Interspecific hybridization between Vicia faba (L.) and Vicia narbonensis (L.): Early pod growth and embryo-sac development

Summary Fertilized embryo-sac development and pod growth was studied in one Vicia faba cultivar, one Vicia narbonensis population and their reciprocal crosses. The initial development of endosperm and embryo was at least four days faster in V. narbonensis than in V. faba. Pods and ovules developed also faster in V. narbonensis than in V. faba. The growth rate of the hybrid pods followed the growth rate of the mother species, but was slower than that of the pods from selfed flowers. In the cross V. narbonensis × V. faba the ovules stopped growing 9 days after pollination, while in the reciprocal cross they stopped growing 15 days after pollination. Hybrid embryo-sacs from V. faba × V. narbonensis were aborted before they reached the stage of 256 endosperm nuclei or 200 embryo cells. Selfed V. faba embryo-sacs reached this stage in less than 9 days after pollination. In the reciprocal cross the embryo-sacs were aborted before they reached the stage of 128 endosperm nuclei or 80 embryo cells. Selfed V. narbonensis embryo-sacs reached this stage at the 4th day after pollination. Given that at these stages the embryo has less than 200 cells it was concluded that an in-ovule embryo culture technique should be developed to obtain hybrid plants.     

Early Embryo-Sac Development and Intraspecific Variation in the Mean Endosperm Cell Cycle Time in Vicia narbonensis (L.)

The early endosperm development in seven Vicia narbonensis populations was studied under a 23/ 16 ° C day/night temperature regime. Double fertilization occurred in less than 24 h after pollination. Endosperm divisions were synchronous until the 8th division of the endosperm nuclei. Aberrant endosperm nuclei were first observed alter the 8th division and their number increased after the 10th division. Endosperm nuclei continued to divide until the 12th day after pollination. During the following days a decrease in the number of endosperm nuclei was observed together with a substantial increase in the number of aberrants. Endosperm nuclei finally disintegrated. Neither cellularization nor starch deposition was observed in the endosperm. A positive correlation (r 0.69) was recorded between early pod length and the number of endosperm nuclei found in the ovules within each pod. In the populations studied the number of endosperm nuclei increased at a steady but different rate. This was followed by embryo development as well. It was concluded that intraspecific variation in the mean endosperm cell cycle time exists in Vicia narbonensis and that populations A 174 and A 202 should be more compatible to Vicia faba ev. ‘Polycarpe’ than population A 201.     

Electrophoresis of the Seed Proteins of Vicia faba L. and Its Immediate Progenitors — A Reappraisal

Electrophoretic patterns of total seed protein analyzed by polyacrylamide gel electrophoresis under non-dissociating and dissociating conditions were found to have diagnostic value for the Vicia species. The close similarity in the seed protein profiles of the cultivated species and Vicia narbonensis narbonensis indicated that this last species can be considered as the immediate progenitor of V. faba. The study also indicated that V. serratifolia should be included as a subspecies in V. narbonensis. The broad bean, Vicia faba, is one of the most important leguminous pulses cultivated over a wide range (from Central Asia to Western Europe and from Ethiopia and Sudan to Scandinavia). Schultz -Motel (1972) was the first to identify remains of V. faba seeds from archeological sites of the Bronze Age, mainly from Central and Southern Europe. Recently, Kislev (1985) found charred seeds of horsebean (V. faba L.) from the 7th millennium B.C. Thus, horsebean should be included among the legumes grown by some early Neolithic people. Zohary and Hopf (1973) have suggested that the wild ancestors of V. faba are species belonging to section Faba. In particular, the French vetch V. narbonensis L., was the promosing candidate; most probably, because the area of distribution of V. narbonensis coincides with that of V. faba. On the other hand, Ieibe (1934), Ladizinsky (1975), and Abdall and Gunzel (1979) refuted the reports that V. narbonensis (and wild species from the section Faba) may be considered as immediate ancestors of the cultivated species of V. faba. These authors reported on the albumin profile of seed protein in Vicia. This study aims to reassess the relationships between V. faba and its taxonomically related species in terms of their storage protein profiles and present some information on the evolution of V. faba.     

Differential response of Vicia faba L. genotypes to 2, 3, 5-triiodobenzoic acid (TIBA)

Summary Response to application of the growth regulator 2, 3, 5-triiodobenzoic acid (TIBA) was examined in the parents and F₁ progenies of a diallel cross of six inbred lines of Vicia faba. TIBA affected the genotypes differentially but in general gave shorter internodes, reduced apical dominance, increased pod set on the lower nodes and earlier seed maturity.     

Inheritance and linkage of a gene for testa-imposed seed dormancy in faba bean (Vicia faba L.)

Seed dormancy in the grain legumes may interfere with germination in some situations, yet is not well described. Dormancy in faba bean (Vicia faba L.) was investigated to determine the mode of inheritance and whether the gene or genes controlling this trait are linked to other genes. Seeds produced by 235 recombinant inbred lines at the F₆ generation were used for this study. The parents were the cultivar ‘Optica’ and 172, an Afghanistan landrace which possesses extended seed dormancy. Germination was scored on a seed sample from each recombinant inbred line. Segregation patterns indicated that the trait is monogenic. This gene, named doz, is linked to a gene controlling anthocyanin and proanthocyanidin synthesis, sp-b, with the genetic distance estimated to be about 25 cM. No associations were detected between seed dormancy and pod dehiscence, seed lustre or mean seed weight. The implications of the persistence of a gene for seed dormancy in the gene pool of V. faba for the introgression of traits from landraces and cultivars possessing dormancy and for the origins of domesticated V. faba are discussed.     

An embryological study of a Pisum sativum x Vicia faba cross

Summary Flowers of Pisum sativum plants grown in the field and greenhouse were self-pollinated and pollinated with Vicia faba. Germination of pollen and pollen tube growth were slower in the Pisum x Vicia cross. About 2% fertile ovules in the field and 8% in the greenhouse were obtained from the Pisum x Vicia cross, compared to 26% and 48% for Pisum x Pisum. Development of the Pisum x Vicia embryo was normal in form, though much slower than the Pisum x Pisum embryo, and about the sixth day it began to collapse. The greatest difference between the two types of crosses was observed in the endosperm. While the Pisum x Pisum endosperm nuclei divided normally and endosperm developed throughout the ovule cavity and around the embryo, the Pisum x Vicia endosperm nuclei formed only scattered masses of densely stained nuclei which were not always in close proximity to the hybrid embryo. It was concluded that faillure of some ovules to develop following Pisum sativum x Vicia faba cross pollination was the result of slow germination of pollen and slow growth of the Vicia pollen tubes, with subsequent lack of fertilization. Collapse of fertilized ovules was associated with abnormal and limited development of the hybrid endosperm, possibly leading to lack of nourishment and eventual collapse of the hybrid embryo.     

Evaluation and utilisation of cacao (Theobroma cacao L.) germplasm at the International Cocoa Genebank, Trinidad

The aim of this study was to identify promising genotypes in the International Cocoa Gene bank, Trinidad (ICG,T) for use in cacao breeding. Subsets of the germ plasm collection were evaluated for bean number, bean weight, pod index (581 genotypes) and resistance to Phytophthora pod rot(500 genotypes). Among three groups of cacao assessed (For astero, Refractario and Trinitario), Trinitario had the highest percentage of genotypes (36.9%) with large bean weight (> 1.2 g), while For astero possessed the highest proportion of genotypes (22.6%) with a large number of beans (> 45). The ICS population had the highest percentage (44.1%) of genotypes with heavy beans, and IMC the highest percentage of genotypes with large bean number (68.6%). A low, but significant negative correlation (r = –0.19, p≤ 0.001) between bean number and bean weight suggests that an increase in bean number may repress an increase in bean weight and vice versa. However, inten genotypes good values of bean weight and number were combined demonstrating that selection for both large bean number and bean weight is possible. The highest percentage (28.1%) of genotypes with low pod index (< 20.1) was observed in the Trinitario group (mainly ICS). The Forastero group had the highest percentage of Phytophthora resistant accessions(18.0%). The PA population had the highest proportion of resistant (24.0%) and moderately resistant (38.0%)genotypes. Sixty-five and 99 genotypes were categorised with large bean weight and high bean number, respectively, and 60 genotypes were found with a low pod index. Seventy-eight genotypes were identified with resistance to Phytophthora podrot. A significant relationship was observed between resistance to Phytophthora pod rot (measured as the frequency of localised lesions) and bean number (r = –0.45, p ≤ 0.001)showing that the two traits may complement each other. The combination of low to intermediate pod index with moderate to high resistance to Phytophthora podrot was found in 87 genotypes, 12 of which were also reported to have resistance to witches’ broom disease. These genotypes are of high potential value in cacao breeding and their inclusion in working and corecollections would be justified. This revised version was published online in July 2006 with corrections to the Cover Date.     

Production and cytogenetics of tetraploid–octoploid Avena hybrids

The objectives of this research were to gather hybridization information about crosses between tetraploid and synthetically derived octoploid lines of Avena and their reciprocals, and to study the cytology of the hybrids obtained. When the octoploid plants were used as females, only 2.6% of the pollinated florets set seed, while seed set increased to 39.0% in reciprocal crosses. However, germination was 95.7% for the first group of hybrids and only 18.2% for the reciprocals. These diverse results can be explained by the paternal: maternal endosperm genomic ratios and the hypothesis of polar nuclei activation. The tetraploid-octoploid hybrids did not always contain 42 chromosomes. Octoploid lines derived indirectly from tetraploid (AABB) × hexaploid (AACCDD) crosses were found to retain their A and B genome chromosomes. Univalents in the above hybrids averaged 15.44 in 1990 and 15.15 in 1991, indicating the presence of C and D genome chromosomes inherited from the octoploid lines. Directly synthesized octoploids from diploid (A_cA_c) × hexaploid (AACCDD) crosses were found to form 20.44 univalents, 5.30 bivalents, and 2.69 trivalents when crossed with AABB tetraploid species. The high number of univalents indicates that chromosomes from at least three genomes, i.e. B, C, and D, remain unpaired, while trivalents are the result of homology between the A and A_c genomes. Hybrids between tetraploid and octoploid lines can be obtained at low frequencies but, regardless of the direction of the cross, these hybrids are highly sterile.     

The identification of faba bean (Vicia faba L.) trisomics by translocation tester set

Summary Five subtelocentric primary trisomics of Vicia faba L. were isolated from crosses between asynaptic mutants and normal plants or translocation tester stocks. The extra chromosome of each trisomic was identified cytologically by critical multivalent association at metaphase I of meiosis.     

Inheritance of resistance to Rhynchosporium secalis in spring barley (Hordeum vulgare L.)

The inheritance of durable resistance of selected spring barley varieties to Rhynchosporium secalis was investigated. Data from the F₂ generation of a 4 × 4 diallel, without reciprocals and the F₄ generation of three crosses selected out of this diallel, suggest that resistance in this sample of varieties tested is complex in inheritance. Significant additive effects were detected indicating that the resistance level of barley cultivars may be improved by the hybridisation of suitable varieties. However, the genes conferring resistance seem to be concealed by the expression of one completely dominant resistance gene in our set of varieties. These results are partly in conflict with previous results on the inheritance of resistance to R. secalis in the breeder's line ‘11258/2286₁₃A’ indicating that the effectiveness of this resistance gene may be greatly influenced by the genetic background of the current population of R. secalis.     

Compatibility between wild and cultivated common bean (Phaseolus vulgaris L.) genotypes of the Mesoamerican and Andean gene pools: Evidence from the inheritance of quantitative characters

The extent and distribution of incompatibility between gene pools (Mesoamerican and Andean) and evolutionary classes (wild, landrace and bred) of the common bean (Phaseolus vulgaris) was explored by seeking anomalous values of highly heritable quantitative traits in the progeny of crosses. Clear incompatibility (no progeny or sterile or deformed progeny) was shown by 28 crosses in a 12-parent wild × bred diallel cross, and 37 crosses in a 12-parent landrace × bred diallel cross. Incompatibility was particularly common in the progeny of certain genotypes, but was not consistently associated with the division between gene pools or evolutionary classes. When crosses showing clear incompatibility were eliminated from the data, days to flowering, number of seeds per pod, log (weight per seed) and seed roundness in the F₁ generation gave a good fit to an additive-dominance model, confirming that there is no overall tendency to incompatibility between the gene pools. There was a division between the gene pools with regard to log (weight per seed), as expected, but there was no such division, with regard either to the means of the parent lines or the distribution of the statistics V _r and W _r (which indicate the distribution of dominant alleles between genotypes), for the other quantitative variables. Differences between reciprocal crosses were strikingly widespread, and appeared generally to be due to cytoplasmic effects or cytoplasmic × nuclear interactions rather than maternal effects, indicating that the direction in which a cross is made may have a perceptible effect on the progeny that can be obtained from it. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rate and inheritance of cross-fertilization in faba bean (Vicia faba L.)

Summary To assess the feasibility for synthetic varieties of Vicia faba L., 108 faba bean genotypes were screened for cross-fertilization rate in five field experiments carried out in 1989 and 1990 at Wageningen.Significant genotypic differences were observed for outcrossing rate, which ranged from 1 to 55%. These percentages, however, are thought to be not high enough for a commercially feasible production of synthetic varieties.The inheritance of cross-fertilization rate, determined by testing the F₄ generation of a cross between two inbreds, both with high outcrossing rates, appeared to be of a polygenic nature, as was indicated by the wide variation in, and the continous distribution of, the cross-fertilization rates. Among the F₄ lines tested some had a significantly higher cross-fertilization rate than the parents. However, this difference was not found when these lines were retested, indicating that possibilities for successful selection for higher outcrossing rates might be limited.     

Genetic relationship in Vigna mungo (L.) Hepper and V. radiata (L.) R. Wilczek based on morphological traits and SDS-PAGE

Thirty seven diverse genotypes of Vigna mungo and three of V. radiataresembling to V. mungo for seed characters were studied to determine the extent of genetic variation based on morphological characters. In addition, 4black seeded genotypes in each species and8 green seeded V. radiata genotypes were included for SDS-PAGE analysis. Seed proteins were analyzed through slab type SDS-PAGE. High variance was observed for plant height, days to flowering, days to maturity, number of branches/plant, number of pods/plant, pod length, seeds per pod,biomass yield/plant, grain yield/plant and harvest index (%) during 2 consecutive years. First four components of PCA with eigenvalues >1 contributed 78.7 and79.1% of the total variance amongst 40genotypes during 1998 and 1999. The populations with high PC₁ values were expected to be high yielding characterised by earlyness, high seed weight and harvest index, all traits strictly related to reproductive phase. Four clusters of genotypes were observed during both the years and genetic diversity was in association for both the years. Based on SDS-PAGE, specific bands were suggested to be used for identifying Vigna radiatafrom mixed germplasm with Vigna mungo. The SDS-PAGE proved to be a powerful tool for differentiating Vigna radiata and Vigna mungo, whereas a low level inter-specific genetic diversity was observed and no clear differentiation was observed both for agronomic characteristics and for geographical origin. This revised version was published online in July 2006 with corrections to the Cover Date.     

QTL mapping of pod tenderness and total soluble solid in yardlong bean [Vigna unguiculata (L.) Walp. subsp. unguiculata cv.-gr. sesquipedalis]

Yardlong bean [Vigna unguiculata ssp. unguiculata cv.-gr. sesquipedalis] is an important vegetable legume, particularly in Asia. Tenderness and sweetness of fresh pods are the key factors in deciding the commercial acceptance of yardlong bean. We report here for the first time quantitative trait loci (QTL) mapping of these traits from crosses between the yardlong bean accession JP81610 and wild cowpea (V. unguiculata ssp. unguiculata var. spontanea) accession JP89083. Two SSR-based linkage maps developed from BC₁F₁ [(JP81610?×?JP89083)?×?JP81610] and F₂ (JP81610?×?JP89083) populations were used for QTL analysis of pod tenderness and total soluble solid (TSS) content. Composite interval mapping (CIM) identified three QTLs for pod tenderness with phenotypic variance explained (PVE) of 5.6?C50?% and alleles from JP81610 increased the tenderness. CIM detected two QTLs for pod TSS with PVE of 7 and 9?%, and alleles from JP89083 increased TSS. Locations of these QTLs were compared with those of QTLs controlling domestication-related traits identified in the same populations. All QTLs for pod tenderness co-localized with QTLs for pod length. QTLs for pod TSS co-located with QTLs for pod dehiscence and/or pod length. The implications of these QTLs in breeding new yardlong bean and cowpea cultivars are discussed.     

A Combined Univariate and Multivariate Approach for Selecting High Performing Genotypes of Vicia faba L.

High performing V. faba genotypes have been successfully selected using an approach that combines the univariate and multivariate biometrical analyses of F|S from two complete 7×7 and 9×9 diallel cross experiments. The method used in the analyses included canonical analysis and cluster analysis of the phenotypic and genetic variance-covariance matrices. All analyses have been applied, to the yield and yield components. Results of analyses provided information on the unit of selection, the selection criteria, and the selection procedure. The choice of an array of F₁S seems to be more efficient than the choice of a single F₂. Among the yield components studied, 100-seed weight is the most important selection criterion which can improve yield most efficiently. The detected importance of the nonadditive genetic effects is that selection after intercrossing random plants from the mixed F₁ progenies of the same array is expected to be more effective than selection after Selfing.     

Histological Observations on Interspecific Crosses in the Genus Lupinus

The hybridization barriers of interspecific lupin crosses were determined by histological investigations. The cross Lupinus hartwegii×L. mutabilis (both of American origin) revealed embryos in the cotyledonary stage as well as cellular endosperm. In the reciprocal combination, L. mutabilis×L. harwegii, embryo development stopped at the end of the globular stage, and simultaneously the coenocytic endosperm did no differentiate into the cellular state. In the combination L. luteus (European origin) ×L. hartwegii, embryo as well as endosperm development were initiated. Embryo development ended at any early globular stage. Twelve days after pollination the coenocytic endosperm had almost degenerated. With L. hartwegii as the female, no pollen germination could be observed.     

Combining ability analysis and association of yield and yield components among selected cowpea lines

The study was carried out to determine combining ability and association of yield and yield components among crosses derived from seven selected cowpea (Vigna unguiculata (L.) Walp) parents. Twenty-one hybrids were generated from diallel crosses excluding reciprocals. Hybrids along with seven parents were studied for combining ability and phenotypic correlations for seed yield and eight yield components. The result indicated that the general combining ability (gca) and specific combining ability (sca) were significant for most characters indicating the importance of both additive and non-additive genetic components. Additive gene action was important for eight characters except pod number, whereas non-additive gene action was not important for nodule number and grain yield. Parental lines IT86D-716 and IT81D-985 were found to be good general combiners for grain yield and other traits. The most promising specific combiners for yield and yield components were from crosses including IT87D-697-2 × IT86D-716, IT88D-867-11 × IT86D-716, IT93K-624 × IT87D-697-2, and IT87D-697-2 × IT92KD-405-1. Significant positive phenotypic correlations were observed between seed yield with pod length (POL), number of pods per plant (PON), and number of seeds per pod (SPD). POL, pod number per plant, SPD, and grain yield were identified as the best selection criteria that could be used in cowpea breeding programs.     

Inheritance of amylose content in rice (Oryza sativa L.)

Summary The inheritance of low and very low amylose contents in six rice crosses and their reciprocals was studied by single grain analysis of parents F₁, F₂, B₁ and B₂ seeds. To minimize the environmental effects, the seeds of all generations of all crosses were produced in a single season. The results indicated different dosage effects in different crosses. One major gene was found to govern a difference of 6–12% in amylose content in low and intermediate amylose parents. Very low amylose content was similarly found to be governed by one major gene in crosses between very low- and low-amylose content parents. Minor genes and modifiers also seem to play some role. In the cross between two low amylose parents differing by about 2.5% in amylose content, the differences appeared to be controlled by some minor genes and modifiers. The selection program in different crosses has been suggested.     

Genetic analysis of yield and quantitative traits in pigeonpea (<Emphasis Type="Italic">Cajanus cajan</Emphasis> L. Millsp.)

Basic information on genetics and inheritance of quantitative characters, which is necessary to develop future breeding programme, is not widely studied in pigeonpea. Hence, present study was conducted among 5 generations in four pigeonpea crosses to know significance of additive-dominance model, gene action involved in inheritance of quantitative characters, heritability and genetic advance. “Scaling” and “joint scaling test” was significant for most characters indicating that additive-dominance model alone is not enough to explain the inheritance of a character. Though additive variance was more, dominance variance also played important role for most of the traits. Positive and negative alleles were found to be distributed between parents. Additive gene effect (d) was significant for pods per plant and seeds per pod whereas dominance gene effect (h) was more predominant among pod yield and seed yield. Dominance × Dominance inter-allelic interactions (l) was more important than Additive × Additive type (i) for most of the traits studied which could be exploited by selecting individuals based on their performance in recurrent selection. Complementary gene action was observed among many traits with few exhibiting duplicate gene action. Heritability and genetic advance was high indicating the effectiveness of selection. Since dominance effects is also present along with additive effects selection could be practised in later generations to identify high yielding genotypes.     

Reciprocal cross differences in a 6×6 diallel set of groundnut (Arachis hypogaea L.) in the F1 generation

Summary Reciprocal cross differences were studied in a 6×6 diallel full set comprising of thirty hybrid combinations of groundnut in the F₁ generation.Reciprocal cross differences were observed for growth habit in four pairs of crosses, for leaf colour, flower colour and stem pigmentation in two pairs of crosses each. It was observed that the inheritance of flower colour, stem pigmentation and testa colour which exhibited different shades of purple colour was likely to be governed by pleiotropic gene(s). Among the quantitative characters significantly positive reciprocal effects were observed in different crosses for number of mature pods per plant, weight of pods per plant and shelling percent. Marked reciprocal cross differences were observed for pod and kernel characters like pod filling, pod beak, pod constriction and testa colour.