Twenty eight rice genotypes were evaluated for their stability in respect of grain yield and growth duration during boro season of 2007-08 over five locations viz. Gazipur, Jamalpur, Comilla, Jinaidhah, and Rajshahi. Variances for genotypes, locations, and G × E interactions were significant for both the traits. Linear components of G × E interactions were insignificant but non- linear components (pooled deviation) were significant. Considering stability parameters (bi and S2 di) for days to maturity, genotypes Raja, Ropa-1, and Sera were least responsive to environment (bi =1) and minimum deviation from regression (S2 di = 0) were stable over the locations. The estimates of stability parameters for grain yield revealed that the genotypes Ropa-1, SL-8, Lily and Sera were higher grain yielder, b value were close to the unity and S2di value were near to the zero. So, these four genotypes could be considered as the most stable over the environments. Considering both growth duration and grain yield based on stability parameters, the genotypes Ropa and Sera were identified as most stable and could be recommended for release as varieties.   Key words: Hybrid rice; stability; exotic. DOI: http://dx.doi.org/10.3329/bjar.v36i1.9233 BJAR 2011; 36(1): 97-102

The study was conducted at Biotechnology Division of Bangladesh Rice Research Institute (BRRI) to investigate the effects of plant growing medium and plant growth regulator (PGR) for the callus induction and high frequency plantlets regeneration of indica rice. Ten indica rice varieties viz. BR5, BR11, BRRI dhan28, BRRI dhan29, BRRI dhan33, BRRI dhan41, BRRI dhan47, BRRI dhan48, BRRI dhan49 and BRRI dhan50 were cultured on MS, N6 and LS media. The MS medium was found better for callus induction as compared to N6 and LS media. Among the tested varieties BRRI dhan48 induced the highest percent and best quality callus. Interaction effects of BRRI dhan48 to MS medium yielded 71.55% callus induction. The regeneration efficiency of BRRI dhan48 was tested on MS medium supplemented with different combination of NAA plus BAP and NAA plus kinetin. MS medium supplemented with 2.0 mg L -1 NAA and 2.0 mg L -1 Kn was found the best in respect of percent regenerated (76.67%) plantlet as well as for the growth of plantlets in vitro.

Screening of different rice (Oryza sativa L.) germplasms or breeding lines is a continuous effort to identify the promising source. A series of experiments (20) were undertaken to identify promising materials for five years of salinity screening from 2015 to 2019. The materials included total of 3,195 rice germplasm and breeding lines, out of which Bangladesh Rice Research Institute (BRRI) developped 2, 295 germplasms, 193 advanced breeding lines from BRRI, and 707 advanced breeding lines from International Rice Research Institute (IRRI), Philippines. From this study, the genotypes were categorized as 122 tolerant, 220 moderately tolerant, 1,207 sensetive, and 1,646 highly sensetive. Among the BRRI germplasms, most of the materials (61%) had sensitive responses against salinity, while only 2 and 3% of rice germplasm exhibited tolerant and moderately tolerant, respectively. BRRI lines comprised 44% sensetive and 35% highly sensetive rice genotypes. In the tolerance level, 4% appeared as tolerant and 17% moderately tolerant against salinity. Likewise, IRRI lines also showed relatively higher tolerance (9%) than the BRRI germplasm and lines. They were classified into 9 % tolerant and 16 % moderately tolerant rice genotypes. Bangladesh Agron. J. 2022, 25(1): 37-45