Abdul Razack Mohammed

High night temperature and plant growth regulator effects on spikelet sterility, grain characteristics and yield of rice (Oryza sativa L.) plants

Mohammed, A. R. and Tarpley, L. 2011. High night temperature and plant growth regulator effects on spikelet sterility, grain characteristics and yield of rice ( Oryza sativa L.) plants. Can. J. Plant Sci. 91: 283–291. The presence of seasonally high night temperature (HNT) as a result of global warming, occurring during the critical stages of development, could reduce rice yield and quality. To understand how a combination of HNT and plant growth regulators (PGR; α-tocopherol and glycine betaine) affects yield and yield-related parameters of rice plants, we conducted three pot experiments under two levels of night temperature (NT; 27 and 32oC) with or without PGR treatments. Plants were subjected to a HNT through the use of continuously controlled infrared heaters, starting 20 d after emergence (DAE), from 2000 until 0600. Plants were treated with α-tocopherol and glycine betaine 20 DAE. The NT had no effect on number of productive tillers, main-stem panicle length or number of primary branches per panicl...

Effects of High Night Temperature on Crop Physiology and Productivity: Plant Growth Regulators Provide a Management Option

Crop production is experiencing both increases in the frequency and intensity of high night temperatures (HNT) (IPCC, 2007). The HNT threatens the sustainability of crop production both currently and in the future. Recent meteorological data indicated faster increases in night temperatures (NT) than day temperatures (Alward et al., 1999). Experimental evidence also indicated the importance of assessing the effects of NT separately from the day temperature, as a smaller increase in NT can show a drastic decrease in crop production (Peng et al., 2004). Studies have indicated decreased crop yields as a result of HNT (Hall, 1992; Mohammed & Tarpley, 2009a). Apart from HNT, climate change will also increase a variety of environmental stresses affecting crop production, namely heat, drought, salinity, and relative humidity, hence farming in the future climate will have to be better adapted to a range of abiotic and biotic stresses. A long-term approach to negate the effects of abiotic stress is to develop stress-tolerant cultivars. The short-term approach includes the use of agrochemicals, especially those with plant growth regulator (PGR) capabilities, for the prevention and/or amelioration of various environmental stresses, including heat stress. Studies focusing on day temperature stress and, more recently, on NT stress have increased, but, studies looking at the effects of PGR under heat stress are rare (Ashraf & Foolad, 2007). This chapter primarily focuses on the effects of HNT on crop production and the beneficial effects of PGR (glycine betaine [GB] and salicylic acid [SA]) application against heat stress on crop production with special emphasis on rice (Oryza sativa L.) production.

Planting Date and Variety Effects on Rice Main and Ratoon Crop Production in South Texas

ABSTRACT Rice ratooning could be a practical way to increase rice production per unit area and per unit time. The objectives of this study were to evaluate variety [two inbreds (Cocodrie and Presidio) and three hybrids (Clearfield XL729, Clearfield XL745, and XL723)] and planting date (early and normal) effects on rice ratoon production in a sandy loam and clay soil at Eagle Lake and Beaumont, Texas, USA, respectively. A randomized design with four replications was used at both sites in 2008 and 2009 with a total of 160 observations. A PROC MIXED model was used to analyze the data with year and site as random factors and planting date and variety as fixed factors, and main crop (MC) and ratoon crop (RC) were analyzed using Repeated Measures analysis of variance (ANOVA). The grain yield of MC was only affected by the variety with hybrids having greater yields than inbreds (p < 0.01). However, both RC and total (MC plus RC) grain yields were affected by both planting date and variety (p < 0.01). For both RC and TC crops, early planting had greater (10%) grain yields than the normal planting (p < 0.01). Hybrids had 12% greater rain yields than inbreds (p < 0.001), but only for RC. The rice milling quality of MC was also affected by planting date and variety with greater milling yields with inbreds under normal planting. The results from this study indicate that rice ratoon and total crop yields could be improved through a combination of selected management practices including optimal variety selection and an earlier planting date.