Phaseolin Diversity in the Tepary Bean, Phaseolus acutifolius A. Gray

The tepary bean (Phaseolus acutifolius A. Gray) is grown mainly in and regions of Mexico and the southwestern U.S. as a subsistence crop by small farmers. It is also a store of genetic variability for traits such as disease and pest resistance and stress tolerance to improve the common bean (P. vulgaris L.). To determine geographic patterns of variation and the influence of domestication on genetic variability, the genetic diversity of phaseolin, the major seed storage protein, was characterized among 55 wild and 8 cultivated teparies using polyacrylamide gel electrophoresis. Fifteen electrophoretic phaseolin patterns were identified among wild forms, whereas only one pattern was exhibited by cultivars. This result suggests a single domestication in this species leading to a strong reduction in diversity. An additional finding is the divergence m phaseolin types between populations east and west of the Sierra Madre Occidental mountains.     

Introgression of Phaseolus acutifolius A. Gray Genes into the Phaseolus vulgaris L. Genome

The tepary bean (Phaseolus acutifolius A. Gray) is a desirable genetic resource for incorporation of improved disease, pest, and stress resistance into common bean (P. vulgaris L.). Reproductive barriers separate the two species and the degree to which tepary genes may be introgressed into the common bean genome has not been well described. Greenhouse studies of gene introgression through recurrent back-crossing to common bean were performed using two first backcross (BC₁) and nine second backcross (BC₂) populations. The truncate primary leaf characteristic of tepary bean was readily observed but the short primary leaf petiole and narrow bract tepary traits were infrequently observed in both BC₁ and BC₂ populations. In one BC, population high frequencies of adaxial stomata (characteristic of P. acutifolius) and the presence of a 30 kD cotyledon polypeptide from P. acutifolius were also observed; however, a diapho-rase isozyme from P. acutifolius appeared to be eliminated from BC₁ progeny at a high rate whereas 6-phosphogluconate dehydrogenase alleles appeared to be transmitted normally. The expression of tepary primary leaf truncate morphology and bract width were correlated with decreased fertility in one of the two BC₁ populations. Given suitable parental genotypes and population sizes it should be possible to transfer genes from P. acutifolius to P. vulgaris, especially in regions of the genome which are not associated with inviability or sterility. It will be difficult to transfer factors from certain regions of the tepary genome which are preferentially eliminated during introgression.     

Genetic Control of Abnormal Seedling Development in Phaseolus vulgaris L. and P. vulgaris×P. acutifolius A. Gray Hybrids

Abnormal hybrid seedling development hinders attempts to introgress diverse germplasm in common bean (Phaseolus vulgaris L.) breeding programs. In this study, the hypothesis that DL₁ and DL₂ loci control abnormal seedling development both in Phaseolus vulgaris L. intraspecific hybrids and in P. vulgaris×P. acutifolius A. Gray interspecific hybrids was tested. Hybrids from crosses between six P. vulgaris lines (two Andean dl₁ d₁, DL₂DL₂, two Mesoamerican DL₁DL₁ dl₂ dl₂, and two facilitators dl₁dl₁, dl₂dl₂) and P. vulgaris cultivar Ex Rico 23 developed normally, indicating that Ex Rico 23 has the facilitator genotype dl₁, dl₁, dl₂dl₂. Previous studies have shown that Ex Rico 23 ×P. acutifolius results in abnormal seedlings, but ‘ICA Pijao’, also dl₁, dl₁ dl₂dl₂, ×P. acutifolius results in normal seedlings. Neither the Andean nor the Mesoamerican lines crossed successfully with P. acutifolius, but crosses between one of the two facilitators (G3807) and P. acutifolius resulted in normal seedlings. These results support the hypothesis that different loci control intra- and interspecific hybrid seedling development.     

Simple Genetic Control of Hybrid Plant Development in Interspecific Crosses between Phaseolus vulgaris L. and P. acutifolius A. Gray

Crosses were performed between nine Phaseolus vulgaris lines (as females) and seven P. acutifolius lines (as- male to examine parental compatibility for the production of vigorous hybrid And backcross plants, in vitro embryo rescue techniques were required to secure hybrid and backcross proseny following interspecific crossing. Seedling development appeared to be dependent on which allele the P. vulgaris parent carried at an interspecific incompatibility locus. Seven of the nine P. vulgaris lines tested carried an allele at this locus which interacted with a nuclear factor in the P. acutifolius genome resulting in stunted, sub-lethal hybrids. The lines, ICA pijao' and ‘Sacramento Light Red Kidney’ did not carry this allele and produced vigorous hybrid progeny in combination with all P. acutifolius parents. Intensive backcrossing produced progeny which also segregated for sub-lethal and viable plant development. The observed segregation patterns suggest that a bridge crossing scheme would facilitate the introgression of P. acutifolius germplasm into incompatible P. vulgaris lines. Similarities, with an intraspecific incompatibility system are discussed.     

Breeding tepary bean (Phaseolus acutifolius) for drought adaptation: A review

Tepary bean (Phaseolus acutifolius A. Gray) is a relatively higher drought-tolerant crop than common bean (P. vulgaris), serving as genetic resource for food and genetic enhancement of related legumes. Tepary bean production is hampered by cultivation of low yielding and abiotic stress-susceptible cultivars. Targeted selection of agronomic, physiological and biochemical traits that maximizes yield gains using Phaseolus gene pool is useful to develop stress-tolerant and high-performing genotypes. The objective of this review is to provide breeding progress made regarding tepary bean improvement for drought adaptation. Agronomic, physiological and biochemical traits utilized for selection of drought-tolerant genotypes are highlighted. Genetic and genomic resources developed for tepary bean or closely related species such as common bean useful for genetic analysis and breeding are discussed. Opportunities and challenges to facilitate breeding of tepary bean genotypes with improved abiotic stress adaptation are highlighted. This will enable development of drought-tolerant tepary bean genotypes targeting selection of agronomic, physiological and biochemical traits. Use of genetically related and complementary Phaseolus species and marker-assisted selection method is key to developing drought-tolerant genotypes.     

Phaseolus Bean Improvement in Tanzania, 1959–2005

Summary Common bean is an important source of dietry protein and starch in Africa and a primary staple in parts of the Great Lakes Region. Tanzania remains one of the worlds' major bean producing countries although according to official statistics, production per capita has almost halved in the last 20 years. The main international bean improvement programmes are run by the Centro Internacional de Agricultura Tropical [CIAT] from Colombia and by the Collaborative Research Support Programme [CRSP] co-ordinated by the Land Grant Universities in the USA. CIAT also maintains the world's largest collection of Phaseolus germplasm. The National Bean Programme in Tanzania is supported by both CIAT and CRSP. Collaboration between these international programmes and the National Programme has resulted in the release of more than 20 improved bean varieties. The paper reviews the development of bean improvement programmes in Tanzania since 1959, the contribution made by the international programmes and the strategies used to develop high-yielding bean varieties with resistance to pests and diseases and tolerance to some edaphic stress factors.     

Root peroxidases and Rhizobium, Bradyrhizobium nodulation affinities of Phaseolus vulgaris L. and P. acutifolius A. Gray congruity backcross populations

Four parents [P. acutifolius var.acutifolius (A₁₉), P. a.var. latifolius `Serowi' (A<sub>9</sub>),P. a. var. latifolius(A<sub>10</sub>), and P. vulgaris `Red Cloud' kidney (V₁)] were used to create six interspecific recurrent and congruity backcross pedigrees (V₁ × A₉, A₉ × V₁, V₁ × A₁₀, A₁₀ × V₁, V₁ × A₁₉, A₁₉ × V₁) for evaluation of Rhizobium, Bradyrhizobium nodulation affinities and root peroxidase banding patterns. Most primary hybrids nodulated with all Rhizobium, Bradyrhizobium strains, while recurrent generations nodulated with strains of the recurrent parent, suggesting a number of independent loci and random assortment for strain-specific nodulation. A proximity matrix of nodulation phenotypes produced a cluster with V₁, two recurrent and two congruity backcross hybrids with V₁ as the cytoplasmic parent; a separate cluster with all primary interspecific and balanced, congruity backcross hybrids. A₉ and A₁₀were clustered the farthest away from V₁. Root peroxidase zymograms of primary hybrids were the summation of the parents and controlled by independent loci. Advanced hybrids exhibited new root peroxidases, matching those found for otherPhaseolus spp., including ancestralP. coccineus. A proximity matrix of root peroxidase phenotypes produced a cluster with only A₉ ³V₁F₁, a cluster containing only A₁₉ ³V₁ F₂, and a large cluster with all P. acutifoliusparents and hybrids with P. acutifolius as the cytoplasmic parent in balanced hybrids or the majority parent in unbalanced hybrids. Estimation of genetic distances showed primary, interspecific hybrids to be more closely related with the cytoplasmic parent. Recurrent and congruity backcross generations varied in genetic distances between each respective parent. This is the first report of congruity backcrossing creating hybrids with biochemical traits of nonparental species. This revised version was published online in August 2006 with corrections to the Cover Date.     

梨属植物等位酶遗传多样性研究

利用超薄平板微型聚丙烯酰胺凝胶的等电聚焦电泳技术,对286份梨材料进行了等位酶遗传变异分析。在8个酶系中共检测到19个清晰位点和82个等位基因,19个位点均为多态位点,位点最大等位基因数为6,体现出梨丰富的遗传种质多样性;不同的居群具有特有等位基因;通过82个等位基因可以将286份材料完全区分开,表明等位酶基因型指纹可用作梨品种区分与鉴定的依据。     

Location-Specific and Across-Location Selections for Seed Yield in Populations of Common Bean, Phaseolus vulgaris L.

Two populations of common bean, Phaseolus vulgaris L., were used to make three independent location-specific selections at Palmira, Quilichao, and Popayán, Colombia. Also, three across-location selections were made by alternating generations between Palmira and Popayan, between Quilichao and Popayán, and among Palmira, Quilichao, and Popayán. The seven highest yielding lines selected from each environment and population along with 14 parents and two checks were evaluated for seed yield, seed weight, maturity, and reaction to an-thracnose, angular leaf spot, and common bacterial blight. Mean squares due to evaluation and selection environments, selected lines, and their interactions were significant for all traits. Mean yields of selected lines were higher than the mean of parents in both populations. Among location-specific selections, lines yielded higher at their respective selection site. Moreover, selections made at Popayán were higher yielding than those made at Quilichao or Palmira when tested across locations and years. Use of Popayán, a relatively wetter and cooler site, either alone or in combination with other locations resulted in higher yield, higher seed weight, and higher resistance to anthracnose. On the average, location-specific selections were lower yielding than the across-location selections. Among across-location selections, those selected between Palmira and Popayán were the highest yielding in both populations. Selections at Palmira and across all three locations resulted in greater stability.     

An estimation of homogeneity in crop plants,with special reference to genetic vulnerability in the dry bean,Phaseolus vulgaris L.

Summary A general method of quantitatively assessing genetic similarity among a set of cultivars of a given crop is proposed, and its application to dry beans in the United States is demonstrated. The method is based upon the multi-variate technique of Principal Components Analysis. Using this method it was possible to calculate a distance metric between any two cultivars in the set and to show that such distances were highly inversely correlated with genetic relationship estimated from a knowledge of breeding ancestry.On the basis of distances among cultivars within given production regions (states in the US in this case) and knowledge of the acres of each cultivar grown in the region, an average weighted distance metric appropriate to each was calculated. Each derived distance metric serves as an index of genetic homogeneity for the crop in that region. Arguments are presented for relating the degree of vulnerability to a disease epidemic to the distance index. Indexes are calculated for nine of the major bean producing states in the US from which it is concluded that, from the standpoint of genetic vulnerability, Colorado is most vulnerable and California least vulnerable to a region-wide epidemic affecting the bean crop. It is suggested that the method demonstrated here is of nearly universal applicability, and particularly meaningful with respect to self-fertilizing crops.     

Modification of Heterosis for Protein and Yield Components by Bean Common Mosaic Virus in Phaseolus vulgaris

The effect of bean common mosaic virus on yield, yield components, and seed protein content was studied in tour bean cultivars and their F1 hybrids. The results of this experiment showed 3 significant decrease for yield in diseased plants; the 100 seed weight was also significantly reduced in one of the diseased varieties. The percentage of protein was increased m virus-diseased plants: this increase was due to non-protein nitrogen. Usually, the percentage of heterosis in virus-diseased F1 hybrid of two susceptible varieties was decreased while in F1 hybrids of “susceptible × resistant” varieties it was increased. This study shows the danger of drawing conclusions in quantitative genetic studies then dealing with both diseased and healthy plants.     

Vergleichende Streßphysiologie von Tepary-Bohnen (Phaseolus acutifolius A. Gray) als "Minor Crop" und Mwezi Moja-Bohnen (Phaseolus vulgaris, GLP 1004) als Hochleistungsleguminose im tropischen Landbau

Comparative stress physiology of tepary beans ( Phaseolus acutifolius ) as "minor crop" and mwezi moja beans ( Phaseolus vulgaris ) as high-yielding variety in tropical agriculture
The study deals with the ecophysiological demands of the "minor pulse" tepary beans ( Phaseolus acutifolius ) – possessing a high nutritional value – as well as of the high-yielding kenyan bean variety mwezi moja ( Phaseolus vulgaris, GLP 1004 ).
Special reference is dedicated on the drought resistance of the crops in order to make recommendations for potential cultivation in the semi-arid and arid drylands of South and Southeast Kenya.
Newly constructed growth containers gave possibilities to simulate different durations and intensities of water stress under controlled environmental conditions in climatic chamber experiments.
It was observed and recorded that teparies possess different mechanisms of morphological and physiological adaptation to high temperature and water stress, apparently including the ability of osmotic adjustment. The patterns of adaptation to water stress are combined with defined hydrature periods closely connected with the reduction of soil moisture.
There was no evidence of morphological adaptation of mwezi moja leaves to water stress. It was observed and recorded that there is a partial drought resistance within the upper leaf unit, apparently caused by osmotic adjustment.
The crop seems to be less adapted than tepary beans to marginal cropping areas (e.g. in agroecological zone, AE2, L 6 or LM 6; ace. to: J ätzold and S chmidt 1982/83) of the drylands due to high crop water requirements (about 30 % more than the "minor pulse"), low drought resistance and a high relative yield decrease under water stress – in spite of a short vegetation cycle (about 60–65 days).     

Genetic diversity in apricot, Prunus armeniaca, aimed at improving resistance to plum pox virus

Plum Pox Virus, a non-persistent virus transmitted by aphids, causes serious damage to stone fruits. The apricot tree is very sensitive and in order to breed apricot cultivars resistant to Plum Pox Virus and establish breeding strategies, genetic diversity based on 10 enzymatic systems, six of which were polymorphic, has been studied. The plant material studied, 94 accessions, included the most important apricot cultivars grown in PPV-affected areas. Genetic diversity is high and showed important differences between the three geographical groups studied (North African, European and North American). The North American group was very diverse and allozymes can be used to identify three subgroups. Some North American PPV-resistant cultivars were very distant from the rest of the cultivars, mainly due to the presence of rare alleles found in an Asian apricot related species. These results support the hypothesis that Asian-related species might be the origin of PPV resistance within the North American cultivars. Three North American cultivars have been considered as putative donors of PPV resistance to the European cultivars because of their agronomic behaviour, chilling requirements and distance from European cultivars. However, to increase the genetic variability of the European group and thereby to favour recombination, the study of Asian apricot resources is also recommended.     

Congruity backcrossing as a means of creating genetic variability in self pollinated crops: seed morphology of Phaseolus vulgaris L. and P. acutifolius A. Gray hybrids

Summary Seeds of early generations of three reciprocal congruity-backcross (CBC) pedigrees, developed by backcrossing Phaseolus vulgaris-P. acutifolius hybrids to each of the parent species in alternate generations, exhibited a preponderance of traits (size, shape, color, and pattern) of the cytoplasmic parent. The large size of Red Cloud (V₁), the P. vulgaris parent common to all of the pedigrees, dominated pedigrees with V₁ as the cytoplasmic parent, while the small size and rounded or square shapes of the tepary parents, wild P. acutifolius var. acutifolius PI 263590 or G400445 (A₁₉), wild P. acutifolius var. latifolius PI 406622 (A₁₀), or cultivated P. acutifolius var. latifolius Serowi PI 319443 (A₉), were the majority phenotypes when P. acutifolius was the cytoplasmic parent. Continuing through the second cycle of CBC, that is the second backcross with each of the parent species or the fourth backcross, began an amelioration of the apparent cytoplasmic effect on gene expression, as reciprocal pedigrees became more alike, usually with intermediate expression of parental traits or the appearance of new traits. The large seed size of V₁ was recovered in hybrids with P. acutifolius cytoplasm and the kidney shape of V₁ became rare in hybrids with P. vulgaris cytoplasm. Although the tepary-bean parents represented two subspecies and both cultivated and wild P. acutifolius, the three sets of reciprocal-hybrid pedigrees with P. vulgaris Red Cloud are surprisingly similar. It may be that the exotic parent used to develop a CBC pedigree should be selected more for combining ability in the interspecific cross than for specific economic traits. While the number of generations (six or more) required to produce fertile, intermediate CBC hybrids (that did not require embryo rescue) may preclude routine use of this method by practical plant breeders, the crossability of advanced hybrids with both parental species and the amount of variability apparent in advanced-hybrids progenies suggests that CBC would be valuable for maintaining exotic germplasm in immediately useful forms.     

Genetic variability among Turkish pop, flint and dent corn (Zea mays L. spp. Mays) races: Enzyme polymorphism

To determine magnitude and pattern of genetic variation, 32 Turkish corn accessions available from the USDA/ARS North Central T-Regional Plant Introduction Station (NCRPIS) collections (Ames, Iowa), representing pop, flint and dent corn races, different climatic, geographic and topographic areas in Turkey, were identified and, 19 isozyme systems were studied. Thirty-nine alleles were detected by 19 isozyme loci in 32 accessions. The PGD-2, Mmm-1, GOT-3 and IDH-1 loci were found to be monomorphic in all accessions. Mean number of alleles per locus varied between 1.2 in Balıkesir-167949 accession to 1.7 in Ankara-177600, Trabzon-185062, Eskişehir-204822 and Samsun-239573 accessions. The proportion of polymorphic loci ranged from as low as 15.8% in Balıkesir-167949 to as high as 57.9% in Trabzon-185049 accession. Observed heterozygosity was the highest in Adana-183779 and the lowest in Ankara-204800 accession. Genetic identities ranged from 0.823 for 170881-Kocaeli and 167949-Balikesir pair to 0.997 for 182327-Iğdır and 168008-Kırklareli pair. Dendrogram constructed by using Nei's genetic distances (1978) revealed three clustering groups, though one of the clusters included only 170881-Kocaeli accession. It is concluded that170881-Kocaeli accession must have experienced with intensive selection, inbreeding and/or bottleneck effects in the past. Corn germplasm managers and breeders could use the results of the present studies for monitoring genetic resources, accession identification, and sampling genetic diversity, but agronomic characteristics of these corn accessions are also needed for a better utlization of Turkish corn land races evolved over the years. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effects of Bean Population and Row Arrangement on the Productivity of Chilli/Dwarf Bean (Capsicum annuum/Phaseolus vulgaris L.) Intercropping in Sri Lanka

Intercropping of chilli ( Capsicum annuum ) and dwarf bean ( Phaseolus vulgaris ) is a recently adopted practice by farmers in Sri Lanka. As chilli fetches a higher market price, the bean population which could be incorporated into a 100% population of chilli has to be found. In the present experiment, effects of three bean populations (100, 75 and 50% of sole crop population 250 000 pl ha⁻¹) and four row arrangements (1:1, 1:2, 2:1 and 2:2) were tested at Kundasale, Sri Lanka. The land equivalent ratio (LER) of all intercrops were significantly greater than one, indicating a greater productivity per unit land area in intercropping than sole cropping. At 100% and 75% bean populations, LER and intercrop yields of bean were significantly greater than at 50%. Row arrangement did not have a significant effect on either LER or bean yield in intercrops. Intercrop bean yields were lower than sole bean yields indicating significant competition from chilli. Chilli yields were not affected by either bean population or row arrangement. Intercrop chilli yields were greater than the sole chilli yield indicating significant positive effects from bean. Greater radiation interception and lower weed growth and the absence of overlap between yield formation periods of the two component crops were probably responsible for the greater productivity (LER) of intercrops.     

Estimation of the Isozymatic Genetic Variability of a Spanish A vena sativa Germplasm Collection

An analysis of Spanish land races of Avena sativa from the Germplasm Bank of the I.N.I.A. was carried out using starch gel electrophoresis. Samples of 15 seedlings per accession were used for estimating the intra- and interpopulational genetic variability. Electrophoretic analyses were performed with crude extracts from 15 day-old seedling leaflets by means of eight isozymatic systems representing a total of ten genetic loci. Two systems were mono-morphic in all the accessions, while the other six showed polymorphism both within and between populations. Intrapopulational variability was particularly high in this collection, only 16 out of the 137 accessions being uniform for all the isozyme systems. Thus the material was shown to represent a high potential of genetic variability for breeding programmes.     

Genetics of Seed Yield and its Components in Common Bean (Phaseolus vulgaris L.) of Middle-American Origin

Genetic variance, heritability, and expected response from selection arc useful in devising alternative methods and criteria of: selection. The objectives of this study were to estimate these for seed yield and its components from 200 F₂: populations involving 80 cultivars and lines of mostly small-seeded dry bush bean (Phaseolus vulgaris L.) of habits growth I, II, and III of Middle-American origin. All cultivars and lines were crossed in eight sets of ten parents each in a Design II mating system. The F₂ populations, without parents, were evaluated in the field in a replicates-in-sets design at two locations in Colombia in 1983. Estimates of additive genetic variance were significant for yield, pods/m², seeds/pod, and seed weight. Interaction with environments was also significant. Values for nonadditive genetic variance were not significant for either yield or yield components. The estimates of narrow sense heritability, based on the F₂ population mean and unbiased by genotype x environment interaction, were 0.21 ± 0.13 for yield. 20 ± 0.13 for pods/m², 0.57 ± 0.13 for seeds/pod, and 0.74 ± 0.15 for seed weight. The expected direct response from selection of the top 20 % of F₂ populations for yield per se would result in a 4.30 % increase in yield with a correlated response of 0.21 % in seed weight. In contrast, the expected gain from direct selection for seed weight would result in a 11.76 % increase in seed weight with a, correlated gain of 0.28 % for yield. Direct selection for pods/m² would decrease yield, seeds/pod and seed weight, while direct selection for seeds/pod would reduce pods/m² and seed weight but increase seed yield by 0.37 %. Data on yield from replicated trials in the early segregating generations could be utilized for identification and selection of promising crosses and families or lines with crosses for dry bean yield improvement.     

Phaseolus coccineus Storage Proteins II. Electrophoretic Analysis and Erythroagglutinating Activity in Various Cultivars

Biochemical analyses of seed storage proteins of Phaseolus coccineus have been carried out to identify seventeen different cultivars. The electrophoretic patterns in native polyacrylamide gel electrophoresis (PAGE) and denaturing conditions (SDS-PAGE); evidenced qualitative and quantitative differences for the three major protein components: legumin, vicilin and phytohaemagglutinin (PHA). The results were confirmed by isoelectrofocusing (IEF) analyses. Erythroagglutination tests showed the presence of high agglutinating activity particularly in cultivars with low vicilin content. The experimental results allow one to distinguish all the cultivars by their electrophoretic spectra and agglutinating activities.