Floret Sterility in Rice in a Cool Environment¹

Abstract

Floret sterility induced by low temperatures of 15 C or below at meiosis (10 to 15 days before heading) is a major factor in reducing yields of Oryza sativa, var. japonica, L. in California. The objective of this study was to reduce Sterility by manipulating genotypic environmental interactions. Field experiments employing differences in plant height, maturity, and water level were conducted at the Davis Rice Research Facility. Microclimatic studies were also conducted to determine temperature profiles within the canopy. Sterility was compared among nine cultivars with similar genetic origin but differing in plant height and maturity. Those that were short‐statured and/ or early‐maturing exhibited significantly less sterility than tall and late cultivars. All cultivars in a water depth study showed less sterility in deep water (15 to 25 cm) than in shallow water (5 to 15 cm). Mean differences were significant at the 0.05 level. The beneficial effect of earliness in reducing sterility was caused by the weather patterns of the rice‐growing region in the Sacramento Valley. The probability of receiving temperatures below 15 C at meiosis was considerably reduced as maturity was shortened. Increased water depth and decreased plant height reduced sterility by placing the panicle in closer proximity to water. Field water temperature at the coldest part of the night was usually 5 to 6 C warmer than air temperature. The microclimatic study demonstrated that absence of substantial nocturnal wind caused a temperature inversion at night between the mid‐canopy level (50 cm above soil surface) and the top of the canopy. Temperature also increased from mid‐canopy to water level because of the warming effect of the water. Thus mid‐canopy is the coldest part of the vertical profile in a rice field.

Effect of the Dwarfing Gene d18-k on Cool Tolerance at Booting Stage under the Genetic Background of an Extremely Cool-tolerant Rice Line Norin-PL11, and its Relation with Water Depth

“…The principal damage is the unfertilization of spikelets resulting from underdevelopment of anther (bowlike shape and/or reduction into various sizes) as well as pollen sterility, which is induced by cool temperature during the booting stage, particularly at the young microspore stage (Kakizaki and Kido 1938, Terao et al 1940, Hayase et al 1969, Ito et al 1970, Satake 1976, Sawada 1978, Satake 1991. This sterile-type damage has been reported in other Asian countries and USA (Kaneda and Beachell 1970, Board et al 1980, Mckenzie et al 1994, Ise et al 1999. Moreover, spikelet degeneration can be induced by cool temperature at the booting stage (Terao et al 1940, Kiyosawa and Aimi 1954, Matsuzaki and Matsushima 1971.…”

Point stresses during reproductive stage rather than warming seasonal temperature determine yield in temperate rice

“…Early in booting, the developing panicle is low on the plant, often at or below flood water in paddy rice, and protected by plant tissue. Yet cold temperature during this stage has been shown to damage cells undergoing meiosis (Board, Peterson, & Ng, ; Farrell, Fox, Williams, & Fukai, ; Peterson, Lin, Jones, & Rutger, ), specifically as microspores release from tetrads in the early microspore stage (Mamun, Alfred, Cantrill, Overall, & Sutton, ). This sensitive phase of booting begins approximately 7 days following panicle initiation and lasts approximately 15 days (Peterson et al., ) (hereafter referred to as simply as “booting”).…”

Water balances and evapotranspiration in water- and dry-seeded rice systems

“…This maintenance flow of water helps flush out salts that may accumulate due to evapo-concentration (Scardaci et al 2002), and maintain a uniform and desired water level. Flood water height during this maintenance flow period is typically between 10 and 15 cm although it may be increased between panicle initiation and flowering to help prevent floret sterility (blanking) caused by cool night time temperatures (Board et al 1980). Differences in early-season water management may result in differences in water partitioning and use between these systems; however, to our knowledge, this has not been tested.…”