Stability of soil plant analytical development (SPAD) chlorophyll meter reading (SCMR) and specific leaf area (SLA) and their association across varying soil moisture stress conditions in groundnut (<Emphasis Type="Italic">Arachis hypogaea</Emphasis> L.)

The complex nature of physiological traits associated with drought tolerance and the difficulties associated with their measurements in segregating populations and large number of genotypes inhibited their use in the past in developing water-use efficient genotypes in breeding programmes. With new knowledge of easily measurable surrogates of transpiration efficiency (TE), a trait associated with drought tolerance—specific leaf area (SLA) and soil plant analytical development (SPAD) chlorophyll meter reading (SCMR), it is now possible to integrate TE through the surrogates in breeding and selection schemes in groundnut (Arachis hypogaea L.). As a noninvasive surrogate of TE, SCMR is easy to operate, reliable, fairly stable and low cost. However, in a large-scale breeding program, it is difficult to complete SCMR observations within a specified time. The present study addressed the issue as to what extent the SCMR measurements can be spread over time by evaluating 18 diverse groundnut genotypes for two physiological traits, SCMR and SLA in two postrainy (Nov–Apr) seasons (2002/2003 and 2003/2004) in India. Observations were recorded at different times during and after the release of moisture deficit stress. There was general agreement in genotype and trait performance in both the seasons. Interaction between SCMR and time of observation was significant in only one season (2002/2003) but its variance relative to genotypes and time of observation was very small. ICGV 99029 and ICR 48, which recorded higher SCMR and lower SLA values in both the seasons, will make good parents for water-use efficiency trait in breeding programmes. Other good parents include ICGS 76, TCGS 647 and TCGP 6. SCMR recorded at three different times under differing soil moisture deficit in each season showed highly significant correlation with each other. Similarly, SLA at different times also correlated significantly with each other. SCMR and SLA were significantly negatively correlated with each other and the relationship was insensitive to time of observation. The results of the present study indicated that SCMR/SLA observations can be recorded at any time after 60 days of crop growth, preferably under moisture deficit conditions. This gives groundnut breeders a large flexibility to record these observations in a large number of segregating populations and breeding lines in the field. Thus, making it easy to incorporate these physiological traits associated with drought tolerance in breeding and selection scheme in groundnut.     

Generation means analysis of resistance to peanut bud necrosis caused by peanut bud necrosis tospovirus in peanut

This study was conducted to evaluate the types of gene action governing the inheritance of resistance to peanut bud necrosis disease (PBND) in populations derived from three crosses involving two resistant (ICGV 86388 and IC 10) and one susceptible (KK 60–1) peanut lines. Populations were composed of P₁ P₂, F₁ F₂, BC₁₁, BC₁₂, BC₁₁S and BC₁₂S. These populations were evaluated for PBND incidence in a farmer's field in Kalasin province in north‐east Thailand, where PBND is a recurring problem. Results showed variations between crosses in the relative contributions of different types of gene effect. The results indicate that multiple genes control the PBND resistance trait, and that the two resistant lines differ in some of these genes. As non‐additive gene effects are important in all three crosses, selection for low PBND incidence in these crosses would be more effective in later generations.     

Phenotypic diversity and identification of wild Arachis accessions with useful agronomic and nutritional traits

Wild relatives harbor novel sources of variation, which can be used to enhance the genetic base of a cultivar gene pool. A total of 269 accessions from 20 wild Arachis species belonging to six sections were evaluated for 41 morpho-agronomic traits and 89 selected accessions for oil, protein and total sugar content. Six plants from each accession were grown in an open Arachis house in large-cylindrical concrete structures during the 2004?C2005 season at Patancheru, India. REML analysis showed significant differences between species and accessions for most of the traits studied. Hierarchical cluster analysis, based on the first five principal component scores accounted for 82.5% variation, resulting in four clusters. Variation in genome relationships and ploidy levels had no bearing on the clustering pattern which was predominated by life forms: clusters 1 and 2, contained mostly annuals and clusters 3 and 4 perennials. A large range of variations were noticed among species for some of the agronomic traits: days to flowering, pod and seed characteristics, specific leaf area (SLA) and for SPAD chlorophyll meter reading (SCMR). Arachis duranensis showed the maximum intraspecific variation as revealed by a high diversity index for 23 of the 41 traits which included: days to flowering, primary branches, plant width, pod length, pod width, SCMR and SLA. The other species with desirable traits were A. pusilla (earliest flowering) and A. villosa (high SCMR at 60 and 80 days after sowing). The latter species is cross compatible with cultivated groundnut, thus, is a good source to enhance the trait value in the cultigen??s gene pool. The best 20 accessions with superior agronomic, nutritional quality and drought related trait combinations have been identified for their use in introgression of diverse and unique alleles from wild Arachis species into A. hypogaea.     

Genetics for speed of plumule emergence in chickpea (Cicer arietinum L.)

Summary Genetics for speed of plumule emergence was studied using six generations (P₁, P₂, F₁, BC₁(P₁), BC₂(P₂) and F₂) in three crosses. Two of the crosses which had parents of different emergence speed were controlled by two genes with duplicate epistasis. The third cross which involved parents of little difference for speed, indicated incomplete dominance for one gene of bit fast parent over the slow one. In all the crosses F₂ segregation pattern was confirmed by the segregation pattern of back crosses. The gene symbols were designated as Sp1Sp1 Sp2Sp2 for fast speed parents: sp1sp1 sp2sp2 for slow parent and sp1sp1 Sp2Sp2 for the parent with bit fastness for speed of plumule emergence.     

Generation mean analysis of spring wheat (Triticum aestivum L.) seedlings tolerant to high levels of manganese

Effective utilisation of wheat (Triticum aestivum L.) germplasm tolerant to high manganese (Mn) in a breeding program requires an understanding of the genetics of Mn tolerance. Five wheat cultivars differing in their response to high Mn were crossed in a half diallel design with no reciprocals. Seedlings of parents and progeny generations were phenotyped in high Mn nutrient solutions. Total chlorophyll concentration, which was positively correlated with leaf elongation rate during recovery from Mn stress, was used for phenotyping Mn tolerance. Means of chlorophyll concentration of P₁, P₂, F₁, F₂, BC₁, and BC₂ generations, in all crosses which showed significant variation among generations, were subjected to line crosses analysis to estimate gene effects. The continuous frequency distribution of seedlings with differential Mn tolerance, the similarity of the F₁ and F₂ means, and the high and significant levels of additive gene action indicated quantitative inheritance for Mn tolerance at seedling stage. A preponderance of additive effects indicated that selection for Mn tolerance in early generations should be effective.     

Genetics of grains per spike in durum wheat under normal and late planting conditions

Parental, F₁, F₂, BC₁, BC₂, BC₁₁, BC₁₂, BC₂₁, BC₂₂, BC₁ self and BC₂ selfed generations of three crosses involving six cultivars of durum wheat (Triticum durum Desf.) were studied for grains per spike under normal and late sown environments to analyze the nature of gene effects. A 10-parameter model did not fully account for the differences among the generation means. In two cases more complex interactions or linkage were involved in the inheritance of grains per spike in durum. Both digenic and trigenic epistatic interactions had a role in controlling the inheritance of grains per spike, however, trigenic interactions contributed more than digenic interactions. Non-fixable gene effects were many times higher than fixable ones in all three crosses and in both sowing environments indicating a major role of non-additive gene effects in the inheritance of this trait. Duplicate epistasis between sets of three genes under both environments was recorded for the cross Raj 911 × DWL 5002. Epistatic interactions, particularly the trigenic ones, contributed the maximum significant heterosis. Epistatic interactions involving dominance in the F₂ generations caused significant inbreeding depression. Selective diallel mating and/or biparental mating could be used for amelioration of grains per spike in durum wheat.     

Inheritance of ‘domestication’ traits in bambara groundnut (Vigna subterranea (L.) Verdc.)

Controlled crosses in bambara groundnut were attempted between a range of thirty-six bambara groundnut landraces (thirty domesticated (V. subterranea var. subterranea) and six wild (V. subterranea var. spontanea)). Ten F₁ seed were produced. Of these, eight germinated producing F₂ populations. On seed set, four populations could be unambiguously confirmed as true crosses by F₃ seed coat colour. A single F₂ population, derived from a domesticated landrace from Botswana (DipC; female parent) crossed with a wild accession collected in Cameroon (VSSP11; male parent) was used to study a range of agronomic and domestication traits. These included; days to emergence, days to flowering, internode (fourth) length at harvest, number of stems per plant, leaf area, Specific Leaf Area (SLA), Carbon Isotope Discrimination (CID), 100 seed weight, testa colour and eye pattern around the hilum. On the basis of variation for internode length and stems per plant, 14 small F₃ families were selected and grown under field conditions to further investigate the genetic basis of the ‘spreading’ versus ‘bunched’ plant character, a major difference between wild and cultivated bambara groundnut. Results presented suggest that traits including leaf area, SLA, CID and 100 seed weight are controlled by several genes. In contrast, the variation for traits such as internode length, stems per plant, days to emergence and seed eye pattern around the hilum are likely to be under largely monogenic control. The results of this work are discussed in relation to the domestication of bambara groundnut.     

Genetic analysis of prolificacy in “Sikkim Primitive”—A prolific maize (Zea mays) landrace of North‐Eastern Himalaya

Prolificacy assumes significance for development of high‐yielding baby corn hybrids. “Sikkim Primitive” is a native landrace of North‐Eastern Himalaya, and is the highest prolific maize germplasm. So far, the genetics of prolificacy in “Sikkim Primitive” has not been deciphered. Here, a prolific inbred (MGU‐SP‐101) developed from “Sikkim Primitive” was crossed with four non‐prolific inbreds viz., LM13, BML7, HKI161 and HKI1128. Six generations (P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂) of the crosses were evaluated at two locations during rainy season 2018. MGU‐SP‐101 possessed 2.50–3.78 ears per plant compared to 1.06–1.86 among non‐prolific inbreds. The variation for ears was the highest in F₂s (1–8), followed by BC₁P₁ (1–7) and BC₁P₂ (1–5). The quantitative inheritance pattern of prolificacy with prevalence of non‐allelic interactions of duplicate epistasis type has been observed. Dominance × dominance effect was predominant over additive × additive and additive × dominance effects. Total number of major gene blocks ranged from 0.41 to 2.86, thereby suggesting the involvement of at least one major gene/QTL governing the prolificacy. This is the first report of genetic dissection of prolificacy in “Sikkim Primitive”.     

偏凸-柱穗山羊草双二倍体与普通小麦不同杂种世代的染色体及性状分离特点

为探讨偏凸山羊草－柱穗山羊草双二倍体SDAU18在小麦遗传改良中的利用价值,以SDAU18和普通小麦品种烟农15及其9个杂种世代为材料,分析不同自交和回交世代染色体和性状分离的特点。结果表明,随自交和以烟农15为轮回亲本回交世代的增加,染色体数目逐渐减少,回交比自交能使后代的染色体数目更快趋近普通小麦的42条,至F₅和BC₃F₁代,染色体数目为42的植株已分别达93.9%和92.0%。与自交世代相比,回交后代减数第一分裂中期的花粉母细胞的染色体构型较为简单,回交次数过多不利于外源染色体与普通小麦染色体发生重组,一般应以回交2~3次为宜;随自交和回交世代的增进,杂种的育性提高,至F₃和BC₂F₁代育性基本稳定。在不同杂种世代可分离出具有矮秆、大穗、大粒、对白粉病、条锈病免疫或高抗及外观品质优良的变异类型,以F₃和BC₁F₁代的变异类型最丰富。     

Genetics of Resistance in Vicia sativa L. to Orobanche crenata Forsk.

The genetics of resistance of common vetch (Vicia sativa L.) to broomrape (Orobanche crenata Forsk.) was studied for two years by using the P₁, P₂, F₁, BC¹, BC₂, F₂ F₃, and F₄ generations obtained from crosses between resistant and susceptible lines. Resistant lines were selected by screening a world collection m a naturally infested plot. Resistance was tested both under field and greenhouse conditions. The best index to measure resistance was the number of emerged broomrapes per host plant. The results fit the additive-dominance model. The main component of the variation was additivity; dominance and interaction effects seemed to depend on the environment. When dominance is expressed, a low number is dominant over a high number of broomrapes per host plant.     

Inheritance of black leaf mold resistance in tomato

Summary Inheritance of black leaf mold (BLM) (caused by Pseudocercospora fuligena) resistance was studied in four crosses involving two resistant Lycopersicon accessions (PI134417, L. hirsutum and PI254655, L. esculentum) and four susceptible Asian Vegetable Research and Development Center tomato lines (CLN657BC₁F₂-267-0-3-12-7, CL143-0-10-3-0-1-10, CLN698BC₁F₂-358-4-13 and CL5915-93D₄-1-0-3). For each cross, six generations, i.e. P₁, P₂, F₁, F₂, BC₁F₁ and BC₁F₂ were evaluated following inoculations with isolate Pf-2 of P. fuligena. Chi-square analyses of the data based on the ratio of resistant to susceptible plants in the F₂ in three of four crosses gave a good fit to a segregation ratio of 1 R : 15 S, and BC₁F₂ data in three of four crosses gave an acceptable fit to the segregation ratio of 1 R : 63 S. The results indicate that resistance to BLM may be conditioned by two recessive genes acting epistatically in both PI134417 and PI254655.     

Backcross variability for grain yield in oat species crosses (Avena sativa L. x A. sterilis L.)

Summary Avena sterilis introductions from the Middle East were useful sources of genes for improving the grain yield of adapted A. sativa cultivars for midwestern US. Introgression of genes from A. sterilis materials into A. sativa oat breeding populations was readily accomplished through a backcrossing procedure. Backcrossing successfully accomplished the recombination required to introgress complexly inherited traits. The BC₁F₂, BC₂F₂, BC₃F₂, and BC₄F₂ generations appeared to be best for selecting high-yielding transgressive segregates from the A. sativa x A. sterilis crosses.Journal Paper No. J-7919 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa 50010. Project No. 1752.     

Estimation of genetic components of variation for salt tolerance in chickpea using the generation mean analysis

Chickpea (Cicer arietinum L.) is known to be salt-sensitive and in many regions of the world its yields are restricted by salinity. Recent identification of large variation in chickpea yield under salinity, if genetically controlled, offers an opportunity to develop cultivars with improved salt tolerance. Two chickpea land races, ICC 6263 (salt sensitive) and ICC 1431 (salt tolerant), were inter-crossed to study gene action involved in different agronomic traits under saline and control conditions. The generation mean analysis in six populations, viz. P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂, revealed significant gene interactions for days to flowering, days to maturity, and stem Na and K concentrations in control and saline treatments, as well as for 100-seed weight under salinity. Seed yield, pods per plant, seeds per plant, and stem Cl concentration were controlled by additive effects under saline conditions. Broad-sense heritability values (>0.5) for most traits were generally higher in saline than in control conditions, whereas the narrow-sense heritability values for yield traits, and stem Na and K concentrations, were lower in saline than control conditions. The influence of the sensitive parent was higher on the expression of different traits; the additive and dominant genes acted in opposite directions which led to lower heritability estimates in early generations. These results indicate that selection for yield under salinity would be more effective in later filial generations after gene fixation.     

Genetic Analysis of Developmental Traits in Chickpea

Chickpea (Cicer arietinum L.) is an important legume crop in India. The present study was conducted to investigate the inheritance of several developmental traits in three crosses of chickpea, viz., WFWG III’בT20’, ‘T88’בBold Seeded’, and ‘NP34’בP1528-1-1’, each having seven generations. The seven generations were P₁, P₂, F₁, B₁, B₂, F₂, and F₃. The experimental lay-out was randomized complete block design with three replications. Data were acquired on days to flowering (DF), days to maturity (DM), plant height in cm (PH), number of primary branches (PB), and number of secondary branches (SB). Generation mean analysis was used to estimate the genetic components; narrow sense heritability was estimated using variance components; and correlation analysis to estimate correlation coefficients among different traits. Genetic differences were found in all three crosses for all traits studied. Additive, dominance, and epistatic effects were found for many traits'. Duplicate epistasis was observed for all traits except number of PB. Higher order interactions and/or linkage were detected for DM and SB. For many traits the relative magnitudes of the genetic effects differed among crosses, thus the extrapolation to other crosses may be difficult. The inheritance becomes more complex as the fate of the character is decided at a later stage in the life cycle. Positive heterosis was observed for some traits, but the exploitation of this component may not Feasible since stable male sterile lines are not available. Early maturity and high yield ‘may be selected independently because of the absence of any significant correlation between these two traits.     

Inheritance of resistance to race F of broomrape in sunflower lines of different origins

A new race F of broomrape overcomes all known resistance genes in cultivated sunflower, but recently, sources of resistance against race F have been developed. The objective of the present research was to study the inheritance of resistance to race F in crosses between 12 resistant sunflower breeding lines, derived from three different sources of resistance, and the susceptible male‐sterile line P‐21. Parental lines and F₁, F₂, F₃ and BC₁ generations were evaluated for broomrape resistance. Segregations in the F₂ and BC₁ to resistant parent approached resistant to susceptible ratios of 1: 15 and 1: 3, respectively, in most of the crosses, suggesting a double dominant epistasis. However, segregations of 3: 13 and 1: 1 for F₂ and BC₁, respectively, indicating a dominant‐recessive epistasis, were also found. The F₃ data confirmed these results. Owing to the recessive nature of this resistance, it must be incorporated into both parental lines for developing resistant hybrid cultivars.     

Pattern of genetic inheritance of morphological and agronomic traits of sorghum associated with resistance to sorghum shoot fly, <Emphasis Type="Italic">Atherigona soccata</Emphasis>

Sorghum shoot fly, Atherigona soccata is an important pest of sorghum during the seedling stage, which influences both fodder and grain yield. To understand the nature of inheritance of shoot fly resistance in sorghum, we performed generation mean analysis using two crosses IS 18551 × Swarna and M 35-1 × ICSV 700 during the 2013–2014 cropping seasons. The F₁, F₂, BC₁ and BC₂ progenies, along with the parental lines were evaluated for agronomic and morphological traits associated with resistance/susceptibility to sorghum shoot fly, A. soccata. The cross IS 18551 × Swarna exhibited significant differences between the parents for shoot fly deadhearts (%) in the postrainy season. The progenies of this cross exhibited lower shoot fly damage, suggesting that at least one of the parents should have genes for resistance to develop shoot fly-resistant hybrids. Leaf glossiness, leafsheath pigmentation and plant vigor score during the seedling stage exhibited non-allelic gene interactions with dominant gene action, whereas 100 seed weight showed both additive and dominant gene interactions. Presence of awns showed recessive nature of the awned gene. Generation mean analysis suggested that both additive and dominance gene effects were important for most of the traits evaluated in this study, but dominance had a more pronounced effect.     

Genetic stability and maintenance of Raphanus sativus lines with an added Brassica rapa chromosome

The genetic stability and maintenance of Raphanus sativus‐Brassica rapa monosomic chromosome addition lines (a‐h‐types MALs, 2n = 19, BC₂), developed by backcrossing the synthesized amphidiploid Raphanobrassica (Raphanus sativus × Brassica rapa, 2n = 38, RRAA) with R. sativus cv. ‘Shogoin’ (2n = 18, RR), was investigated. Transmission of the added alien chromosome through selected smaller seeds (SSS) and the inheritance of morphological traits and random amplified polymorphic DNA (RAPD)‐specific markers together with meiotic chromosome configuration and seed fertility were also investigated for three successive generations (BC₃ to BC₅). The distinctive traits and the RAPD‐specific markers of the eight types of MAL were substantially inherited and stably maintained throughout three generations, although a few variant plants (2n =18) resembling MALs (2n = 19) and hyperploidal plants (2n = 26 and 2n = 37) were generated in the earlier generations of BC₃ and BC₄ in comparison with BC₅. The average transmission rates for three generations ranged from 26% for both the b‐type and the d‐type to 44% for the e‐type through SSS. On the other hand, the transmission rates through randomly selected seeds (RSS) were lower, ranging from 6.5% for the f‐type to 23.5% for the b‐type. In meiosis, more than 90% of PMCs showed the 9II +1I pairing configuration at metaphase I throughout three generations. For seed fertility, when backcrossed with the radish cv. ‘Shogoin’, the values were approximately 180% to 500% with the mode around 300% with the seed harvested from a pod increasing with the advancing generations. Genetic recombination between the radish chromosomes and the added chromosome is probably rare, suggesting that the added chromosome is mostly maintained unaltered in the background of the radish genome.     

Estimation of additive, dominance and digenic epistatic interaction effects for certain yield characters in Vigna sesquipedalis Fruw

Inheritance of yield and yield contributing characters were investigated using generation mean analysis, utilising the means of six basic populations viz., P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂ in four crosses of Vigna sesquipedalis. The analysis reiterated that the importance of dominance (h) gene effects for pod yield/plant and pods/plant as compared to additive (d) gene effects. However, significant and positive additive effects were noticed for pod yield/plant, pods/plant, pod weight and seed weight in different crosses. The three types of gene interactions (additive, dominance and epistasis) were significantly involved for pods/plant in cross KU 7 ×KU 8. Among the digenic epistatic interactions, both additive ×additive (i) and dominance × dominance (l) contributed more for pod yield/plant and pods/plant, however, it varied among the crosses. Populations having earliness can be developed as indicated by reducing dominance effects. Pedigree selection and heterosis breeding is suggested to exploit the fixable and non fixable components of variation respectively in Vigna sesquipedalis. This revised version was published online in July 2006 with corrections to the Cover Date.     

Analysis of genetic architecture for some physiological characters in sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.)

Combining ability for some important physiological parameters in sesame were examined to understand the nature of gene action and to identify parents for breeding programme. Seven diverse genotypes of sesame, their 21 F₁s and 21 F₂s were grown in summer, 2003, in a randomized complete block design with three replications. Data were collected on leaf area index (LAI) at 30, 45, 60 and 75 days after sowing (DAS), crop growth rate (CGR) estimated between 30–45 DAS, 45–60 DAS and 60–75 DAS, days to peak flowering (DPF), duration of flowering (DF), duration from peak flowering to maturity (DFM), oil content in percentage (OC) and oil yield (OY) plant⁻¹. Analysis of combining ability was done on the above physiological characters following Method-2, Model-I of Griffing (Aust J Biol Sci 9:463–493 1956). Variances due to general combining ability (GCA) and specific combining ability (SCA) for all the physiological traits were highly significant in both F₁ and F₂ generations indicating importance of both additive and non-additive gene actions for the inheritance of all the physiological characters in both F₁ and F₂ generations. Preponderance of non-additive gene action was recorded for CGRs, LAI 3, LAI 4, DPF, DF and OY in both the F₁ and the F₂ generations. For OC additive gene action was predominant in F₁ while non-additive gene action in F₂. The genotype OS-Sel-2 appeared as best overall general combiner in both the F₁ and the F₂ generations. For DPF, DF and DFM, the variety B 67 was best general combiner, followed by CST 2002, which could be utilized for developing early flowering and early maturing lines with determinate growth habit. Association between GCA-effects and mean performance of the parents suggested that the performance per se could be a good indicator of its ability to transmit the desirable attributes to its progenies. Crosses CST 2002 × TKG 22, CST 2002 × MT 34, MT 34 × AAUDT 9304-14-4, AAUDT 9304-14-4 × B 67, TKG 22 × Rama and TKG 22 × B 67 which showed high SCA-effect for OY, also exhibited positive and significant SCA-effects for other physiological component characters in F₁ generation. The overall results indicated that crosses CST 2002 × TKG 22 and MT 34 × AAUDT 9304-14-4 could be utilized for development of high oil yielding hybrids. The crosses OS-Sel-2 × AAUDT 9304-14-4, AAUDT 9304-14-4 × B 67 and MT 34 × OS-Sel-2 could be promising for isolation of superior recombinants for high oil yield coupled with early maturity and other growth characters in advanced generations of segregation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Development and characterisation of a <Emphasis Type="Italic">Brassica carinata</Emphasis> inbred line incorporating genes for low glucosinolate content from <Emphasis Type="Italic">B. juncea</Emphasis>

The presence of high levels of sinigrin in the seeds represents a serious constraint for the commercial utilisation of Ethiopian mustard (Brassica carinata A. Braun) meal. The objective of this research was the introgression of genes for low glucosinolate content from B. juncea into B. carinata. BC₁F₁ seed from crosses between double zero B. juncea line Heera and B. carinata line N2-142 was produced. Simultaneous selection for B. carinata phenotype and low glucosinolate content was conducted from BC₁F₂ to BC₁F₄ plant generations. Forty-three BC₁F₄ derived lines were selected and subject to a detailed phenotypic and molecular evaluation to identify lines with low glucosinolate content and genetic proximity to B. carinata. Sixteen phenotypic traits and 80 SSR markers were used. Eight BC₁F₄ derived lines were very close to N2-142 both at the phenotypic and molecular level. Three of them, with average glucosinolate contents from 52 to 61 micromoles g⁻¹, compared to 35 micromoles g⁻¹ for Heera and 86 micromoles g⁻¹ for N2-142, were selected and evaluated in two additional environments, resulting in average glucosinolate contents from 43 to 56 micromoles g⁻¹, compared to 29 micromoles g⁻¹ for Heera and 84 micromoles g⁻¹ for N2-142. The best line (BCH-1773), with a glucosinolate profile made up of sinigrin (>95%) and a chromosome number of 2n = 34, was further evaluated in two environments (field and pots in open-air conditions). Average glucosinolate contents over the four environments included in this research were 42, 31 and 74 micromoles g⁻¹ for BCH-1773, Heera and N2-142, respectively. These are the lowest stable levels of glucosinolates reported so far in B. carinata.