ABSTRACT
Bacterial blight (BB) is a devastating disease of rice in the tropics of Indian sub-continent, where the presence of Xoo races with varying levels of genetic diversity and virulence renders disease management extremely challenging. In this context, marker-assisted improvement of plant resistance has been proven as one of the most promising approaches for the development of sustainable rice cultivars. The present study demonstrates the marker-assisted introgression of the three BB resistant genes (Xa21 + xa13 + xa5) into the background of HUR 917, a popular aromatic short grain (ASG) rice cultivar in India. The performance of the resulting improved products (near isogenic lines (NILs), HR 23-5-37-83-5, HR 23-5-37-121-10, HR 23-5-37-121-14, HR 23-65-6-191-13, HR 23-65-6-237-2, HR 23-65-6-258-10 and HR 23-65-6-258-21) establishes the utility of marker-assisted selection (MAS) approach for accelerated trait introgression in rice. The MAS-bred lines carrying three introgressed genes showed broad spectrum BB resistance (lesion length, LL of 1.06 ± 1.35 cm to 4.61 ± 0.87 cm). Besides, these improved lines showed the complete product profile of recurrent parent HUR 917 along with the enhanced level of durable BB resistance. The improved introgression lines with durable BB resistance would contribute to sustainable rice production in India, particularly in the Indo-Gangetic plane that has substantial acreage under HUR 917.
ABSTRACT
The evaluation of crop research institutes in the developing world under limited data availability has not been assessed in the past due to resource constraints. The paper assesses the social benefits of rice research taking the case of a research institute from India following a new approach. The area coverage of the varieties was estimated to be 3.4 million ha and the gain in production was 6.2 million tonnes per year in India. The additional return obtained due to the adoption of these varieties was about â¹ 14,621 million (US$ 232 million) per year at constant 2014-5 prices. The return per rupee investment in the institute's research and extension was â¹ 17. This approach is recommended for the impact evaluation of other crop research institutes in India and the developing world under resource constraints.
Subject(s)
Academies and Institutes , Humans , Program Evaluation , IndiaABSTRACT
Background The closure of the appendiceal stump is a crucial step during an appendectomy. The purpose of this study is to evaluate the LigaSure Vessel Sealing System in laparoscopic appendectomy (LA) for sealing and dividing the base of the appendix. Material and methods Laparoscopic appendectomy was performed using the 5-mm LigaSure Vessel Sealer in 53 patients, and the mesoappendix along with the base of the appendix was divided by LigaSure. Patient demographic details, operative time, return to oral feed, duration of hospital stay, and postoperative complications were recorded, and statistical analysis was done. Results Out of 53 patients (24 women and 29 men), no complications occur in 51 patients. The mean age and standard deviation (SD) were 26.50 ± 10.46 years. The mean operative time for 53 appendectomies by LigaSure was 27.8 ± 6.72 minutes. The mean duration of hospital stay after surgery was 3.3 ± 0.72 days. One patient developed mild subcutaneous emphysema over the abdomen (1.8%), and surgical site infection occurred in one patient (1.8%). Conclusion This study demonstrated that sealing and dividing the base of the appendix by the LigaSure Vessel Sealing System is safe and feasible. It is associated with low complication rate and may help in simplifying the operative procedure.
ABSTRACT
An immense increase in human population along with diminished lands necessitates the increase of rice production since, it serves the human population as a staple food. Though rice hybrids (RH) are showing considerable yield enhancement over inbreds in terms of both quality and quantity, farmers' adoption of hybrid rice technology has been much slower than expected because of several constraints such as seed cost and quality. Doubled haploid (DH) technology was considered useful for the development of inbred lines from rice hybrids in a single generation. Androgenesis shows its significance in development of DHs in rice which requires an efficient method to establish the production of large population. To start the anther culture, anthers are the main component of androgenesis to be isolated from unopened spikes. However, the duration of spikes availability for anther culture coupled with the segregation of rice hybrids in the next generation requires the main crop be ratooned to reduce the cost of cultivation. Therefore, the efficiency of the androgenic method was tested in main crop using a quality indica rice hybrid, 27P63 and its ratooned ones. The effects of various factors such as cold temperature pre-treatment of boots, treatment duration, and different combination of plant growth regulators (PGR) on callus response along with shoot regeneration were tested for development of DHs from both ratooned and non-ratooned plants. The N6 medium supplemented with 2.0 mg/L 2,4-D (2,4-dichlrophenoxy acetic acid), 0.5 mg/L BAP (6-benzylamino purine), and 30 g/L maltose was found to be most effective for callusing as compared to MS (Murashige and Skoog) medium. The N6 media inducted calli showed maximum response rate for green shoot regeneration in MS media supplemented with 0.5 mg/L NAA (1-napthaleneacetic acid), 0.5 mg/L Kn (Kinetin; 6-furfurylaminopurine), 1.5 mg/L BAP and 30 g/L sucrose after 2 weeks of culture. The pre-treatment of spikes at 10 °C for 2 d followed by a 7th and 8th d were found to be most effective for callusing as well as for regeneration, producing a total of 343 green plants from ratooned and main rice hybrid, 27P63. Morpho-agronomic trait-based assessment of ploidy status revealed 94.46% diploids, 3.49% polyploids, 0.58% mixploids, and 1.45% haploids. Microsatellite markers could authenticate all 324 fertile diploids as true DHs. Though this study shows a reduction in generation of DHs from ratooned plants as compared to the main crop, manipulation of chemical factors could optimize the method to enhance the production of considerable number of DHs. Utilization of ratooned of hybrid rice in androgenesis would save time and cost of cultivation.
