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Brassica juncea (L.) Czern. & Coss. (Indian mustard) is an economically important edible oil crop. Over the years, plant breeders have developed many elite varieties of B. juncea with better yield traits, but research work on the introgression of stress resilience traits has largely been lagging due to scarcity of resistant donors. Crop wild relatives (CWRs) are the weedy relatives of domesticated plant species which are left unutilized in their natural habitat due to the presence of certain undesirable alleles which hamper their yield potential, and thus, their further domestication. CWRs of B. juncea namely include Sinapis alba L. (White mustard), B. tournefortii Gouan. (African mustard), B. fruticulosa Cirillo (Twiggy turnip), Camelina sativa L. (Gold-of-pleasure), Diplotaxis tenuisiliqua Delile (Wall rocket), D. erucoides L. (White wall rocket), D. muralis L. (Annual wall rocket), Crambe abyssinica R.E.Fr. (Abyssinian mustard), Erucastrum gallicum Willd. (Common dogmustard), E. cardaminoides Webb ex Christ (Dogmustard), Capsella bursa-pastoris L. (Shepherds purse), Lepidium sativum L. (Garden Cress) etc. These CWRs have withstood several regimes of biotic and abiotic stresses over the past thousands of years which led them to accumulate many useful alleles contributing in resistance against various environmental stresses. Thus, CWRs could serve as resourceful gene pools for introgression of stress resilience traits into Indian mustard. This review summarizes research work on the introgression of resistance against Sclerotinia stem rot (caused by Sclerotinia sclerotiorum), Alternaria blight (caused by Alternaria brassicae), white rust (caused by Albugo candida), aphid attack, drought and high temperature from CWRs into B. juncea. However, various pre- and post-fertilization barriers due to different ploidy levels are major stumbling blocks in the success of such programmes, therefore, we also insightfully discuss how the advances made in -omics technology could be helpful in assisting various breeding programmes aiming at improvisation of stress resilience traits in B. juncea. [ABSTRACT FROM AUTHOR]

The present investigation was carried out to develop derived Brassica carinata (BBCC) lines from Brassica juncea and Brassica napus. Brassica juncea was crossed with B. napus and a variable gene pool was generated. B. carinata type variants were selected followed by intraspecific hybridization with high yield potential B. carinata lines/varieties viz., MCR-1-6, MCR-1-19, Kiran and Pusa-swarnim. Interspecific hybridization and population improvement were initiated to enrich B. carinata gene pool for desired traits and documentation of potential lines which can be further exploited for commercial breeding. Among all these lines, PDC 37-5, PDC 37-2, PDC 82-2, PDC 37-3, PDC 32-1 and PDC 36-1 having low level of SFA and high erucic acid are desirable as the former prevents crystal formation under colder climates, whereas, the latter with longer carbon chains allows more efficient conversion into aviation fuel and emission of fewer particulates than conventional oil. For seed yield, PDC 64-1, PDC 96-1 and PDC 55-1 were found promising lines. The developed lines infused with desired agronomic traits presented genetic stock for rainfed oilseed crop as well as environmentally sustainable source of renewable fuel. [ABSTRACT FROM AUTHOR]

In this study, we evaluated genetic diversity in a panel of 87 Indian mustard varieties using 200 genomic-SSR markers. A total of 189 SSRs resulted into positive amplification with 174 (92.06%) SSRs generating polymorphic products and 15 (7.94%) SSRs producing monomorphic amplicons. A total of 552 alleles were obtained and allele number varied from 2–6 with an average number of 3.17 alleles per SSR marker. The major allele frequency ranged from 0.29 (ENA23) to 0.92 (BrgMS841) with an average value of 0.58 per SSR locus. The polymorphic information content (PIC) value ranged from 0.10 (BrgMS841) to 0.68 (BrgMS519) with 0.39 as mean PIC value. The gene diversity per locus ranged from 0.13 (BrgMS841) to 0.72 (ENA23 & BrgMS519) with a mean value of 0.48 per SSR primer pair. Both Unweighted Neighbor Joining-based dendrogram and population structure analysis divided all the 87 varieties into two major groups/subpopulations. Analysis of molecular variance (AMOVA) inferred the presence of more genetic variation (98%) among individuals than among groups (2%). A total of 31 SSRs produced 36 unique alleles for 27 varieties which will serve as unique DNA-fingerprints for the identification and legal protection of these varieties. Further, the results obtained provided a deeper insight into the genetic structure of Indian mustard varieties in India and will assist in formulating future breeding strategies aimed at Indian mustard genetic improvement. [ABSTRACT FROM AUTHOR]

Heat stress at the seedling stage can increase mortality and has become an increasing threat for Indian mustard cultivation. Indian mustard is being predominantly grown under a rainfed ecosystem. In this context, the selection of heat tolerant genotypes may be one of the panaceas. Hence, this study was planned to evolve, evaluate and identify some of the promising early maturing heat stress tolerant from a pool of advanced breeding lines, to be used as probable donors for transferring heat tolerance. For this purpose, heat stress was imposed on 10 Indian mustard advanced breeding lines at the seedling period. The mean performance of the ten advanced breeding lines of Indian mustard with respect to morphophysiology revealed that the genotype DRMRHT-13-13-5-4 recorded earliest in maturity (117.5 days), high oil content (43.14 %) and seed yield of 3182.82 (kg/ha) which was 19.75 per cent higher seed yield over best check NPJ-112 under heat stress conditions. Similarly, the genotype DRMRHT-13-13-5-6 also recorded early in maturity (118.5 days), oil content (42.18%) and seed yield of 2964.92 (kg/ha) which was 11.55 per cent higher seed yield over the best check NPJ-112. There was a positive correlation between relative water content and membrane stability index (r=0.945) but both of these traits were negatively associated with excised-leaf water loss. Cluster survey classified 10 advanced breeding lines in five divergent groups. The tree diagram revealed abundant diversity between the Indian mustard genotypes for different characters and some magnitude of a consortium between different clusters. Based on the higher membrane stability index, water retention capacity of leaves, relative water content, minimum excised-leaf water loss and seed yield, advanced breeding lines DRMRHT-13-13-5-4 and DRMRHT-13-13-5-6 were identified as early in maturity and heat tolerant at a seedling stage which could be used in breeding programmes. [ABSTRACT FROM AUTHOR]

Oleiferous Brassica species are economically important agricultural commodities. India is one of the largest rapeseed-mustard growing countries. Indian mustard (Brassica juncea) is predominantly grown oilseed crop of India, where it is widely cultivated under diverse agro-climatic situations. As a consequence of breeding research over a century in this crop, many varieties have been bred, however little information is available about extent of variability and diversity among these varieties. Variability for 18 agro-morphological traits and for 6 computed variables was estimated in 62 extant varieties. Multivariate analyses based upon principal components and hierarchical cluster revealed 4 distinct groups of varieties based upon geographical region of their originating centers. Much of the variability could be accounted for leaf and stem characteristics and phenological stages. Closely resembling as well as distinct varieties were identified. Varieties from different clusters based upon genetic distance were suggested for utilization in hybridization program. [ABSTRACT FROM AUTHOR]

Stability of oil, protein and glucosinolates, erucic, ecosenoic, oleic, linoleic, linolenic, palmitic and stearic acid along with seed yield was investigated in 25 genotypes (23 for seed yield) of Indian mustard (Brassica juncea L.) using AMMI (additive main effect and multiplicative interaction) and bi-plot analyses based on double centred principal component analysis (PCA). Experiments were conducted during 2003-04 to 2005-06 using randomized complete block design with three replications. Combined analysis of variance showed highly significant (P<0.01) difference between the genotypes, locations and G×E interaction, suggesting differential response of genotypes across growing environments, which could be attributed to differential ranking of genotypes. PCA 1 and PCA2 axes were significant (P<0.01) and captured the largest portion of the variation of the G×E interaction for all the characters, indicating that AMMI 2 model was the best for the data set, therefore, a bi-plot of PCA1 and PCA2 was constructed to identify the most stable genotypes for different quality characters. AMMI's stability parameter - ASV (AMMI stability value) has been calculated for each genotype. Higher ASV reflected variable response to different environment and lower ASV reflects stability across the environments. AMMI analysis revealed that IPCA1 and IPCA2 captured almost 100% of the interaction sum of squares and were also significant (P < 0.01) for all the characters investigated, suggesting that the AMMI model with two principal components was the best predictive model. Considering results from AMMI and n\bi-plot analyses, genotypes RH 30, RH 8812; Sanjucta Asech, Sej 2 and Varuna were most stable for oil, protein, glucosinolate content, fatty acid profile and seed yield. [ABSTRACT FROM AUTHOR]

Six cytoplasmic male sterility (CMS) systems, viz. moricandia, ogura, oxyrrhina, siifolia, tournefortii and trachystoma of Indian mustard ( Brassica juncea L.) were characterized for agronomic and floral characteristics. Introgression of alien cytoplasm caused alterations in different floral traits in ogura, siifolia, tournefortii and trachystoma CMS systems. Varied response to different genetic backgrounds of CMS lines indicated the presence of cytoplasmic–nuclear interaction in alteration of floral traits. On the basis of floral characteristics, CMS systems could be grouped into distinct classes. Siifolia, tournefortii and trachystoma CMS lines had narrow petals, while moricandia, ogura and oxyrrhina had wider petals, which were distinguishable on the basis of visual observations. The ratio between length and width of petals were >2.0 in wide petal group but <2.0 in narrow petal group. Further, the relative position of anther and stigma, which was estimated as the ratio between stamen and style length could differentiate the CMS systems. Stamens were longer than styles in oxyrrhina, equal in moricandia and shorter in ogura, siifolia, tournefortii and trachystoma male sterile lines. Non-viable pollen grains were present in moricandia and oxyrrhina systems, but absent in other systems. In tournefortii and trachystoma, few flowers showed petaloid corolla. All male sterile lines, except trachystoma, which showed crooked siliqua formation were at par with their respective maintainers for flower initiation, plant height, primary branches, seeds per siliqua, seed yield, harvest index, oil and protein content. In general, flower senescence and maturity occurred earlier in male sterile lines than in their respective maintainer lines. [ABSTRACT FROM AUTHOR]