GRiSP announces new director
Bas Bouman, currently head of IRRI’s Crop and Environmental Sciences Division, has been named director of the Global Rice Science Partnership (GRiSP)—the research program for rice of the CGIAR, effective 1 September 2012. Read more
News
Former IRRI scientist joins USAID as agriculture development officer
Gary Jahn, former IRRI entomologist and crop protection specialist based in Cambodia, headquarters, and Laos over the years (1995-2008), recently joined USAID in Washington D.C. as an agriculture development officer. He will be working with Rob Bertram and Saharah Moon Chapotin in the Food Security Bureau. View
News
App to gauge rice crop health via phone image wins award
A mobile phone application that allows a user to check the quality of his or her rice crop through a smartphone image has won the 2012 SWEEP Innovation and Excellence Awards, hosted by Smart Communications Inc. in the Philippines. Read more
IRRI Seminar
Managing rice diseases in a changing rice production scenario
By Casiana Vera Cruz, senior scientist, plant pathology, PBGB, IRRI1315-1415 H, Thursday, 21 June 2012, Havener Auditorium, IRRI
Abstract:
Rice production has been challenged by recent changes in crop production technologies that impact disease occurrence. The movement of plant pathogens into new agroecosystems, pathogen evolution, and increasing growing season temperatures have had profound effects on expression of disease resistance.
Recent developments in rice research brought about by advances in genomics, transcriptomics, and proteomics have provided insights into the identification of genes and their functions, QTLs, and the convergence of regulatory mechanisms in host-pathogen interactions involved in resistance. There are continuing multidisciplinary efforts among partners to use these sources of resistance in developing a sound management strategy for specific diseases and provide sustainable solutions to these challenges.
Social Sciences Division Seminar
Patterns of varietal adoption and economics of rice production in Asia
By Huaiyu Wang, postdoctoral fellow, Social Sciences Division, IRRI1330-1430 H, Friday, 22 June 2012, SSD Conference Room, Drilon Hall, IRRI
Crop and Environmental Sciences Division Seminar
Time of anthesis in response to environmental conditions in rice (Oryza sativa)
By Cécile Julia (engineer in plant breeding; Ph.D. student in rice ecophysiology, CIRAD-AGAP, Montpellier, France; and Ph.D. research scholar, Crop Physiology Unit, CESD, IRRI)1315-1415 H, Tuesday, 26 June 2012, Room A, D.L. Umali Auditorium, IRRI
Abstract:
Thermal stress and in particular heat during anthesis causes sterility in rice inflorescences. Rice spikelets open in the morning and close a few hours later. Genotypic variation in the time of day of anthesis is considered an escape mechanism from thermal stress, but little is known on its dependency on environmental conditions.
One traditional, cold-tolerant rice cultivar and three improved tropical rice cultivars were grown in the field in four different climatic environments under flooded conditions to study the environmental response of time of day of anthesis. The time of day when the first spikelets opened, a maximum of spikelets were open and the last spikelets closed was observed daily on a population basis (2m² plots replicated 3 times).
Within the same environment, genotypic differences in time of anthesis and duration of anthesis were small. Across all genotypes and environments, the differences were broader and 80% of the variation of the time of maximum anthesis could be explained with the mean minimum air temperature (Tmin) during the 7 days preceding any given anthesis event. Linear, multiple regression models determined for each cultivar using Tmin and vapor pressure deficit (VPD) observations from the three tropical environments explained 94% of variation of time of anthesis onset and end. Low Tmin thereby delayed and low VPD advanced anthesis processes.
Under the assumption that panicle temperature during anthesis is indeed a major determinant of spikelet fertility in rice, it is concluded that the sensitivity of time of day of anthesis to air temperature and humidity is an effective eco-physiological adaptation of the rice crop.
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