Combined efforts of farmers, rice scientists, extension personnel and Government of Bangladesh have yielded clean rice growth rate of 0.34 million ton (MT) year -1 during 2009-10 to 2013-14 in the country. In 2014-15, the country acquired a rice surplus of about 2 MT. However, maintaining the current surplus of rice in the coming decades is a great challenge. Authentic estimation of future rice requirement and future resource availability would guide to way forward. This paper presents rice vision for Bangladesh leading to 2050 and beyond. In this study, secondary data from different government-owned statistics and research institutes were collected, analyzed and synthesized to develop models and/or model parameters to generate outputs such as future population, rice production and rice requirement. Population of Bangladesh will reach 215.4 million in 2050, when 44.6 MT of clean rice will be required. With the pace of rice-production-increase in the last five years, production can reach 47.2 MT, having a surplus of 2.6 MT in 2050. The study sets 2.6 MT as the target for clean rice surplus every year leading to 2050 and beyond. Several hurdles, such as increasing population, decreasing resources and increasing climate vulnerability, can hinder achieving the target. Three major interventions-accelerating genetic gain, minimizing yield gap and curtailing adoption lag-are proposed to break the barriers to achieve the target. Major challenges to implement the interventions include shrinking net cropped area, decreasing availability of irrigation water and increasing pressure on soil fertility. Smart technology such as, location specific variety, profitable cropping sequences, innovative cultural management, and mechanization coupled with smart dissemination using multiple means would ease production barriers. We recommend a number of measures, such as, guaranteeing a minimum cropped area, accelerating the rate of genetic gain in varietal development and intensifying collaboration among the stakeholders to reduce adoption lag of newly released promising rice varieties, to achieve the rice vision of Bangladesh leading to 2050 and beyond.

This simulation study aimed to predict the effects of potential change of temperature and carbon dioxide on winter rice (Boro rice) production in Bangladesh. We assessed the effects of temperature and carbon dioxide on yield of Boro rice using DSSAT model for six major rice growing AgroEcological Zones (AEZs). The sensitivity analysis included variation of maximum and minimum temperature at 2 0 C and 4 0 C and different levels of CO2 concentrations (50 ppm, 100 ppm and 200 ppm) above the value reported in 2005 of IPCC Fourth Assessment Report (379 ppm). The model predicted that the change of maximum temperature drastically reduced rice yield at all selected locations. The average value of yield reductions (average percentage change of rice yield for 6 locations) of Boro rice were 6% and 16% for increasing maximum temperature at 2 0 C and 4 0 C respectively. Minimum temperature had also negative impacts on Boro rice yields that reduced yield by 4% for 2 0 C and 8% for 4 0 C. However, a slight increase in rice yield due to increase in CO2 concentration could not overcome the negative effect of temperature. Such yield reductions under changing climatic conditions could significantly affect the rice production in Bangladesh in future.

The most sensitive stages of Boro rice against the low temperature are agronomic panicle initiation (API), reduction division (RD) and flowering/anthesis. The critical low temperature is growth stage specific. The time and intensity of the critical low temperature during Boro season has a direct impact on the growth and yield of a crop. Therefore, it is necessary to understand the probability of the critical low temperature with respect to the growth stages to have a good planning for safe harvest. Long term weekly low temperature data have been used to estimate the probability of falling low temperature on those stages and the return period was computed. The growth durations of 1-and 30-November seeded Boro rice crop from 45-day-old seedling of BRRI dhan28 (short duration) and BRRI dhan29 (long duration) are considered to observe the probability. A Boro crop encountering critical low temperature is appeared to suffer from cool injury. The extent of cool injury depends on the nature and duration of low temperature and diurnal change of low (night) and high (day) temperature. The critical low temperature for a rice crop at API, RD and anthesis are 18, 19 and 22°C, respectively. Boro rice is grown between November and May. The low temperature occurs from October to early March. There is, therefore, the probability of low temperature occurrence from the crop establishment to the flowering stage is a great concern. The probability of experiencing stage-wise critical temperature approaches to 100% for early established and short duration crop. However, the late established and long duration crop has the probability little less than the early and short duration crop. In a study it has been observed that short duration BRRI dhan28 having 64.6% sterility to yield 2.5 t ha-1 and BRRI dhan29, 40.8% sterility to yield 6.5 t ha-1. The percentages of corresponding sterility for late established crops were 35.9 and 32.8%. Irrespective of growth duration, the yield is affected a little of the late established crop. Despite low temperature along with the reproductive phase, the late established crop is quite safe due to the parallel high (day) temperature (31-35°C). The high maximum temperature appears to play an important role through the alleviating effect of low temperature. But for early-established particularly short duration variety could not escape the low temperature at some of its sensitive growth stages as the high temperature appears to stay a several degree low (27-29°C) at that time. The low level of high temperature is appeared to drag down the low temperature to aggravate the growth and development of a crop. Therefore, not only the variation of high temperature of the day but also the variation of critical low temperature might have some role in alleviating effect of cool-injury. The periodic return of critical low temperature (10-15°C) during the reproductive stage may occur every year or every alternate year depending on the time across the cropping season and the region as well. Therefore, the critica...

Rice false smut (RFSm), considered as a minor importance, has become a serious disease in many rice growing areas of Bangladesh and other parts of the world. Many aspects of its epidemiology still remained unclear, notable the life cycle of RFSm pathogen, its infection site and the smut ball formation on infected panicles. Present research was undertaken to investigate the density and distribution of false smut balls on infected rice panicles aiding to understand on how severe the disease can be in a rice-ecosystem, on which position the smut balls form on infected panicles and likely yield reduction from such disease severity. This study included field observation of natural RFSm infection during 2014, 2015 and 2016, and simulated infection during 2015 in T. Aman rice in the experimental farm of the Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh. While the number of smut balls reached as many as 136 (recorded in one panicle in 2015), the study shows there was 81, 54 and 30% probability that maximum of nine, three and only one smut ball would form, respectively. With the scenarios of density of smut ball formation in the study area, the yield loss was estimated as 0.15% for each 1% incidence level. The level of smut ball density varied between years; this severity was most likely influenced by low daily minimum temperature. In the natural observation 34.4, 53.9 and 11.7% of the smut balls were located at the base, mid and apex part of the infected panicles, respectively. When compared the balls of these three positions in relation to potential grain number, the proportion accounted for the base and mid remained almost similar, whereas the proportion in the apex was much lower. It is concluded that false smut balls predominantly form on the lower half of the infected rice panicles.

Rice false smut (RFSm) is a disease of interest globally and in Bangladesh. Its occurrence and spread have drawn attention since 2010 in the country. While many reports are available on the yield loss from the disease, little is known of its effect on grain quality. Besides, there has been no information on how RFSm affects the seed quality with respect to germination. This study attempted evaluation of seed germination and grain quality of rice as affected by false smut disease. Three years’ study provided strong indication of inferior milling outturn and head rice yield in RFSm contaminated seeds. Results further revealed reduced amylose content and increased protein content in the contaminated seeds. Tendency in reduced seed germination, and less cooking time was observed in RFSm contaminated seeds. Future research is suggested to fully understand those causations. Bangladesh Rice j. 2018, 22(1): 1-7