as resources for an uncertain future.

India has shown high vulnerability towards the impact of climate change due to the dependency of 58 per cent of India's population on agriculture. The study was carried on 180 respondents in three districts selected randomly of eastern Uttar Pradesh to evaluate farmer-led adaptation strategies to the impact of climate change, activities that are predominantly led by farmers to make them more adaptable to long-term changes in weather patterns. All the respondents had experienced extreme climatic events in the last 5-10 years, making the region climate-prone. Nine farmers'-led adaptation strategies to climate change followed in crop farming were documented and quantified by using Climate Change Adaptation Index. Adaptation strategies were evaluated using the Quantification of Indigenous Knowledge method (QuIK) method; by involving the key informants followed by peer farmers. Crop diversification, use of high yielding varieties of crops and preparations of bunds to control water flow were the most preferred adaptation strategies to climate change. The irregular rainfall increased the incidence of floods in eastern Uttar Pradesh; thus, the preparation of bunds to regulate water flow in crop fields was the most efficient adaptation strategy.

Crop wild relatives are valuable genetic resources for crop improvement. Knowledge gaps, including with regard to taxonomy, distributions, and characterization for traits of interest constrain their use in plant breeding. These deficiencies also affect conservation planning, both with regard to in situ habitat protection, and further collection of novel diversity for ex situ maintenance.
Here we model the potential ranges of all 16 known wild cucurbit taxa (Cucurbita L.), use ecogeographic information to infer their potential adaptations to abiotic stresses, and assess their ex situ and in situ conservation status.
The taxa occur from the central USA to Central America, plus two South American species. Predicted taxon richness was highest in central Mexico and in the western borderlands between Mexico and the USA. We find substantial ecogeographic variation both across taxa and among populations within taxa, with regard to low temperatures, high and low precipitation, and other adaptations of potential interest for crop breeding.
We categorize 13 of the taxa medium priority for further conservation as a combination of the ex situ and in situ assessments, two low priority, and one sufficiently conserved. Further action across the distributions of the taxa, with emphasis on taxonomic richness hotspots, is needed to comprehensively conserve wild Cucurbita populations.

This paper from a multi-author volume by ICTSD (available on its website) seeks to clarify the scale of the challenges facing the international community with a view to identifying ways that governments and international organisations, cooperating or working separately, can advance SDG 2.5 through trade and market-related actions and policies. Trade can potentially help by encouraging increased productivity and incomes for small producers, facilitating access to and circulation of plant genetic resources and relevant technologies, increasing employment in rural areas, and providing new opportunities for value addition. None of this automatically arises from trade but rather requires the right actions to be adopted. International forums for negotiation on trade and related matters, multilateral institutions, and agreements relevant to trade, as well as the shifting and evolving architecture of preferential trade agreements, create “policy spaces” to engage in meaningful dialogue on this and other SDGs. International cooperation is essential, but governments also have broad freedoms to operate independently, and it is important to identify where opportunities lie and how they can act upon them.

In 2015 Tucson was recognized as the first UNESCO City of Gastronomy in the US. I was only a very minor contributor to this project. Jonathan and Gary did most of the work. I was privileged to be associated with this fine group of scholars. My major contribution was suggesting some other folks who might have something to add. It is nice to have a more recent publication on my page.

In 2011 and 2012, several expedition in the upper flow of the river Pĉinja, southeastern Serbia, rediscovered a complex wild population of Pisum elatius in the forest on the slopes of the Mount Kozjak An in situ analysis of his pea taxon showed a considerable potential for forage and grain production of very good quality. It has also shown a good tolerance to both length and intensity of low temperatures. P. elatius is regarded as able to bring more light onto the pea crop domestication.

La yuca es determinante para la seguridad alimentaria de cientos de millones de personas alrededor del mundo. A pesar de que el principal medio de propagación del cultivo es a través de semilla asexual por estacas (tallos maduros) se ha revelado una relativamente alta diversidad intraespecífica, principalmente en los sistemas de cultivo de manejo tradicional. En esta revisión se documentan algunos estudios realizados sobre la diversidad de la yuca, tanto por marcadores moleculares como morfológicos, centrándose en aquellos realizados en el Amazonas. También se exponen los principales factores que han determinado el aprovechamiento y conservación de esta diversidad, tales como la aparición espontánea de semillas de origen sexual, el sistema de chagras indígenas, la memoria biocultural y la facilidad de intercambio de semilla entre comunidades. Finalmente, se pone de manifiesto que en los sistemas de manejo tradicional la conservación y uso de la diversidad intraespecífica se constituye en un elemento prioritario que se ha perdido en los sistemas de cultivo a gran escala. En los sistemas de manejo tradicional existe un vínculo etnobotánico que pervive e invita a buscar prácticas alternativas que aseguran un mantenimiento de la diversidad, permitiendo una productividad eficiente e incluso se hace un mejor manejo para disminuir los riesgos de incidencia de algunas plagas y enfermedades.

Cassava is crucial for the food security of hundreds of millions of people around the world. Even though the main source of propagation of the crop is through asexual seed by stakes (stems-cuttings) a relative high intraspecific diversity has been identified, mainly in the traditionally managed cultivation systems. Some studies on the diversity of cassava, based on molecular and morphological markers, are documented focusing on those made in the Amazon in this review. Also, the main factors that have determined the use and conservation of this diversity are exposed, such as the spontaneous appearance of seeds of sexual origin, the system of indigenous chagras, the biocultural memory and the ease of seed exchange between communities. From this perspective, it is evident that in traditional management systems the conservation and use of intraspecific diversity is a priority element that has been lost in large-scale farming systems. In traditional management systems, there is an ethnobotanical link that survives and invites us to seek alternative practices that ensure the maintenance of diversity, allowing efficient productivity and even better management to reduce the risk of incidence of some pests and diseases.

Citation/Citar este artículo como: Pérez D, Mora R, López-Carrascal C. Conservación de la diversidad de yuca en los sistemas tradicionales de cultivo de la Amazonía. Acta biol. Colomb. 2019;24(2):202-212. DOI: http://dx.doi.org/10.15446/abc.v24n2.75428

The objective of study was to assess genetic diversity in exotic germplasm (8 th EBWYT) of wheat (Triticum aestivum L.) based on cluster analysis and principle component analysis (PCA). There was a significant relationship among the studied traits i.e. days to heating, plant height, spike length, canopy temperature and grain yield per plant. A positive significant correlation was observed between spike length and number of spikelet per spike while a negative significant correlation was assessed between canopy temperature and thousand kernel weight. Out of seven, three PCA's axes inhibited more than one Eigen value but the level of dissimilarity was high which indicated that the germplasm was with broad genetic base. Cluster analysis expressed high level of diversity because two main groups were observed, one with 14 and the other with 16 genotypes.