Significant yield increase has been achieved by simultaneous introduction of three trait-related QTLs in three rice varieties with multiplex editing by CRISPR-Cas9. Using traditional breeding approaches to develop new elite rice varieties with high yield and superior quality is challenging. It usually requires introduction of multiple trait-related quantitative trait loci (QTLs) into an elite background through multiple rounds of crossing and selection. CRISPR-Cas9-based multiplex editing of QTLs represents a new breeding strategy that is straightforward and cost effective. To test this approach, we simultaneously targeted three yield-related QTLs for editing in three elite rice varieties, namely J809, L237 and CNXJ. The chosen yield-related QTL genes are OsGS3, OsGW2 and OsGn1a, which have been identified to negatively regulate the grain size, width and weight, and number, respectively. Our approach rapidly generated all seven combinations of single, double and triple mutants for the target genes in elite backgrounds. Detailed analysis of these mutants revealed differential contributions of QTL mutations to yield performance such as grain length, width, number and 1000-grain weight. Overall, the contributions are additive, resulting in 68 and 30% yield per panicle increase in triple mutants of J809 and L237, respectively. Our data hence demonstrates a promising genome editing approach for rapid breeding of QTLs in elite crop varieties.

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The cities of the world are facing serious problems due to environmental hazards. The Department of Agricultural Extension has been implementing a pilot project on expansion of roof gardening in the Dhaka city since 2018 to reduce the increasing temperature, air pollution and for food production. However, no study has been conducted to find out the suitable technologies for producing fresh, safe and nutritious foods in the roof garden and to investigate the role of this roof garden on environment conservation for the Dhaka city dwellers with changing climate. Therefore, a research based roof garden model was developed at Sher-e-Bangla Agricultural University with the financial help of NATP-2 project. The experimental results showed that roof garden reduced upper surface temperature of roof more than 9°C and lower surface temperature of roof by 1.74°C and believe to reduce the electricity consumption for cooling the room of the top floor of the building during summer season. The oxygen and carbon dioxide percent were higher and lower, respectively in the garden than the bare roof. Therefore, the results suggest that urban crop production and environmental balance can be achieved to a certain extent by increasing the intensity of roof gardening in the Dhaka city

Salt stress has a large impact on controlling the plant growth and development. The present study was conducted to examine the role of salicylic acid on alleviation of salt stress in wheat. In this experiment, the treatment consisted of four different salinity levels viz. S0 = without salt (control), S1 = 2.8 g NaCl kg -1 soil ≈ 3-4 dSm -1 , S2 = 6.0 g NaCl kg -1 soil ≈ 7-8 dSm -1 , S3 = 9.0 g NaCl kg -1 soil ≈ 11-12 dSm -1 and three different levels of salicylic acid (SA) viz. A0 = 0 mmol, A1= 0.2 mmol and A2 = 0.4 mmol. It was done by using two factors Randomized Complete Block Design (RCBD) with four replications. The total treatment combinations were 12 (4x3). Results of the experiment showed a significant dissimilarity among the treatments in respect of the major parameters. Yield of wheat were exaggerated by different levels of salinity. The higher levels of salinity showed greater reduction of yield. The highest grain yields (1.55 tha -1 ) were recorded at S0A2 (Without Salt+0.4 mmol salicylic acid) treatment combination which did not show any difference with S0A0 (Without Salt+Without SA) and S0A1 (Without Salt+0.2 mmol SA). But the grain yield was gradually decreased with the increasing level of salinity. The application of salicylic acid increased the grain yield differently according to the levels of salinity. The minimum grain yields were found 1.14 t ha -1 , 1.07 tha -1 and 0.26 t ha -1 at 3-4 dSm -1 , 7-8 dSm -1 and 11-12 dSm -1 NaCl respectively. These yields were increased with SA (0.4 mmol) from 1.14 to 1.32 tha -1 , 1.07 to 1.14 tha -1 and 0.26 to 0.31 tha -1 at 3-4 dSm -1 , 7-8 dSm -1 and 11-12 dSm -1 NaCl respectively. These results suggest that salicylic acid can alleviate the detrimental impacts of salinity and increase the grain yield of wheat.

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