Development of salt tolerance in rice through breeding program is mainly depends on the salinity responses of the potential rice germplasms. Coastal rice landraces of Bangladesh possess diverse morphological and physiological responses to salinity. Hence, our target is to identify candidate salt-tolerant coastal rice genotypes as a new source of salt tolerance (12 dS/m). Here, we annotated 20 Bangladeshi coastal Aus landrace rice regarding their phenotypic and genetic relatedness to salinity tolerance through multivariate analyses of five morpho-physiological traits namely, salt injury score (SIS), ion-leakage, chlorophyll concentration, root-shoot reduction percentage and profiling of DNA using simple sequence repeat (SSR). Based on the standard evaluation score (SES) the salt-induced coastal rice landraces were grouped into highly susceptible (HS), susceptible (S), moderately tolerant (MT), tolerant (T) and highly tolerant (HT). Besides, a canonical discrimination analysis of the mean trait values of five morpho-physiological parameters confirmed the above mentioned five categories of salinity tolerance. Based on all morpho-physiological parameters one genotype (Kalihytta) as highly tolerant (HT), two genotypes (Manikmuri and Monsur IRRI) as tolerant (T) and five genotypes (Nara, Iratom 27, Matichak, Abdul high IRRI and Parija) were identified as moderately tolerant (MT) against salinity. Finally, the molecular characterization using two SSR markers (RM493 and RM3412) revealed Kalihytta, Nara, Iratom 27, Parija, Lal jamaibabu and Fullbadam, as tolerant against salt stress. Our candidate salt tolerant Aus rice genotypes could be useful as novel sources of salt tolerance for thriving salt-tolerant high yielding varieties in the coastal ecosystem of Bangladesh.

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• Marker-assisted breeding accelerates the development of multiple-stress-tolerant rice genotypes adapted to wider environments
  Vignesh Mohanavel, Valarmathi Muthu, Rohit Kambale, Rakshana Palaniswamy, Prisca Seeli, Bharathi Ayyenar, Veeraranjani Rajagopalan, Sudha Manickam, Raghu Rajasekaran, Hifzur Rahman, Jagadeeshselvam Nallathambi, Manonmani Swaminathan, Gopalakrishnan Chella
  Frontiers in Plant Science.2024;[Epub]     CrossRef

Traditional rice landraces of coastal areas in Bangladesh are distinct in respect to their phenotypes, responses to salt stress and yield attributes. In characterization of coastal rice landraces, 46 rice genotypes were tested for salt tolerance at their seedling and reproductive growth stages. Through the cluster analysis following standard evaluation score (SES), genotypes were divided into five categories (highly susceptible, susceptible, moderately tolerant, tolerant and highly tolerant) at their seedling stage. Three coastal genotypes, viz. chorbindi, joyni and kedgrangal mota, were grouped as highly saline tolerant at their seedling stage. In studying reproductive stage salinity screening, based on mean score values obtained from different morphological and yield parameters (plant height, number of effective tillers/hill, number of filled grains, panicle length, 100-grain weight, and straw dry weight), kutiakon and kajolshail were identified as the salinity tolerant landraces while tulsimala, dudhkalom, birindi, bushihara, lalmota, chorboleshor, lalchikon and bashful chikon were found as moderately tolerant to salinity. Finally, the molecular characterization using two simple sequence repeat (SSR) markers, viz., RM493 and RM3412 revealed holde mota, dingamoni, kedgrangal mota, sada mota, laxmima, dishari, lal chikon, kalijira, kalo khaya, khaioz, chorbindi, kajolshail, kutiakon, bamonkhir, dudhmora, sakhorkhora, mota dhan, and sorbimaloti as tolerant landraces. These identified salt-tolerant landraces can be used as promising germplasm resources for breeding salt-tolerant high-yielding rice varieties in the future.

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• Diversity Analysis of Bangladeshi Coastal Rice Landraces (Oryza sativa) for Morpho-Physiological and Molecular Markers' Responses to Seedling Salinity Tolerance
  Hafsa Sultana, Uzzal Somaddar, Swadesh Chandra Samanta, Abul Kashem Chowdhury, Gopal Saha
  Plant Breeding and Biotechnology.2022; 10(2): 115.     CrossRef

MADS-box genes are well known for the ABC model of flower development. In this study, we investigated the expressions of A, B and C functions Brassica rapa MADS-box genes in different Ogura cytoplasmic male sterile (CMS) lines of B. juncea, B. oleracea, and their wild types. We observed two AP1-like (BjAP1 and BoCAL1), three PISTILLATA-like (PI-like; BjPI1, BoPI1, and BoPI2) and six AGAMOUS-like (AG-like; BjAGL1, BjAGL2, BjAGL3, BjAGL4, BoAGL1, and BoAGL2) genes to be altered their expressions in the CMS B. juncea and B. oleracea compared to their wild types. Partial and complete petaloidy in the third whorl (stamen) were observed of two CMS B. juncea lines J26 and J27, respectively. Besides, a sepaloidy structure was evident in the third whorl of CMS B. oleracea line 25053. Altered expressions of BjAP1 and BjPI1 in the fourth whorl (pistil) can be correlated with curved and robust stature of pistils in CMS B. juncea. Furthermore, an in silico protein interaction analysis revealed that AP-like, PI-like, and AG-like proteins are in close association with different MADS-box proteins and LEAFY (LFY), UNUSUAL FLORAL ORGANS (UFO), SEUSS (SEU), LEUNIG (LUG) for different floral organ development. We suggest that expressions of MADS-box genes might be dependent on mitochondrial signaling for cytoplasmic homeosis in CMS B. juncea and B. oleracea. The expression dataset on A, B, and C functions MADS-box genes of CMS and wild type B. juncea and B. oleracea presented in this study might be useful for the development of CMS in different Brassica species.