Inheritance of siliqua characters in Indian colza I. Locule number and siliqua position

Summary F₁, F₂, BC₁ and BC₂ generations, involving bilocular and tetralocular siliquae and with upright and pendent siliqua position, were studied with their parents. The segregation pattern in these generations indicated that number of locules is monogenically governed with the allel for bilocular type (VV-two valved pods) showing complete dominance over tetralocular (vv). Upright siliqua position is governed by two dominant genes (Up₁ Up₁ Up₂ Up₂) and pendent by two recessive genes (up₁ up₁ up₂ up₂). However, in absence of even a single dominant gene it give rise to a third type of siliqua position i.e. parallel.     

Inheritance of siliqua orientation and seed coat colour in Brassica tournefortii

The inheritance of siliqua orientation and seed coat colour in Brassica tournefortii was investigated using four genotypes varying in these two characters. The F₁, F₂ and backcross generations of two crosses were used for studying the segregation pattern of the traits. The plants were classified for seed colour as having brown or yellow seeds and for siliqua orientation as having upright, semi‐spread or spread siliqua. Seed colour was found to be under monogenic control with brown being dominant over yellow. Siliqua orientation was under digenic polymeric gene action: upright siliqua was produced by the presence of two dominant genes and spread siliqua by two recessive genes. The absence of even a single dominant gene resulted in a third type of siliqua orientation, semi‐spread siliqua.     

Inheritance of petal colour and its independent segregation from seed colour in Brassica rapa

The inheritance of petal (flower) colour and seed colour in Brassica rapa was investigated using two creamy‐white flowered, yellow‐seeded yellow sarson (an ecotype from Indian subcontinent) lines, two yellow‐flowered, partially yellow‐seeded Canadian cultivars and one yellow‐flowered, brown‐seeded rapid cycling accession, and their F₁, F₂, F₃ and backcross populations. A joint segregation of these two characters was examined in the F₂ population. Petal colour was found to be under monogenic control, where the yellow petal colour gene is dominant over the creamy‐white petal colour gene. The seed colour was found to be under digenic control and the yellow seed colour (due to a transparent coat) genes of yellow sarson are recessive to the brown/partially yellow seed colour genes of the Canadian B. rapa cvs.‘Candle’ and ‘Tobin’. The genes governing the petal colour and seed colour are inherited independently. A distorted segregation for petal colour was found in the backcross populations of yellow sarson × F₁ crosses, but not in the reciprocal backcrosses, i.e. F₁× yellow sarson. The possible reason is discussed in the light of genetic diversity of the parental genotypes.     

Development of yellow-seeded Brassica napus of double low quality

Two yellow‐seeded white‐petalled Brassica napus F₇ inbred lines, developed from interspecific crosses, containing 26–28% emcic acid and more than 40 μmol glucosinolates (GLS)/g seed were crossed with two black/dark brown seeded B. napus varieties of double low quality and 287 doubled haploid (DH) lines were produced. The segregation in the DH lines indicated that three to four gene loci are involved in the determination of seed colour, and yellow seeds are formed when all alleles in all loci are in the homozygous recessive state. A dominant gene governed white petal colour and is linked with an erucic acid allele that, in the homozygous condition, produces 26–28% erucic acid. Four gene loci are involved in the control of total GLS content where low GLS was due to the presence of recessive alleles in the homozygous condition in all loci. From the DH breeding population a yellow‐seeded, yellow‐petalled, zero erucic acid line was obtained. This line was further crossed with conventional B. napus varieties of double low quality and, following pedigree selection, a yellow seeded B. napus of double low quality was obtained. The yellow seeds had higher oil plus protein content and lower fibre content than black seeds. A reduction of the concentration of chromogenic substances was found in the transparent seed coat of the yellow‐seeded B. napus.     

Identification and inheritance of a partially dominant gene for yellow seed colour in Brassica napus

A yellow‐seeded doubled haploid (DH) line no. 2127‐17, derived from a resynthesized Brassica napus L., was crossed with two black‐seeded Brassica cultivars ‘Quantum’ and ‘Sprint’ of spring type. The inheritance of seed colour was investigated in the F₂, and BC1 populations of the two crosses and also in the DH population derived from the F1 of the cross ‘Quantum’× no. 2127‐17. Seed colour analysis was performed with the colorimeter CR‐300 (Minolta, Japan) together with a visual classification system. The immediate F1 seeds of the reciprocals in the two crosses had the same colour as the self‐pollinated seeds of the respective black‐ and yellow‐seeded female parents, indicating the maternal control of seed colour. The F1 plants produced yellow‐brown seeds that were darker in colour than the seeds of no. 2127‐17, indicating the partial dominance of yellow seed over black. In the segregating BC1 progenies of the two crosses, the frequencies of the black‐ and yellow‐seeded plants fit well with a 1 : 1 ratio. In the cross with ‘Quantum’, the frequencies of yellow‐seeded and black‐seeded plants fit with a 13 : 3 ratio in the F₂ progeny, and with a 3 : 1 ratio in the DH progeny. However, a 49 : 15 segregation ratio was observed for the yellow‐seeded and black‐seeded plants in the F₂ progeny of the cross with ‘Sprint’. It was postulated from these results that seed colour was controlled by three pairs of genes. A dominant yellow‐seeded gene (Y) was identified in no. 2127‐17 that had epistatic effects on the two independent dominant black‐seeded genes (B and C), thereby inhibiting the biosynthesis of seed coat pigments.     

Maternal and embryonal control of seed colour by different Brassica alboglabra chromosomes

Most oilseed rape, Brassica napus, cultivars are black‐seeded. The progenitor species, Brassica rapa, has either yellow or black seeds, while known cultivars of the other progenitor species Brassica oleracea/alboglabra have black seeds. To determine which chromosomes of B. alboglabra are carriers of seed colour genes, B. rapaalboglabra monosomic addition lines were produced from a B. napus resynthesized from yellow‐seeded B. rapa and brown/black‐seeded B. alboglabra. Eight out of nine possible lines have been developed and transmission frequencies of the alien chromosomes were estimated. Three B. alboglabra chromosomes in three of these lines influenced seed colour. B. rapa plants carrying alien chromosome 1 exhibited a maternal control of seed colour and produced only brown seeds, which gave rise to plants with either yellow or brown seeds. However, B. rapa plants carrying alien chromosome 4 or another as yet unidentified alien chromosome exhibited an embryonal control of seed colour and produced a mixture of yellow and brown seeds. The yellow seeds gave rise to yellow‐seeded plants, while the brown seeds gave rise to plants that yielded a mixture of yellow and brown seeds, depending on the absence or presence, respectively, of the B. alboglabra chromosome. Consequently, both maternal and embryonal control of seed colour are expected to contribute to the black‐seeded phenotype of oilseed rape.     

The inheritance of partial self-compatibility in Brassica oleracea L.: Results from a half diallel homozygous for a moderately recessive S-allele

Summary In a study of partial self-compatibility in Brassica oleracea, flower number, seeded siliqua and seed production were recorded on self-and cross-pollinated inflorescences of the progenies of a half diallel between six in bred Brussels sprout plants homozygous for the same moderately recessive incompatibility allele S₄₅.On both self-and cross-pollinated inflorescences significant amounts of additively controlled genetic variation were found for seed set per flower. For cross-pollinated inflorescences this was also the case for the two components of seed set, seeded siliquae per flower and seeds per seeded siliquae, but for self-pollinated ones only seeded siliquae production showed significant additive variation. Considerable heterosis and gene interaction were always present and a simple additive dominance model did not explain the variation.Two of the parents transmitted lower levels of partial self-compatibility to their progenies and, in one of these, dominant genes appeared to be responsible. The most important feature determining the production of self seeds was found to be the number of flowering sites at which the incompatibility mechanism failed rather than the number of seeds produced at each site.     

Inheritance of seed colour in Brassica campestris L. and breeding for yellow-seeded B. napus L.

Summary Seed colour inheritance was studied in five yellow-seeded and one black-seeded B. campestris accessions. Diallel crosses between the yellow-seeded types indicated that the four var. yellow sarson accessions of Indian origin had the same genotype for seed colour but were different from the Swedish yellow-seeded breeding line. Black seed colour was dominant over yellow. The segregation patterns for seed colour in F₂ (Including reciprocals) and BC₁ (backcross of F₁ to the yellow-seeded parent) indicated that the black seed colour was conditioned by a single dominant gene. Seed colour was mainly controlled by the maternal genotype but influenced by the interplay between the maternal and endosperm and/or embryonic genotypes. For developing yellow-seeded B. napus genotypes, resynthesized B. napus lines containing genes for yellow seed (Chen et al., 1988) were crossed with B. napus of yellow/brown seeds, or with yellow-seeded B. carinata. Yellow-seeded F₂ plants were found in the crosses that involved the B. napus breeding line. However, this yellow-seeded character did not breed true up to F₄. Crosses between a yellow-seeded F₃ plant and a monogenomically controlled black-seeded B. napus line of resynthesized origin revealed that the black-seeded trait in the B. alboglabra genome was possibly governed by two independently dominant genes with duplicated effect. Crossability between the resynthesized B. napus lines as female and B. carinata as male was fairly high. The sterility of the F₁ plants prevented further breeding progress for developing yellow-seeded B. napus by this strategy.     

Cytogenetics of Brassica juncea×Brassica rapa hybrids and patterns of variation in the hybrid derivatives

Interspecific hybridization is an important tool to elucidate intergenomic relationships, transfer characters across species and develop synthetic amphidiploids, and it has been widely applied for improving Brassicas. The objective of the present study was to create genetic variability in Brassica through interspecific hybridization. Crosses between Brassica juncea (AABB, 2n= 36), and Brassica rapa (AA, 2n = 20) vars toria, yellow sarson, and brown sarson were attempted, and the hybrid derivatives were advanced to the F4 generation. Hybrids were obtained from the crosses B. juncea× toria and B. juncea× yellow sarson. The F₁ plants were vigorous and intermediate to the parents in many morphological traits. The meiotic study of AAB hybrids showed 10 II + 8 I in the majority (71.8%) of cells analysed. A maximum of 12 and a minimum of seven bivalents were also observed in a few cells. The occurrence of multivalent associations (trivalents to pentavalents) at diakinesis/metaphase I and a bridge‐fragment configuration at anaphase I were attributed to homoeology between A and B genomes. A high percentage of plants resembling B. juncea was observed in the F₂ generation. Transgressive segregation in both directions was found for plant height, primary branches, main raceme length, siliquae on main raceme, siliqua intensity, seeds per siliqua and seed yield. There were significant differences for the 14 characters in the F₄ derivatives. Moderate to high estimates of phenotypic and genotypic coefficients of variation, broad‐sense heritability, and expected genetic advance were found for seed yield, 1000‐seed weight, siliquae per plant, seeds per siliqua and days to flowering. Intergenomic recombination, reflected as wide variation in the hybrid progenies, permitted the selection of some useful derivatives.     

Genetics of seed coat colour in lentil

Summary Four grey mottled seed coat colour lentil lines/cultivars were crossed to one brown seed coat colour cultivar. The F₁ hybrids were brown seeded in all the crosses. Segregation pattern for seed coat colour in F₂ and F₃ generations revealed that it is under control of a single dominant gene, which is present in the parent UPL 175 while a recessive gene is responsible for grey mottled seed coat colour in Pant L 406, Pant L 639, LG 120 and Rau 101.     

Production of yellow-seeded Brassica napus through interspecific crosses

Yellow‐seeded Brassica napus was developed from interspecific crosses between yellow‐seeded Brassica rapa var.‘yellow sarson’ (AA), black‐seeded Brassica alboglabra (CC), yellow‐seeded Brassica carinata (Bbcc) and black‐seeded B. napus (AACC). Three different interspecific crossing approaches were undertaken. Approaches 1 and 2 were designed directly to develop yellow‐seeded B. napus while approach 3 was designed to produce a yellow‐seeded CC genome species. Approaches 1 and 2 differed in the steps taken after trigenomic interspecific hybrids (ABC) were generated from B. carinata×B. rapa crosses. The aim of approach 1 was to transfer the yellow seed colour genes from the A to the C genome as an intermediate step in developing yellow‐seeded B. napus. For this purpose, the ABC hybrids were crossed with black‐seeded B. napus and the three‐way interspecific hybrids were self‐pollinated for a number of generations. The F₇ generation resulted in the yellowish‐brown‐seeded B. napus line, No. 06. Crossing this line with the B. napus line No. 01, resynthesized from a black‐seeded B. alboglabra x B. rapa var.‘yellow sarson’ cross (containing the yellow seed colour genes in its AA genome), yielded yellow‐seeded B. napus. This result indicated that the yellow seed colour genes were transferred from the A to the C genome in the yellowish‐brown seed colour line No. 06. In approach 2, trigenomic diploids (AABBCC) were generated from the above‐mentioned trigenomic haploids (ABC). The seed colour of the trigenomic diploid was brown, in contrast to the yellow seed colour of the parental species. Trigenomic diploids were crossed with the resynthesized B. napus line No. 01 to eliminate the B genome chromosomes, and to develop yellow‐seeded B. napus with the AA genome of ‘yellow sarson’ and the CC genome of B. carinata with yellow seed colour genes. This interspecific cross failed to generate any yellow‐seeded B. napus. Approach 3 was to develop yellow‐seeded CC genome species from B. alboglabra×B. carinata crosses. It was possible to obtain a yellowish‐brown seeded B. alboglabra, but crossing this B. alboglabra with B. rapa var.‘yellow sarson’ failed to produce yellow seed in the resynthesized B. napus. The results of approaches 2 and 3 demonstrated that yellow‐seeded B. napus cannot be developed by combining the yellow seed colour genes of the CC genome of yellow‐seeded B. carinata and the AA genome of ‘yellow sarson’.     

Inheritance of black testa colour in lentil (Lens culinaris Medik.)

The inheritance of testa (seed coat) colour and interaction of cotyledon and testa colours were studied in seven crosses of lentil (Lens culinaris Medik.) involving parents with black, brown, tan or green testa and with orange, yellow or dark green cotyledons. Analysis of F₂ and F₃ seed harvested from F₁ and F₂ plants, respectively, revealed that although black testa is dominant over nonblack testa, its penetrance is not complete since both F₁ plants and heterozygous F₂ plants produced varying proportions of seeds with either black or nonblack testa. The F₂ populations of the crosses between parents with brown and tan, as well as brown and green, testa segregated in the ratio of 3 brown : 1 tan and 3 brown : 1 green, respectively, indicating monogenic dominance of brown testa colour over tan or green. The expression of testa colour was influenced by cotyledon colour when parents with brown or green testa are crossed with those having orange or green cotyledons. Thus F₂ seeds from these crosses with a green testa always had green cotyledons and never orange cotyledons. F₂ seeds from these crosses with a brown testa always had orange cotyledons and never green cotyledons. These results suggest diffusion of a soluble pigment from the cotyledons to the testa. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetics of colour traits in common vetch (Vicia sativa L.)

Five parents of common vetch (Vicia sativa L.) having orange/beige cotyledon colour, brown/white testa colour, purple/green seedling colour and purple/white flower colour were crossed as a full diallele set. The inheritance patterns of cotyledon, testa or seed coat colour, flower and seedling colour, were studied by analyzing their F₁, F₂, BC₁ and BC₂ generations. The segregation pattern in F₂, BC₁ and BC₂, showed that cotyledon colour was governed by a single gene with incomplete dominance and it is proposed that cotyledon colour is controlled by two allelic genes, which have been designated Ct₁ and Ct₂. Testa colour was governed by a single gene with the brown allele dominant and the recessive allele white. This gene has been given the symbol H. Two complementary genes governed both flower and seedling colours. These flower and seedling colour genes are pleiotropic and the two genes have been given the symbols S and F.     

A Comparison of Genetic Segregation in Traditional and Microspore-Derived Populations of Brassica juncea L. Czern and Coss.

An isolated microspore culture procedure was used to produce doubled haploid lines of Brassica juncea from F¹ plants of reciprocal crosses between the cultivar‘RLM514’and a canola quality breeding line. The inheritance of two qualitative markers, seed color and leaf hairiness, was compared using traditional and microspore-derived populations from these crosses. Chi-square tests indicated that each trait is controlled by different sets of duplicate pairs of genes. Brown seeds or hairy leaves can result from the presence of either of two dominant alleles, whereas yellow seed or glabrous leaves are produced when alleles at both loci are recessive. The segregation of genes controlling seed color and leaf hairs in doubled haploid progeny did not differ significantly from that expected under random assortment, indicating that doubled haploids can be used in this species for genetic studies, and probably cultivar development as well.     

Development of Yellow Seeded Brassica napus Through Interspecific Crosses

Yellow seeded Brassica napus was developed through interspecific crosses with the two mustard species, B. juncea and B. carinata. The objective of these two interspecific crosses was the introgression of genes for yellow seed colour from the A genome of B. juncea and C genome of B. carinata into the A and C genomes of B. napus, respectively. The interspecific F₁ generations were backcrossed to B. napus in an attempt to eliminate B genome chromosomes and to improve fertility. Backcross F₂ plants of the (B. napus×B. juncea) ×B. napus cross were then crossed with backcross F₂ plants of the (B. napus×B. carinata) ×B. napus cross. The objective of this intercrossing was to combine the A and C genome yellow seeded characteristics of the two backcross populations into one genotype. The F₂ generation of the backcross F₂ intercrosses was grown in the field, plants were individually harvested and visually rated for seed colour. Ninety-one yellow seeded plants were identified among the 4858 plants inspected. This result indicated that the interspecific crossing scheme was successful in developing yellow seeded B. napus.     

38–48 kDa subunits of buckwheat 13S globulins are controlled by a single locus

The inheritance of buckwheat (Fagopyrum esculentum Moench) seed storage proteins was investigated by control crosses between accessions containing different SDS‐PAGE protein patterns in the range of 38–48 kDa. Analysis of segregation of individual F₁ and F₂ seeds obtained by 17 crosses showed segregation of eight electrophoretic bands, from which 12‐banding variants were inferred. Two variants contained one band, nine contained two bands and one variant contained three bands and behaved as a single co‐dominant unit. The segregation of banding variants fits the expected ratios and thus supports the hypothesis of single Mendelian gene inheritance and that alleles are co‐dominant. The results therefore suggest that the genes controlling globulin subunits are tightly linked and inherited as a single locus. The locus was designated Glob‐1 and the twelve segregated protein variants as alleles a‐l. This is the first buckwheat globulin locus identified with multiple alleles, phenotypically expressed as groups of protein bands and thus applicable as a functional marker in buckwheat genomic studies.     

Introgression of alleles of the isozymic locus glucosephosphate isomerase-2 (GPI-2) from the CC genome of Brassica carinata to the CC genome of Brassica alboglabra and their independent segregation from seed colour

A yellowish brown‐seeded Brassica alboglabra was resynthesized from a (B. alboglabra×Brassica carinata) ×B. alboglabra cross, followed by self‐pollination. The resynthesized B. alboglabra lost the allele of the isozymic locus glucosephosphate isomerase‐2 (GPI‐2) from natural B. alboglabra, which was replaced by an allele from the corresponding genome in B. carinata. A simple Mendelian segregation of these two alleles was observed in the F₂ population of a natural × resynthesized B. alboglabra cross. Furthermore, these two alleles segregated independently from the seed colour.     

Genetic characterization of the red coloured corolla phenotype for Gossypium arboreum accession PI 529731

Flower corolla colour is an important trait for the attraction of pollinators and for the horticultural industry. Gossypium arboreum (L.) accessions from the United States Department of Agriculture germplasm collection frequently show flowers with a yellow coloured corolla. Accession PI 529731 is unique in that the flowers have a red coloured corolla. Genetic characterization of corolla pigmentation was conducted by crossing PI 529731 with two white flower accessions. Flowers with a red corolla were observed in the F₁ generations suggesting a dominant trait. Variation in corolla colour was observed for plants in the F₂ populations including dark red, red, light red, white, yellow and white with petals having red coloured margins. These data support a single dominant gene conferring the four red corolla phenotypes. The yellow corolla phenotype also supported a single dominant gene model. Dominant alleles at both loci are required for expression of the PI 529731 phenotype and data support a two gene model with a 9:3:3:1 segregation ratio. These data are useful for the characterization of genetic mechanisms controlling tissue‐specific pigmentation.     

Blue aleurone trait diagnoses developmental origin of three pistils in a floret in common wheat

The common ‘three‐pistil’ (TP) wheat mutation line expresses TPs in a floret normally containing TPs forming three grains set close back‐to‐back. The developmental origin of the TP trait in common wheat had been diagnosed non‐destructively using the blue aleurone trait. The aleurone colour of F₂ seeds grown in F₁ plants of cross TP/UC66049 was evaluated. Due to xenia, the hue of blue grain colour depended on dose of the Ba1 gene for blue aleurone in the triploid endosperm. The TP trait produced four types of segregation in three‐seed clusters: (i) white grain only, (ii) two white grains and one blue, (iii) one white grain and two blue, and (iv) three blue grains only. The observed frequency of blue–white seed within clusters followed the binominal distribution ₃C_r (0.75)^r·(0.25)^3–r, where r is the number of colour variants in three‐seed clusters (r = 0–3). Intrafloret segregation of seed colour and F₂ segregation derived from aleurone colour of F₃ seeds indicated an independent origin of the TP trait.     

Seed colour, seed weight and seed oil content in Linum usitatissimum accessions held by Plant Gene Resources of Canada

The purpose of this study was to investigate variation of and relationships among seed colour, seed weight and seed oil content in cultivated flax (Linum usitatissimum L. ssp. usitatissimum). Seed from 2934 flax genebank accessions recently grown at Saskatoon, SK, Canada, originating from 72 countries was used to describe the variation of the seed characters. The dominant seed colour of the accessions was medium brown (2730 accessions, 93.0%), followed by yellow (126 accessions, 4.3%). Based on single observations for all accessions, the overall mean and standard deviation was 5.95 ± 1.22 mg/seed for seed weight and 38.3 ± 1.74% for oil concentration. Within three infraspecific groups of flax, seed weight, oil concentration and oil amount per seed increased in the following order: fibre flax (convar. elongatum), intermediate flax (convar. usitatissimum), large‐seeded flax (convar. mediterraneum). The world collection exceeded the range of variation of seed weight and oil concentration found in 52 North American cultivars. There was a weak, positive association of higher oil concentration with higher seed weight (r² = 0.32; P < 0.001). Yellow‐seeded flax had a higher seed weight (6.31 vs. 5.92 mg/seed) and oil concentration (39.4% vs. 38.3%) than brown‐seeded flax. There was a tendency for yellow seed colour to be associated with higher oil concentration in all seed weight classes. The results suggested that indirect selection for increased seed oil concentration in flax is possible by selection for higher seed weight and yellow seed colour.